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Freezing of gait is a frequent and disabling symptom experienced by many patients with Parkinson's disease. A number of executive deficits have been shown to be associated with the phenomenon suggesting a common underlying pathophysiology, which as of yet remains unclear. Neuroimaging studies have also implicated the role of the cognitive control network in patients with freezing. To explore this concept, the current study examined error-monitoring as a measure of cognitive control. Thirty-four patients with and 38 without freezing of gait, who were otherwise well matched on disease severity, completed a colour-word interference task that allowed the specific assessment of error monitoring during conflict. Whilst both groups performed colour-naming and word-reading tasks equally well, those patients with freezing showed a pattern between conditions whereby they were better able to monitor performance and self-correct errors in the pure inhibition task but not after a switching rule was introduced. The novel results shown here provide insight into possible pathophysiological mechanisms involved in cognitive load and error monitoring in patients with freezing of gait. These results provide further evidence for the role of functional frontostriatal circuitry impairments in patients with freezing of gait and have implications for future studies and possible therapeutic interventions.

This study aimed to evaluate the efficacy of a multifactorial 'healthy brain ageing cognitive training program' for Parkinson's disease. Using a single-blinded waitlist control design, 50 participants with Parkinson's disease were recruited from the Brain & Mind Research Institute, Sydney, Australia. The intervention encompassed both psychoeducation and cognitive training; each component lasted 1-hour. The 2-hour sessions were delivered in a group format, twice-weekly over a 7-week period. Multifactorial psychoeducation was delivered by a range of health professionals. In addition to delivering cognitive strategies, it targeted depression, anxiety, sleep, vascular risk factors, diet, and exercise. Cognitive training was computer-based and was conducted by clinical neuropsychologists. The primary outcome was memory. Secondary outcomes included other aspects of cognition and knowledge pertaining to the psychoeducation material. Results demonstrated that cognitive training was associated with significant improvements in learning and memory corresponding to medium to large effect sizes. Treatment was also associated with medium effect size improvements in knowledge. Although the study was limited by the lack of randomized allocation to treatment and control groups, these findings suggest that a healthy brain ageing cognitive training program may be a viable tool to improve memory and/or slow cognitive decline in people with Parkinson's disease. It also appeared successful for increasing awareness of adaptive and/or compensatory cognitive strategies, as well as modifiable risk factors to optimize brain functioning.

Background: Recent attempts to standardise the definition of Mild Cognitive Impairment (MCI) in Parkinson s disease (PD) by the Movement Disorder Society Task Force has led to a greater understanding of this entity but to date, there has been a paucity of research regarding the impact of PD-MCI on caregiver outcomes. Objective: The aim of this study was to utilise the newly established PD-MCI diagnostic criteria to investigate caregiver outcomes in relation to four specific aspects: (1) caregiver burden, (2) quality of life (QoL), (3) caregiving experience, and (4) psychological distress. Methods: This study included a total of 166 patient-caregiver dyads. Caregiver outcomes including quality of life, caregiver burden, mood disturbances, and caregiver experience were compared between caregivers of PD patients classified as having normal cognition (PD-NC) and PD-MCI. Results: Despite the two groups being matched on demographic and clinical features, caregivers of PD-MCI patients reported a lower level of QoL with regard to physical health and more interruptions with usual activities. On the other hand, a higher impact on finances was reported in caregivers of PD-NC patients, relative to caregivers of PD-MCI patients. Conclusions: This study has shown that even at earlier stages of cognitive impairment, PD-MCI caregivers already experience elevated levels of distress in the role of providing care to their care-recipients. These findings highlight the need to include management of caregiver distress and associated sequelae alongside the management of PD-MCI patients, early on in the disease course.

