134 results on '"Christensen, BK"'
Search Results
2. Physical and Mental Health Effects of Bushfire and Smoke in the Australian Capital Territory 2019-20
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Rodney, RM, Swaminathan, A, Calear, AL, Christensen, BK, Lal, A, Lane, J, Leviston, Z, Reynolds, J, Trevenar, S, Vardoulakis, S, Walker, I, Rodney, RM, Swaminathan, A, Calear, AL, Christensen, BK, Lal, A, Lane, J, Leviston, Z, Reynolds, J, Trevenar, S, Vardoulakis, S, and Walker, I
- Abstract
The 2019-20 bushfire season in south-eastern Australia was one of the most severe in recorded history. Bushfire smoke-related air pollution reached hazardous levels in major metropolitan areas, including the Australian Capital Territory (ACT), for prolonged periods of time. Bushfire smoke directly challenges human health through effects on respiratory and cardiac function, but can also indirectly affect health, wellbeing and quality of life. Few studies have examined the specific health effects of bushfire smoke, separate from direct effects of fire, and looked beyond physical health symptoms to consider effects on mental health and lifestyle in Australian communities. This paper describes an assessment of the health impacts of this prolonged exposure to hazardous levels of bushfire smoke in the ACT and surrounding area during the 2019-20 bushfire season. An online survey captured information on demographics, health (physical and mental health, sleep) and medical advice seeking from 2,084 adult participants (40% male, median age 45 years). Almost all participants (97%) experienced at least one physical health symptom that they attributed to smoke, most commonly eye or throat irritation, and cough. Over half of responders self-reported symptoms of anxiety and/or feeling depressed and approximately half reported poorer sleep. Women reported all symptoms more frequently than men. Participants with existing medical conditions or poorer self-rated health, parents and those directly affected by fire (in either the current or previous fire seasons) also experienced poorer physical, mental health and/or sleep symptoms. Approximately 17% of people sought advice from a medical health practitioner, most commonly a general practitioner, to manage their symptoms. This study demonstrated that prolonged exposure to bushfire smoke can have substantial effects on health. Holistic approaches to understanding, preventing and mitigating the effects of smoke, not just on physical health
- Published
- 2021
3. The effects of proprioceptive neuromuscular facilitation and dynamic stretching techniques on vertical jump performance.
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Christensen BK and Nordstrom BJ
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The purpose of this study was to investigate the effects of 3 different warm-ups on vertical jump performance. The warm-ups included a 600-m jog, a 600-m jog followed by a dynamic stretching routine, and a 600-m jog followed by a proprioceptive neuromuscular facilitation (PNF) routine. A second purpose was to determine whether the effects of the warm-ups on vertical jump performance varied by gender. Sixty-eight men and women NCAA Division I athletes from North Dakota State University performed 3 vertical jumps on a Just Jump pad after each of the 3 warm-up routines. The subjects were split into 6 groups and rotated between 3 warm-up routines, completing 1 routine each day in a random order. The results of the 1-way repeated measures analysis of variance showed no significant differences in the combined (p = 0.927), men's (p = 0.798), or women's (p = 0.978) results. The results of this study showed that 3 different warm-ups did not have a significant affect on vertical jumping. The results also showed there were no gender differences between the 3 different warm-ups. [ABSTRACT FROM AUTHOR]
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- 2008
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4. Clarifying problems and offering solutions for correlated error when assessing the validity of selected-subtest short forms.
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Girard TA and Christensen BK
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The correlation between a short-form (SF) test and its full-scale (FS) counterpart is a mainstay in the evaluation of SF validity. However, in correcting for overlapping error variance in this measure, investigators have overattenuated the validity coefficient through an intuitive misapplication of P. Levy's (1967) formula. The authors of the present article clarify that such corrections should be based on subtest-level versus FS-level data. Additionally, the authors propose a simple, modified equation incorporating FS-level scores that provides liberal and conservative validity measures for comparison across estimation methods, and they demonstrate its use in both a normative (N = 2,450) and clinical psychiatric (N = 216) sample. [ABSTRACT FROM AUTHOR]
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- 2008
5. Inhibitory deficits for negative information in persons with major depressive disorder.
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Lau MA, Christensen BK, Hawley LL, Gemar MS, and Segal ZV
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ABSTRACT BACKGROUND: Within Beck's cognitive model of depression, little is known about the mechanism(s) by which activated self-schemas result in the production of negative thoughts. Recent research has demonstrated that inhibitory dysfunction is present in depression, and this deficit is likely valence-specific. However, whether valence-specific inhibitory deficits are associated with increased negative cognition and whether such deficits are specific to depression per se remains unexamined. The authors posit the theory that inhibitory dysfunction may influence the degree to which activated self-schemas result in the production of depressive cognition.MethodIndividuals with major depressive disorder (MDD, n=43) versus healthy (n=36) and non-depressed anxious (n=32) controls were assessed on the Prose Distraction Task (PDT), a measure of cognitive inhibition, and the Stop-Signal Task (SST), a measure of motor response inhibition. These two tasks were modified in order to present emotionally valenced semantic stimuli (i.e. negative, neutral, positive). RESULTS: Participants with MDD demonstrated performance impairments on the PDT, which were most pronounced for negatively valenced adjectives, relative to both control groups. Moreover, these impairments correlated with self-report measures of negative thinking and rumination. Conversely, the performance of the MDD participants did not differ from either control group on the SST. CONCLUSIONS: Implications of these findings for understanding the mechanisms underlying the development and maintenance of depressive cognition are discussed. [ABSTRACT FROM AUTHOR]
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- 2007
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6. Actigraphic measurement of the effects of single-dose haloperidol and olanzapine on spontaneous motor activity in normal subjects.
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Kiang M, Daskalakis ZJ, Christensen BK, Remington G, and Kapur S
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OBJECTIVE: To quantitatively examine the effects of haloperidol and olanzapine on spontaneous motor activity in normal subjects. DESIGN: Randomized, double-blind, placebo-controlled medication study. PARTICIPANTS: Normal volunteers (n = 30). INTERVENTIONS: Subjects received 1 dose of either haloperidol 2 mg (n = 9), olanzapine 10 mg (n = 10) or placebo (n = 10) and were admitted to hospital for the next 24 hours. OUTCOME MEASURES: Subjects wore an actigraphic monitor, which recorded movement in 15-second epochs. The Simpson-Angus Extrapyramidal Side Effect Scale (SAS) and the Barnes Akathisia Scale (BAS) were administered before and 7 and 24 hours after medication was given. RESULTS: Compared with placebo, total motor activity was decreased by 41% with olanzapine (p = 0.004) and by 12% with haloperidol (NS). There were significantly more epochs with zero movement with olanzapine than with haloperidol or placebo. For non-zero epochs, the mean activity count and the distribution of activity counts did not differ significantly among groups. There were no positive findings on the SAS or the BAS. CONCLUSIONS: Olanzapine decreased total motor activity by increasing the amount of time during which subjects were immobile, rather than by affecting the magnitude of movement during periods in which there was activity. This effect occurred at a dose of olanzapine low enough not to cause clinically observed extrapyramidal side effects. Our results suggest that actigraphy is useful as a sensitive, noninvasive tool for measuring the effect of antipsychotics on spontaneous motor activity. [ABSTRACT FROM AUTHOR]
- Published
- 2003
7. Cognitive function and brain structure in females with a history of adolescent-onset anorexia nervosa.
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Chui HT, Christensen BK, Zipursky RB, Richards BA, Hanratty MK, Kabani NJ, Mikulis DJ, and Katzman DK
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OBJECTIVE: Abnormalities in cognitive function and brain structure have been reported in acutely ill adolescents with anorexia nervosa, but whether these abnormalities persist or are reversible in the context of weight restoration remains unclear. Brain structure and cognitive function in female subjects with adolescent-onset anorexia nervosa assessed at long-term follow-up were studied in comparison with healthy female subjects, and associations with clinical outcome were investigated. PATIENTS AND METHODS: Sixty-six female subjects (aged 21.3 +/- 2.3 years) who had a diagnosis of adolescent-onset anorexia nervosa and treated 6.5 +/- 1.7 years earlier in a tertiary care hospital and 42 healthy female control subjects (aged 20.7 +/- 2.5 years) were assessed. All participants underwent a clinical examination, magnetic resonance brain scan, and cognitive evaluation. Clinical data were analyzed first as a function of weight recovery (n = 14, <85% ideal body weight; n = 52, >or=85% ideal body weight) and as a function of menstrual status (n = 18, absent/irregular menses; n = 29, oral contraceptive pill; n = 19, regular menses). Group comparisons were made across structural brain volumes and cognitive scores. RESULTS: Compared with control subjects, participants with anorexia nervosa who remained at low weight had larger lateral ventricles. Twenty-four-hour urinary free-cortisol levels were positively correlated with volumes of the temporal horns of the lateral ventricles and negatively correlated with volumes of the hippocampi in clinical participants. Participants who were amenorrheic or had irregular menses showed significant cognitive deficits across a broad range of many domains. CONCLUSIONS: Female subjects with adolescent-onset anorexia nervosa showed abnormal cognitive function and brain structure compared with healthy individuals despite an extended period since diagnosis. To our knowledge, this is the first study to report a specific relationship between menstrual function and cognitive function in this patient population. Possible mechanisms underlying neural and cognitive deficits with anorexia nervosa are discussed. Additional examination of the effects of estrogen on cognitive function in female subjects with anorexia nervosa is necessary. [ABSTRACT FROM AUTHOR]
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- 2008
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8. Meta-analysis of Face Perception in Schizophrenia Spectrum Disorders: Evidence for Differential Impairment in Emotion Face Perception.
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Mewton P, Dawel A, Miller EJ, Shou Y, and Christensen BK
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Background and Hypothesis: Schizophrenia spectrum disorders (SSD) are associated with face perception impairments. It is unclear whether impairments are equal across aspects of face perception or larger-indicating a differential impairment-for perceiving emotions relative to other characteristics (eg, identity, age). While many studies have attempted to compare emotion and non-emotion face perception in SSD, they have varied in design and produced conflicting findings. Additionally, prior meta-analyses on this topic were not designed to disentangle differential emotion impairments from broader impairments in face perception or cognition. We hypothesize that SSD-related impairments are larger for emotion than non-emotion face perception, but study characteristics moderate this differential impairment., Study Design: We meta-analyzed 313 effect sizes from 104 articles to investigate if SSD-related impairments are significantly greater for emotion than non-emotion face perception. We tested whether key study characteristics moderated these impairments, including SSD severity, sample intelligence matching, task difficulty, and task memory dependency., Study Results: We found significantly greater impairments for emotion (Cohen's d = 0.74) than non-emotion face perception (d = 0.55) in SSD relative to control samples, regardless of SSD severity, intelligence matching, or task difficulty. Importantly, this effect was obscured when non-emotion tasks used a memory-dependent design., Conclusions: This is the first meta-analysis to demonstrate a differential emotion impairment in SSD that cannot be explained by broader impairments in face perception or cognition. The findings also underscore the critical role of task matching in studies of face perception impairments; to prevent confounding influences from memory-dependent task designs., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center.)
