Neuropsychological effects of sleep loss: implication for neuropsychologists

Heat Exposure and Dementia-Related Mortality in China

Importance

Although existing research has found daily heat to be associated with dementia-related outcomes, there is still a gap in understanding the differing associations of nighttime and daytime heat with dementia-related deaths.

Objectives

To quantitatively assess the risk and burden of dementia-related deaths associated with short-term nighttime and daytime heat exposure and identify potential effect modifications.

Design, Setting, and Participants

This case-crossover study analyzed individual death records for dementia across all mainland China counties from January 1, 2013, to December 31, 2019, using a time-stratified case-crossover approach. Statistical analysis was conducted from January 1, 2013, to December 31, 2019.

Exposures

Two novel heat metrics: hot night excess (HNE) and hot day excess (HDE), representing nighttime and daytime heat intensity, respectively.

Main Outcomes and Measures

Main outcomes were the relative risk and burden of dementia-related deaths associated with HNE and HDE under different definitions. Analysis was conducted with conditional logistic regression integrated with the distributed lag nonlinear model.

Results

The study involved 132 573 dementia-related deaths (mean [SD] age, 82.5 [22.5] years; 73 086 women [55.1%]). For a 95% threshold, the median hot night threshold was 24.5 °C (IQR, 20.1 °C-26.2 °C) with an HNE of 3.7 °C (IQR, 3.1 °C-4.3 °C), and the median hot day threshold was 33.3 °C (IQR, 29.9 °C-34.7 °C) with an HDE of 0.6 °C (IQR, 0.5 °C-0.8 °C). Both nighttime and daytime heat were associated with increased risk of dementia-related deaths. Hot nights' associations with risk of dementia-related deaths persisted for 6 days, while hot days' associations with risk of dementia-related deaths extended over 10 days. Extreme HDE had a higher relative risk of dementia-related deaths, with a greater burden associated with extreme HNE at more stringent thresholds. At a 97.5% threshold, the odds ratio for dementia-related deaths was 1.38 (95% CI, 1.22-1.55) for extreme HNE and 1.46 (95% CI, 1.27-1.68) for extreme HDE, with an attributable fraction of 1.45% (95% empirical confidence interval [95% eCI], 1.43%-1.47%) for extreme HNE and 1.10% (95% eCI, 1.08%-1.11%) for extreme HDE. Subgroup analyses suggested heightened susceptibility among females, individuals older than 75 years of age, and those with lower educational levels. Regional disparities were observed, with individuals in the south exhibiting greater sensitivity to nighttime heat and those in the north to daytime heat.

Conclusions and Relevance

Results of this nationwide case-crossover study suggest that both nighttime and daytime heat are associated with increased risk of dementia-related deaths, with a greater burden associated with nighttime heat. These findings underscore the necessity of time-specific interventions to mitigate extreme heat risk.

Understanding the cognitive and neuroimaging bases underlying the detrimental impact of sleep deprivation on reciprocity

Although the impact of sleep loss on social behaviors has been widely observed in recent years, the mechanisms underpinning these impacts remain unclear. In this study, we explored the detrimental effects of sleep deprivation on reciprocity behavior as well as its underlying psychological and neuroimaging mechanisms by combining sleep manipulation, an interpersonal interactive game, computational modeling and neuroimaging. Our results suggested that after sleep deprivation, individuals showed reduced reciprocity behavior, mainly due to their reduced weights on communal concern when making social decisions. At neural level, we demonstrated that sleep deprivation's effects were observed in the precuneus (hyperactivity) and temporoparietal junction, dorsal lateral prefrontal cortex (DLPFC) (both hypoactivity), and reduced reciprocity was also accounted for by increased precuneus-thalamus connectivity and DLPFC-thalamus connectivity. Our findings contributed to the understanding of the psychological and neuroimaging bases underlying the deleterious impact of sleep deprivation on social behaviors.

Sleep quality and executive function in a diverse sample of healthy young adults

Few studies examine the relationship between sleep and executive function in diverse samples of young adults. Our research aims to fill this gap by analyzing how self-reported sleep quality is related to informant-rated executive function as a whole and its working memory component in a diverse sample of 29 healthy college students. Using the self-report measure, the Pittsburgh Sleep Quality Index (PSQI), we divided our sample into two groups based on cutoff criteria (score ≥5: poor sleep): good sleep quality (n = 11) and poor sleep quality (n = 18). Participants were on average 20.86 years old. Informants rated participants' executive functioning and working memory using the Frontal Systems Behavior Scale (FrSBe) and Behavior Rating Inventory of Executive Function (BRIEF). Individuals in the poor sleep quality group were reported as having significantly worse executive function and working memory scores. Young adult college students who report less than 7 hours of sleep per night have lower scores on informant measures of working memory and executive function. This study raises awareness about how self-reported sleep experiences are related to other's observation of cognitive abilities in everyday life in a diverse young adult sample.

Effects of age on the relationship between sleep quality and cognitive performance: Findings from the Human Connectome Project-Aging cohort

BACKGROUND

The association between sleep quality and cognition is widely established, but the role of aging in this relationship is largely unknown.

OBJECTIVE

To examine how age impacts the sleep-cognition relationship and determine whether there are sensitive ranges when the relationship between sleep and cognition is modified. This investigation could help identify individuals at risk for sleep-related cognitive impairment.

SUBJECTS

Sample included 711 individuals (ages 36.00-89.8359.66 ± 14.9155.7 % female) from the Human Connectome Project-Aging (HCP-A).

METHODS

The association between sleep quality (Pittsburgh Sleep Quality Index, PSQI) and cognition (Crystallized Cognition Composite and Fluid Cognition Composite from the NIH Toolbox, the Trail Making Test, TMT, and the Rey Auditory Verbal Learning Test, RAVLT) was measured using linear regression models, with sex, race, use of sleep medication, hypertension, and years of education as covariates. The interaction between sleep and age on cognition was tested using the moderation analysis, with age as both continuous linear and nonlinear (quadratic) terms.

RESULTS

There was a significant interaction term between the PSQI and nonlinear age term (age2) on TMT-B (p = 0.02) and NIH Toolbox crystallized cognition (p = 0.02), indicating that poor sleep quality was associated with worse performance on these measures (sensitive age ranges 50-75 years for TMT-B and 66-70 years for crystallized cognition).

CONCLUSIONS

The sleep-cognition relationship may be modified by age. Individuals in the middle age to early older adulthood age band may be most vulnerable to sleep-related cognitive impairment.

It's complicated: Executive functioning moderates impacts of daily busyness on everyday functioning in community-dwelling older adults

OBJECTIVE

Research shows that cognitively healthy older adults with mild executive function (EF) weaknesses are vulnerable to the negative impacts of life complexity (or daily busyness) when performing instrumental activities of daily living (IADLs). However, past research assessed life complexity only at one timepoint, not capturing daily fluctuations. Importantly, fluctuations in busyness can themselves have deleterious impacts on functioning. This study extended past research by examining whether (1) variability in daily busyness would be more detrimental than level of busyness to performance of IADLs, and (2) EF assessed at home would moderate deleterious impact of busyness on IADLs.

METHOD

Fifty-two community-dwelling older adults aged 60 to 95 completed daily IADL tasks and daily measures of EF and busyness via ecological momentary assessment, independently at home for 18 days.

RESULTS

(1) In a subset of participants with mild EF weaknesses, high variability in busyness across days was associated with fewer tasks completed correctly; and (2) across all participants (regardless of EF), high levels of daily busyness were associated with fewer tasks completed on time.

CONCLUSIONS

Findings indicate that high variability in daily busyness, potentially reflecting a lack of daily routine, was associated with IADL errors among cognitively healthy older adults with mild EF weaknesses. Additionally, consistently high levels of busyness were associated with failures to complete tasks, or failures to complete them on time, regardless of EF. These results further support the Contextually Valid Executive Assessment (ConVExA) model, which posits that EF and contextual factors interact to predict functional outcomes.