BackgroundLearning and memory impairments in older adults with depression are linked to hippocampal atrophy. However, other subcortical regions may also be contributing to these deficits. We aimed to examine whether anterior caudate nucleus volume is significantly reduced in older adults with depression compared to controls; whether anterior caudate volume is associated with performance on tasks of episodic learning and memory, and if so, whether this association is independent of the effects of the hippocampus.MethodEighty-four health-seeking participants meeting criteria for lifetime major depressive disorder (mean age = 64.2,s.d.= 9.1 years) and 27 never-depressed control participants (mean age = 63.9,s.d.= 8.0 years) underwent neuropsychological assessment including verbal episodic memory tests [Rey Auditory Verbal Learning Test and Logical Memory (WMS-III)]. Magnetic resonance imaging was conducted, from which subregions of the caudate nucleus were manually demarcated bilaterally and hippocampal volume was calculated using semi-automated methods.ResultsDepressed subjects had smaller right anterior caudate (RAC) (t= 2.3,p= 0.026) and poorer memory compared to controls (t= 2.5,p< 0.001). For depressed subjects only, smaller RAC was associated with poorer verbal memory (r= 0.3,p= 0.003) and older age (r= −0.46,p< 0.001). Multivariable regression showed that the RAC and hippocampus volume uniquely accounted for 5% and 3% of the variance in memory, respectively (β= 0.25,t= 2.16,p= 0.033;β= 0.19,t= 1.71,p= 0.091).ConclusionsIn older people with depression, the anterior caudate nucleus and the hippocampus play independent roles in mediating memory. While future studies examining this structure should include larger sample sizes and adjust for multiple comparisons, these findings support the critical role of the striatum in depression.

STUDY OBJECTIVES: Sleep disordered breathing (SDB) is common in older adults and is strongly associated with cognitive decline, with increasing evidence suggesting that it may represent a risk factor for dementia. Given that SDB is characterized by intermittent episodes of hypoxemia during sleep, it is possible that cognitive impairment may relate to cerebral oxidative stress. This study aimed to examine the relationship between nocturnal markers of hypoxemia and proton magnetic resonance spectroscopy (1H-MRS) markers of oxidative stress within the anterior cingulate cortex (ACC) of the brain. METHODS: Twenty-four older adults (mean age = 67.9 y) at-risk for dementia were recruited from our Healthy Brain Ageing Research Clinic. At-risk was defined as participants seeking help for assessment and/or intervention for cognitive decline, including those with subjective and/or objective cognitive complaints. This could occur in the context of prior depression or risk factors (e.g., vascular) for dementia. All participants underwent psychiatric, medical and neuropsychological assessment followed by overnight polysomnography. In addition, participants underwent 1H-MRS to derive levels of ACC GSH reported as a ratio to creatine (GSH/Cr). RESULTS:Increased levels of GSH/Cr were associated with lower oxygen desaturation (r = -0.54, P = 0.007) and more severe apnea-hypopnea index scores during rapid eye movement sleep (r = 0.42, P = 0.05). In addition, ACC GSH/Cr correlated with poorer executive functioning (i.e., response inhibition: r = -0.49, P = 0.015; set shifting: r = -0.43, P = 0.037). CONCLUSIONS: Markers of nocturnal hypoxemia and SDB are associated with cerebral oxidative stress in older people at-risk for dementia, suggesting a potential mechanism by which SDB may contribute to brain degeneration, cognitive decline, and dementia. Further work focused on utilizing this biomarker for the early identification and treatment of this possible modifiable risk factor in older persons is now warranted. Copyright© 2016 Associated Professional Sleep Societies, LLC. All rights reserved.

Given projected increases in dementia prevalence, emphasising earlier stages of cognitive impairment in older adults enables targeted early intervention strategies. Strategy-based cognitive training (SCT) is a remedial approach involving guidance and practice in compensatory techniques to improve cognition, including memory and attention. It may also be effective for improving executive functions (EF) integral to everyday tasks. This review systematically evaluates SCT effects on EF in older adults without dementia. Following PRISMA guidelines, we reviewed eligible trials according to pre-defined criteria, differentiating SCT from other cognitive interventions and stipulating total EF-focused intervention time, study design and target population (healthy older adults or mild cognitive decline). We then evaluated trials according to design, methodological quality and outcomes. Unfortunately, with too few studies in mild cognitive impairment, we refocused our review only on healthy older adults. Thirteen studies with 4120 participants in total were included, primarily targeting inductive reasoning. Despite heterogeneous study designs and SCT programs, 11/13 trials reported significant EF improvements, generally of moderate effect size (Hedges' g > 0.3). Four studies reported sustained benefits from one month to 10 years. There was some evidence of far transfer. We conclude that there is promising evidence for SCT as a targeted intervention for EF in healthy older adults and preliminary evidence for maintaining effects over time. Fewer trials have investigated far transfer (e.g. improved everyday functioning) or capacity to delay/prevent dementia, which are most relevant to clinical utility. Limitations include the inability to calculate effect sizes for four studies and absence of statistical meta-analysis.