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- 2024
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9. A Bayesian model of the jumping-to-conclusions bias and its relationship to psychopathology.
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Tan N, Shou Y, Chen J, and Christensen BK
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- Humans, Female, Male, Delusions psychology, Models, Psychological, Adult, Young Adult, Bayes Theorem, Decision Making, Anxiety psychology
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The mechanisms by which delusion and anxiety affect the tendency to make hasty decisions (Jumping-to-Conclusions bias) remain unclear. This paper proposes a Bayesian computational model that explores the assignment of evidence weights as a potential explanation of the Jumping-to-Conclusions bias using the Beads Task. We also investigate the Beads Task as a repeated measure by varying the key aspects of the paradigm. The Bayesian model estimations from two online studies showed that higher delusional ideation promoted reduced belief updating but the impact of general and social anxiety on evidence weighting was inconsistent. The altered evidence weighting as a result of a psychopathological trait appeared insufficient in contributing to the Jumping-to-Conclusions bias. Variations in Beads Task aspects significantly affected subjective certainty at the point of decisions but not the number of draws to decisions. Repetitions of the Beads Task are feasible if one assesses the Jumping-to-Conclusions bias using number of draws to decisions.
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- 2024
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10. The Brief Solastalgia Scale: A Psychometric Evaluation and Revision.
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Christensen BK, Monaghan C, Stanley SK, Walker I, Leviston Z, Macleod E, Rodney RM, Greenwood LM, Heffernan T, Evans O, Sutherland S, Reynolds J, Calear AL, Kurz T, and Lane J
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- Humans, Male, Female, Adult, Middle Aged, Australia, Surveys and Questionnaires, Reproducibility of Results, Factor Analysis, Statistical, Aged, Stress, Psychological, Young Adult, Psychometrics
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Witnessing degradation and loss to one's home environment can cause the negative emotional experience of solastalgia. We review the psychometric properties of the 9-item Solastalgia subscale from the Environmental Distress Scale (Higginbotham et al. (EcoHealth 3:245-254, 2006)). Using data collected from three large, independent, adult samples (N = 4229), who were surveyed soon after the 2019/20 Australian bushfires, factor analyses confirmed the scale's unidimensionality, while analyses derived from Item Response Theory highlighted the poor psychometric performance and redundant content of specific items. Consequently, we recommend a short-form scale consisting of five items. This Brief Solastalgia Scale (BSS) yielded excellent model fit and internal consistency in both the initial and cross-validation samples. The BSS and its parent version provide very similar patterns of associations with demographic, health, life satisfaction, climate emotion, and nature connectedness variables. Finally, multi-group confirmatory factor analysis demonstrated comparable construct architecture (i.e. configural, metric, and scalar invariance) across validation samples, gender categories, and age. As individuals and communities increasingly confront and cope with climate change and its consequences, understanding related emotional impacts is crucial. The BSS promises to aid researchers, decision makers, and practitioners to understand and support those affected by negative environmental change., (© 2024. The Author(s).)
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- 2024
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11. Bench Press Range-of-Motion and Velocity-based Repetition Control: Effects on Ballistic Push-up Performance in Males.
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Collins KS, Bradley AP, Christensen BK, Waldera RW, Klawitter LA, Ogren L, and Salatto RW
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The purpose of this study was to investigate whether the ballistic push-up (BPU) is responsive to post-activation performance enhancement (PAPE) after a bench press conditioning exercise using velocity-based repetition control. Additionally, we aimed to evaluate the effects of range of motion (ROM) conditions on subsequent BPU performance. In a randomized crossover design, 18 males performed two conditions (full ROM and self-selected partial ROM) of bench press at 80% of their 1RM until mean concentric velocity dropped 10%. Each participant performed two pre- and six post-test BPUs to assess the PAPE effect. Paired sample t-tests assessed bench press performance measures. Multiple two-way repeated measures ANOVAs assessed differences in flight time, impulse, and peak power for the pre- and post-test BPUs. No significant differences existed between ROM conditions for total repetitions, volume load, or peak velocity. Compared to partial ROM, full ROM showed greater displacement (0.42 ± 0.05 vs. 0.34 ± 0.05 m), work (331.99 ± 67.72 vs. 270.92 ± 61.42 J), and mean velocity (0.46 ± 0.09 vs. 0.44 ± 0.08 m/s). Neither bench press ROM condition enhanced the BPU and were detrimental in some cases. Several time points showed partial ROM (flight time: 2 min post, impulse: 12 min post, peak power: 12 min post) significantly greater than full ROM, possibly indicating less fatigue accumulation. The BPU may require a different stimulus or may not be practical for PAPE effects in college-aged males. Partial ROM can be an alternative that achieves similar peak velocities while requiring less overall work.
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- 2024
12. Predictors of individual mental health and psychological resilience after Australia's 2019-2020 bushfires.
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Macleod E, Heffernan T, Greenwood LM, Walker I, Lane J, Stanley SK, Evans O, Calear AL, Cruwys T, Christensen BK, Kurz T, Lancsar E, Reynolds J, Rodney Harris R, and Sutherland S
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- Adult, Humans, Male, Female, Mental Health, Australia epidemiology, Stress, Psychological, Resilience, Psychological, Disasters, COVID-19
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Aims: We assessed the mental health effects of Australia's 2019-2020 bushfires 12-18 months later, predicting psychological distress and positive psychological outcomes from bushfire exposure and a range of demographic variables, and seeking insights to enhance disaster preparedness and resilience planning for different profiles of people., Methods: We surveyed 3083 bushfire-affected and non-affected Australian residents about their experiences of bushfire, COVID-19, psychological distress (depression, anxiety, stress, post-traumatic stress disorder) and positive psychological outcomes (resilient coping, wellbeing)., Results: We found high rates of distress across all participants, exacerbated by severity of bushfire exposure. For people who were bushfire-affected, being older, having less financial stress, and having no or fewer pre-existing mental disorders predicted both lower distress and higher positive outcomes. Being male or having less income loss also predicted positive outcomes. Severity of exposure, higher education and higher COVID-19-related stressors predicted both higher distress and higher positive outcomes. Pre-existing physical health diagnosis and previous bushfire experience did not significantly predict distress or positive outcomes., Recommendations: To promote disaster resilience, we recommend investment in mental health, particularly for younger adults and for those in rural and remote areas. We also recommend investment in mechanisms to protect against financial distress and the development of a broader definition of bushfire-related impacts than is currently used to capture brushfires' far-reaching effects., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.
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- 2024
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13. Bushfires and Mothers' Mental Health in Pregnancy and Recent Post-Partum.
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Cherbuin N, Bansal A, Dahlstrom JE, Carlisle H, Broom M, Nanan R, Sutherland S, Vardoulakis S, Phillips CB, Peek MJ, Christensen BK, Davis D, and Nolan CJ
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- Female, Pregnancy, Infant, Newborn, Humans, Cross-Sectional Studies, Australia epidemiology, Mothers psychology, Smoke, Postpartum Period, Mental Health, COVID-19 epidemiology
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Background: The compounding effects of climate change catastrophes such as bushfires and pandemics impose significant burden on individuals, societies, and their economies. The enduring effects of such syndemics on mental health remain poorly understood, particularly for at-risk populations (e.g., pregnant women and newborns). The aim of this study was to investigate the impact of direct and indirect exposure to the 2019/20 Australian Capital Territory and South-Eastern New South Wales bushfires followed by COVID-19 on the mental health and wellbeing of pregnant women and mothers with newborn babies., Methods: All women who were pregnant, had given birth, or were within three months of conceiving during the 2019/2020 bushfires, lived within the catchment area, and provided consent were invited to participate. Those who consented were asked to complete three online surveys. Mental health was assessed with the DASS-21 and the WHO-5. Bushfire, smoke, and COVID-19 exposures were assessed by self-report. Cross-sectional associations between exposures and mental health measures were tested with hierarchical regression models., Results: Of the women who participated, and had minimum data ( n = 919), most (>75%) reported at least one acute bushfire exposure and 63% reported severe smoke exposure. Compared to Australian norms, participants had higher depression (+12%), anxiety (+35%), and stress (+43%) scores. Women with greater exposure to bushfires/smoke but not COVID-19 had poorer scores on all mental health measures., Conclusions: These findings provide novel evidence that the mental health of pregnant women and mothers of newborn babies is vulnerable to major climate catastrophes such as bushfires.
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- 2023
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14. Characterising modulatory effects of high-intensity high frequency transcranial random noise stimulation using the perceptual template model.
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Gotsis ES, van Boxtel JJA, Teufel C, Edwards M, and Christensen BK
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- Humans, Noise, Photic Stimulation methods, Transcranial Direct Current Stimulation methods
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Neural noise is an inherent property of all nervous systems. However, our understanding of the mechanisms by which noise influences perception is still limited. To elucidate this relationship, we require techniques that can safely modulate noise in humans. Transcranial random noise stimulation (tRNS) has been proposed to induce noise into cortical processing areas according to the principles of stochastic resonance (SR). Specifically, it has been demonstrated that small to moderate intensities of noise improve performance. To date, however, high intensity tRNS effects on neural noise levels have not been directly quantified, nor have the detrimental effects proposed by SR been demonstrated in early visual function. Here, we applied 3 mA high-frequency tRNS to primary visual cortex during an orientation-discrimination task across increasing external noise levels and used the Perceptual Template Model to quantify the mechanisms by which noise changes perceptual performance in healthy observers. Results show that, at a group level, high-intensity tRNS worsened perceptual performance. Our computational analysis reveals that this change in performance was underpinned by an increased amount of additive noise and a reduced ability to filter external noise compared to sham stimulation. Interestingly, while most observers experienced detrimental effects, a subset of participants demonstrated improved performance. Preliminary evidence suggests that differences in baseline internal noise levels might account for these individual differences. Together, these results refine our understanding of the mechanisms underlying the influence of neural noise on perception and have important implications for the application of tRNS as a research tool., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2023
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15. Prevalence and Trends of Weakness Among Middle-Aged and Older Adults in the United States.