Association between impulsivity and cognitive capacity decrease is mediated by smartphone addiction, academic procrastination, bedtime procrastination, sleep insufficiency and daytime fatigue among medical students: a path analysis

BACKGROUND

Medical students are at high risk for sleep disturbance. One possible cause of their sleeping problem is impulsivity. We aim to investigate the possible mediators between medical students' impulsivity and sleep outcomes. Thus, we developed and investigated a model where the predictors were attentional, non-planning, and motor impulsivity subtraits. In the final model, subjective cognitive capacity decrease was the outcome variable. In light of previous findings, academic procrastination, smartphone addiction, and bedtime procrastination were considered important mediators as well as two variables of poor sleep, sleeping insufficiency, and daytime fatigue.

METHODS

Medical students (N = 211; age_M = 22.15 years; age_SD = 3.47 years; 71.6% women) were recruited to complete an online survey comprised of demographics (age, gender), self-administered scales (Abbreviated Impulsiveness Scale, Bedtime Procrastination Scale, Abbreviated Impulsiveness Scale, Academic Procrastination Scale-Short Form) and questions on tiredness, daily fatigue and subjective cognitive capacity decrease. Correlation and path analyses were implemented to examine hypothesized relationships between the variables.

RESULTS

Both attentional impulsivity (β = 0.33, p < .001) and non-planning impulsivity (β = -0.19, p < .01) had a direct relationship with cognitive capacity decrease. Attentional impulsivity was also associated with decreased cognitive capacity with a serial mediation effect via smartphone addiction, academic procrastination, bedtime procrastination, sleep insufficiency and fatigue (estimate = 0.017, p < .01). The indirect link between non-planning impulsivity and cognitive capacity decrease was mediated by academic procrastination, bedtime procrastination, sleep insufficiency and fatigue (estimate = 0.011, p < .01).

CONCLUSIONS

Inability to stay focused and plan tasks effectively (directly and indirectly) predicts poor sleep outcomes. This relationship is mediated by excessive smartphone use, academic procrastination, and bedtime procrastination. Our findings are relevant in light of self-regulatory learning, which is crucial in medical education. This is a recursive cycle of planning, emotion regulation, proper strategy selection and self-monitoring. Future interventions addressing attentional and non-planning impulsivity, problematic smartphone use, academic procrastination, and in turn, bedtime procrastination might make this routine more effective. In the conclusion section, practical implications of the results are discussed.

Prospective Implications of Insufficient Sleep for Athletes

CONTEXT

Poor sleep is common in collegiate student-athletes and is associated with heterogeneous self-reported complaints at baseline. However, the long-term implications of poor sleep at baseline have been less well studied.

OBJECTIVE

To examine the implications of insufficient sleep at baseline, as well as factors such as symptom reporting and neurocognitive performance at baseline associated with insufficient sleep, for the risk of sport-related concussion (SRC).

DESIGN

Cross-sectional study.

SETTING

Undergraduate institution.

PATIENTS OR OTHER PARTICIPANTS

Student-athletes (N = 614) were divided into 2 groups based on the hours slept the night before baseline testing: sufficient (>7.07 hours) or insufficient (≤5.78 hours) sleepers. Athletes who went on to sustain an SRC during their athletic careers at our university were identified.

MAIN OUTCOME MEASURE(S)

Four symptom clusters (cognitive, physical, affective, and sleep) and headache were examined as self-reported outcomes. Four neurocognitive outcome measures were explored: mean composite of memory, mean composite of attention/processing speed, memory intraindividual variability (IIV), and attention/processing speed IIV.

RESULTS

Insufficient sleepers at baseline were nearly twice as likely (15.69%) as sufficient sleepers (8.79%) to go on to sustain an SRC. Insufficient sleepers at baseline, whether or not they went on to sustain an SRC, reported a higher number of baseline symptoms than did sufficient sleepers. When compared with either insufficient sleepers at baseline who did not go on to incur an SRC or with sufficient sleepers who did go on to sustain an SRC, the insufficient sleep group that went on to incur an SRC performed worse at baseline on mean attention/processing speed.

CONCLUSIONS

The combination of insufficient sleep and worse attention/processing speed performance at baseline may increase the risk of sustaining a future SRC.

Functional Outcomes, Injury Variables, and Athlete Characteristics Associated with Post-Concussion Sleep Disturbance

OBJECTIVE

To examine the relationship between sleep disturbance and functional outcomes following a concussion. Also, to explore athlete and injury-related variables that may be related to risk factors for poor sleep following concussion.

METHOD

124 collegiate athletes completed a neuropsychological evaluation within 14 days of sustaining a sport-related concussion (SRC). Athletes were categorized as sleep disturbed (n = 52) or not sleep disturbed (n = 72). Outcome variables included symptom reports, cognitive performance (mean performance and variability), and mood (depression). Injury characteristics and athlete characteristics explored were loss of consciousness (LOC) associated with the injury, whether the athlete was immediately removed from play, and history of prior concussions.

RESULTS

Sleep disturbed athletes reported more symptoms, F(4, 119) = 7.82, p < 0.001, ƞ2 = 0.21, were more likely to be symptomatic at the time of testing, χ2(1, N = 124) = 19.79, p < 0.001, φ = 0.40, and were marginally more likely to experience clinically significant depression, χ2(1, N = 120) = 3.03, p = 0.08, φ = 0.16, than not sleep disturbed athletes. There were no cognitive differences between the groups, p > 0.05. A greater proportion of sleep disturbed athletes experienced LOC (30%) compared to not sleep disturbed athletes (13%), χ2(1, N = 118) = 4.99, p = 0.03, φ = -0.21.

CONCLUSION

Sleep disturbances following SRC are associated with a broad range of self-reported symptoms. LOC may be associated with an increased risk of developing sleep disturbances; alternatively, sleep disturbances may increase the risk of LOC following concussion.

Sleep characteristics and excessive daytime sleepiness in adolescents and adults: results from the birth cohorts of three Brazilian cities - RPS Consortium

OBJECTIVE

To describe the prevalence of insufficient sleep duration, long sleep latency, terminal or maintenance insomnia, subjective sleep quality, and excessive daytime sleepiness among participants of birth cohorts conducted in three Brazilian cities, and to evaluate differences in prevalence rates within cohorts according to sociodemographic characteristics.

METHODS

Cross-sectional analyses involving adolescents and adults participating in four birth cohorts conducted in Ribeirão Preto (RP78 and RP94), Pelotas (PEL93) and São Luís (SL97/98). Sleep duration, latency, terminal or maintenance insomnia, and subjective sleep quality were obtained through the Pittsburgh Sleep Quality Index; and excessive daytime sleepiness was assessed using the Epworth Sleepiness Scale. Differences in the prevalence of the outcomes were analyzed in each cohort according to sociodemographic characteristics (skin color, marital status, socioeconomic status, study and working at the time of the interview) stratified by sex.

RESULTS

Insufficient sleep duration was the most common outcome at the four cohorts, with higher frequency among men. Long latency was more frequently reported by young adult women in RP94 and PEL93 cohorts, and insomnia by women of the four cohorts, when compared to men of the same age. Women generally suffered more from excessive daytime sleepiness and evaluated the quality of their sleep more negatively than men. In addition to sex, being a student and working were associated with the largest number of outcomes in both sexes.

CONCLUSION

Sleep disorders are more prevalent in women, reinforcing the need for greater investment in sleep health in Brazil, without disregarding gender and socioeconomic determinants.

Association between rest-activity rhythm and cognitive function in the elderly: The U.S. National Health and Nutrition Examination Survey, 2011-2014

BACKGROUND

Circadian rhythm plays an essential role in various physiological and pathological processes related to cognitive function. The rest-activity rhythm (RAR) is one of the most prominent outputs of the circadian system. However, little is known about the relationships between RAR and different domains of cognitive function in older adults. The purpose of this study was to examine the relationships between RAR and various fields of cognitive function in older Americans.