Major depression is often associated with neuropsychological deficits, most commonly in the areas of executive functioning (e.g. set-shifting, problem-solving, decision-making), information processing speed, new learning and memory. These cognitive deficits may be even more pronounced in older adults with depression and particularly in those with cardiovascular risk factors, where cognitive impairment is linked with multiple pathophysiologies including white matter lesions and alterations in key grey matter brain structures. In this group, underlying neurodegenerative pathology is also an important consideration. Of concern, cognitive deficits are predictive of treatment responsiveness and may persist despite depressive symptom resolution. However, most traditional treatments for depression (i.e. antidepressants and psychological therapies) do not focus on cognition. By contrast, cognitive training is a novel non-pharmacological therapy that may be used to directly target cognition and psychosocial functioning, by promoting neural plasticity. In this chapter, we review the evidence for cognitive training in depression with additional reference to work in healthy samples and those with neuropsychiatric and neurodegenerative disease. Studies using both computer-based and strategy-based training approaches are discussed. To date, there is a lack of well-controlled studies utilising cognitive training for people with depression. Nonetheless, 13 studies employing computer-based cognitive training programs reveal promising results, particularly for improving memory and mood. Further randomised controlled trials in those with depression are now required, to examine the potential magnitude of cognitive improvement and to determine which individual, clinical and treatment-related factors may influence treatment efficacy.

As the population ages, the economic and societal impacts of neurodegenerative and neuropsychiatric disorders are expected to rise sharply. Like dementia, late-life depressive disorders are common and are linked to increased disability, high healthcare utilisation, cognitive decline and premature mortality. Considerable heterogeneity in the clinical presentation of major depression across the life cycle may reflect unique pathophysiological pathways to illness; differentiating those with earlier onset who have grown older (early-onset depression), from those with illness onset after the age of 50 or 60 years (late-onset depression). The last two decades have witnessed significant advances in our understanding of the neurobiology of early- and late-onset depression, and has shown that disturbances of fronto-subcortical functioning are implicated. New biomedical models extend well beyond perturbations of traditional monoamine systems to include altered neurotrophins, endocrinologic and immunologic system dysfunction, inflammatory processes and gene expression alterations. This more recent research has highlighted that a range of illness-specific, neurodegenerative and vascular factors appear to contribute to the various phenotypic presentations. This review highlights the major features of late-life depression, with specific reference to its associated aetiological, clinical, cognitive, neuroimaging, neuropathological, inflammatory and genetic correlates. Data examining the efficacy of pharmacological, non-pharmacological and novel treatments for depression are discussed. Ultimately, future research must aim to evaluate whether basic biomedical knowledge can be successfully translated into enhanced health outcomes via the implementation of early intervention paradigms.

Background: The use of informant rating scales in older adults at risk of dementia may assist with early detection and intervention strategies. This study aims to evaluate whether informants rate greater cognitive change in patients with mild cognitive impairment (MCI) compared to cognitively intact individuals, and to determine the relationship between informant ratings of cognitive change and neuropsychological performance.Methods: One hundred and nine health-seeking older adults underwent clinical and neuropsychological assessments, and informants completed the Cambridge Behavioral Inventory-Revised (CBI-R). Patients were rated according to MCI criteria, including amnestic and non-amnestic subtypes, or as being cognitively intact. CBI-R ratings were evaluated with respect to MCI diagnosis and neuropsychological performance.Results: Compared to cognitively intact individuals, informants rated patients with MCI as having significantly more change in overall functioning (p < 0.05) as well as in specific domains of memory and orientation (p < 0.01), everyday skills (p < 0.05), and motivation (p < 0.05), even after controlling for depressive symptom severity. In further analyses, the non-amnestic MCI subgroup only had more informant-rated mood changes compared to the amnestic subgroup. In relation to neuropsychological performance, informant ratings were related to poorer visual memory, verbal learning and memory, language, and psychomotor speed, with correlations ranging from –0.19 to –0.43 (p < 0.05).Conclusions: These findings indicate that informants are sensitive to subtle early cognitive change in individuals with MCI, and that their ratings are related to objectively measured neuropsychological performance. Thus, the CBI-R may be valuable in assisting early screening and intervention processes.