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McGrath R, FitzSimmons S, Andrew S, Black K, Bradley A, Christensen BK, Collins K, Klawitter L, Kieser J, Langford M, Orr M, and Hackney KJ
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- Male, Middle Aged, Humans, Female, United States epidemiology, Aged, Prevalence, Muscle Weakness epidemiology, Body Mass Index, Hand Strength physiology, Retirement
- Abstract
Abstract: McGrath, R, FitzSimmons, S, Andrew, S, Black, K, Bradley, A, Christensen, BK, Collins, K, Klawitter, L, Kieser, J, Langford, M, Orr, M, and Hackney, KJ. Prevalence and trends of weakness among middle-aged and older adults in the United States. J Strength Cond Res 37(12): 2484-2490, 2023-Muscle weakness, which is often determined with low handgrip strength (HGS), is associated with several adverse health conditions; however, the prevalence and trends of weakness in the United States is not well-understood. We sought to estimate the prevalence and trends of weakness in Americans aged at least 50 years. The total unweighted analytic sample included 22,895 Americans from the 2006-2016 waves of the Health and Retirement Study. Handgrip strength was measured with a handgrip dynamometer. Men with weakness were below at least one of the absolute or normalized (body mass, body mass index) cut points: <35.5 kg, <0.45 kg/kg, <1.05 kg/kg/m 2 . The presence of any weakness in women was also identified as being below one of the absolute or normalized HGS cut points: <20.0 kg, <0.34 kg/kg, or <0.79 kg/kg/m 2 . There was an increasing trend in the prevalence of any weakness over time ( p < 0.001). The prevalence of weakness was 45.1% (95% confidence interval [CI]: 44.0-46.0) in the 2006-2008 waves and 52.6% (CI: 51.5-53.7) in the 2014-2016 waves. Weakness prevalence was higher for older (≥65 years) Americans (64.2%; CI: 62.8-65.5) compared with middle-aged (50-64 years) Americans (42.2%; CI: 40.6-43.8) in the 2014-2016 waves. Moreover, the prevalence of weakness in the 2014-2016 waves was generally higher in women (54.5%; CI: 53.1-55.9) than in men (50.4%; CI: 48.7-52.0). Differences existed in weakness prevalence across races and ethnicities. The findings from our investigation suggest that the prevalence of weakness is overall pronounced and increasing in Americans. Efforts for mitigating and better operationalizing weakness will elevate in importance as our older American population grows., (Copyright © 2023 National Strength and Conditioning Association.)
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- 2023
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16. Examining the role of different weakness categories for mobility and future falls in older Americans.
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McGrath R, Jurivich DA, Christensen BK, Choi BJ, Langford M, Rhee Y, Tomkinson GR, and Hackney KJ
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- Male, Humans, Female, Aged, Retirement, Self Report, Body Mass Index, Hand Strength, Accidental Falls
- Abstract
Background: Recently developed absolute and body size normalized handgrip strength (HGS) cut-points could be used individually and collectively to predict mobility problems and falls., Aims: We examined the associations of (1) each absolute and normalized weakness cut-point, (2) collective weakness categories, and (3) changes in weakness status on future falls in older Americans., Methods: The analytic sample included 11,675 participants from the 2006-2018 waves of the Health and Retirement Study. Falls were self-reported. Men were classified as weak if their HGS was < 35.5-kg (absolute), < 0.45 kg/kg (body mass normalized), or < 1.05 kg/kg/m
2 (body mass index normalized). While, women were considered weak if their HGS was < 20.0-kg, < 0.337 kg/kg, or < 0.79 kg/kg/m2 . Collective weakness categorized those below 1, 2, or all 3 cut-points. The collective weakness categories were also used to observe changes in weakness status over time., Results: Older Americans below each absolute and normalized cut-point had greater odds for future falls: 1.23 (95% confidence interval (CI): 1.15-1.32) for absolute weakness, 1.20 (CI 1.11-1.29) for body mass index normalized weakness, and 1.26 (CI 1.17-1.34) for body mass normalized weakness. Persons below 1, 2, or all 3 weakness cut-points had 1.17 (CI 1.07-1.27), 1.29 (CI 1.18-1.40), and 1.36 (CI 1.24-1.48) greater odds for future falls, respectively. Those in some changing weakness categories had greater odds for future falls: 1.26 (CI 1.08-1.48) for persistent and 1.31 (CI 1.11-1.55) for progressive., Discussion: Collectively using these weakness cut-points may improve their predictive value., Conclusion: We recommend HGS be evaluated in mobility and fall risk assessments., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)- Published
- 2023
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17. Using Electronic Handgrip Dynamometry and Accelerometry to Examine Multiple Aspects of Handgrip Function in Master Endurance Athletes: A Pilot Study.
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Klawitter LA, Hackney KJ, Christensen BK, Hamm JM, Hanson M, and McGrath R
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- Humans, Pilot Projects, Athletes, Electronics, Fatigue, Hand Strength, Accelerometry
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Abstract: Klawitter, LA, Hackney, KJ, Christensen, BK, Hamm, JM, Hanson, M, and McGrath, R. Using electronic handgrip dynamometry and accelerometry to examine multiple aspects of handgrip function in master endurance athletes: A Pilot Study. J Strength Cond Res 37(9): 1777-1782, 2023-Electronic handgrip dynamometry and accelerometry may provide novel opportunities to comprehensively measure muscle function for human performance, especially for master athletes. This investigation sought to determine the multivariate relationships between maximal strength, asymmetry, rate of force development, fatigability, submaximal force control, bimanual coordination, and neuromuscular steadiness to derive one or more handgrip principal components in master-aged endurance athletes. We included n = 31 cyclists and triathletes aged 35-70 years. Maximal strength, asymmetry, rate of force development, fatigability, submaximal force control, bimanual coordination, and neuromuscular steadiness were measured twice on each hand using electronic handgrip dynamometry and accelerometry. The highest performing measures were included in the analyses. A principal component analysis was conducted to derive a new collection of uncorrelated variables from the collected handgrip measurements. Principal components with eigenvalues >1.0 were kept, and individual measures with a factor loading of |>0.40| were retained in each principal component. There were 3 principal components retained with eigenvalues of 2.46, 1.31, and 1.17. The first principal component, "robust strength," contained maximal strength, rate of force development, submaximal force control, and neuromuscular steadiness. The second principal component, "bilateral synergy," contained asymmetry and bimanual coordination, whereas the third principal component, "muscle conditioning," contained fatigability. Principal components 1, 2, and 3 explained 44.0, 31.6, and 24.4% of the variance, respectively. Different dimensions of muscle function emerged from our findings, suggesting the potential of a muscle function battery. Further research examining how these measures are associated with appropriate human performance metrics and lower extremity correlates is warranted., Competing Interests: This research was funded by an intramural pilot mechanism at North Dakota State University. The results of this study do not constitute endorsement of the product by the authors or the NSCA. The authors report no conflicts of interest., (Copyright © 2023 National Strength and Conditioning Association.)
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- 2023
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18. Heatwaves and wildfires suffocate our healthy start to life: time to assess impact and take action.
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Bansal A, Cherbuin N, Davis DL, Peek MJ, Wingett A, Christensen BK, Carlisle H, Broom M, Schoenaker DAJM, Dahlstrom JE, Phillips CB, Vardoulakis S, Nanan R, and Nolan CJ
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- Child, Infant, Humans, Child, Preschool, Female, Pregnancy, Pandemics, Environmental Exposure, Mothers, Wildfires, COVID-19 epidemiology
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Adverse environmental exposures in utero and early childhood are known to programme long-term health. Climate change, by contributing to severe heatwaves, wildfires, and other natural disasters, is plausibly associated with adverse pregnancy outcomes and an increase in the future burden of chronic diseases in both mothers and their babies. In this Personal View, we highlight the limitations of existing evidence, specifically on the effects of severe heatwave and wildfire events, and compounding syndemic events such as the COVID-19 pandemic, on the short-term and long-term physical and mental health of pregnant women and their babies, taking into account the interactions with individual and community vulnerabilities. We highlight a need for an international, interdisciplinary collaborative effort to systematically study the effects of severe climate-related environmental crises on maternal and child health. This will enable informed changes to public health policy and clinical practice necessary to safeguard the health and wellbeing of current and future generations., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)
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- 2023
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19. Strategic regulation of memory in dsyphoria: a quantity-accuracy profile analysis.
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King MJ, Girard TA, Benjamin AS, and Christensen BK
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- Humans, Mental Recall physiology, Memory Disorders, Metacognition physiology, Memory, Episodic, Depressive Disorder, Major
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The mechanisms underlying a tendency among individuals with depression to report personal episodic memories with low specificity remain to be understood. We assessed a sample of undergraduate students with dysphoria to determine whether depression relates to a broader dysregulation of balancing accuracy and informativeness during memory reports. Specifically, we investigated metamnemonic processes using a quantity-accuracy profile approach. Recall involved three phases with increasing allowance for more general, or coarse-grained, responses: (a) forced-precise responding, requiring high precision; (b) free-choice report with high and low penalty incentives on accuracy; (c) a lexical description phase. Individuals with and without dysphoria were largely indistinguishable across indices of retrieval, monitoring, and control aspects of metamemory. The results indicate intact metacognitive processing in young individuals with dysphoria and provide no support for the view that impaired metacognitive control underlies either memory deficits or bias in memory reports that accompany dysphoria.
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- 2023
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20. Exploring the internal forward model: action-effect prediction and attention in sensorimotor processing.