METHODS

This study included a total of 2090 older adults ≥ 60 years old from the National Health and Nutrition Examination Survey (NHANES) in 2011-2014. RAR parameters were derived from accelerometer recordings. Cognitive function was assessed using the word learning subtest developed by the Consortium to Establish a Registry for Alzheimer's disease (CERAD W-L), the Animal Fluency Test (AFT) and the Digital Symbol Substitution Test (DSST). Linear regression was used to determine the relationships between RAR parameters (IS, IV, RA, L5, M10) and cognitive function scores (CERAD W-L, AFT, DSST).

RESULTS

After adjusting for potential confounders, lower IS and M10 were associated with lower CERAD W-L scores (P=0.033 and P=0.002, respectively). Weaker RA and higher L5 were associated with lower AFT scores (P<0.001 and P=0.001, respectively). And lower IS, RA, and higher L5 were associated with lower DSST scores (P=0.019, P<0.001 and P<0.001, respectively). In addition, the results of sensitivity analysis were similar to those of our main analyses. The main correlation results between the RAR indicators and cognitive function were robust.

CONCLUSIONS

This study suggested that the weakened and/or disrupted RAR was associated with cognitive decline in different domains in Americans over the age of 60.

Association of Food Intake with Sleep Durations in Adolescents from a Capital City in Northeastern Brazil

(1) Background: During adolescence, there are significant changes in food consumption, such as reducing the consumption of in natura or minimally processed foods and increasing the consumption of ultra-processed foods. Thus, eating habits can influence sleep duration and, consequently, affect the quality of life of young people. This study thus aims to estimate the association of consumption of in natura or minimally processed, processed, and ultra-processed foods with sleep durations in adolescents. (2) Methods: This is a cross-sectional study including 964 adolescents (18 to 19 years old) from the 1997 to 1998 birth cohort in São Luís, Maranhão. Food consumption was assessed using the food frequency questionnaire (FFQ) and stratified based on the NOVA classification. Sleep duration was verified using accelerometry in hours. The analysis of the association between the consumption of in natura or minimally processed, processedand ultra-processed foods with sleep durations in adolescents used crude and adjusted linear regression (by gender, age, skin color, education, economic class, work, consumption of alcohol, smoking, screen time, physical activity, use of illicit drugs, anxiety, depressive symptoms, and lean and fat mass). A directed acyclic graph (DAG) was used to determine the minimum set of adjustment factors. (3) Results: Of the 964 individuals evaluated, 52.0% were female. The mean sleep duration was 6 h (± 0.95). In the crude and adjusted analyses, no association was observed between food consumption according to the degree of processing and adolescent sleep durations. (4) Conclusion: There was no association between the consumption of in natura or minimally processed, processed, and ultra-processed foods with sleep durations.

Specific Sleep Health Domains as Predictors of Executive Function in Older Adults

OBJECTIVES

Sleep health and executive function are multifaceted constructs that decline with age. Some evidence suggests that poor sleep health may underlie declines in executive function, but this relationship is not consistently found in cognitively normal older adults. The authors systematically investigated distinct sleep health domain associations with specific aspects of executive function.

METHODS

Community-dwelling older adults completed clinical interviews, comprehensive neuropsychological assessments, and subjective sleep measures. Four sleep health domains were investigated: satisfaction/quality, sleep efficiency, sleep duration, and daytime sleepiness/fatigue. Hierarchical multiple regression analyses, adjusting for significant covariates, examined whether the sleep health domains differentially predicted executive function.

RESULTS

Separate analyses found that greater sleep efficiency was associated with better response inhibition, while greater daytime sleepiness/fatigue was associated with worse cognitive flexibility. Categorical differences in sleep duration indicated that average durations, compared with short and long durations, had better executive function performance across measures. Sleep satisfaction/quality was not statistically associated with executive function.

CONCLUSIONS

These findings have implications for sleep assessment and its intervention. Routine screening of sleep duration, efficiency, and daytime fatigue may be particularly useful in identifying those at greater risk of executive dysfunction. Targeting specific problems in sleep may serve to improve cognitive control and efficiency in older adults. Future research is warranted to establish the optimal hours of sleep duration for cognitive health.

The effects of night-time warming on mortality burden under future climate change scenarios: a modelling study

BACKGROUND

The health impacts of climate warming are usually quantified based on daily average temperatures. However, extra health risks might result from hot nights. We project the future mortality burden due to hot nights.

METHODS

We selected the hot night excess (HNE) to represent the intensity of night-time heat, which was calculated as the excess sum of high temperature during night time. We collected historical mortality data in 28 cities from three east Asian countries, from 1981 to 2010. The associations between HNE and mortality in each city were firstly examined using a generalised additive model in combination with a distributed lag non-linear model over lag 0-10 days. We then pooled the cumulative associations using a univariate meta-regression model at the national or regional levels. Historical and future hourly temperature series were projected under two scenarios of greenhouse-gas emissions from 1980-2099, with ten general circulation models. We then projected the attributable fraction of mortality due to HNE under each scenario.

FINDINGS

Our dataset comprised 28 cities across three countries (Japan, South Korea, and China), including 9 185 598 deaths. The time-series analyses showed the HNE was significantly associated with increased mortality risks, the relative mortality risk on days with hot nights could be 50% higher than on days with non-hot nights. Compared with the rise in daily mean temperature (lower than 20%), the frequency of hot nights would increase more than 30% and the intensity of hot night would increase by 50% by 2100s. The attributable fraction of mortality due to hot nights was projected to be 3·68% (95% CI 1·20 to 6·17) under a strict emission control scenario (SSP126). Under a medium emission control scenario (SSP245), the attributable fraction of mortality was projected to increase up to 5·79% (2·07 to 9·52), which is 0·95% (-0·39 to 2·29) more than the attributable fraction of mortality due to daily mean temperature.

INTERPRETATION

Our study provides evidence for significant mortality risks and burden in association with night-time warming across Japan, South Korea, and China. Our findings suggest a growing role of night-time warming in heat-related health effects in a changing climate.

FUNDING

The National Natural Science Foundation of China, Shanghai International Science and Technology Partnership Project.

Self-Reported Sleep Quality Across Age Modulates Resting-State Functional Connectivity in Limbic and Fronto-Temporo-Parietal Networks: An Exploratory Cross-Sectional fMRI Study

Sleep problems are increasingly present in the general population at any age, and they are frequently concurrent with—or predictive of—memory disturbances, anxiety, and depression. In this exploratory cross-sectional study, 54 healthy participants recruited in Naples (Italy; 23 females; mean age = 37.1 years, range = 20–68) completed the Pittsburgh Sleep Quality Index (PSQI) and a neurocognitive assessment concerning both verbal and visuospatial working memory as well as subjective measures of anxiety and depression. Then, 3T fMRI images with structural and resting-state functional sequences were acquired. A whole-brain seed-to-seed functional connectivity (FC) analysis was conducted by contrasting good (PSQI score <5) vs. bad (PSQI score ≥5) sleepers. Results highlighted FC differences in limbic and fronto-temporo-parietal brain areas. Also, bad sleepers showed an anxious/depressive behavioural phenotype and performed worse than good sleepers at visuospatial working-memory tasks. These findings may help to reveal the effects of sleep quality on daily-life cognitive functioning and further elucidate pathophysiological mechanisms of sleep disorders.

Association Between Sleep Disorders and Cognitive Impairment in Middle Age and Older Adult Hemodialysis Patients: A Cross-Sectional Study

Objective: The aims of the current study were to (1) explore the features of overall poor sleep and specific sleep disorders in Chinese middle age and older adult hemodialysis patients; (2) examine the association between sleep disorders and cognitive impairment (CI) in middle age and older patients undergoing hemodialysis in China.

