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Although standing plantar perception training (SPPT) may improve standing postural stability, the underlying neural mechanisms remain unclear. The authors investigated the relationship between regional cortical responses to SPPT using a balance pad and training outcomes in 32 older participants (mean ± SD:72.2 ± 6.0, range:60–87). Regional cortical activity was measured in the bilateral supplementary motor area, primary sensorimotor area, and parietal association area using near-infrared spectroscopy. Postural sway changes were compared before and after SPPT. Changes in two-point plantar discrimination and regional cortical activity during SPPT, associated with standing postural stability improvements, were examined using multiple regression and indicated improved standing postural stability after SPPT (p

A link has been suggested between somatic anxiety (SA) and insomnia in the cognitive model of chronic insomnia. This cross-sectional study examined if the possible link between insomnia symptoms and SA is related to an increased dosage of hypnotics/anxiolytics and poor clinical outcome in residual major depressive disorder (MDD). We studied 72 MDD outpatients, in partial or complete remission, enrolled in a rehabilitation program. Contributory subscales of the Hamilton Depression Rating Scale for residual symptoms were identified using principal component analysis. Unfavorable effects of SA × insomnia interaction on GABAergic pharmacotherapy and the probability of remission were assessed using moderation analysis. Patients with insomnia symptoms (43%) were less likely to achieve remission than those without. Residual symptoms formed the first component, and insomnia symptoms alone formed the second component (R2X = .33, Q2 = .09). The presence of insomnia symptoms was associated with an increase in SA (p = .048) but not with core depression or somatic symptoms. The SA × insomnia interaction was associated not only with increased hypnotic (b = –2.30, p = .014) and anxiolytic (b = 9.78, p = .002) dosages but also with a lower probability of remission (b = 1.18, p = .037). These results suggest a mutual detrimental interaction between SA and insomnia symptoms for maintaining residual MDD. Addressing the link between SA and insomnia symptoms may be important for effectively treating MDD.

BACKGROUND: Temporal processing, crucial to guide behavior toward a goal, may have a role in forming a depressive episode, yet it remains unclear which properties of temporal processing are central to antidepressant response. Production of a short duration oscillates in a circadian manner. Altered circadian organization of physiology and behavior are a hallmark of bipolar disorder. We thus tested whether circadian dynamics of time production associate with treatment response in bipolar disorder. METHODS: Over the three cycles of total sleep deprivation combined with light therapy (chronotherapeutics) in one week, 20 inpatients with a major depressive episode in the course of bipolar disorder produced 10s and rated their subjective mood and vigilance levels repeatedly. RESULTS: Eleven patients (58%) among 19 completers achieved remission. Produced time intervals (PTIs) fluctuated more synchronously with mood levels (r=-0.77) than vigilance levels (r=-0.59) during treatment. A higher degree of shortening of PTIs, but not changes in mood or vigilance levels, during the initial 24-h period of treatment predicted better response (LR χ2=4.58, P=0.032). Strong opposite daily changes for PTIs and mood levels observed at baseline were both attenuated after treatment only in remitters (F=7.25, P=0.015). LIMITATIONS: Potential external confounders that affect time perception were not controlled. CONCLUSIONS: The results are the first to demonstrate an association of the circadian properties of time perception with antidepressant effects of chronotherapeutics and suggest the potential utility of time production in predicting clinical outcome of bipolar depression.

This study aimed to determine whether both subjective sleep quality and sleep duration are directly associated with quality of life (QOL), as well as indirectly associated with QOL through insomnia symptoms. Individuals aged 20–69 years without mental illness (n = 9305) were enrolled in this web-based cross-sectional survey. The Short Form-8 was used to assess physical and mental QOL. We used the Pittsburgh Sleep Quality Index (PSQI) and extracted items related to subjective sleep quality and sleep duration. Insomnia symptoms were also extracted from the PSQI. The hypothesized models were tested using structural equation modeling. Worse sleep quality, but not shorter sleep duration, was related to worse physical QOL. Both worse sleep quality and shorter sleep duration were related to worse mental QOL. Insomnia symptoms mediated these relationships. Subgroup analyses revealed a U-shaped relationship between sleep duration and physical/mental QOL. However, the relationship between sleep quality and physical/mental QOL was consistent regardless of sleep duration. The results suggest that subjective sleep quality has a more coherent association with QOL than subjective sleep duration. Because of its high feasibility, a questionnaire on overall sleep quality could be a useful indicator in future epidemiological studies of strategies for improving QOL.