The concept of differing clinical phenotypes within Parkinson’s disease (PD) is well represented in the literature. However, there is no consensus as to whether any particular disease phenotype is associated with an increased risk of mild cognitive impairment (MCI) using the newly proposed Movement Disorders Society diagnostic criteria for this feature. To explore the expression of PD-MCI in relation to the heterogeneity of idiopathic PD. A cluster analysis incorporating a range of specific demographic, clinical and cognitive variables was performed on 209 patients in the early stages of PD (between Hoehn and Yahr stages I–III). Post hoc analyses exploring variables not included in the clustering solution were performed to interrogate the veracity of the subgroups generated. This study identified four distinct PD cohorts: a younger disease-onset subgroup, a tremor dominant subgroup, a non-tremor dominant subgroup, and a subgroup with rapid disease progression. The present study identified a differential expression of PD-MCI across these subgroups, with the highest frequency observed in the non-tremor dominant cluster. The non-tremor dominant subgroup was also associated with a higher prevalence of freezing of gait, hallucinations, daytime somnolence, and rapid eye movement sleep behavior disorder compared with other subgroups. This study confirms the existence of heterogeneity within the early clinical stages of PD and for the first time highlights the differential expression of PD-MCI using the newly defined diagnostic criteria for this feature. An improved understanding of PD-MCI and its clinical relationships may lead to an improved understanding of the pathophysiology underlying heterogeneity in PD. A subset of patients with Parkinson’s disease (PD) shows a higher frequency of mild cognitive impairment (MCI). Disease pathways underlying cognitive symptoms of PD are not well understood, making it difficult to determine which patients are at highest risk. Researchers in Australia led by Simon Lewis at the University of Sydney analyzed cognitive and other variables in 209 patients with early stage PD, using new diagnostic criteria proposed by the International Parkinson and Movement Disorder Society. The team confirmed that patients could be divided into four groups: younger onset, tremor dominant, non-tremor dominant (NTD), and rapid disease progression. The NTD subgroup showed the highest frequency of MCI (54%), combined with a higher prevalence of other symptoms. Improving understanding of MCI in PD may therefore help to identify patients who would benefit from dementia intervention strategies.

Freezing of gait is a poorly understood symptom of Parkinson's disease (PD) that is commonly accompanied by executive dysfunction. This study employed an antisaccade task to measure deficits in inhibitory control in patients with freezing, and to determine if these are associated with a specific pattern of grey matter loss using voxel-based morphometry. PD patients with (n = 15) and without (n = 11) freezing along with 10 age-matched controls were included. A simple prosaccade task was administered, followed by a second antisaccade task that required subjects to either look towards or away from a peripheral target. Behavioral results from the antisaccade task were entered as covariates in the voxel-based morphometry analysis. Patient and control groups performed equally well on the first task. However, patients with freezing were significantly worse on the second, which was driven by a specific impairment in suppressing their responses toward the target on the antisaccade trials. Impaired antisaccade performance was associated with grey matter loss across bilateral visual and fronto-parietal regions. These results suggest that patients with freezing have a significant deficit of inhibitory control that is associated with volume reductions in regions crucial for orchestrating both complex motor behaviors and cognitive control. These findings highlight the inter-relationship between freezing of gait and cognition and confirm that dysfunction along common neural pathways is likely to mediate the widespread cognitive dysfunction that emerges with this symptom.