Methods: Data of patients undergoing maintenance hemodialysis were collected from the prospective cohort study of CI in Chinese patients undergoing hemodialysis (Registered in Clinical Trials.gov, ID: NCT03251573). We included 613 patients (mean age = 63.7; SD = 7.8) in this study. We assessed sleep conditions using the Pittsburgh Sleep Quality Index (PSQI) questionnaire and cognitive function by the Chinese Beijing version of the Montreal Cognitive Assessment (MoCA-BJ) scale. Then the association between sleep disorders and CI was evaluated using multivariate logistic regression analysis.

Results: The prevalence of sleep disorders in this group of 613 hemodialysis patients was 77.0%. Patients with CI were more inclined to have sleep disorders in specific aspects of sleep latency, habitual sleep efficiency, sleep disturbances, and daytime dysfunction (p < 0.05). In multivariate logistic regression analyses, every 1-point increase in global PSQI score was associated with a 1.2-fold increased risk of CI (adjusted OR = 1.201; 95%CI = 1.123–1.284, p < 0.001). For each specific PSQI, every 1-point increase in sleep disturbances score was associated with a 2.6-fold increased risk of CI (adjusted OR = 2.624; 95%CI = 1.891–3.640, p < 0.001), and every 1-point increase in daytime dysfunction score was associated with a 3.7-fold increased risk of CI (adjusted OR = 3.709; 95%CI = 2.653–5.184, p < 0.001), whereas every 1-point increase in sleep duration score was associated with a decreased risk of CI (adjusted OR = 0.600; 95%CI = 0.434–0.830, p = 0.002).

Conclusion: Poor sleep quality especially sleep disturbances, daytime dysfunction, and long sleep duration are associated with CI in middle age and older adult hemodialysis patients. Thus, the early detection of sleep disorders may help identify patients with cognitive impairment among hemodialysis individuals.

Clinical Trial Registration: [Clinical Trials.gov], identifier [NCT03251573]

Sleep quality, neurocognitive performance, and memory self-appraisal in middle-aged and older adults with memory complaints

OBJECTIVE

Because of inconsistent findings regarding the relationship between sleep quality and cognitive function in people with age-related memory complaints, we examined how self-reports of sleep quality were related to multiple domains of both objective and subjective cognitive function in middle-aged and older adults.

DESIGN

A cross-sectional study involving analysis of baseline data, collected as part of a clinical trial.

MEASUREMENTS

Two hundred and three participants (mean age = 60.4 [6.5] years, 69.0% female) with mild memory complaints were asked to rate their sleep quality using the Pittsburgh Sleep Quality Index (PSQI) and their memory performance using the Memory Functioning Questionnaire (MFQ), which measures self-awareness of memory ability. Neurocognitive performance was evaluated using the Continuous Performance Test (CPT), Trail Making Test, Buschke Selective Reminding Test, and the Brief Visuospatial Test - Revised (BVMT-R).

RESULTS

Total PSQI scores were significantly associated with objective measures of sustained attention (CPT hit reaction time by block and standard error by block) and subjective memory loss (MFQ frequency and seriousness of forgetting). The PSQI components of (poorer) sleep quality and (greater) sleep disturbance were related to (worse) sustained attention scores while increased sleep latency and daytime sleepiness were associated with greater frequency and seriousness of forgetting.

CONCLUSIONS

Sleep quality is related to both objective measures of sustained attention and self-awareness of memory decline. These findings suggest that interventions for improving sleep quality may contribute not only to improving the ability to focus on a particular task but also in reducing memory complaints in middle-aged and older adults.

Rest-activity rhythm disturbance in liver cirrhosis and association with cognitive impairment

Cognitive impairment and disturbed sleep-wake rhythms are disabling complications of liver cirrhosis, yet there is limited understanding of how they are related. We tested the hypothesis that alterations of sleep, rest-activity, and light exposure patterns are associated with worse cognition in cirrhosis. A total of 54 ambulatory adult patients with cirrhosis and 41 age-/gender-matched healthy controls wore wrist actigraphy for rest-activity and light measurements and completed Patient-Reported Outcomes Measurement Information System sleep instruments for self-reported sleep quality. We used standard nonparametric descriptors to characterize rest-activity and light patterns, and wake after sleep onset and sleep efficiency to assess objective sleep quality. The NIH Toolbox cognition battery was used for objective cognitive evaluation using T-scores from a demographically adjusted population reference. Spearman's correlation and multivariable models were used to explore associations between measures of cognition, sleep, rest-activity, and light. Cognition was significantly impaired in cirrhosis patients. Sleep quality was worse in cirrhosis patients by subjective and objective measures compared with controls. Cirrhosis patients exhibited fragmented and dampened rest-activity rhythms, lower daytime and higher nighttime light exposure compared with controls. Worse working memory and processing speed was associated with lower daytime activity level, higher rest-activity fragmentation, lower day-to-day stability, and greater nocturnal light exposure. No association was found between cognition and sleep quality. Rest-activity fragmentation and abnormal light exposure patterns are common in patients with liver disease and are associated with the severity of cognitive impairment. Further research is needed to investigate the effects of timed bright light and exercise intervention on cognitive function in patients with liver disease.

Poor sleep is associated with small hippocampal subfields in cognitively normal elderly individuals

Recent studies demonstrated reduced hippocampal volumes in elderly healthy individuals who are cognitively normal but poor sleepers. The association between sleep quality and the pattern of volume loss across hippocampal subfields (HSs) is not well known. Thus, it is the focus of the present study. Sleep quality was self-assessed using the Pittsburgh Sleep Quality Index (PSQI). The HS volumes were measured using sub-millimetre in-plane resolution T2-weighted magnetic resonance imaging data. A total of 67 cognitively normal elderly individuals aged 60-83 years were classified into 30 normal sleepers with a PSQI <5 and 37 poor sleepers with a PSQI ≥5. The two groups were equivalent in age, gender distribution, ethnicity, education attainment, handedness and cognitive performance. Compared to normal sleepers, poor sleepers exhibited significantly lower normalised volumes in the left cornu ammonis field 1 (CA1), dentate gyrus (DG) and subiculum. In contrast, there were no significant differences in normalised grey and white matter volumes between the two groups. The global PSQI was negatively associated with the normalised volumes of the left CA1, DG and subiculum. Sleep duration was associated with the normalised volumes of the bilateral CA1, DG, left CA2 and subiculum. Verbal memory scores were associated with the left CA1 volume. In conclusion, poor sleep quality, especially insufficient sleep duration, was associated with volume loss in several HSs that are involved in specific learning and memory tasks. As the hippocampus does not regulate sleep, it is more likely that poor sleep leads to small hippocampi. Thus, based on this assumption, improving sleep quality of poor sleeper elderly individuals could benefit hippocampal health.

Association between sleep quality and subjective cognitive decline: evidence from a community health survey

OBJECTIVES

Little is known concerning whether subjective cognitive decline (SCD) is associated with sleep quality. This study aimed to identify the association between self-reported quality of sleep and SCD in a large population of middle-aged and older adults in Korea.

METHODS

We conducted this study based on data collected from the 2018 Korean Community Health Survey. Individuals aged 40 years and older who responded to the Behavioral Risk Factor Surveillance System (BRFSS) and Pittsburgh Sleep Quality Index (PSQI) assessments and did not lack data about multiple covariates were included. A total of 37,712 respondents with SCD and 135,119 those without SCD were included. Sleep quality was estimated using the PSQI, which includes seven self-reported components for sleep health assessment. SCD was assessed using the BRFSS. Logistic regression models adjusted for confounders were used to examine whether each component of the sleep quality index was related to SCD. Additional analysis of the correlation between quantified scores for each component and SCD-related functional limitations as ordinal variables was performed.

RESULTS

The mean age was 62.7 years in the SCD group and 56.4 years in the control group. In total, 13,777 (28.9%) respondents were male in the SCD group and 62,439 (50.7%) in the control group. The adjusted odds ratios of SCD were 1.25 for very bad sleep quality, 1.26 for long sleep latency, 1.16 for <5 h of sleep duration, 1.08 for <65% habitual sleep efficiency, 2.29 for high sleep disturbance, 1.26 for use of sleep medication ≥3 times a week, and 2.47 for high daytime dysfunction due to sleep problems compared to good sleep conditions. Furthermore, a higher score for each component of the sleep quality index correlated with greater SCD-related functional limitations.