ObjectivesThere are numerous reports on the psychological burden of medical workers after the COVID-19 outbreak; however, no study has examined the influence of developmental characteristics on the mental health of medical workers. The objective of this study was to examine whether the developmental characteristics of medical workers are associated with anxiety and depression after the COVID-19 outbreak.DesignWe conducted an online cross-sectional questionnaire survey in October 2020.Participants and settingThe data of 640 medical workers were analysed. The questionnaire included items on sociodemographic data, changes in their life after the COVID-19 outbreak and symptoms of depression, anxiety, attention-deficit/hyperactivity disorder (ADHD) traits and autism spectrum disorder traits.Main outcomesDepression symptoms were assessed by the Patient Health Questionnaire-9 and anxiety symptoms were assessed by the Generalised Anxiety Disorder-7. A series of hierarchical multiple regression analyses were performed to test the effects of developmental characteristics on depression and anxiety symptoms after controlling for sociodemographic factors and changes in participants’ lives after the COVID-19 outbreak.ResultsIncreases in physical and psychological burden were observed in 49.1% and 78.3% of the subjects, respectively. The results of a multiple regression analysis showed that ADHD traits were significantly associated with both depression (β=0.390, pConclusionGlobally, the burden on medical workers increased. This study suggested that medical workers with higher ADHD traits may need special attention during the COVID-19 pandemic.

Associations of sleep duration with human health could differ depending on whether sleep is restorative. Using data from 5804 participants of the Sleep Heart Health Study, we examined the longitudinal association of sleep restfulness combined with polysomnography-measured total sleep time (TST) or time in bed (TIB), representing different sleeping behaviors, with all-cause mortality. Among middle-aged adults, compared with restful intermediate TST quartile, the lowest TST quartile with feeling unrested was associated with higher mortality (hazard ratio [HR], 1.54; 95% confidence interval [CI] 1.01–2.33); the highest TST quartile with feeling rested was associated with lower mortality (HR, 0.55; 95% CI 0.32–0.97). Among older adults, the highest TIB quartile with feeling unrested was associated with higher mortality, compared with restful intermediate TIB quartile (HR, 1.57; 95% CI 1.23–2.01). Results suggest a role of restorative sleep in differentiating the effects of sleep duration on health outcomes in midlife and beyond.

Bright light (BL) therapy is clinically utilized for treatment of sleep–wake disorders through the manipulation of circadian oscillation. It is also extended to depressive disorders including seasonal affective disorder through emotional regulation. Recently, it has been suggested that BL facilitates memory encoding and consolidation via another psychophysiological mechanism of perceptual information processing in the brain. In particular, BL can help to alleviate stress associated with processing of fear memories. In this study, we explored a potential application of BL for treatment of stress-induced and fear circuitry disorders in patients receiving exposure-based cognitive behavioral therapy (CBT). Fourteen patients with panic disorder (PD) or posttraumatic stress disorder (PTSD) were enrolled in a single-blind, randomized control trial to assess BL exposure (8000-lux, 30 min, 9 times, 2 weeks apart) compared to sham light (SL) exposure (800-lux, the same duration and frequency), while patients were concurrently receiving exposure-based CBT. The State Trait Anxiety Index (STAI) and the self-rating version of Montgomery–Asberg Depression Rating Scale (MADRS-S) assessed anxiety-related severity scores before and after therapy. After dropouts, 10 participants remained. STAI and MADRS-S scores showed a significantly greater reduction in the BL group than in the SL group. BL may be an effective augmentative therapy when used with exposure-based CBT for PD and PTSD patients. Future trials with larger sample sizes that are adequately statistically powered are required to confirm these preliminary findings.

Background:Cognitive behavioral therapy for insomnia (CBT-I) is a first-line therapy for insomnia disorders. We assessed changes in discrepancies between subjective and objective sleep measures and correlations between discrepancy changes and clinical insomnia severity for CBT-I in patients with primary insomnia METHODS: Fifty-two outpatients (mean age, 60.3 years; 26 women) with primary insomnia were treated by individual CBT-I (50 min, maximum six sessions, once every 1-2 weeks). One week before and after CBT-I, patients recorded a sleep log and wore an actigraphy device. Subjective and objective time in bed (TIB), total sleep time (TST), sleep-onset latency (SOL), wake time after sleep onset (WASO), and sleep efficiency (SE) were evaluated by averaging 1-week records. Relative values of sleep discrepancy in TIB, TST, SOL, WASO, and SE were calculated for estimating effects of CBT-I. The therapeutic effects were also evaluated using psychological scales before and after CBT-I., Results:Subjective and objective discrepancies in sleep measures decreased by 36, 25, and 37 min in TST, SOL, and WASO, respectively, and 7% in SE (all P < 0.001) after CBT-I. Seven patients transitioned from underestimating SE before CBT-I to overestimating SE after CBT-I. Although CBT-I improved relative values of discrepancy in WASO and SE, alongside ISI, the improvement in insomnia severity only correlated with SOL discrepancy., Conclusions:CBT-I may reduce the discrepancy between subjective and objective sleep measures in patients with primary insomnia. However, a greater therapeutic effect of CBT-I was observed in reducing the ISI, which was slightly influenced by improvements in sleep discrepancies.

