Usual sleep duration and cognitive function in older adults in Spain

The few studies that have examined the association between usual sleep duration and cognitive function have shown conflicting results. This cross‐sectional study examined the association between sleep duration and cognitive function among 3212 people, representative of the non‐institutionalized population aged 60 years and over in Spain. Sleep duration was self‐reported, and cognitive function was measured with the Mini‐Examen Cognoscitivo (MEC), a version of the Mini‐Mental State Examination that has been validated in Spain. Linear regression, with adjustment for the main confounders, was used to obtain mean differences in the MEC between the categories of sleep duration (≤5, 6, 7, 8, 9, 10, ≥11 h day^?1). The MEC score decreased progressively (became worse) across sleep categories from 7 to ≥11 h (P for linear trend <0.001). People who slept for ≥11 h had a significantly lower MEC score than those who slept for 7 h (mean difference ?1.48; 95% confidence interval ?2.12 to ?0.85). This difference in the MEC was similar to that observed for a 10‐year increase in age. The results did not vary significantly by sex (P for interaction >0.05). No association was observed between short sleep duration (<7 h) and cognitive function. We conclude that long sleep duration is associated with poorer cognitive function in older adults from the general population.     

阻塞性睡眠呼吸暂停综合征患者轻度认知功能障碍的MoCA评估

目的 探讨简易精神状态检查量表(MMSE)、蒙特列尔认知评估量表(MoCA)评估阻塞性睡眠呼吸暂停综合征(OSAS)患者轻度认知功能障碍(MCI)的可行性.方法 用便携式多导睡眠仪、MMSE及MoCA对51名OSAS患者和35名单纯鼾症者进行睡眠监测和认知功能的评价.结果 OSAS组MoCA评分结果为21.1 ±3.0,显著低于对照组的25.0 ±2.6(P＜0.01);MMSE评分结果在OSAS组与对照组中分别为27.8±1.8及28.1±1.7,无统计学意义.结论 MoCA对于OSAS患者MCI的早期诊断敏感性优于MMSE,对于MMSE测试结果正常但高度怀疑存在MCI者,MoCA是一种简便可行的筛查工具.     

Associations between brain structure and sleep patterns across adolescent development

Study ObjectivesStructural brain maturation and sleep are complex processes that exhibit significant changes over adolescence and are linked to many physical and mental health outcomes. We investigated whether sleep–gray matter relationships are developmentally invariant (i.e. stable across age) or developmentally specific (i.e. only present during discrete time windows) from late childhood through young adulthood.MethodsWe constructed the Neuroimaging and Pediatric Sleep Databank from eight research studies conducted at the University of Pittsburgh (2009–2020). Participants completed a T1-weighted structural MRI scan (sMRI) and 5–7 days of wrist actigraphy to assess naturalistic sleep. The final analytic sample consisted of 225 participants without current psychiatric diagnoses (9–25 years). We extracted cortical thickness and subcortical volumes from sMRI. Sleep patterns (duration, timing, continuity, regularity) were estimated from wrist actigraphy. Using regularized regression, we examined cross-sectional associations between sMRI measures and sleep patterns, as well as the effects of age, sex, and their interaction with sMRI measures on sleep.ResultsShorter sleep duration, later sleep timing, and poorer sleep continuity were associated with thinner cortex and altered subcortical volumes in diverse brain regions across adolescence. In a discrete subset of regions (e.g. posterior cingulate), thinner cortex was associated with these sleep patterns from late childhood through early-to-mid adolescence but not in late adolescence and young adulthood.ConclusionsIn childhood and adolescence, developmentally invariant and developmentally specific associations exist between sleep patterns and gray matter structure, across brain regions linked to sensory, cognitive, and emotional processes. Sleep intervention during specific developmental periods could potentially promote healthier neurodevelopmental outcomes.     