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Harrison AW, Hughes G, Rudman G, Christensen BK, and Whitford TJ
- Subjects
- Evoked Potentials physiology, Attention physiology, Sound, Evoked Potentials, Auditory physiology, Acoustic Stimulation methods, Electroencephalography, Auditory Perception physiology
- Abstract
Action-effect predictions are believed to facilitate movement based on its association with sensory objectives and suppress the neurophysiological response to self- versus externally generated stimuli (i.e. sensory attenuation). However, research is needed to explore theorized differences in the use of action-effect prediction based on whether movement is uncued (i.e. volitional) or in response to external cues (i.e. stimulus-driven). While much of the sensory attenuation literature has examined effects involving the auditory N1, evidence is also conflicted regarding this component's sensitivity to action-effect prediction. In this study (n = 64), we explored the influence of action-effect contingency on event-related potentials associated with visually cued and uncued movement, as well as resultant stimuli. Our findings replicate recent evidence demonstrating reduced N1 amplitude for tones produced by stimulus-driven movement. Despite influencing motor preparation, action-effect contingency was not found to affect N1 amplitudes. Instead, we explore electrophysiological markers suggesting that attentional mechanisms may suppress the neurophysiological response to sound produced by stimulus-driven movement. Our findings demonstrate lateralized parieto-occipital activity that coincides with the auditory N1, corresponds to a reduction in its amplitude, and is topographically consistent with documented effects of attentional suppression. These results provide new insights into sensorimotor coordination and potential mechanisms underlying sensory attenuation., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)
- Published
- 2023
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21. Lower memory specificity in individuals with dysphoria is not specific to autobiographical memory.
- Author
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King MJ, Courtenay K, Christensen BK, Benjamin AS, and Girard TA
- Subjects
- Humans, Female, Male, Mental Recall physiology, Memory Disorders diagnosis, Memory, Episodic, Depressive Disorder, Major
- Abstract
Background: A core cognitive attribute of depression is lower specificity in the expression of autobiographical memories. Despite interventions targeting memory specificity in depression, its underlying mechanisms are not yet fully understood. Depression also relates to poorer memory for episodic details; here we examine whether reduced specificity might simply reflect broader episodic memory deficits and weakened memory traces with the passage of time., Methods: Undergraduate students with and without symptoms of depression completed the Autobiographical Interview and prose-reading episodic memory tasks to assess both same-day and delayed memory., Results: Dysphoria and nondysphoria groups performed similarly on the tasks of immediate episodic and autobiographical memory; notably, the dysphoria group did not display evidence of lower specificity at this time point. After a delay, however, both groups demonstrated less specific memory responses on both memory tasks, and these declines were more pronounced in the group with dysphoria. That is, after a delay, individuals high in dysphoria showed a greater decrease in the quantity of specific event details reported on both the episodic and the autobiographical memory task. Additional analyses incorporating other clinical and cognitive measures indicated that these relations are largely unique to symptoms of depression., Limitations: The sample comprised mostly female students; the study should be replicated with more diverse samples., Conclusions: These findings support the claim that lower memory specificity is not peculiar to autobiographical memory, but rather, reflects impoverished memory more generally. This is an important consideration for theories and remedial strategies targeting memory specificity., Competing Interests: Conflict of interest All authors declare that they have no conflicts of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)
- Published
- 2023
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22. Prejudice towards people with mental illness, schizophrenia, and depression among mental health professionals and the general population.
- Author
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Bizumic B, Gunningham B, and Christensen BK
- Subjects
- Humans, Depression, Mental Health, Prejudice, Schizophrenia, Mental Disorders psychology
- Abstract
The aim of the study was to measure and compare prejudice towards people with specific mental illnesses between mental health professionals and the general population, and examine personality, ideological, and attitudinal antecedents of prejudice. To do so, we also aimed to validate three shortened scales of prejudice. A sample of mental health professionals (N = 299) and a sample from the general population (N = 427) completed shortened versions of the Prejudice towards People with Mental Illness, Prejudice towards People with Schizophrenia, and Prejudice towards People with Depression scales. They also completed measures of validity criteria and demographics. The scales demonstrated construct validity in both samples. Although prejudice was highest towards people with schizophrenia and lowest towards people with depression, mental health professionals demonstrated significantly less prejudice overall than the general population. Prejudice was associated with higher social dominance orientation, right wing authoritarianism, ethnocentrism, conservatism, and generalized prejudice, and lower agreeableness, openness to experience, and contact. These antecedents of prejudice were better predictors than any demographic or profession-related variables examined. This study contributes increased knowledge of the structure and correlates of prejudice towards people with mental disorders. This knowledge should inform more nuanced and effective interventions, therapy, and training., Competing Interests: Declaration of Competing Interest We have no conflicts of interest to disclose., (Copyright © 2022. Published by Elsevier B.V.)
- Published
- 2022
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23. The Association Between Handgrip Strength Asymmetry Severity and Future Morbidity Accumulation: Results from the Health and Retirement Study.
- Author
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Klawitter LA, Collins KS, Ringhofer D, Christensen BK, and McGrath R
- Abstract
Analyzing the severity of handgrip strength (HGS) asymmetry in aging populations may help to screen for morbidities and add utility to handgrip dynamometer testing. Our study sought to determine the relationships between HGS asymmetry severity and future accumulating morbidities in older Americans. Secondary analyses from the 2006-2016 waves of the Health and Retirement Study included 18,506 adults ≥ 50 years old. The highest recorded HGS values from each hand were used to calculate HGS asymmetry ratio (non-dominant HGS/dominant HGS). If the HGS asymmetry ratio < 1.0, it was inversed to make all asymmetry ratios ≥ 1.0. Participants were categorized into groups based on the severity of their HGS asymmetry ratio: 1) 0.0% - 10.0%, 2) 10.1% - 20.0%, 3) 20.1% - 30.0%, and 4) > 30.0%. Healthcare provider-diagnosed morbidities (hypertension, diabetes, cancer, chronic lung disease, cardiovascular disease, stroke, arthritis, and psychiatric problems) were self-reported. Covariate-adjusted ordinal generalized estimating equations evaluated the relationships between HGS asymmetry severity on future accumulating morbidities. Results showed 8,936 (48.3%) participants had HGS asymmetry 0.0%-10.0%, 6,105 (33.0%) participants had HGS asymmetry 10.1%-20.0%, 2,411 (13.0%) participants had HGS asymmetry 20.1%-30.0%, and 1,054 (5.7%) participants had HGS asymmetry > 30.0%. Overall, every 10% increase in HGS asymmetry was associated with a 1.17 (CI: 1.05, 1.32) greater odds of future morbidity accumulation. Additionally, asymmetry between 10.1% - 20.0%, 20.1% - 30.0%, and > 30.0% was associated with a 1.10 (CI: 1.05, 1.15), 1.11 (CI: 1.04, 1.18), and 1.20 (CI: 1.09, 1.33) greater odds for morbidity accumulation during aging. These findings suggest that severe functional asymmetries may elevate the odds for accumulating morbidities.
- Published
- 2022
24. Shifting threat criterion for morphed facial expressions reduces negative affect.
- Author
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O'Brien SLB, Christensen BK, and Goodhew SC
- Subjects
- Affect, Anxiety Disorders, Bias, Humans, Anxiety psychology, Facial Expression
- Abstract
It is well-established that anxiety and/or depression are associated with a negative bias when interpreting ambiguous information. This study tested the novel hypothesis that the criterion one sets for judging a stimulus as threatening is a core aspect of this bias. A sample of 174 participants were divided into neutral (n = 87) and threatening (n = 87) training conditions. Participants performed a facial expression detection task, in which criterion was shifted in the liberal (threatening condition) or conservative (neutral condition) direction via differential reward contingencies. Training conditions were successful in inducing large shifts in criterion as intended. There was also a small change in sensitivity in the neutral condition, however, the manipulation is still considered successful given the substantive effect size for change in criterion compared to change in sensitivity. As predicted, conservative criterion-training resulted in significantly lower levels of negative affect post-training. No significant change was found for liberal criterion-training on negative affect. Positive affect also decreased across time regardless of condition. Overall, the reduction in negative affect following conservative criterion-training demonstrates that modifying criterion impacts affect and identifies criterion setting as a potential target in the treatment of mental health disorders with prominent negative affect., (Copyright © 2022 Elsevier Ltd. All rights reserved.)
- Published
- 2022
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25. The effect of social anxiety on top-down attentional orienting to emotional faces.
- Author
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Delchau HL, Christensen BK, Lipp OV, and Goodhew SC
- Subjects
- Anger, Anxiety psychology, Facial Expression, Fear, Humans, Reaction Time, Attentional Bias, Emotions
- Abstract
One of the fundamental factors maintaining social anxiety is biased attention toward threatening facial expressions. Typically, this bias has been conceptualized as driven by an overactive bottom-up attentional system; however, this potentially overlooks the role of top-down attention in being able to modulate this bottom-up bias. Here, the role of top-down mechanisms in directing attention toward emotional faces was assessed with a modified dot-probe task, in which participants were given a top-down cue ("happy" or "angry") to attend to a happy or angry face on each trial, and the cued face was either presented with a face of the other emotion (angry, happy) or a neutral face. This study found that social anxiety was not associated with differences in shifting attention toward cued angry faces. However, participants with higher levels of social anxiety were selectively impaired in attentional shifting toward a cued happy face when it was paired with an angry face, but not when paired with a neutral face. The results indicate that top-down attention can be used to orient attention to emotional faces, but that higher levels of social anxiety are associated with selective deficits in top-down control of attention in the presence of threat. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
- Published
- 2022
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26. Analysis of Total and Segmental Body Composition Relative to Fitness Performance Measures in Law Enforcement Recruits.
- Author
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Collins KS, Christensen BK, Orr RM, Dulla JM, Dawes JJ, and Lockie RG
- Abstract
Law enforcement agencies often test the fitness performance and body composition of incoming recruits. This study investigated the relationships between whole and segmental body composition, and fitness tests in law enforcement recruits. A retrospective analysis of 72 male and 11 female recruits was performed. Bioelectrical impedance analysis (BIA) variables were: lean mass (LM), upper-extremity lean mass (UELM), trunk LM, lower-extremity lean mass (LELM), fat mass (FM), upper-extremity fat mass (UEFM), trunk FM, and lower-extremity fat mass (LEFM). Fitness tests included: vertical jump (VJ), peak anaerobic power (PAPw), 75-yard pursuit run (75PR), push-ups, sit-ups, 2-kg medicine ball throw (MBT), and the multi-stage fitness test (MSFT). Partial correlations and ANCOVAs between quartiles assessed relationships between body composition and performance. Significant moderate-to-large relationships were found; LM, UELM, trunk LM, LELM all related to PAPw ( r = 0.500-0.558) and MBT ( r = 0.494-0.526). FM, UEFM, trunk FM, LEFM all related to VJ ( r = -0.481 to -0.493), 75PR ( r = 0.533-0.557), push-ups ( r = -0.484 to -0.503), sit-ups ( r = -0.435 to -0.449), and MSFT ( r = -0.371 to -0.423). The highest LM quartile (4) had superior PAPw and MBT than LM quartiles 1-3. Higher FM quartiles performed poorer in VJ, push-ups, and sit-ups. The 75PR quartiles 2, 3, and 4 were slower than quartile 1, and MSFT quartile 4 completed less shuttles. Total and segmental measures of LM and FM shared the same relationships; lower FM and higher LM related to better performance. Monitoring body composition could help guide training to optimize performance.