Background: Interest in electronic health (eHealth) technologies to screen for and treat a variety of medical and mental health problems is growing exponentially. However, no studies to date have investigated the feasibility of using such e-tools for older adults with mild cognitive impairment (MCI) or dementia. Objective: The objective of this study was to describe patterns of Internet use, as well as interest in and preferences for eHealth technologies among older adults with varying degrees of cognitive impairment. Methods: A total of 221 participants (mean age=67.6 years) attending the Healthy Brain Ageing Clinic at the University of Sydney, a specialist mood and memory clinic for adults ≥50 years of age, underwent comprehensive clinical and neuropsychological assessment and completed a 20-item self-report survey investigating current technology use and interest in eHealth technologies. Descriptive statistics and Fisher exact tests were used to characterize the findings, including variability in the results based on demographic and diagnostic factors, with diagnoses including subjective cognitive impairment (SCI), MCI, and dementia. Results: The sample comprised 27.6% (61/221) SCI, 62.0% (137/221) MCI, and 10.4% (23/221) dementia (mean Mini-Mental State Examination=28.2). The majority of participants reported using mobile phones (201/220, 91.4%) and computers (167/194, 86.1%) routinely, with most respondents having access to the Internet at home (204/220, 92.6%). Variability was evident in the use of computers, mobile phones, and health-related websites in relation to sociodemographic factors, with younger, employed respondents with higher levels of education being more likely to utilize these technologies. Whereas most respondents used email (196/217, 90.3%), the use of social media websites was relatively uncommon. The eHealth intervention of most interest to the broader sample was memory strategy training, with 82.7% (172/208) of participants reporting they would utilize this form of intervention. Preferences for other eHealth interventions varied in relation to educational level, with university-educated participants expressing greater interest in interventions related to mood (P=.01), socialization (P=.02), memory (P=.01), and computer-based exercises (P=.046). eHealth preferences also varied in association, with diagnosis for interventions targeting sleep (P=.01), nutrition (P=.004), vascular risk factors (P=.03), and memory (P=.02). Conclusions: Technology use is pervasive among older adults with cognitive impairment, though variability was noted in relation to age, education, vocational status, and diagnosis. There is also significant interest in Web-based interventions targeting cognition and memory, as well as other risk factors for cognitive decline, highlighting the urgent need for the development, implementation, and study of eHealth technologies tailored specifically to older adults, including those with MCI and early dementia. Strategies to promote eHealth use among older adults who are retired or have lower levels of education will also need to be considered.

Freezing of gait (FOG) is a disabling motor symptom experienced by a large proportion of patients with Parkinson’s disease (PD). While it is known that FOG contributes to lower health-related quality of life (HRQoL), previous studies have not accounted for other important factors when measuring the specific impact of this symptom. The aim of this study was to examine FOG and HRQoL while controlling for other factors that are known to impact patient well-being, including cognition, motor severity, sleep disturbance and mood. Two hundred and three patients with idiopathic PD (86 with FOG) were included in the study. All patients were between Hoehn and Yahr stages I–III. A forced entry multiple regression model evaluating the relative contribution of all symptoms was conducted, controlling for time since diagnosis and current dopaminergic treatment. Entering all significantly correlated variables into the regression model accounted for the majority of variance exploring HRQoL. Self-reported sleep–wake disturbances, depressive and anxious symptoms and FOG were individually significant predictors. FOG accounted for the highest amount of unique variance. While sleep–wake disturbance and mood have a significant negative impact on HRQoL in PD, the emergence of FOG represents the most substantial predictor among patients in the earlier clinical stages of disease. This finding presumably reflects the disabling loss of independence and fear of injury associated with FOG and underlines the importance of efforts to reduce this common symptom.

Aims: To examine the rates and clinical characteristics of mild cognitive impairment (MCI) in older people with depressive symptoms and to determine the relative contribution of hippocampal volume and MCI to memory change. Method: One hundred and fifty-two participants with lifetime Major Depression and remitted or mild symptoms and 28 healthy controls underwent psychiatric and neuropsychological assessments. Magnetic resonance imaging was also conducted in a subset of the patients (n = 81) and healthy controls (n = 18). Results: MCI was diagnosed in 75.7% of the patients and was associated with increasing age, medical burden, vascular risk factors, later age of depression onset and smaller hippocampi. Multiple regression showed that both hippocampal volume and MCI diagnosis mediate memory performance in depression. Conclusions: MCI occurs in older adults with a history of depression and is not simply due to symptom severity. Memory change is linked to underlying hippocampal atrophy in this patient group.