Associations between children's intelligence and academic achievement: the role of sleep

Sleep problems (long wake episodes, low sleep efficiency) were examined as moderators of the relation between children's intelligence and academic achievement. The sample was comprised of 280 children (55% boys; 63% European Americans, 37% African Americans; mean age = 10.40 years, SD = 0.65). Sleep was assessed during seven consecutive nights of actigraphy. Children's performance on standardized tests of intelligence (Brief Intellectual Ability index of the Woodcock–Johnson III) and academic achievement (Alabama Reading and Math Test) were obtained. Age, sex, ethnicity, income‐to‐needs ratio, single parent status, standardized body mass index, chronic illness and pubertal development were controlled in analyses. Higher intelligence was strongly associated with higher academic achievement across a wide range of sleep quality. However, the association between intelligence and academic achievement was slightly attenuated among children with more long wake episodes or lower sleep efficiency compared with children with higher‐quality sleep.     

Subjective–objective sleep discrepancy in patients with insomnia during and after cognitive behavioural therapy: An actigraphy study

Although patients with insomnia often show a discrepancy between self‐reported and objective sleep parameters, the role of and change in this phenomenon during treatment remain unclear. The present study aimed to assess the effect of cognitive behavioural therapy for insomnia on subjective and objective sleep discrepancy of total sleep time, sleep‐onset latency and wake after sleep onset. The total sleep time discrepancy was also assessed across the entire therapy. The second aim was to examine the treatment outcome of two insomnia groups differing in sleep perception. Thirty‐six adults with insomnia (mean age = 46.7 years, SD = 13.9; 22 females) were enrolled in the final analyses. Patients underwent a 6‐week group cognitive behavioural therapy for insomnia programme. Sleep diary and actigraphy measurements were obtained during the therapy. Patients who underestimated total sleep time (n = 16; underestimating group) were compared with patients who accurately perceived or overestimated total sleep time (n = 20; accurate/overestimating group). After cognitive behavioural therapy for insomnia, a significant decrease of total sleep time and sleep‐onset latency discrepancy was observed without a change in wake after sleep onset discrepancy in the total sample. Only the underestimating group reported decreased sleep‐onset latency discrepancy after the treatment, whereas total sleep time discrepancy significantly changed in both groups. The underestimating group showed a significant decrease of total sleep time discrepancy from Week 1 to Week 2 when the sleep restriction was implemented, whereas the accurate/overestimating group showed the first significant change at Week 4. In conclusion, both groups differing in sleep perception responded similarly to cognitive behavioural therapy for insomnia, although different In conclusion, both groups differing in sleep perception responded similarly to cognitive behavioural therapy for insomnia, although different therapeutic components could play important roles in each group. components could play important roles in each group.     

Disagreement between subjective and actigraphic measures of sleep duration in a population-based study of elderly persons

Sleep duration is an important concept in epidemiological studies. It characterizes a night's sleep or a person's sleep pattern, and is associated with numerous health outcomes. In most large studies, sleep duration is assessed with questionnaires or sleep diaries. As an alternative, actigraphy may be used, as it objectively measures sleep parameters and is feasible in large studies. However, actigraphy and sleep diaries may not measure exactly the same phenomenon. Our study aims to determine disagreement between actigraphic and diary estimates of sleep duration, and to investigate possible determinants of this disagreement. This investigation was embedded in the population-based Rotterdam Study. The study population consisted of 969 community-dwelling participants aged 57-97 years. Participants wore an actigraph and kept a sleep diary for, on average, six consecutive nights. Both measures were used to determine total sleep time (TST). In 34% of the participants, the estimated TST in the sleep diaries deviated more than 1 h from actigraphically measured TST. The level of disagreement between diary and actigraphic measures decreased with subjective and actigraphic measures of sleep quality, and increased with male gender, poor cognitive function and functional disability. Actigraphically measured poor sleep was often accompanied by longer subjective estimates of TST, whereas subjectively poor sleepers tended to report shorter TST in their diaries than was measured with actigraphy. We recommend, whenever possible, to use multiple measures of sleep duration, to perform analyses with both, and to examine the consistency of the results over assessment methods.     

The association between sleep disordered breathing, academic grades, and cognitive and behavioral functioning among overweight subjects during middle to late childhood

Study Objectives:

(1) to determine the associations of sleep disordered breathing (SDB) with behavioral functioning, cognitive test scores, and school grades during middle- to late-childhood, an under-researched developmental period in the SDB literature, and (2) to clarify whether associations between SDB and school grades are mediated by deficits in cognitive or behavioral functioning.