- Published
- 2022
27. Identifying the contingencies of self-worth associated with eating disorder symptoms: The use of choice-based conjoint analysis.
- Author
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Rieger E, Prasetya K, Christensen BK, and Shou Y
- Subjects
- Female, Humans, Male, Psychometrics, Regression Analysis, Surveys and Questionnaires, Thinness, Feeding and Eating Disorders diagnosis
- Abstract
Objective: Self-worth contingent on shape/weight is a diagnostic criterion and key maintaining factor for eating disorders. However, the role of other contingencies of self-worth (i.e., domains in which self-worth is invested) is largely unknown. Moreover, research has relied on self-ratings of contingency strength, which are subject to distortion through socially desirable responding and limited self-awareness, and may have limitations in terms of ecological validity. To overcome these limitations, the present study investigated a broad range of contingencies of self-worth in relation to eating disorder pathology and employed a choice-based conjoint (CBC) approach for assessing these contingencies., Method: Young women and men from the community (N = 428) completed a CBC task to assess the domains in which self-worth is invested, the Eating Disorder Examination Questionnaire (EDE-Q) to assess eating disorder symptomatology, and the Balanced Inventory of Desirable Responding to assess socially desirable responding., Results: Beta regression analyses showed that CBC thinness and athletic competence predicted higher scores on all EDE-Q scales. CBC muscularity and facial attractiveness predicted higher scores, while coping ability and quality of relationships predicted lower scores, on various aspects of eating disorder symptoms. CBC social acceptance predicted lower eating disorder symptoms in males only., Discussion: The findings suggest that a broader range of contingencies of self-worth beyond shape/weight are relevant to eating disorder pathology and should be considered as potential underlying mechanisms and treatment targets. In addition, this first use of the CBC method in eating disorder research provides initial support for its validity and utility., (© 2021 Wiley Periodicals LLC.)
- Published
- 2021
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28. A cognitive model of delusion propensity through dysregulated correlation detection.
- Author
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Harrison AW, Shou Y, and Christensen BK
- Subjects
- Humans, Personality Inventory, Cognition, Delusions diagnosis
- Abstract
Background: We present a novel account of delusion propensity that integrates the roles of working memory (WM), decision criteria, and information gathering biases. This framework emphasises the role of aberrant correlation detection, which leads to the spurious perception of relationships between one's experiences. The frequency of such outcomes is moderated by the scaling of one's decision criteria which, for reasons discussed, must also account for WM capacity. The proposed dysregulated correlation detection account posits that propensity for delusional ideation is influenced by disturbances in this mechanism., Methods: Hypotheses were tested using a novel task that required participants (N = 92) to identify correlation between binary manipulations of simple shapes, presented as sequential pairs. Decision criteria and correlation detection were assessed under a Signal Detection Theory framework, while WM capacity was assessed through the Automated Operation Span Task and delusion propensity was measured using the Peters Delusion Inventory. Structural equation modeling was conducted to evaluate the proposed model., Results: Consistent with the central hypothesis, an interaction between decision criteria and WM was found to contribute significantly to delusion propensity through its effect on correlation detection accuracy. Greater delusion propensity was observed among participants with more liberal decision criteria, which was also in accordance with hypotheses. At the same time, the total effect of WM on delusion propensity was not found to be significant., Conclusions: These findings provide preliminary support for the proposed dysregulated correlation detection account of propensity for delusional ideation., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2021
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29. Physical and Mental Health Effects of Bushfire and Smoke in the Australian Capital Territory 2019-20.
- Author
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Rodney RM, Swaminathan A, Calear AL, Christensen BK, Lal A, Lane J, Leviston Z, Reynolds J, Trevenar S, Vardoulakis S, and Walker I
- Subjects
- Adult, Australia epidemiology, Australian Capital Territory, Female, Humans, Male, Middle Aged, Quality of Life, Air Pollution, Mental Health
- Abstract
The 2019-20 bushfire season in south-eastern Australia was one of the most severe in recorded history. Bushfire smoke-related air pollution reached hazardous levels in major metropolitan areas, including the Australian Capital Territory (ACT), for prolonged periods of time. Bushfire smoke directly challenges human health through effects on respiratory and cardiac function, but can also indirectly affect health, wellbeing and quality of life. Few studies have examined the specific health effects of bushfire smoke, separate from direct effects of fire, and looked beyond physical health symptoms to consider effects on mental health and lifestyle in Australian communities. This paper describes an assessment of the health impacts of this prolonged exposure to hazardous levels of bushfire smoke in the ACT and surrounding area during the 2019-20 bushfire season. An online survey captured information on demographics, health (physical and mental health, sleep) and medical advice seeking from 2,084 adult participants (40% male, median age 45 years). Almost all participants (97%) experienced at least one physical health symptom that they attributed to smoke, most commonly eye or throat irritation, and cough. Over half of responders self-reported symptoms of anxiety and/or feeling depressed and approximately half reported poorer sleep. Women reported all symptoms more frequently than men. Participants with existing medical conditions or poorer self-rated health, parents and those directly affected by fire (in either the current or previous fire seasons) also experienced poorer physical, mental health and/or sleep symptoms. Approximately 17% of people sought advice from a medical health practitioner, most commonly a general practitioner, to manage their symptoms. This study demonstrated that prolonged exposure to bushfire smoke can have substantial effects on health. Holistic approaches to understanding, preventing and mitigating the effects of smoke, not just on physical health but on mental health, and the intersection of these, is important. Improved public health messaging is needed to address uncertainty about how individuals can protect their and their families health for future events. This should be informed by identifying subgroups of the population, such as those with existing health conditions, parents, or those directly exposed to fire who may be at a greater risk., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Rodney, Swaminathan, Calear, Christensen, Lal, Lane, Leviston, Reynolds, Trevenar, Vardoulakis and Walker.)
- Published
- 2021
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30. Differences in Muscle Activity and Kinetics Between the Goblet Squat and Landmine Squat in Men and Women.
- Author
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Collins KS, Klawitter LA, Waldera RW, Mahoney SJ, and Christensen BK
- Subjects
- Electromyography, Female, Humans, Kinetics, Male, Quadriceps Muscle, Hamstring Muscles, Muscle, Skeletal
- Abstract
Abstract: Collins, KS, Klawitter, LA, Waldera, RW, Mahoney, SJ, and Christensen, BK. Differences in muscle activity and kinetics between the goblet squat and landmine squat in men and women. J Strength Cond Res 35(10): 2661-2668, 2021-Squat exercise variations are widely used and extensively researched. However, little information exists on the goblet squat (GBS) and landmine squat (LMS) and differences between men and women. This study investigated the differences in muscle activity and kinetics between the GBS and the LMS in 16 men and 16 women. Five repetitions of each squat type were performed loaded at 30% of their body mass. Vertical and anteroposterior ground reaction forces for the eccentric and concentric phases and peak vertical force were recorded with a force plate. Electromyographic (EMG) signals were recorded for the vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST), and biceps femoris (BF). Normalized mean EMG values and ground reaction forces were analyzed with repeated measures analysis of variance (p < 0.05). Significant main effects for squat condition and sex were found. The LMS reduced activity in the quadriceps (VM and VL) muscles and vertical forces, while increasing posterior horizontal forces. In the LMS, men showed decreased ST activity, whereas women had decreased BF activity. Women exhibited greater quadriceps activity in both the GBS and LMS and greater ST in the LMS. Women also produced greater eccentric vertical force in both the GBS and LMS and less posterior horizontal forces in the LMS. The LMS may be useful to balance hamstring to quadriceps activity, increase horizontal loading, and reduce vertical loading. Conversely, the GBS can better target quadriceps activity and increase vertical loading. Sex differences should be considered for training programs that include the GBS and LMS., (Copyright © 2021 National Strength and Conditioning Association.)
- Published
- 2021
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31. The Associations between Asymmetric Handgrip Strength and Chronic Disease Status in American Adults: Results from the National Health and Nutrition Examination Survey.
- Author
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Klawitter L, Bradley A, Hackney KJ, Tomkinson GR, Christensen BK, Kraemer WJ, and McGrath R
- Abstract
This study examined the associations between asymmetric handgrip strength (HGS) and multimorbidity in American adults. Secondary analyses of data from persons aged at least 40 years from the 2011-2012 and 2013-2014 waves of the National Health and Nutrition Examination Survey were conducted. A handheld dynamometer collected HGS on each hand and persons with a strength imbalance >10% between hands were classified as having asymmetric HGS. Adults with the presence of ≥2 of the following conditions had multimorbidity: cardiovascular disease, chronic obstructive pulmonary disease, chronic kidney disease, asthma, arthritis, cancer, obesity, stroke, hypertension, high cholesterol, and diabetes. Of the n = 3483 participants included, n = 2700 (77.5%) had multimorbidity. A greater proportion of adults with multimorbidity had HGS asymmetry ( n = 1234 (45.7%)), compared to persons living without multimorbidity ( n = 314 (40.1%); p < 0.05). Relative to individuals without asymmetry, adults with asymmetric HGS had 1.31 (95% confidence interval (CI): 1.03-1.67) greater odds for multimorbidity. Moreover, persons with HGS asymmetry had 1.22 (CI: 1.04-1.44) greater odds for accumulating morbidities. Asymmetric strength, as another indicator of diminished muscle function, is linked to chronic morbidity status. Healthcare providers should recommend healthy behaviors for reducing asymmetries to improve muscle function and mitigate morbidity risk after completing asymmetry screenings.
- Published
- 2021
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32. Increased velocity at VO 2 max and load carriage performance in army ROTC cadets: prescription using the critical velocity concept.