CONCLUSIONS

Our study provides evidence that poor sleep quality is closely related to both SCD and SCD-related functional limitations.

Shift work is associated with increased risk of COVID-19: Findings from the UK Biobank cohort

Despite the strong evidence on circadian rhythm disruption in shift workers and consequent increased vulnerability for infection, longitudinal association between shift work and COVID-19 infection is unexplored. In this study, data from UK Biobank participants who were tested for COVID-19 infection (16 March to 7 September 2020) were used to explore the link between shift work and COVID-19 infection. Using the baseline occupational information, participants were categorised as non-shift workers, day shift workers, mixed shift workers and night shift workers. Multivariable regression models were used to assess the association between shift work and COVID-19 infection. Among the 18,221 participants (9.4% positive cases), 11.2% were health workers, and 16.4% were involved in shift-work-based jobs. Ethnic minorities (18%) and people in night-shift-based jobs (18.1%) had a significantly higher prevalence of COVID-19 infection than others. Adjusted logistics regression model suggest that, compared with their counterparts, people employed in a night-shift-based job were 1.85-fold (95% CI: 1.42-2.41) more likely to have COVID-19 infection. Sensitivity analysis focusing on people working in a non-healthcare setting suggests that people in shift-work-based jobs had 1.81-fold (95% CI: 1.04%-3.18%) higher odds of COVID-19 infection than their counterparts. Shift workers, particularly night shift workers, irrespective of their occupational group, seem to be at high risk of COVID-19 infection. If similar results are obtained from other studies, then it would mandate to revisit the criteria for defining high-risk groups for COVID-19 and implementing appropriate interventions to protect people in shift-based jobs.

Self-reported suboptimal sleep and receipt of sleep assessment and treatment among persons with and without a mental health condition in Australia: a cross sectional study

BACKGROUND

Poor sleep and poor mental health go hand in hand and, together, can have an adverse impact on physical health. Given the already disproportionate physical health inequities experienced by people with a mental health condition worldwide, the need to consider and optimise sleep has been highlighted as a means of improving both physical and mental health status. Sleep recommendations recently developed by the United States' National Sleep Foundation incorporate a range of sleep parameters and enable the identification of 'suboptimal' sleep. Among community-dwelling persons with and without a 12-month mental health condition in Australia, this study reports: [1] the prevalence of 'suboptimal' sleep and [2] rates of sleep assessment by a health care clinician/service and receipt of and desire for sleep treatment.

METHODS

A descriptive study (N = 1265) was undertaken using self-report data derived from a cross-sectional telephone survey of Australian adults, undertaken in 2017.

RESULTS

Fifteen per cent (n = 184) of participants identified as having a mental health condition in the past 12 months. Across most (7 of 8) sleep parameters, the prevalence of suboptimal sleep was higher among people with a mental health condition, compared to those without (all p < 0.05). The highest prevalence of suboptimal sleep for both groups was seen on measures of sleep duration (36-39% and 17-20% for people with and without a mental health condition, respectively). In terms of sleep assessment and treatment, people with a mental health condition were significantly more likely to: desire treatment (37% versus 16%), have been assessed (38% versus 12%) and have received treatment (30% versus 7%).

CONCLUSIONS

The prevalence of suboptimal sleep among persons with a mental health condition in Australia is significantly higher than those without such a condition, and rates of assessment and treatment are low for both groups, but higher for people with a mental health condition. Population health interventions, including those delivered as part of routine health care, addressing suboptimal sleep are needed.

A Randomized Controlled Trial of High-Intensity Exercise and Executive Functioning in Cognitively Normal Older Adults

BACKGROUND

There is a paucity of interventional research that systematically assesses the role of exercise intensity and cardiorespiratory fitness, and their relationship with executive function in older adults. To address this limitation, we have examined the effect of a systematically manipulated exercise intervention on executive function.

METHODS

Ninety-nine cognitively normal participants (age = 69.10 ± 5.2 years; n = 54 female) were randomized into either a high-intensity cycle-based exercise, moderate-intensity cycle-based exercise, or no-intervention control group. All participants underwent neuropsychological testing and fitness assessment at baseline (preintervention), 6-month follow-up (postintervention), and 12-month postintervention. Executive function was measured comprehensively, including measures of each subdomain: Shifting, Updating/ Working Memory, Inhibition, Verbal Generativity, and Nonverbal Reasoning. Cardiorespiratory fitness was measured by analysis of peak aerobic capacity; VO₂peak.

RESULTS

First, the exercise intervention was found to increase cardiorespiratory fitness (VO₂peak) in the intervention groups, in comparison to the control group (F =10.40, p≤0.01). However, the authors failed to find mean differences in executive function scores between the high-intensity, moderate intensity, or inactive control group. On the basis of change scores, cardiorespiratory fitness was found to associate positively with the executive function (EF) subdomains of Updating/Working Memory (β = 0.37, p = 0.01, r = 0.34) and Verbal Generativity (β = 0.30, p = 0.03, r = 0.28) for intervention, but not control participants.

CONCLUSION

At the aggregate level, the authors failed to find evidence that 6-months of high-intensity aerobic exercise improves EF in older adults. However, it remains possible that individual differences in experimentally induced changes in cardiorespiratory fitness may be associated with changes in Updating/ Working Memory and Verbal Generativity.

Socioeconomic status and sleep disturbances among pediatric population: a continental systematic review of empirical research

To this day, no consensus has been established on the definition and the conceptualization of the socioeconomic status (SES), since all the available studies on the relation between SES and health did not use the same conceptual framework and operationalization to assess SES. While literature reported that SES markers (such as income, social support networks, education, employment or occupation) influence the health of populations by shaping living conditions; empirical research does not tell us which SES markers affect more strongly the sleep components of the individuals, as well as which sleep disorders (SD) are affected and how. Even though several original studies have tried to assess how changes in socioeconomic status of parents may affect the psychosocial environment and mental health of an individual directly or through his community, no systematic reviews on the influence of SES on children's sleep are available. This systematic review make an update on the different measures of SES and sleep disturbances used for pediatric population across the different regions of the world. Recommendations for a future standardization of SES measures is proposed, for a better understanding of its influence on sleep disturbances.

Sleep and neurobehavioral functioning in survivors of pediatric cancer

OBJECTIVES

Sleep problems are a common late effect in survivors of pediatric cancer. Growing literature suggests deficits in sleep functioning may be related to more impairing neurobehavioral outcomes. The purpose of the present study was to evaluate the prevalence of parent reported sleep concerns in survivors of pediatric cancer, as well as evaluate the relationship between sleep and neurobehavioral functioning utilizing both parent and teacher input.

METHODS

The study included parent-teacher dyads of 75 survivors of pediatric cancer between the ages of six and 17 who completed a clinical neuropsychological evaluation with embedded measures of neurobehavioral functioning and sleep, including excessive daytime sleepiness and snoring. Bivariate correlations and multiple linear regressions were conducted to evaluate the relationship between sleep and neurobehavioral functioning.

RESULTS

No significant difference in parent reported sleep concerns was found with regard to demographic, diagnostic, or treatment variables. Daytime sleepiness was significantly elevated for 28% of the sample; snoring was not identified as a significant concern. Daytime sleepiness was significantly associated with worse neurobehavioral outcomes as reported by parents and teachers, including inattention, hyperactivity/impulsivity, peer difficulties, anxiety, depression, somatic complaints, and aggressive behaviors. Daytime sleepiness was not significantly related to report of learning problems.

CONCLUSIONS

Results further support that daytime sleepiness, as reported by parents, impacts approximately one third of survivors of pediatric cancer and is associated with worse neurobehavioral outcomes across home and school environments. As a result, it is vital that sleep functioning is a target of assessment in annual survivorship care. Future longitudinal studies are needed to further delineate the directionality of the sleep-neurobehavioral relationship in survivors.