Design:

Cross-sectional correlative study.

Setting:

Office/hospital, plus reported functioning at home and at school.

Participants:

163 overweight subjects aged 10-16.9 years were divided into 4 groups based upon their obstructive apnea+hypopnea index (AHI) during overnight polysomnography and parent report of snoring: Moderate-Severe OSA (AHI > 5, n = 42), Mild OSA (AHI = 1-5, n = 58), Snorers (AHI < 1 + snoring, n = 26), and No SDB (AHI < 1 and nonsnoring, n = 37).

Measurements:

Inpatient overnight polysomnography, parent- and self-report of school grades and sleep, parent- and teacher-report of daytime behaviors, and office-based neuropsychological testing.

Results:

The 4 groups significantly differed in academic grades and parent- and teacher-reported behaviors, particularly inattention and learning problems. These findings remained significant after adjusting for subject sex, race, socioeconomic status, and school night sleep duration. Associations with SDB were confined to reports of behavioral difficulties in real-world situations, and did not extend to office-based neuropsychological tests. Findings from secondary analyses were consistent with, but could not definitively confirm, a causal model in which SDB affects school grades via its impact on behavioral functioning.

Conclusions:

SDB during middle- to late-childhood is related to important aspects of behavioral functioning, especially inattention and learning difficulties, that may result in significant functional impairment at school.

Citation:

Beebe DW; Ris MD; Kramer ME; Long E; Amin R. The association between sleep disordered breathing, academic grades, and cognitive and behavioral functioning among overweight subjects during middle to late childhood. SLEEP 2010;33(11):1447-1456.     

Self‐reported sleep duration and cognitive functioning in the general population

This study investigated the relationship between self‐reported sleep factors (sleep duration, insomnia, use of sleeping medicine, probable sleep apnoea and feelings of fatigue and tiredness) with cognitive functioning in 5177 people aged 30 years or older from a cross‐sectional representative sample of the adult population in Finland (The Finnish Health 2000 Survey). Previous studies have indicated a U‐shaped association between increased health risks and sleep duration; we hypothesized a U‐shaped association between sleep duration and cognitive functioning. Objective cognitive functioning was assessed with tasks derived from the Consortium to Establish a Registry for Alzheimer’s Disease test battery (verbal fluency, encoding and retaining verbal material). Subjective cognitive functioning and sleep‐related factors were assessed with questionnaires. Health status was assessed during a health interview. Depressive and alcohol use disorders were assessed with the Composite International Diagnostic Interview. Medication was recorded during the health examination. Short and long sleep duration, tiredness and fatigue were found to be associated with both objectively assessed and self‐reported decreased cognitive functioning. The association was stronger between sleep factors and subjective cognitive function than with objective cognitive tests. These data suggest that self‐reported habitual short and long sleep duration reflect both realization of homeostatic sleep need and symptom formation in the context of the individual’s health status.     

Fragmentation of the rest-activity rhythm correlates with age-related cognitive deficits

Aging affects both cognitive performance and the sleep-wake rhythm. The recent surge of studies that support a role of sleep for cognitive performance in healthy young adults suggests that disturbed sleep-wake rhythms may contribute to 'age-related' cognitive decline. This relationship has however not previously been extensively investigated. The present correlational study integrated a battery of standardized cognitive tests to investigate the association of mental speed, memory, and executive function with actigraphically recorded sleep-wake rhythms in 144 home-dwelling elderly participants aged 69.5 ± 8.5 (mean ± SD). Multiple regression analyses showed that the partial correlations of the fragmentation of the sleep-wake rhythm with each of the three cognitive domains ( r  = −0.16, −0.19, and −0.16 respectively) were significant. These associations were independent from main effects of age, implying that a unique relationship between the rest-activity rhythm and cognitive performance is present in elderly people.     