- Author
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Dicks ND, Mahoney SJ, Kramer M, Lyman KJ, Christensen BK, Pettitt RW, and Hackney KJ
- Subjects
- Exercise Test, Female, Humans, Male, Prescriptions, Young Adult, High-Intensity Interval Training, Military Personnel, Running
- Abstract
The purpose of this study was to evaluate the effects of using the critical velocity (CV) concept to prescribe two separate high-intensity interval training (HIT) exercise programs aimed at enhancing CV and load carriage performance. 20 young adult participants (male = 15, female = 5) underwent a 4-week training period where they exercised 2 d wk
-1 . Participants were randomly assigned into two groups: (1) HIT or (2) Load Carriage-HIT (LCHIT). Pre- and post-training assessments included running 3-minute All-Out Test (3MT) to determine critical velocity (CV) and distance prime ( D ') and two load carriage tasks (400 and 3200 m). There were significant increases in CV ( p = 0.005) and velocity at V ˙ O2max ( v V ˙ O2max ) ( p = 0.037) among the sample but not between training groups. Improvements were observed in 3200 m load carriage performance time ( p < 0.001) with a 9.8 and 5.4% decrease in the LCHIT and HIT groups, respectively. Practitioner summary: Critical velocity has shown efficacy as a marker for performance in tactical populations. With the addition of load carriage, there is a reduction in the individual's CV. The CV-concept-prescribed exercises (HIT and LCHIT) 2 days per week for 4 weeks showed improvements in CV, v V ˙ O2max and load carriage performance. The use of the CV concept provides a method to prescribe HIT to increase running and load carriage performances in tactical populations.- Published
- 2021
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33. What is top-down about seeing enemies? Social anxiety and attention to threat.
- Author
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Delchau HL, Christensen BK, O'Kearney R, and Goodhew SC
- Subjects
- Humans, Memory, Short-Term, Anxiety, Attention, Fear
- Abstract
An attentional bias to threat is an important maintaining and possibly aetiological factor for social anxiety. Despite this, little is known about the underlying mechanisms of threat biases, such as the relative contributions of top-down and bottom-up attention. In order to measure attentional bias toward threat, the current study employed a variation of the dot-probe task in which participants' attention was initially cued to the left or right side of the screen before an angry face paired with a neutral face was displayed, and subsequently participants responded to a probe in the locus of one of the faces. This design provides separate measures of engagement with and disengagement from threat. In addition, in order to manipulate the availability of top-down attentional resources, participants completed this task under no, low (simple arithmetic task), and high (difficult arithmetic task) working memory load. Higher levels of social anxiety were found to be associated with increased engagement with threat under no-load, whereas this effect was eliminated under low-load and high-load conditions. Moreover, social anxiety was not associated with delayed disengagement from threat. These results highlight the critical role of top-down attention for engaging attention with threat.
- Published
- 2020
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34. Searching for emotion: A top-down set governs attentional orienting to facial expressions.
- Author
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Delchau HL, Christensen BK, Lipp OV, O'Kearney R, Bandara KH, Tan N, Yabuki H, and Goodhew SC
- Subjects
- Adolescent, Adult, Female, Humans, Male, Reaction Time physiology, Young Adult, Attention physiology, Cues, Emotions physiology, Facial Expression, Orientation physiology, Photic Stimulation methods
- Abstract
Research indicates that humans orient attention toward facial expressions of emotion. Orienting to facial expressions has typically been conceptualised as due to bottom-up attentional capture. However, this overlooks the contributions of top-down attention and selection history. In the present study, across four experiments, these three attentional processes were differentiated using a variation of the dot-probe task, in which participants were cued to attend to a happy or angry face on each trial. Results show that attention toward facial expressions was not exclusively driven by bottom-up attentional capture; instead, participants could shift their attention toward both happy and angry faces in a top-down manner. This effect was not found when the faces were inverted, indicating that top-down attention relies on holistic processing of the face. In addition, no evidence of selection history was found (i.e., no improvement on repeated trials or blocks of trials in which the task was to orient to the same expression). Altogether, these results suggest that humans can use top-down attentional control to rapidly orient attention to emotional faces., (Copyright © 2020 Elsevier B.V. All rights reserved.)
- Published
- 2020
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35. Simulated Casualty Evacuation Performance Is Augmented by Deadlift Peak Force.
- Author
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Poser WM, Trautman KA, Dicks ND, Christensen BK, Lyman KJ, and Hackney KJ
- Subjects
- Adult, Exercise Test instrumentation, Exercise Test methods, Humans, Male, Manikins, Muscle Strength physiology, North Dakota, Weight Lifting standards, Weight Lifting statistics & numerical data, Exercise Test statistics & numerical data, Military Personnel statistics & numerical data, Weight Lifting physiology
- Abstract
Introduction: The purpose of the current study was to examine if isometric peak force and rate of force development (RFD) were related to the ability to successfully perform a simulated casualty evacuation task in both unweighted and weighted conditions., Methods: Eighteen male participants from Army Reserve Officers' Training Corps (ROTC) completed a maximum isometric deadlift on a force plate (IRB#HE16227). Isometric peak force and RFD were calculated from ground reaction force. Two simulated casualty evacuation performance trials were then completed. The unweighted trial consisted of lifting and carrying a 75 kg dummy as quickly as possible for 50 m. The weighted trial was similar except 9 kg vests were added to both the simulation dummy and the participant to represent 18 kg of duty gear. Independent sample t-tests and Pearson correlations were performed to compare the characteristics of those who passed and failed the weighted trial., Results: All of the participants (n = 18) completed the unweighted casualty evacuation trial, while 72% (n = 13) were able to complete the weighted casualty evacuation trial. The participants that successfully completed the weighted evacuation trial had significantly (p < 0.05) greater isometric peak force (1420 ± 165 vs. 1076 ± 256 N) and lean mass (74.18 ± 3.89 vs. 65.34 ± 3.89 kg) when compared to participants (n = 5) that could not complete the weighted evacuating task trial. Additionally, greater Army Physical Fitness Test scores (288 ± 13 vs. 269 ± 16 arbitrary units) and significantly faster (30.34 ± 4.41 vs. 44.92 ± 10.62 seconds) unweighted evacuation trial times were observed in participants that could complete the weighted evacuation task. Peak force was also significantly correlated with lean mass (r = 0.51, p < 0.05). There was no relationship between RFD and performance of the unweighted or weight trial., Conclusion: Isometric deadlift peak force represents an important determinant for the success of a simulated casualty evacuation task and may be a useful marker to include in periodic fitness evaluations of military personnel., (© Association of Military Surgeons of the United States 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2019
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36. Spontaneous spatial navigation circuitry in schizophrenia spectrum disorders.
- Author
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Wilkins LK, Girard TA, Christensen BK, King J, Kiang M, and Bohbot VD
- Subjects
- Adult, Female, Humans, Magnetic Resonance Imaging, Male, Nerve Net diagnostic imaging, Schizophrenia diagnostic imaging, Temporal Lobe diagnostic imaging, Young Adult, Frontal Lobe physiopathology, Nerve Net physiopathology, Schizophrenia physiopathology, Spatial Memory physiology, Spatial Navigation physiology, Temporal Lobe physiopathology, Virtual Reality
- Abstract
Spatial memory is core to wayfinding and everyday memory. Interestingly, individuals with schizophrenia using spatial navigation strategies (cognitive mapping) are impaired, whereas those using response-based (e.g., single-landmark) strategies show relatively intact memory performance. We observed abnormal brain communication in schizophrenia participants who used a spatial strategy during a virtual-reality navigation task, particularly between temporal and frontal brain regions. In contrast, schizophrenia participants using a response strategy recruited similar brain systems to healthy participants, but to a greater extent to support memory performance. These findings highlight that strategy use is an important consideration for understanding memory systems and navigation in schizophrenia., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2019
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37. Acute Cardiovascular, Metabolic, and Muscular Responses to Blood Flow Restricted Rowing Exercise.
- Author
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Mahoney SJ, Dicks ND, Lyman KJ, Christensen BK, and Hackney KJ
- Subjects
- Adult, Electromyography, Healthy Volunteers, Humans, Male, Muscle Strength physiology, Muscle, Skeletal blood supply, Muscular Atrophy diagnosis, Muscular Atrophy etiology, Muscular Atrophy physiopathology, Physical Endurance physiology, Regional Blood Flow physiology, Time Factors, Water Sports physiology, Young Adult, Muscle, Skeletal physiology, Muscular Atrophy prevention & control, Resistance Training methods, Space Flight, Weightlessness adverse effects
- Abstract
INTRODUCTION: Microgravity leads to a progressive loss in muscular strength, endurance, and aerobic capacity (Vo
2peak ). Blood flow restricted (BFR) exercise has been shown to elicit rapid gains in muscular strength and Vo2peak . Rowing exercise combined with BFR could be a supplemental countermeasure to maintain preflight muscle function and Vo2peak , especially within future space vehicles with restricted physical volume. METHODS: There were 20 men who completed 19 min of rowing exercise during CON or BFR in a randomized order. Exercise intensity for all sets was 30% of peak work load achieved during a separate incremental maximal exercise test. Kaatsu training cuffs were inflated around each leg during BFR. Muscle oxygen saturation (Smo₂) and heart rate (HR) were measured throughout exercise and rest. Rate of perceived exertion (RPE) and muscle activation, using surface electromyography (sEMG), were measured during the last 30 s of each exercise set. Blood pressure (BP) and whole blood lactate ([La- ]b ) were measured at rest and postexercise. RESULTS: Smo₂ declined significantly in BFR during exercise and rest by 13% and 14%, respectively. HR and RPE showed significant increases during BFR (120.5 ± 5.53 vs. 128.9 ± 9.86 bts · min-1 ) (9.8 ± 1.85 vs. 11.8 ± 1.88 arbitrary units). No differences were observed for BP, [La- ]b , and sEMG. DISCUSSION: Findings indicate exercise intensity and cuff pressure elicited acute muscular, cardiovascular, and perceptual responses. BFR rowing exercise could be advantageous as an adjunct for future exercise countermeasures where aerobic and anaerobic exercise may be performed on one device or in limited physical space. Mahoney SJ, Dicks ND, Lyman KJ, Christensen BK, Hackney KJ. Acute cardiovascular, metabolic, and muscular responses to blood flow restricted rowing exercise . Aerosp Med Hum Perform. 2019; 90(5):440-446.- Published
- 2019
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38. Investigating service features to sustain engagement in early intervention mental health services.