Neuropsychology of Bipolar Disorder

Bipolar disorder is associated with significant dysfunction in a broad range of neuropsychological domains and processes. Deficits have been reported to occur in symptomatic states (depression, [hypo]mania) as well as in remission (euthymia), having consequences for psychological well-being and social and occupational functioning. The profile and magnitude of neuropsychological deficits in bipolar disorder have been explored in a number of systematic reviews and meta-analyses. After discussing these briefly, this chapter will focus on examining the clinical and demographic factors that influence and modify the pattern and magnitude of deficits, as well as reviewing methods of assessment and analysis approaches which may improve our understanding of these problems.

Facial Emotion Recognition and Executive Functions in Insomnia Disorder: An Exploratory Study

BACKGROUND

Clinical and experimental findings suggest that insomnia is associated with changes in emotional processing and impairments in cognitive functioning. In the present study, we investigate the relationship between facial emotion recognition and executive functioning among individuals with insomnia as well as healthy controls.

METHOD

A total of 11 individuals (mean age 31.3 ± 9.4) diagnosed with insomnia disorder and 15 control participants (mean age 24.8 ± 4.6) took part in the study. Participants responded to a facial emotion recognition task which presented them with static and dynamic stimuli, and were evaluated with regard to cognition, sleep, and mood.

RESULTS

Compared to controls, we found that participants with insomnia performed worse in the recognition of the facial emotion of fear (p = 0.001; η p 2 = 0.549; β = 0.999) and had lower scores in tests of verbal comprehension and perceptual organization (104.00 vs. 115.00, U = 135.5; p = 0.004; Cohen's, 2013 d = 1.281). We also found a relationship between facial emotion recognition and performance in cognitive tests, such as those related to perceptual organization, cognitive flexibility, and working memory.

CONCLUSION

Results suggest that participants with insomnia may present some impairment in executive functions as well as in the recognition of facial emotions with negative valences (fear and sadness).

Sleep disturbance and cognitive functioning among firefighters

Firefighters are at risk for chronic sleep disruption due to their rotating 24-hour on and 48-hour off work schedule and hazardous work conditions. Forty-five firefighters were assessed to determine the impact of their shift schedule on sleep duration, sleep quality, processing speed, sustained attention, vigilance, and mental health. Assessments were conducted at the start and end of shift. Firefighters endorsed sleeping 5 hours 21 minutes at work, and the results suggest that even minimal sleep disruption affected cognitive functioning (e.g. processing speed, visual-motor coordination, and reaction time), increasing the likelihood of poor work performance or injury.

Differences in visual-spatial working memory and driving behavior between morning-type and evening-type drivers

Circadian rhythms are changes in life activities over a cycle of approximately 24 hours. Studies on chronotypes have found that there are significant differences in physiology, personality, cognitive ability and driving behavior between morning-type and evening-type people. The purpose of this study is to explore the relationship between visual-spatial working memory and driving behavior between morning-type and evening-type drivers in China. A total of 42 Chinese drivers were selected to participate in this study according to their score on the Morningness-Eveningness Questionnaire, including 22 morning-type drivers and 20 evening-type drivers. During the experiment, the participants completed one cognitive task (visual-spatial working memory), two simulated driving tasks (car-following task and pedestrian-crossing task), and the Dula Dangerous Driving Index (DDDI). The results showed that evening-type drivers self-reported more dangerous driving behaviors but had better lateral control on the simulated driving task than morning-type drivers. In addition, evening-type drivers had greater accuracy when performing the visual-spatial working memory task. Moreover, the accuracy on the visual-spatial working memory task positively predicted the percentage of time over the speed limit by 10 mph (POS10) and negatively correlated with the reaction time measure (time to meet pedestrians) in the pedestrian-crossing task. The relationships among chronotype, cognitive ability and driving behavior are also discussed. Understanding the underlying mechanisms could help explain why evening-type drivers perform dangerous driving behaviors more often.

Objective cognitive functioning in self-reported habitual short sleepers not reporting daytime dysfunction: examination of impulsivity via delay discounting

Study Objectives

(1) Examine performance on an objective measure of reward-related cognitive impulsivity (delay discounting) among self-reported habitual short sleepers and medium (i.e. recommended 7-9 hours) length sleepers either reporting or not reporting daytime dysfunction; (2) Inform the debate regarding what type and duration of short sleep (e.g. 21 to 24 hours of total sleep deprivation, self-reported habitual short sleep duration) meaningfully influences cognitive impulsivity; (3) Compare the predictive utility of sleep duration and perceived dysfunction to other factors previously shown to influence cognitive impulsivity via delay discounting performance (age, income, education, and fluid intelligence).

Methods

We analyzed data from 1190 adults from the Human Connectome Project database. Participants were grouped on whether they reported habitual short (≤6 hours) vs. medium length (7-9 hours) sleep duration and whether they perceived daytime dysfunction using the Pittsburgh Sleep Quality Index.

Results

All short sleepers exhibited increased delay discounting compared to all medium length sleepers, regardless of perceived dysfunction. Of the variables examined, self-reported sleep duration was the strongest predictor of delay discounting behavior between groups and across all 1190 participants.

Conclusions

Individuals who report habitual short sleep are likely to exhibit increased reward-related cognitive impulsivity regardless of perceived sleep-related daytime impairment. Therefore, there is a reason to suspect that these individuals exhibit more daytime dysfunction, in the form of reward-related cognitive impulsivity, than they may assume. Current findings suggest that assessment of sleep duration over the prior month has meaningful predictive utility for human reward-related impulsivity.

Effects of Nocturnal Sleep Quality on Diurnal Cortisol Profiles and Attention in Nurses: A Cross-Sectional Study

Objective:

Low sleep quality (LSQ) activates the hypothalamic–pituitary–adrenal (HPA) axis and is related to arousal. Nursing staff, who work in shifts, tend to exhibit LSQ, which affects the level of vigor after awakening. This study investigated the effects of nocturnal sleep quality on diurnal cortisol profiles and sustained attention in day-shift nurses.

Method:

This study adopted a prospective cross-sectional design. Participants were recruited from a university-affiliated hospital in northern Taiwan. In the initial stage of this study, the Chinese Pittsburgh Sleep Quality Index (PSQI) Questionnaire was administered to 199 participants to categorize them as either LSQ (PSQI > 5) or high sleep quality (HSQ; PSQI ≤ 5). Participants were then randomly sampled from the two groups. Nocturnal sleep data and four diurnal saliva samples were collected for each participant. Sustained attention was measured before they started work. A total of 32 and 29 participants in the HSQ and LSQ groups, respectively, completed the data collection process.

Results:

Compared with the HSQ group, the LSQ group exhibited earlier wake-up times ( p = .02), a flatter cortisol awakening response (CAR) slope ( p < .01), a flatter morning-to-evening slope ( p < .01), and prolonged reaction speed and mean reaction time before starting work ( p < .01).

Conclusion:

Compared with the HSQ group, the LSQ group exhibited impaired HPA-axis regulation, with a flatter CAR and diurnal cortisol slope and poor sustained attention in the morning. Nursing staff are advised to achieve HSQ to improve attention and performance levels and maintain optimum work safety.

Poor Sleep Quality and Compromised Visual Working Memory Capacity

OBJECTIVES

Reduction in the amount of information (storage capacity) retained in working memory (WM) has been associated with sleep loss. The present study examined whether reduced WM capacity is also related to poor everyday sleep quality and, more importantly, whether the effects of sleep quality could be dissociated from the effects of depressed mood and age on WM.

METHODS

In two studies, WM was assessed using a short-term recall task, producing behavioral measures for both the amount of retained WM information (capacity) and how precise the retained WM representations were (precision). Self-report measures of sleep quality and depressed mood were obtained using questionnaires.