Background: With predicted increases in dementia incidence, interventions targeting neuroplasticity and neuroprotection are required. Cognitive Training (CT) is an intervention which has been shown to improve aspects of cognition, but the pathophysiological mechanisms contributing to its efficacy are unknown. Objective: We aimed to explore the neurobiological correlates of CT using Mismatch Negativity (MMN), a neurophysiological marker of pre-attentive information processing, which in turn, is postulated to underpin higher-order cognitive processes. Methods: As part of a larger randomized controlled trial, forty 'at risk' (i.e., mild cognitive impairment or late-life depression) participants aged 51-79 years underwent neurophysiological, neuropsychological, and psychiatric assessments before and after a multi-faceted seven-week CT program or a 'treatment-as-usual' seven-week waitlist period. Results: The treatment group demonstrated significantly increased fronto-central MMN responses (p < 0.05), as well as improved phonemic verbal fluency (p < 0.05) and decreased self-rated memory difficulties (p < 0.05) following CT, in comparison to the waitlist control group. However, there were no significant correlations between enhanced MMN and cognitive/psychosocial outcomes. Conclusions: Results from this preliminary investigation indicate that CT is associated with enhanced neurophysiological mechanisms suggestive of improved pre-attentive processing, which may reflect alterations in underlying neurobiology. Further research is warranted to confirm these findings, to explicate whether CT is associated with restorative or compensatory neuroplastic processes and to determine whether MMN is a useful biomarker for treatment response. © 2014 - IOS Press and the authors. All rights reserved.

Over the past two decades, within the field of healthy ageing and dementia prevention there has been a substantial growth of interest in the potential of cognitive training (CT) interventions (see Figure 1). Whilst various studies have employed different methodologies, generally the term refers to programs which provide theoretically driven skills and strategies, involving guided practice on tasks reflecting specific cognitive functions (Mowszowski et al., 2010). The focus of such interventions is to improve functioning of particular cognitive skills such as memory, working memory, attention, and executive functions, as decline in these or other cognitive domains may lead to functional impairment in day-to-day activities as well as contribute to reduced quality of life and disability (Salthouse, 2004). Improvements in these cognitive abilities may lead to more effective or independent functioning and may be instigated through various CT approaches including repetitive computerized exercise, pen and paper tasks, and clinically-driven strategy learning.

Freezing of gait (FOG) is a complex motor symptom of Parkinson's disease that manifests as an inability to generate effective gait, leading to a significant falls risk and a severe impact on quality of life. Research into effective treatment options has provided relatively limited benefits and is often hindered by substantial limitations. In this article, current treatment and research options are briefly discussed and a proposal for the further exploration of non-invasive therapeutic approaches is given. Recent advances in the literature continue to identify a pattern of selective executive dysfunction in patients with freezing of gait and such findings highlight a possible common underlying pathophysiology. Therefore, cognitive training is of particular interest as it may be able to improve executive processes thus reducing the manifestation of FOG. This article focuses on the existing evidence for such intervention strategies and proposes that targeted cognitive training may offer a novel treatment option for FOG that is worthy of an increased research focus.

With estimates of dementia expected to rise over the coming decades, there is interest in understanding the factors associated with promoting neuroprotection and limiting neurodegeneration. In this study, we examined the change in the volume of the hippocampus over a 2-month period in 34 older people “at risk” of cognitive decline (mean age = 66.8 years, 38% male). Factors that were examined included cognitive reserve, neuropsychological functioning, depression as well as a lifestyle (cognitive training) intervention. The results showed that over a 2-month period, increases in hippocampal size were associated with having higher premorbid intellect, greater occupational attainment, superior memory, and higher levels of functioning. Conversely, depression and disability were associated with decreases in hippocampal volume. Cognitive training was not associated with changes in hippocampal volume. These findings suggest that factors associated with cognitive reserve, cognition and depression may play an integral pathophysiological role in determining hippocampal volumes in “at-risk” older adults.