Background To date, no previous studies have evaluated the relationship between sleep duration and quality of life (QOL) or depression in the general population after controlling for daytime sleepiness and sleep disturbances. Methods A web-based cross-sectional survey was conducted with 8698 subjects aged 20–69 years. We examined the relationships between weekday sleep duration and daytime sleepiness, sleep disturbance, QOL and depression, using the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index (without the item for sleep duration), 8-item Short Form and Center for Epidemiological Studies Depression Scale (CES-D). Results Daytime sleepiness tended to increase in proportion to shorter weekday sleep durations. Sleep disturbances, physical and mental QOL, and CES-D scores were worse in both the shorter and longer sleep groups compared with the group with 7–8 h of sleep. Hierarchical logistic regression analyses revealed that short sleep duration but not long sleep duration was significantly associated with reduction of both physical and mental QOL, even after controlling for the presence of daytime sleepiness and sleep disturbance. Both short and long sleep duration were independently and significantly correlated with depression after controlling for daytime sleepiness; however, there was no statistically significant association after adjusting for the effects of sleep disturbance. Conclusions The results suggested adverse effects of short sleep but not long sleep on both physical and mental QOL. In addition, the negative impact of specific types of sleep disturbance on depression may be greater than the impact of shortening of sleep duration.

Delayed encephalopathy (DE) affects not only the cerebral white matter and globus pallidus but also the cortex and thalamus. However, it remains unknown whether these brain lesions alter sleep along with clinical manifestations of DE. A 46-year-old man with DE underwent repetitive hyperbaric oxygen therapy. The patient was evaluated by not only neuropsychological and neuroimaging testing but polysomnography over the clinical course. Neurological symptoms improved markedly; however, profound frontal cognitive deficits continued. The polysomnography revealed prolonged absence and delayed recovery of sleep spindles across recordings. Alterations in spindle oscillations in DE could provide further insight into sleep regulatory networks.

Higher wake promotion against sleep drive boosts cognitive processing, but it also seems to increase the risk of insomnia by reinforcing an obsession with sleep in neurotic patients. To explore whether a personality trait of neuroticism simultaneously facilitates wake-promoting ability and sleep devaluation via a common regional prefrontal function under a sleep-restricted condition, working memory tasks were administered to 49 healthy humans after a 2-h sleep restriction. Higher wake-promoting ability demonstrated in a high-load task was correlated with lower bilateral prefrontal activation, as measured by near-infrared spectroscopy. Structural equation modeling revealed that neuroticism predicts sleep devaluation and wake-promoting ability via left and right regional prefrontal efficiency, respectively. Our results indicate that neuroticism-related neural efficiency increases resilience to sleepiness, but decreases sleep satisfaction.

The effectiveness of D-cycloserine (DCS), an N-methyl-D-aspartate glutamate receptor partial agonist, and valproic acid (VPA), a histone deacetylase inhibitor, in facilitating the extinction of fear-conditioned memory has been explored in humans and animals. Here, we confirmed whether DCS (100 mg) and VPA (400 mg) act in off-line learning processes during sleep or waking, for further clinical application to anxiety disorders and posttraumatic stress disorder (PTSD). We performed a randomized, blind, placebo-controlled clinical trial in 90 healthy adults. Visual cues and electric shocks were used as the conditioned stimulus (CS) and unconditioned stimulus (US), respectively. The extinction effect was observed not in simple recall after the extinction of coupled CS-US, but was observed in the post-re-exposure phase after unexpected re-exposure to reinstatement CS-US coupling. Newly acquired conditioned fear was also eliminated or habituated by DCS and VPA administration, in line with previous findings. Furthermore, VPA facilitated the off-line learning process of conditioned fear extinction and habituation during sleep, while DCS facilitated this process during waking. These novel findings suggest that DCS and VPA might enhance exposure-based cognitive therapy for anxiety disorders and PTSD by reducing the vulnerability to reinstatement and preventing relapses of fear-conditioned responses, and provide evidence for a peculiarity of the sleep-dependent off-line learning process for conditioned fear extinction. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

The sense of body ownership constantly adapts to new environments, and awareness of a distinction between oneself and others is a fundamental ability. However, it remains unclear whether plasticity in the sense of body ownership is dependent on genetic factors. The present study investigated the influence of the catechol-O-methyltransferase (COMT) Val158Met genotype on illusory learning of a sense of body ownership and dissociation. 76 healthy Japanese participants experienced the rubber hand illusion (RHI), which is produced by sensory integration of conflicting modalities, with the intent to experimentally alter objective perceived locations and subjective ownership ratings. We found that Val/Val homozygous participants had more intense RHI experiences than Val/Met heterozygous and Met homozygous participants. Furthermore, RHI sensation was correlated with a dissociative personality trait in Val/Val homozygous participants. Our findings indicate an interaction between COMT genotype, RHI sensation, and dissociative personality traits: Val/Val genotypes were associated with RHI induction and greater vulnerability to dissociation. The findings suggest that Val/Val homozygous individuals may be more flexible regarding self-attribution/body ownership and that biological factors may contribute to reduced awareness regarding the distinction between self and others.