Absent gender differences of hippocampal atrophy in amnestic type mild cognitive impairment

Hippocampus displayed progressively gender-associated damage in Alzheimer's disease. However, gender effects have been largely neglected in studies of amnestic type mild cognitive impairment (aMCI) patients who were believed to represent an early stage of this disease. The goal of this study was to use in vivo neuroimaging techniques to determine whether there were any evidences of gender differences in hippocampal atrophy in aMCI. A region of interest-based magnetic resonance imaging approach was used to compare hippocampal volume between aMCI patients (22 male, 17 female) and normal aging controls (12 male, 11 female). Independent of group, male hippocampal volumes were larger than female volumes and right hippocampal volumes were typically smaller than left volumes. Hippocampal volumes were significantly reduced in the clinical group but no gender differences were noted in terms of degree of atrophy present. However, female patients showed more impaired cognitive function than male patients despite this apparent equivalence in atrophy. The absence of a gender difference suggested that early neuropathological progression might be independent of gender. However, the data also suggested female aMCI patients had an increased vulnerability to cognitive impairment earlier in the illness course.     

Comparison between subjective and actigraphic measurement of sleep and sleep rhythms

Sleep is often assessed in circadian rhythm studies and long-term monitoring is required to detect any changes in sleep over time. The present study aims to investigate the ability of the two most commonly employed methods, actigraphy and sleep logs, to identify circadian sleep/wake disorders and measure changes in sleep patterns over time. In addition, the study assesses whether sleep measured by both methods shows the same relationship with an established circadian phase marker, urinary 6-sulphatoxymelatonin. A total of 49 registered blind subjects with different types of circadian rhythms were studied daily for at least four weeks. Grouped analysis of all study days for all subjects was performed for all sleep parameters (1062-1150 days data per sleep parameter). Good correlations were observed when comparing the measurement of sleep timing and duration (sleep onset, sleep offset, night sleep duration, day-time nap duration). However, the methods were poorly correlated in their assessment of transitions between sleep and wake states (sleep latency, number and duration of night awakenings, number of day-time naps). There were also large and inconsistent differences in the measurement of the absolute sleep parameters. Overall, actigraphs recorded a shorter sleep latency, advanced onset time, increased number and duration of night awakenings, delayed offset, increased night sleep duration and increased number and duration of naps compared with the subjective sleep logs. Despite this, there was good agreement between the methods for measuring changes in sleep patterns over time. In particular, the methods agreed when assessing changes in sleep in relation to a circadian phase marker (the 6-sulphatoxymelatonin (aMT6s) rhythm) in both entrained (n = 30) and free-running (n = 4) subjects.     

Affective symptoms and risk of progression to mild cognitive impairment or dementia in subjective cognitive decline: A systematic review and meta-analysis

AimsTo systematically review the literature on outcomes for individuals with subjective cognitive decline (SCD) with concurrent affective symptoms. To conduct a meta-analysis to establish whether either higher depressive symptoms or higher levels of anxiety increased the risk of progression SCD to mild cognitive impairment (MCI) or dementia.MethodsFive databases were searched from inception to February 2021 for longitudinal studies of older adults with SCD, reporting depressive and anxiety symptoms at baseline and risk of MCI or dementia at follow-up. Data were extracted and pooled using a random-effects meta-analysis.ResultsTwelve studies were identified. Pooled effect sizes indicated higher depressive symptoms did not increase risk of clinical progression to either MCI (RR = 0.98; 95 % CI: 0.75–1.26) or dementia (RR = 0.69; 95 % CI: 0.27–1.79). However, presence of anxiety or SCD-related worry did significantly increase risk of progression from subjective to objective cognitive impairment by 40 % (RR = 1.40; 95 % CI:1.20 – 1.63).ConclusionsAffective symptoms in the form of anxiety, but not depressive symptoms, increase the risk of progression to objective cognitive impairment in individuals with SCD. Further research should focus on establishing whether psychological interventions aimed at reducing anxiety and worry also reduce the risk of clinical progression.     