RESULTS

In a sample of college students, Study 1 found that poor sleep quality and depressed mood could independently predict reduced WM capacity, but not WM precision. Study 2 generalized these sleep- and mood-related WM capacity effects to a community sample (aged 21-77 years) and further showed that age was associated with reduced WM precision.

CONCLUSIONS

Together, these findings demonstrate dissociable effects of three health-related factors (sleep, mood, and age) on WM representations and highlighte the importance of assessing different aspects of WM representations (e.g., capacity and precision) in future neuropsychological research.

Individual Differences in the Neural Basis of Response Inhibition After Sleep Deprivation Are Mediated by Chronotype

Sleep deprivation (SD) has been reported to severely affect executive function, and interindividual differences in these effects may contribute to the SD-associated cognition impairment. However, it is unclear how individual differences in chronotypes (morning-type, MT; evening-type, ET) influence neurobehavioral functions after SD. To address this question, we used functional magnetic resonance imaging (fMRI) to evaluate whether 24 h of SD differentially affect response inhibition, a core component of executive function, in MT and ET individuals. Accordingly, MT and ET participants were instructed to follow their preferred 7–9-h sleep schedule for 2 weeks at home both prior to and throughout the course of the study, and then performed a go/no-go task during fMRI scanning at 08:00 a.m. both at rested wakefulness (RW) and following SD. We also examined whether the neurobehavioral inhibition differences in the chronotypes in each session can be predicted by subjective ratings (sleepiness, mood, and task) or objective attention. Behaviorally, SD led to an increased response time of go trials (hit RT), more attentional lapses, higher subjective sleepiness, and worse mood indices, but it did not impair the accuracy of go trials (hit rate) and no-go trials (stop rate). Regardless of the presence of SD, ET individuals exhibited a lower stop rate, higher subjective ratings of sleepiness, exhausted mood, and task difficulty in comparison with MT individuals. On the neural level, SD resulted in decreased inhibition-related activation of the right lateral inferior frontal gyrus (rIFG) in MT individuals and increased rIFG activation in ET individuals. Moreover, the rIFG activation in ET individuals after SD was positively correlated to the subjective ratings of sleepiness and effort put into the task, which was considered as a compensatory response to the adverse effects of SD. These findings suggest that individual differences in inhibition-related cerebral activation after SD are influenced by chronotypes. In addition, ET individuals may be vulnerable to response inhibition. Thus, it is essential to take into consideration the chronotype in SD research and sleep medicine.

Self-regulation and social behavior during sleep deprivation

An emerging literature is specifically focusing on the effects of sleep deprivation on aspects of social functioning and underlying neural changes. Two critical facets of social behavior emerge that are negatively impacted by sleep deprivation-self-regulation, which includes behavioral and emotional regulation, and social monitoring, which includes perceiving and interpreting cues relating to self and others. Sleep deprived individuals performing tasks with social components show altered brain activity in areas of the prefrontal cortex implicated in self-control, inhibition, evaluation, and decision-making, in proximity to mesocorticolimbic pathways to reward and emotional processing areas. These cognitive changes lead to increased reward seeking and behaviors that promote negative health outcomes (such as increased consumption of indulgence foods). These changes also lead to emotional disinhibition and increased responses to negative stimuli, leading to reductions in trust, empathy, and humor. Concomitant attentional instability leads to impaired social information processing, impairing individual and team performance and increasing likelihood of error, incident, and injury. Together, changes to reward seeking, the foundational components of social interaction, and interpretation of social cues, can result in unpleasant or deviant behavior. These behaviors are perceived and negatively responded to by others, leading to a cycle of conflict and withdrawal. Further studies are necessary and timely. Educational and behavioral interventions are required to reduce health-damaging behaviors, and to reduce emotionally-laden negative interpretation of sleep-deprived exchanges. This may assist with health, and with team cohesion (and improved performance and safety) in the workplace and the home.

Brain Microdialysate Monoamines in Relation to Circadian Rhythms, Sleep, and Sleep Deprivation - a Systematic Review, Network Meta-analysis, and New Primary Data

Disruption of the monoaminergic system, e.g. by sleep deprivation (SD), seems to promote certain diseases. Assessment of monoamine levels over the circadian cycle, during different sleep stages and during SD is instrumental to understand the molecular dynamics during and after SD. To provide a complete overview of all available evidence, we performed a systematic review. A comprehensive search was performed for microdialysis and certain monoamines (dopamine, serotonin, noradrenaline, adrenaline), certain monoamine metabolites (3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA)) and a precursor (5-hydroxytryptophan (5-HTP)) in PubMed and EMBASE. After screening of the search results by two independent reviewers, 94 publications were included. All results were tabulated and described qualitatively. Network-meta analyses (NMAs) were performed to compare noradrenaline and serotonin concentrations between sleep stages. We further present experimental monoamine data from the medial prefrontal cortical (mPFC). Monoamine levels varied with brain region and circadian cycle. During sleep, monoamine levels generally decreased compared to wake. These qualitative observations were supported by the NMAs: noradrenaline and serotonin levels decreased from wakefulness to slow wave sleep and decreased further during Rapid Eye Movement sleep. In contrast, monoamine levels generally increased during SD, and sometimes remained high even during subsequent recovery. Decreases during or after SD were only reported for serotonin. In our experiment, SD did not affect any of the mPFC monoamine levels. Concluding, monoamine levels vary over the light-dark cycle and between sleep stages. SD modifies the patterns, with effects sometimes lasting beyond the SD period.

The Impacts of Sexual Arousal and Its Suppression on Executive Functioning

Suppression of certain types of reflexive emotional responses is thought to temporarily deplete executive functions (EF), as evidenced by poorer performance on measures of EF, but does not deplete other, lower-order cognitive processes. This study examined whether similar decrements in performance on EF tests would occur following suppression of sexual arousal. A sample of 44 male college students underwent baseline cognitive assessment (EF and lower-order cognitive processes), followed by experimental manipulation consisting of exposure to sexually explicit audiovisual stimuli. Sexual arousal was monitored using penile plethysmography. In this study, 21 participants were assigned to a suppression condition and were instructed to suppress sexual arousal during the video, while 23 were assigned to an arousal condition and were instructed to allow themselves to become aroused. Following experimental manipulation, cognition was reassessed. Unexpectedly, results showed EF decrements in the arousal group but not in the suppression group. As expected, only EF was affected by experimental manipulation, with no group differences in lower-order cognitive processes. Thus, the findings suggest that sexual arousal is associated with temporary decrements in EF performance, at least among young, primarily White, male college students. The results contribute to understanding why sexually charged situations are sometimes associated with poor decisions or unsafe/reckless sexual practices.

Joint analysis of cognitive and circadian variation in Schizophrenia and Bipolar I Disorder

BACKGROUND

Impairment in cognitive variables and alterations in circadian function have been documented among patients with schizophrenia (SZ) and bipolar I disorder (BP1), but it is not known whether joint analysis of these variables can define clinically relevant sub-groups in either disorder.

OBJECTIVES

To evaluate the pattern and relationship of cognitive and circadian function in SZ and BP1 patients with respect to diagnosis and indices of clinical severity.

METHODS

Among patients with SZ and BP1, cognitive function was evaluated using the Penn Computerized Neurocognitive Battery and circadian function was assessed using the Composite Scale of Morningness/ Eveningness (CSM). Clinical severity was estimated using the Global Assessment of Function (GAF) scale, and age at onset of illness (AAO). The patients were compared with community based non-psychotic control individuals and non-psychotic first degree relatives of the SZ patients. The cluster distributions of cognitive function, circadian function and clinical severity were investigated and identified clusters compared across diagnostic groups.

RESULTS

Across participants, the cognitive domains could be separated into two clusters. Cluster 1 included the majority of control individuals and non-psychotic relatives, while SZ patients predominated in Cluster 2. BP1 patients were distributed across both clusters. The clusters could be differentiated by GAF scores, but not AAO. CSM scores were not significantly correlated with individual cognitive domains or with the clusters.