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Becker M, Cunningham CE, Christensen BK, Furimsky I, Rimas H, Wilson F, Jeffs L, Madsen V, Bieling P, Chen Y, Mielko S, and Zipursky RB
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- Adolescent, Adult, Canada, Family psychology, Female, Humans, Male, Mental Disorders diagnosis, Mental Disorders psychology, Middle Aged, Patient Care Team, Surveys and Questionnaires, Young Adult, Early Medical Intervention methods, Mental Disorders therapy, Mental Health Services, Patient Compliance, Patient Satisfaction
- Abstract
Aim: To understand what service features would sustain patient engagement in early intervention mental health treatment., Methods: Mental health patients, family members of individuals with mental illness and mental health professionals completed a survey consisting of 18 choice tasks that involved 14 different service attributes. Preferences were ascertained using importance and utility scores. Latent class analysis revealed segments characterized by distinct preferences. Simulations were carried out to estimate utilization of hypothetical clinical services., Results: Overall, 333 patients and family members and 183 professionals (N = 516) participated. Respondents were distributed between a Professional segment (53%) and a Patient segment (47%) that differed in a number of their preferences including for appointment times, individual vs group sessions and mode of after-hours support. Members of both segments shared preferences for many of the service attributes including having crisis support available 24 h per day, having a choice of different treatment modalities, being offered help for substance use problems and having a focus on improving symptoms rather than functioning. Simulations predicted that 60% of the Patient segment thought patients would remain engaged with a Hospital service, while 69% of the Professional segment thought patients would be most likely to remain engaged with an E-Health service., Conclusions: Patients, family members and professionals shared a number of preferences about what service characteristics will optimize patient engagement in early intervention services but diverged on others. Providing effective crisis support as well as a range of treatment options should be prioritized in the future design of early intervention services., (© 2017 John Wiley & Sons Australia, Ltd.)
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- 2019
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39. The unexpected killer: effects of stimulus threat and negative affectivity on inattentional blindness.
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Beanland V, Tan CH, and Christensen BK
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- Adolescent, Adult, Attentional Bias, Cues, Female, Humans, Male, Photic Stimulation, Young Adult, Affect physiology, Attention physiology, Blindness physiopathology, Eye Movements physiology, Fear physiology
- Abstract
Inattentional blindness (IB) occurs when observers fail to detect unexpected objects or events. Despite the adaptive importance of detecting unexpected threats, relatively little research has examined how stimulus threat influences IB. The current study was designed to explore the effects of stimulus threat on IB. Past research has also demonstrated that individuals with elevated negative affectivity have an attentional bias towards threat-related stimuli; therefore, the current study also examined whether state and trait levels of negative affectivity predicted IB for threat-related stimuli. One hundred and eleven participants (87 female, aged 17-40 years) completed an IB task that included both threat-related and neutral unexpected stimuli, while their eye movements were tracked. Participants were significantly more likely to detect the threatening stimulus (19%) than the neutral stimulus (11%) p = .035, odds ratio (OR) = 4.0, 95% confidence interval OR [1.13, 14.17]. Neither state nor trait levels of negative affectivity were significantly associated with IB. These results suggest observers are more likely to detect threat-related unexpected objects, consistent with the threat superiority effect observed in other paradigms. However, most observers were blind to both unexpected stimuli, highlighting the profound influence of expectations and task demands on our ability to perceive even potentially urgent and life-threatening information.
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- 2018
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40. Temporal dynamics of anxiety-related attentional bias: is affective context a missing piece of the puzzle?
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Cox JA, Christensen BK, and Goodhew SC
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- Emotions, Female, Humans, Male, Photic Stimulation, Time Factors, Young Adult, Anxiety psychology, Attentional Bias
- Abstract
Previous research has demonstrated that anxious individuals attend to negative emotional information at the expense of other information. This is commonly referred to as attentional bias. The field has historically conceived of this process as relatively static; however, research by [Zvielli, A., Bernstein, A., & Koster, E. H. W. (2014). Dynamics of attentional bias to threat in anxious adults: Bias towards and/or away? PLoS ONE, 9(8), e104025; Zvielli, A., Bernstein, A., & Koster, E. H. W. (2015). Temporal dynamics of attentional bias. Clinical Psychological Science, 3(5), 772-788.], and others, challenges this assumption by demonstrating considerable temporal variability in attentional bias amongst anxious individuals. Still, the mechanisms driving these temporal dynamics are less well known. Using a modified dot-probe task, the present study examined the impact of two relevant contextual variables- affective valence and trial repetition. Affective context was instantiated by the presentation of negative versus neutral pictures before each trial, while repetition context was achieved via the presentation of the valenced pictures in either a blocked- or mixed-trial design. Results indicate that individuals with higher trait-anxiety levels were significantly more influenced by blocked presentations of negative affective information, leading to greater temporal fluctuations in attentional bias. Furthermore, our findings provide additional evidence that attentional bias is best conceptualised as dynamic and variable, and that an individual's affective experience is one factor that regulates attentional bias dynamics. Implications relating to theoretical and methodological factors are discussed.
- Published
- 2018
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41. Traditional test administration and proactive interference undermine visual-spatial working memory performance in schizophrenia-spectrum disorders.
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Girard TA, Wilkins LK, Lyons KM, Yang L, and Christensen BK
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- Adult, Case-Control Studies, Female, Humans, Male, Middle Aged, Young Adult, Cognition Disorders physiopathology, Memory, Short-Term physiology, Neuropsychological Tests standards, Schizophrenia physiopathology, Spatial Memory physiology
- Abstract
Introduction Working-memory (WM) is a core cognitive deficit among individuals with Schizophrenia Spectrum Disorders (SSD). However, the underlying cognitive mechanisms of this deficit are less known. This study applies a modified version of the Corsi Block Test to investigate the role of proactive interference in visuospatial WM (VSWM) impairment in SSD. Methods Healthy and SSD participants completed a modified version of the Corsi Block Test involving both high (typical ascending set size from 4 to 7 items) and low (descending set size from 7 to 4 items) proactive interference conditions. Results The results confirmed that the SSD group performed worse overall relative to a healthy comparison group. More importantly, the SSD group demonstrated greater VSWM scores under low (Descending) versus high (Ascending) proactive interference; this pattern is opposite to that of healthy participants. Conclusions This differential pattern of performance supports that proactive interference associated with the traditional administration format contributes to VSWM impairment in SSD. Further research investigating associated neurocognitive mechanisms and the contribution of proactive interference across other domains of cognition in SSD is warranted.
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- 2018
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42. Effect of Progressive Calisthenic Push-up Training on Muscle Strength and Thickness.
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Kotarsky CJ, Christensen BK, Miller JS, and Hackney KJ
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- Adolescent, Adult, Humans, Male, Middle Aged, Ultrasonography, Young Adult, Muscle Strength physiology, Pectoralis Muscles diagnostic imaging, Resistance Training methods
- Abstract
Kotarsky, CJ, Christensen, BK, Miller, JS, and Hackney, KJ. Effect of progressive calisthenic push-up training on muscle strength and thickness. J Strength Cond Res 32(3): 651-659, 2018-Calisthenics, a form of resistance training, continue to increase in popularity; however, few studies have examined their effectiveness for muscle strength improvement. The purpose of this study was to determine whether progressive calisthenic push-up training (PUSH) is comparable with traditional bench press training (BENCH) as a technique for increasing muscle strength and thickness. Twenty-three healthy, moderately trained men (mean ± SD: age 23 ± 6.8 years) completed the study. Subjects were randomly assigned to PUSH (n = 14) and BENCH (n = 9) groups and were trained 3 days per week for 4 weeks. Muscle thickness (MT), seated medicine ball put (MBP), 1 repetition maximum (1RM) bench press, and push-up progression (PUP) were measured before and after training. Results revealed significant increases in 1RM (p < 0.001) and PUP (p < 0.001) for both groups after training. The increase in PUP was significantly greater for PUSH (p < 0.001). No significant differences were found within groups for MT and MBP (p > 0.05). This study is the first to demonstrate that calisthenics, using different progressive variations to maintain strength training programming variables, can improve upper-body muscle strength.
- Published
- 2018
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43. Social anxiety and attentional biases: A top-down contribution?
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Boal HL, Christensen BK, and Goodhew SC
- Subjects
- Adult, Cues, Female, Fixation, Ocular, Humans, Male, Orientation, Young Adult, Anxiety psychology, Attentional Bias physiology, Facial Recognition physiology, Memory, Short-Term physiology
- Abstract
Selective attention toward threatening facial expressions has been found to precipitate and maintain symptoms of social anxiety. However, the automaticity of this bias is under debate. In the present study, we aimed to test whether top-down (controlled) engagement and disengagement of attention toward threatening faces is associated with social anxiety. This was examined by testing the impact of a secondary working memory (WM) load on attentional biases. In a variation of the dot-probe task, participants' attention was initially cued to the left or right of fixation before an upright face paired with an inverted face was presented (displaying a disgust or neutral expression), and participants responded to a subsequently presented probe. The task was performed under no-load, low-load (one-digit memory task), and high-load (six-digit memory task) conditions. Social anxiety was not found to be associated with delayed disengagement from threat. However, surprisingly, high social anxiety was associated with an engagement bias away from threat, whereas low social anxiety was associated with a bias toward threat. These results were unaffected by the WM load manipulation. This indicates that engagement with threatening facial expressions has minimal contributions from top-down mechanisms, since it is likely that orienting to facial expressions occurs relatively automatically.
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- 2018
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44. Hippocampal activation and memory performance in schizophrenia depend on strategy use in a virtual maze.
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Wilkins LK, Girard TA, Herdman KA, Christensen BK, King J, Kiang M, and Bohbot VD
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- Adult, Brain physiopathology, Female, Humans, Magnetic Resonance Imaging, Male, Spatial Navigation physiology, Video Games psychology, Hippocampus physiopathology, Maze Learning physiology, Memory physiology, Psychotic Disorders physiopathology, Schizophrenia physiopathology
- Abstract
Different strategies may be spontaneously adopted to solve most navigation tasks. These strategies are associated with dissociable brain systems. Here, we use brain-imaging and cognitive tasks to test the hypothesis that individuals living with Schizophrenia Spectrum Disorders (SSD) have selective impairment using a hippocampal-dependent spatial navigation strategy. Brain activation and memory performance were examined using functional magnetic resonance imaging (fMRI) during the 4-on-8 virtual maze (4/8VM) task, a human analog of the rodent radial-arm maze that is amenable to both response-based (egocentric or landmark-based) and spatial (allocentric, cognitive mapping) strategies to remember and navigate to target objects. SSD (schizophrenia and schizoaffective disorder) participants who adopted a spatial strategy performed more poorly on the 4/8VM task and had less hippocampal activation than healthy comparison participants using either strategy as well as SSD participants using a response strategy. This study highlights the importance of strategy use in relation to spatial cognitive functioning in SSD. Consistent with a selective-hippocampal dependent deficit in SSD, these results support the further development of protocols to train impaired hippocampal-dependent abilities or harness non-hippocampal dependent intact abilities., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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45. Modeling the mental health service utilization decisions of university undergraduates: A discrete choice conjoint experiment.