The association between white matter hyperintensities and executive decline in mild cognitive impairment is network dependent

White matter hyperintensities (WMH) in Mild Cognitive Impairment (MCI) have been associated with impaired executive functioning, although contradictory findings have been reported. The aim of this study was to examine whether WMH location influenced the relation between WMH and executive functioning in MCI participants (55-90 years) in the European multicenter memory-clinic-based DESCRIPA study, who underwent MRI scanning at baseline (N = 337). Linear mixed model analysis was performed to test the association between WMH damage in three networks (frontal-parietal, frontal-subcortical and frontal-parietal-subcortical network) and change in executive functioning over a 3-year period. WMH in the frontal-parietal and in the frontal-parietal-subcortical network were associated with decline in executive functioning. However, the frontal-subcortical network was not associated with change in executive functioning.Our results suggest that parietal WMH are a significant contributor to executive decline in MCI and that investigation of WMH in the cerebral networks supporting cognitive functions provide a new way to differentiate stable from cognitive declining MCI individuals.     

Association of sleep with cognitive function during retirement transition: the Whitehall II study

Study ObjectivesSleep duration and difficulties have been shown to associate with cognitive function. This study examined how changes in sleep and in cognitive function are associated during retirement transition.MethodsThe study population consisted of 2980 Whitehall II study participants, who retired during the follow-up, whose sleep was queried, and cognitive function measured (inductive reasoning and verbal memory) before and after retirement (follow-up 16 years). Using the last information on sleep before and the first after retirement, participants were categorized into constantly without (59%), increasing (13%), decreasing (11%), and constantly with (18%) sleep difficulties; and constantly short (26%), increasing (19%), decreasing (8.5%), and constantly mid-range (47%) sleep duration. Change in cognitive function during retirement transition was examined by sleep change groups using linear regression analyses with generalized estimating equations.ResultsMore pronounced decline in inductive reasoning during retirement transition was observed among participants with increasing sleep difficulties (−1.96, 95% CI −2.52 to −1.41) compared to those constantly without sleep difficulties (−1.25, 95% CI −1.52 to −0.98) and constantly with sleep difficulties (−1.26, 95% CI −1.75 to −0.92). Decreasing sleep difficulties (−0.64, 95% CI −0.86 to −0.43) were associated with a more pronounced decline in verbal memory when compared to constantly without sleep difficulties (−0.42, 95% CI −0.52 to −0.32) in post-retirement period. No statistically significant differences across sleep duration groups in cognitive function were observed.ConclusionsIncreasing and decreasing sleep difficulties may be associated with accelerated decline in cognitive function during retirement transition and post-retirement.     

Insomnia with objective short sleep duration is associated with cognitive impairment: a first look at cardiometabolic contributors to brain health

Study ObjectivesInsomnia with objective short sleep duration has been previously associated with adverse cardiometabolic health outcomes as well as poorer cognitive performance in otherwise noncognitively impaired adults. However, studies demonstrating an increased prevalence of cognitive impairment (CI) in this insomnia phenotype are lacking.MethodsWe analyzed data from Penn State Adult Cohort (N = 1,524; 48.9 ± 13.4 years; 53.4% women). Self-reported sleep difficulty was defined as normal sleep (n = 899), poor sleep (n = 453), and chronic insomnia (n = 172). Objective short sleep duration was defined as less than 6-h of sleep, based on in-lab, 8-h polysomnography. CI (n = 155) and possible vascular cognitive impairment (pVCI, n = 122) were ascertained using a comprehensive neuropsychological battery. Analyses adjusted for age, sex, race, education, body mass index, apnea/hypopnea index, smoking, alcohol, psychoactive medication, and mental and physical health problems.ResultsParticipants who reported poor sleep or chronic insomnia and slept objectively less than 6 hours were associated with a 2-fold increased odds of CI (OR = 2.06, 95% confidence limits [CL] = 1.15–3.66 and OR = 2.18, 95% CL = 1.07–4.47, respectively) and of pVCI (OR = 1.94, 95% CL = 1.01–3.75 and OR = 2.33, 95% CL = 1.07–5.06, respectively). Participants who reported poor sleep or chronic insomnia and slept objectively more than 6 hours were not associated with increased odds of either CI (OR = 0.72, 95% CL = 0.30–1.76 and OR = 0.75, 95% CL = 0.21–2.71, respectively) or pVCI (OR = 1.08, 95% CL = 0.42–2.74 and OR = 0.76, 95% CL = 0.16–3.57, respectively).ConclusionsInsomnia with objective short sleep duration is associated with an increased prevalence of CI, particularly as it relates to cardiometabolic health (i.e. pVCI). These data further support that this insomnia phenotype may be a more biologically severe form of the disorder associated with cardiovascular, cerebrovascular, and neurocognitive morbidity.     