CONCLUSIONS

Clusters based on levels of cognitive function can discriminate SZ patients from control individuals, but not BP1 patients. CSM scores do not contribute to such discrimination.

Is self-report sleepiness associated with cognitive performance in temporal lobe epilepsy?

OBJECTIVES

Sleepiness and cognitive impairment are common symptoms observed in patients with epilepsy. We investigate whether self-reported sleepiness is associated with cognitive performance in patients with refractory mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Seventy-one consecutive patients with MTLE-HS were evaluated with the Stanford Sleepiness Scale (SSS) before neuropsychological evaluation. Their mean SSS scores were compared with controls. Each cognitive test was compared between patients with (SSS ≥ 3) or without sleepiness (SSS < 3). Imbalances were controlled by regression analysis. Patients reported a significantly higher degree of sleepiness than controls (p < 0.0001). After multiple linear regression analysis, only one test (RAVLT total) remained associated with self-reported sleepiness.

CONCLUSION

Self-reported sleepiness was significantly higher in MTLE-HS patients than controls, but did not affect their cognitive performance. If confirmed in other populations, our results may have implications for decision making about sleepiness screening in neuropsychological settings.

Neuropsychological functioning in opioid use disorder: A research synthesis and meta-analysis

BACKGROUND

Research has demonstrated that patients with opioid use disorders (OUD; including both opioid abuse and/or dependence) have poorer neuropsychological functioning compared to healthy controls; however, the pattern and robustness of the findings remain unknown.

OBJECTIVES

This study meta-analyzed the results from previous research examining the neuropsychological deficits associated with opioids across 14 neurocognitive domains.

METHOD

Articles comparing patients with OUD to healthy controls were selected based on detailed inclusion/exclusion criteria and variables of interest were coded. In total, 61 studies were selected for the analyses. These consisted of 2580 patients with OUD and 2102 healthy control participants (15.9% female). Drug-related variables were analyzed as potential moderators.

RESULTS

The largest effect size difference in neuropsychological performance was observed in complex psychomotor ability. With the exception of the motor and processing speed domains, which showed no group differences, small-to-medium effect sizes were associated with all neurocognitive domains examined. Meta-regression revealed that increases in the length of abstinence were associated with decreases in effect sizes of the complex psychomotor domain. Additionally, attentional ability predicted effect size differences in executive functioning as well as verbal memory ability. Although the majority of meta-analyzed studies demonstrated significant differences between patients with OUD and controls, the average raw scores for patients with OUD in these studies typically fell within the normal range.

CONCLUSION

The pattern of neuropsychological performance among patients with OUD appears to reflect mild generalized cognitive dysfunction, with a large effect in complex psychomotor abilities.

The relationship between naturalistic sleep variation and error monitoring in young adults: An event-related potential (ERP) study

Sleep deprivation studies have highlighted the importance of adequate sleep for optimal daytime functioning. However, there is limited research exploring whether variations in natural sleep patterns produce similar difficulties to those seen in sleep deprivation studies. The aim of the current study was to explore whether naturalistic reductions in sleep duration and/or sleep quality were associated with behavioural and electrophysiological measures of cognitive control. Sixty undergraduate students were asked to wear an actigraph for 7 consecutive nights before completing a hybrid Flanker-Go/NoGo task whilst continuous EEG data were recorded. Participants were assigned to high or low sleep quality and short or long sleep duration groups using the National Sleep Foundation guidelines. Results indicated that individuals who, on average, slept <7 h each night showed inefficiencies in error-monitoring, as reflected by a reduction in amplitude of the error-related negativity (ERN) in comparison to those with longer sleep duration. These findings suggest that natural variations in sleep quantity are associated with atypical error detection.

Positive neuropsychology: The science and practice of promoting cognitive health

Positive psychology has influenced multiple subfields within psychology and areas outside of psychology. While positive psychology's focus on positive mental health and character strengths did not appear to meaningfully impact neuropsychology in its earlier stages, more recent indications suggest that the neuropsychological literature, and perhaps the field as a whole, has begun to embrace related research and practice applications. In this context, positive neuropsychology has emerged as a neuropsychological orientation focused on the study and practice of promoting cognitive health. The present review discusses the origins of positive neuropsychology and elaborates on its six key evidence-based domains: compensatory strategy use, activity engagement, prevention of cognitive impairment, public education, exceptional cognition, and positive cognitive outcomes in neuropsychiatric populations. This broad perspective on cognitive wellness can easily be embraced by both clinicians and researchers and offers multiple directions for future growth. Ultimately, consideration of various methods to promote cognitive health can inform our understanding of optimal brain function, maximize functioning in individuals with cognitive limitations, and enhance quality of life among populations served by neuropsychologists.

Neuropsychologists as primary care providers of cognitive health: A novel comprehensive cognitive wellness service delivery model

By virtue of their extensive knowledge base and specialized training in brain-behavior relationships, neuropsychologists are especially poised to execute a unique broad-based approach to overall cognitive wellness and should be viewed as primary care providers of cognitive health. This article will describe a novel comprehensive cognitive wellness service delivery model including cognitive health, anti-aging, lifelong wellness, and longevity-oriented practices. These practice areas include brain-based cognitive wellness, emotional and spiritually centric exploration, and related multimodality health interventions. As experts in mind-body connections, neuropsychologists can provide a variety of evidence-based treatment options, empowering patients with a sense of value and purpose. Multiple areas of clinical therapy skill-based learning, tailor-made to fit individual needs, will be discussed including: brain stimulating activities, restorative techniques, automatic negative thoughts and maladaptive thinking reduction, inflammation and pain management techniques, nutrition and culinary focused cognitive wellness, spirituality based practices and mindfulness, movement and exercise, alternative/complimentary therapies, relationship restoration/social engagement, and trauma healing/meaning. Cognitive health rests upon the foundation of counteracting mind-body connection disruptions from multiple etiologies including inflammation, chronic stress, metabolic issues, cardiac conditions, autoimmune disease, neurological disorders, infectious diseases, and allergy spectrum disorders. Superimposed on these issues are lifestyle patterns and negative health behaviors that develop as ill-fated compensatory mechanisms used to cope with life stressors and aging. The brain and body are electrical systems that can "short circuit." The therapy practices inherent in the proposed cognitive wellness service delivery model can provide preventative insulation and circuit breaking against the shock of illness.

Sleep Biomarkers, Health Comorbidities, and Neurocognition in Obstructive Sleep Apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is associated with cognitive impairment but the relationships between specific biomarkers and neurocognitive domains remain unclear. The present study examined the influence of common health comorbidities on these relationships. Adults with suspected OSA (N=60; 53% male; M age=52 years; SD=14) underwent neuropsychological evaluation before baseline polysomnography (PSG). Apneic syndrome severity, hypoxic strain, and sleep architecture disturbance were assessed through PSG.

METHODS

Depression (Center for Epidemiological Studies Depression Scale, CESD), pain, and medical comorbidity (Charlson Comorbidity Index) were measured via questionnaires. Processing speed, attention, vigilance, memory, executive functioning, and motor dexterity were evaluated with cognitive testing. A winnowing approach identified 9 potential moderation models comprised of a correlated PSG variable, comorbid health factor, and cognitive performance.

RESULTS

Regression analyses identified one significant moderation model: average blood oxygen saturation (AVO2) and depression predicting recall memory, accounting for 31% of the performance variance, p<.001. Depression was a significant predictor of recall memory, p<.001, but AVO2 was not a significant predictor. The interaction between depression and AVO2 was significant, accounting for an additional 10% of the variance, p<.001. The relationship between low AVO2 and low recall memory performance emerged when depression severity ratings approached a previously established clinical cutoff score (CESD=16).

CONCLUSIONS

This study examined sleep biomarkers with specific neurocognitive functions among individuals with suspected OSA. Findings revealed that depression burden uniquely influence this pathophysiological relationship, which may aid clinical management. (JINS, 2018, 28, 864-875).