Appropriate inhibitory response control is associated with goal-directed behavior. Sleep accelerates the offline consolidation of acquired motor skills that are explicitly predictable; however, the effect of sleep on implicit (unpredictable) motor skills remains controversial. We speculated that a key component of response inhibition skill differentiates between these skill consolidation properties because explicit prediction can minimize the inhibitory efforts in a motor skill. We explored the offline skill learning properties of response inhibition during sleep and wakefulness using auditory Go and Go/Nogo tasks. We attempted to discriminate the possible effects of time elapsed after training (12 or 24 h), post-training sleep/wake state (sleep or wakefulness) and time of day (nighttime or daytime) in 79 healthy human subjects divided into 6 groups that underwent various sleep regimens prior to training and retesting. We found that delayed response inhibition skill improvement was achieved via a simple passage of daytime, regardless of the participants’ alertness level. Our results suggest that sleep-independent neuroplasticity occurs during the daytime and facilitates a delayed learning of response inhibition skill.

Sleep deprivation immediately following an aversive event reduces fear by preventing memory consolidation during homeostatic sleep. This suggests that acute insomnia might act prophylactically against the development of posttraumatic stress disorder (PTSD) even though it is also a possible risk factor for PTSD. We examined total sleep deprivation and memory suppression to evaluate the effects of these interventions on subsequent aversive memory formation and fear conditioning. Active suppression of aversive memory impaired retention of event memory. However, although the remembered fear was more reduced in sleep-deprived than sleep-control subjects, suppressed fear increased and seemed to abandon the sleep-dependent plasticity of fear. Active memory suppression, which provides a psychological model for Freud's ego defense mechanism, enhances fear and casts doubt on the potential of acute insomnia as a prophylactic measure against PTSD. Our findings bring into question the role of sleep in aversive-memory consolidation in clinical PTSD pathophysiology.

Copyright: © 2013 Kuriyama K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Approximately 10-30% of individuals experience insomnia worldwide [1,2]. Chronic insomnia causes disturbances to nighttime sleep, including prolonged sleep latency, disturbance of sleep maintenance, and non-restorative sleep. It can also cause various Impairments of Daytime Functioning (IDFs) such as fatigue, mood disturbance, irritability, reduced motivation and interest, attention deficit, and memory impairment, with a consequent decline in occupational, social, or leisure quality [3]. A socioeconomic study has predicted that IDFs have a greater impact on the global economy rather than disturbances in night time sleep resulting from insomnia [4]. As a result, IDFs associated with insomnia have recently been a subject of particular interest. However, since the biological background and pathogeny of IDFs has not yet been clarified, they are not unconsidered in the differential diagnosis of insomnia subtypes in the latest version of the International Classification of Sleep Disorders (ICSD-2) [5], published in 2005. However, the criteria of “primary insomnia” in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) will be changed to “insomnia disorder” in the fifth edition (DSM-V) [6], which will be released in 2013 [7]. In line with this modification, IDFs will be clearly defined as specified sequelae based on specific biological vulnerabilities to illness, contrasting with the traditional, ambiguous definitions of IDFs.

Working memory (WM) capacity improvement is impacted by sleep, and possibly by N-methyl-D-aspartate (NMDA) agonists such as D-cycloserine (DCS), which also affects procedural skill performance. However, the mechanisms behind these relationships are not well understood. In order to investigate the neural basis underlying relationships between WM skill learning and sleep, DCS, and both sleep and DCS together, we evaluated training-retest performances in the n-back task among healthy subjects who were given either a placebo or DCS before the task training, and then followed task training sessions either with wakefulness or sleep. DCS facilitated WM capacity enhancement only occurring after a period of wakefulness, rather than sleep, indicating that WM capacity enhancement is affected by a cellular heterogeneity in synaptic plasticity between time spent awake and time spent asleep. These findings may contribute to development, anti-aging processes, and rehabilitation of higher cognition.

s / Brain Stimulation 8 (2015) 360e377 371 Discussion: This novel observation suggests that PFC stimulation via anodal tDCS may help in correcting deficits in antisaccade task performance. These preliminary findings suggest that enhancement of inhibitory function might be one of the mechanisms underlying the ameliorating effect of add-on tDCS on persistent auditory hallucinations in schizophrenia.