Increased tau protein differentiates mild cognitive impairment from geriatric depression and predicts conversion to dementia

Significantly increased cerebrospinal fluid (CSF) total tau (t-tau) and phosphorylated at threonine 181 tau (p-tau) levels were frequently found in patients with mild cognitive impairment (MCI) who have an increased risk of developing Alzheimer's disease (AD). Though MCI often overlaps with depressive symptoms making early diagnosis difficult, to date no CSF marker has been probed to support the differential diagnosis of geriatric major depressive disorder and MCI eventually converting to AD. CSF levels of t-tau and p-tau were determined by ELISA in 80 subjects with MCI (aging associated cognitive decline criteria), 54 patients with major depression and 24 cognitively healthy controls. Patients were reassessed after a follow-up period of at least 12 month. During follow-up, 29% of the MCI patients but only one patient with major depression converted to AD. Already at baseline converters to AD were characterized by significantly higher t-tau and p-tau levels compared to non-converters and the other diagnostic groups. Our findings demonstrate that both, CSF t-tau and p-tau levels facilitate the differential diagnosis of MCI and are of prognostic value.     

Upregulation of select rab GTPases in cholinergic basal forebrain neurons in mild cognitive impairment and Alzheimer's disease

Endocytic system dysfunction is one of the earliest disturbances that occur in Alzheimer's disease (AD), and may underlie the selective vulnerability of cholinergic basal forebrain (CBF) neurons during the progression of dementia. Herein we report that genes regulating early and late endosomes are selectively upregulated within CBF neurons in mild cognitive impairment (MCI) and AD. Specifically, upregulation of rab4, rab5, rab7, and rab27 was observed in CBF neurons microdissected from postmortem brains of individuals with MCI and AD compared to age-matched control subjects with no cognitive impairment (NCI). Upregulated expression of rab4, rab5, rab7, and rab27 correlated with antemortem measures of cognitive decline in individuals with MCI and AD. qPCR validated upregulation of these select rab GTPases within microdissected samples of the basal forebrain. Moreover, quantitative immunoblot analysis demonstrated upregulation of rab5 protein expression in the basal forebrain of subjects with MCI and AD. The elevation of rab4, rab5, and rab7 expression is consistent with our recent observations in CA1 pyramidal neurons in MCI and AD. These findings provide further support that endosomal pathology accelerates endocytosis and endosome recycling, which may promote aberrant endosomal signaling and neurodegeneration throughout the progression of AD.     

Executive dysfunction and gray matter atrophy in amnestic mild cognitive impairment

Recent studies have shown that impairment in executive function (EF) is common in patients with amnestic mild cognitive impairment (aMCI). However, the neuroanatomic basis of executive impairment in patients with aMCI remains unclear. In this study, multiple regression voxel-based morphometry analyses were used to examine the relationship between regional gray matter volumes and EF performance in 50 patients with aMCI and 48 healthy age-matched controls. The core EF components (response inhibition, working memory and task switching, based on the EF model of Miyake et al) were accessed with computerized tasks. Atrophic brain areas related to decreases in the three EF components in patients with aMCI were located in the frontal and temporal cortices. Within the frontal cortex, the brain region related to response inhibition was identified in the right inferior frontal gyrus. Brain regions related to working memory were located in the left anterior cingulate gyrus, left premotor cortex, and right inferior frontal gyrus, and brain regions related to task shifting were distributed in the bilateral frontal cortex. Atrophy in the right inferior frontal gyrus was most closely associated with a decrease in all three EF components in patients with aMCI. Our data, from the perspective of brain morphology, contribute to a better understanding of the role of these brain areas in the neural network of EF.     

Conversion from mild cognitive impairment to Alzheimer's disease is predicted by sources and coherence of brain electroencephalography rhythms

Objective. Can quantitative electroencephalography (EEG) predict the conversion from mild cognitive impairment (MCI) to Alzheimer’s disease (AD)?