This study aimed to evaluate the efficacy of a multifactorial 'healthy brain ageing cognitive training program' for Parkinson's disease. Using a single-blinded waitlist control design, 50 participants with Parkinson's disease were recruited from the BrainMind Research Institute, Sydney, Australia. The intervention encompassed both psychoeducation and cognitive training; each component lasted 1-hour. The 2-hour sessions were delivered in a group format, twice-weekly over a 7-week period. Multifactorial psychoeducation was delivered by a range of health professionals. In addition to delivering cognitive strategies, it targeted depression, anxiety, sleep, vascular risk factors, diet, and exercise. Cognitive training was computer-based and was conducted by clinical neuropsychologists. The primary outcome was memory. Secondary outcomes included other aspects of cognition and knowledge pertaining to the psychoeducation material. Results demonstrated that cognitive training was associated with significant improvements in learning and memory corresponding to medium to large effect sizes. Treatment was also associated with medium effect size improvements in knowledge. Although the study was limited by the lack of randomized allocation to treatment and control groups, these findings suggest that a healthy brain ageing cognitive training program may be a viable tool to improve memory and/or slow cognitive decline in people with Parkinson's disease. It also appeared successful for increasing awareness of adaptive and/or compensatory cognitive strategies, as well as modifiable risk factors to optimize brain functioning.

Neuroanatomical evidence suggests that the human brain has dedicated pathways to rapidly process threatening stimuli. This processing bias for threat was examined using the repetition blindness (RB) paradigm. RB (i.e., failure to report the second instance of an identical stimulus rapidly following the first) has been established for words, objects and faces but not, to date, facial expressions.78 (Study 1) and 62 (Study 2) participants identified repeated and different, threatening and non-threatening emotional facial expressions in rapid serial visual presentation (RSVP) streams.In Study 1, repeated facial expressions produced more RB than different expressions. RB was attenuated for threatening expressions. In Study 2, attenuation of RB for threatening expressions was replicated. Additionally, semantically related but non-identical threatening expressions reduced RB relative to non-threatening stimuli.These findings suggest that the threat bias is apparent in the temporal processing of facial expressions, and expands the RB paradigm by demonstrating that identical facial expressions are susceptible to the effect.

Mild cognitive impairment (MCI) refers to a transitory state between healthy aging and dementia. Biomarkers are needed to facilitate early identification of MCI and predict progression to dementia. One potential neurophysiological biomarker, mismatch negativity (MMN), is an event-related potential reflecting fundamental, pre-attentive cognitive processes. MMN is reduced in normal aging and dementia and in neuropsychiatric samples and is associated with verbal memory deficits and poor executive functioning. This study aimed to investigate auditory MMN and its relationship to neuropsychological performance in MCI. Twenty-eight MCI participants and fourteen controls, aged ≥50 years, underwent neurophysiological and neuropsychological assessment, and completed questionnaires pertaining to disability. Relative to controls, the MCI group demonstrated reduced temporal MMN amplitude (p < 0.01). Reduced right temporal MMN was significantly associated with poorer verbal learning (r = 0.496; p < 0.01) and reduced left temporal MMN was significantly associated with increased self-reported disability (r = -0.419; p < 0.05). These results indicate that patients with MCI exhibit altered pre-attentive information processing, which in turn is associated with memory and psychosocial deficits. These findings overall suggest that MMN may be a viable neurophysiological biomarker of underlying disease in this 'at risk' group.

Depression in older people has been consistently linked with a variety of neurobiological brain changes. One measure of preattentive auditory processing, the mismatch negativity (MMN), has not been previously examined in late-life depression. This study examined MMN elicited by duration deviant stimuli in older people with lifetime depression, and explored its relationship with neuropsychological functioning and disability.Twenty-two older health-seeking patients (mean age=65.2 years) with lifetime major depressive disorder and twelve age and sex-matched control participants (mean age=64.6 years) completed detailed clinical and neuropsychological assessments and the WHO-DAS as a measure of disability. MMN amplitudes were elicited using a two-tone passive auditory oddball paradigm and measured at frontal (Fz), central (Cz) and temporal (left and right mastoid: M1 and M2, respectively) sites.Patients with depression demonstrated reduced mean MMN amplitude at temporal (M1, t=3.1, p0.01; M2, t=3.8, p0.01), but not fronto-central sites. Reduced temporal MMN amplitudes did not relate to depressive symptom severity, but were associated with reduced semantic fluency and greater self-rated functional disability.The contribution of depressive symptom 'state' and medications on MMN need to be considered.Reduced mean amplitudes of mastoid MMN in older patients with lifetime depression may reflect underlying brain changes. This preattentive marker relates to neuropsychological probes of frontotemporal circuits, and importantly, is associated with disability. Longitudinal analysis of MMN in this group will determine its predictive utility as a biomarker for ongoing cognitive decline and illness chronicity.