- Author
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Cunningham CE, Zipursky RB, Christensen BK, Bieling PJ, Madsen V, Rimas H, Mielko S, Wilson F, Furimsky I, Jeffs L, and Munn C
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- Adolescent, Decision Making, Female, Humans, Male, Mental Disorders psychology, Student Health Services, Universities, Attitude to Health, Mental Health, Students psychology
- Abstract
Objective: We modeled design factors influencing the intent to use a university mental health service., Participants: Between November 2012 and October 2014, 909 undergraduates participated., Method: Using a discrete choice experiment, participants chose between hypothetical campus mental health services., Results: Latent class analysis identified three segments. A Psychological/Psychiatric Service segment (45.5%) was most likely to contact campus health services delivered by psychologists or psychiatrists. An Alternative Service segment (39.3%) preferred to talk to peer-counselors who had experienced mental health problems. A Hesitant segment (15.2%) reported greater distress but seemed less intent on seeking help. They preferred services delivered by psychologists or psychiatrists. Simulations predicted that, rather than waiting for standard counseling, the Alternative Service segment would prefer immediate access to E-Mental health. The Usual Care and Hesitant segments would wait 6 months for standard counseling., Conclusions: E-Mental Health options could engage students who may not wait for standard services.
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- 2017
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46. The beneficial influence of inattention on visual interference in schizophrenia.
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Brodeur MB, Kiang M, and Christensen BK
- Subjects
- Adult, Cognitive Dysfunction etiology, Female, Humans, Male, Middle Aged, Schizophrenia complications, Attention physiology, Cognitive Dysfunction physiopathology, Evoked Potentials physiology, Schizophrenia physiopathology, Space Perception physiology, Visual Perception physiology
- Abstract
Objective: Schizophrenia is associated with poor spatial attention. However, although this deficit undermines the perception of target information, it may be helpful for ignoring irrelevant inputs. The present study examined whether event-related brain potential (ERP) indices of visual spatial attention predicted the magnitude of the brain response to interference in schizophrenia., Method: ERPs were recorded in 16 schizophrenia patients and 20 healthy control participants who had to indicate whether the target E was global or local in compound letter stimuli. The nontarget could be either highly similar to the target (i.e., a global E composed of local Ss and vice versa) and thus produce more interference, or it could be dissimilar (i.e., a global E composed of local Hs and vice versa) and generate less interference., Results: Both groups' responses were slowed by interference. Voltage amplitudes of the P1, and of ERP interference effects from 300-500 ms after stimulus onset, were significantly smaller in schizophrenia patients than in healthy participants when the target was global. In patients, larger P1 amplitudes were correlated with larger interference effects and with more severe symptoms of attentional deficits and conceptual disorganization. Schizophrenia participants thus exhibited abnormal ERPs to interference despite normal behavioral performance., Conclusions: Schizophrenia patients likely pay less attention to stimuli in general; however, the impact of this impairment on target detection is compensated by relatively greater inattention to irrelevant components of the stimuli, and this explains why they are not more influenced by interference than healthy participants at the behavioral level. (PsycINFO Database Record, ((c) 2016 APA, all rights reserved).)
- Published
- 2016
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47. Inhibiting reactions to emotional versus non-emotional response cues in schizophrenia: Insights from a motor-process paradigm.
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Patrick RE, Christensen BK, and Smolewska K
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- Adult, Case-Control Studies, Female, Humans, Male, Neuropsychological Tests, Reaction Time, Schizophrenia diagnosis, Young Adult, Cues, Emotions, Inhibition, Psychological, Psychomotor Performance, Schizophrenic Psychology
- Abstract
Recent models of schizophrenia suggest deficient use of contextual response cues when confronted with countermanding emotional cues. It is important to clinically validate these models by testing patients diagnosed with schizophrenia on tasks with competing emotional and contextual response determinants. Control and schizophrenia groups completed a novel task that elicited motor responses consistent with, or in opposition to, pre-potent emotional actions (i.e., approach vs. avoidance). An analogous non-emotional task was also used to examine cue-conflict impairment more generally. The groups demonstrated statistically equivalent performance decrements on incongruent versus congruent trials on both tasks. However, within the schizophrenia group, the incongruency effect was significantly greater in the emotional versus non-emotional task. These data suggest that, while patients with schizophrenia were able to employ contextual response cues to override competing emotional responses, they were slower to resolve emotional versus non-emotional response conflict. When patients were subdivided according to the presence or absence of disorganized symptoms, this effect was confined to patients with disorganized symptoms., (© 2014 The British Psychological Society.)
- Published
- 2016
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48. Preferences for Early Intervention Mental Health Services: A Discrete-Choice Conjoint Experiment.
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Becker MP, Christensen BK, Cunningham CE, Furimsky I, Rimas H, Wilson F, Jeffs L, Bieling PJ, Madsen V, Chen YY, Mielko S, and Zipursky RB
- Subjects
- Adolescent, Adult, Canada, Family, Female, Humans, Male, Mental Disorders psychology, Middle Aged, Young Adult, Attitude to Health, Choice Behavior, Early Medical Intervention, Mental Disorders therapy, Mental Health Services, Patient Preference
- Abstract
Objective: Early intervention services (EISs) for mental illness may improve outcomes, although treatment engagement is often a problem. Incorporating patients' preferences in the design of interventions improves engagement. A discrete-choice conjoint experiment was conducted in Canada to identify EIS attributes that encourage treatment initiation., Methods: Sixteen four-level attributes were formalized into a conjoint survey, completed by patients, family members, and mental health professionals (N=562). Participants were asked which EIS option people with mental illness would contact. Latent-class analysis identified respondent classes characterized by shared preferences. Randomized first-choice simulations predicted which hypothetical options, based on attributes, would result in maximum utilization., Results: Participants in the conventional-service class (N=241, 43%) predicted that individuals would contact traditional services (for example, hospital location and staffed by psychologists or psychiatrists). Membership was associated with being a patient or family member and being male. Participants in the convenient-service class (N=321, 57%) predicted that people would contact services promoting easy access (for example, self-referral and access from home). Membership was associated with being a professional. Both classes predicted that people would contact services that included short wait times, direct contact with professionals, patient autonomy, and psychological treatment information. The convenient-service class predicted that people would use an e-health model, whereas the conventional-service class predicted that people would use a primary care or clinic-hospital model., Conclusions: Provision of a range of services may maximize EIS use. Professionals may be more apt to adopt EISs in line with their beliefs regarding patient preferences. Considering several perspectives is important for service design.
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- 2016
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49. Neurophysiological correlates of emotional directed-forgetting in persons with Schizophrenia: An event-related brain potential study.
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Patrick RE, Kiang M, and Christensen BK
- Subjects
- Adult, Analysis of Variance, Attention physiology, Cues, Electroencephalography, Female, Humans, Male, Middle Aged, Neuropsychological Tests, Psychiatric Status Rating Scales, Statistics as Topic, Young Adult, Brain Mapping, Emotions physiology, Evoked Potentials physiology, Memory Disorders etiology, Schizophrenia complications, Schizophrenic Psychology
- Abstract
Background: Recent research has shown that patients with schizophrenia (SCZ) exhibit reduced directed forgetting (DF) for negative words, suggesting impaired ability to instantiate goal-directed inhibition in order to suppress a competing, emotion-driven responses (i.e., emotional memory enhancement). However, disrupted inhibition is not the only possible mechanism by which patients could manifest reduced emotional DF. Therefore, the primary objective of the current study was to use event-related brain potential (ERP) recordings to investigate alternative hypotheses., Methods: ERPs were recorded while patients and controls completed an item-method DF paradigm using negative and neutral words. The N2 indexed goal-directed inhibition of to-be-forgotten items. The late positive potential (LPP) indexed emotional memory enhancement for negative study items. The P300 indexed selective rehearsal of to-be-remembered items., Results: The SCZ group exhibited a reduced DF effect overall, but this was not modulated by emotion. N2 amplitude at anterior sites was larger for forget versus remember cues in the control group only, but this effect was not modulated by emotion. LPP amplitude was greater for negative versus neutral words in both groups, independent of region. P300 amplitude at posterior sites was greater for remember versus forget cues in the control group only., Discussion: These data suggest that reduced DF in SCZ may be due, in part, to both diminished goal-directed inhibition of to-be-forgotten items and reduced selective rehearsal of to-be-remembered items. However, these data do not support the hypothesis that goal-directed, inhibitory processes are disrupted by competing, emotion-driven processes in SCZ. Patients' ERP data also suggested that they did not exhibit disproportionately heightened encoding of emotional stimuli, nor did they have deficient selective rehearsal of to-be-remembered emotional items., (Copyright © 2015 Elsevier B.V. All rights reserved.)
- Published
- 2015
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50. Effortful versus automatic emotional processing in schizophrenia: Insights from a face-vignette task.
- Author
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Patrick RE, Rastogi A, and Christensen BK
- Subjects
- Adult, Case-Control Studies, Comprehension, Cues, Humans, Intelligence, Memory, Short-Term, Middle Aged, Reading, Young Adult, Emotions, Facial Expression, Schizophrenic Psychology
- Abstract
Adaptive emotional responding relies on dual automatic and effortful processing streams. Dual-stream models of schizophrenia (SCZ) posit a selective deficit in neural circuits that govern goal-directed, effortful processes versus reactive, automatic processes. This imbalance suggests that when patients are confronted with competing automatic and effortful emotional response cues, they will exhibit diminished effortful responding and intact, possibly elevated, automatic responding compared to controls. This prediction was evaluated using a modified version of the face-vignette task (FVT). Participants viewed emotional faces (automatic response cue) paired with vignettes (effortful response cue) that signalled a different emotion category and were instructed to discriminate the manifest emotion. Patients made less vignette and more face responses than controls. However, the relationship between group and FVT responding was moderated by IQ and reading comprehension ability. These results replicate and extend previous research and provide tentative support for abnormal conflict resolution between automatic and effortful emotional processing predicted by dual-stream models of SCZ.
- Published
- 2015
- Full Text
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