Sleep-wake Measures Research Articles

Sleep-wake behaviors associated with cognitive performance in middle-aged participants of the Hispanic Community Health Study/Study of Latinos

ObjectivesMany sleep-wake behaviors have been associated with cognition. We examined a panel of sleep-wake/activity characteristics to determine which are most robustly related to having low cognitive performance in midlife. Secondarily, we evaluate the predictive utility of sleep-wake measures to screen for low cognitive performance. MethodsThe outcome was low cognitive performance defined as being >1 standard deviation below average age/sex/education internally normalized composite cognitive performance levels assessed in the Hispanic Community Health Study/Study of Latinos. Analyses included 1006 individuals who had sufficient sleep-wake measurements about 2years later (mean age=54.9, standard deviation= 5.1; 68.82% female). We evaluated associations of 31 sleep-wake variables with low cognitive performance using separate logistic regressions. ResultsIn individual models, the strongest sleep-wake correlates of low cognitive performance were measures of weaker and unstable 24-hour rhythms; greater 24-hour fragmentation; longer time-in-bed; and lower rhythm amplitude. One standard deviation worse on these sleep-wake factors was associated with ∼20%-30% greater odds of having low cognitive performance. In an internally cross-validated prediction model, the independent correlates of low cognitive performance were: lower Sleep Regularity Index scores; lower pseudo-F statistics (modellability of 24-hour rhythms); lower activity rhythm amplitude; and greater time in bed. Area under the curve was low/moderate (64%) indicating poor predictive utility. ConclusionThe strongest sleep-wake behavioral correlates of low cognitive performance were measures of longer time-in-bed and irregular/weak rhythms. These sleep-wake assessments were not useful to identify previous low cognitive performance. Given their potential modifiability, experimental trials could test if targeting midlife time-in-bed and/or irregular rhythms influences cognition.

Sleep-wake behavioral characteristics associated with depression symptoms: findings from the Multi-Ethnic Study of Atherosclerosis.

To help prioritize target/groups for experimental intervention studies, we characterized cross-sectional associations between 24-hour sleep-wake measures and depression symptoms, and evaluated if similar sleep-wake-depression relationships existed in people with and without higher insomnia severity. Participants had ≥3 days of actigraphy data (n = 1884; mean age = 68.6/SD = 9.1; 54.1% female). We extracted 18 sleep, activity, timing, rhythmicity, and fragmentation measures from actigraphy. We used individual and multivariable regressions with the outcome of clinically significant depression symptoms (Center for Epidemiologic Studies Depression Scale ≥ 16). We conducted sensitivity analyses in people with higher insomnia severity (top quartile of the Women's Health Initiative Insomnia Rating Scale total score). From separate models in the overall sample, the odds of having depression symptoms were higher with: later timing (e.g. activity onset time odds ratio [OR]/1 SD = 1.32; 95% confidence interval [CI]: 1.16 to 1.50), lower rhythmicity (e.g. pseudo-F OR/1 SD = 0.75; 95% CI: 0.66 to 0.85), less activity (e.g. amplitude OR/1 SD = 0.83; 95% CI: 0.72 to 0.95), and worse insomnia (OR/1 SD = 1.48, 95% CI: 1.31 to 1.68). In multivariable models conducted among people with lower insomnia severity, later timing, lower rhythmicity, and higher insomnia severity were independent correlates of depression. In people with higher insomnia symptom severity, measures of later timing were most strongly associated with depression symptoms. These correlative observations suggest that experimental studies are warranted to test if: broadly promoting 24-hour sleep-wake functioning reduces depression even in people without severe insomnia, and if advancing timing leads to depression symptom reductions in people with insomnia.

OBJECTIVE SLEEP AND CIRCADIAN REST–ACTIVITY RHYTHMS AND MULTIPLE DOMAINS OF COGNITIVE FUNCTION IN OLDER ADULTS

Abstract Evidence suggests that sleep and circadian rest-activity rhythms (RAR) play a key role in dementia and Alzheimer Disease (AD) pathology. Studies with objective measures of sleep and RAR and multiple domains of cognition remain limited. We studied 820 older adults enrolled in the Study of Muscle, Mobility and Aging (SOMMA). Actigraphs were worn for one week, and processed for sleep-wake measures including total sleep time (TST) and sleep efficiency (SE); and parametric (acrophase, pseudo-F) and non-parametric (interdaily stability [IS], intradaily variability [IV], and relative amplitude [RA]) 24-hour RAR variables. Cognitive assessments included global cognition (the Montreal Cognitive Assessment), executive function (Trails B test), memory (California Verbal Learning Test-short form; and psychomotor performance (Digit-Symbol Coding Test). Adjusting for age, sex, clinic site and education, we examined adjusted mean cognitive test scores by categories of sleep and RAR exposures. Mean age was 76 years, 58% were female, and 15% were non-white. Higher RA, reflecting a more robust 24-hour RAR, was associated with better cognition on all tests (p for trend <0.05). Reduced SE was related to lower cognitive function (psychomotor performance, global cognition, memory; p<.05). There were no associations with TST and any cognitive measures examined. SE and RAR were variably associated with both global and specific domains of cognition in older men and women. The RA in particular was strongly related to multiple domains of cognition related to AD, and may be useful in identifying individuals at risk. Additional analyses will explore sex differences and longitudinal associations.

Sleep-wake state discrepancy among cancer survivors with insomnia symptoms.

To evaluate the discrepancy and correlation between sleep-wake measures (i.e., time in bed (TIB), total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), and sleep efficiency (SE%)) reported on sleep diary and measured by actigraphy among cancer survivors with insomnia symptoms; and examine the influences of sociodemographic and clinical variables on these measurement differences. A heterogenous sample of cancer survivors with insomnia symptoms (n = 120; M age = 63.7 ± 10.1; female = 58.3%) was included. Seven consecutive days of sleep diary and actigraphic data were obtained along with information on demographic, sleep, and mental health symptoms. Bland-Altman plot, Pearson correlation coefficient, concordance correlation coefficient, and mixed linear model approach were used to conduct the analysis. Self-reported TIB, SOL, and WASO were longer than measured by actigraphy (TIB: 8.6min. (95% CI, 3.7, 13.5; p < .001); SOL: 14.8min. (95% CI, 9.4, 20.2; p < .0001); and WASO: 20.7min. (95% CI, 9.4, 20.2; p < .0001), respectively); and self-reported TST and SE% were shorter than measured by actigraphy (TST: 6.8min. (95% CI, -18.7, 5.13); and SE%: 0.7% (95%CI, -3.0, 2.0), respectively), but were not statistically significant. Sex, higher insomnia severity, and poor sleep quality were associated with discrepancy between several sleep-wake measures. Subjective and objective sleep-wake measures may present discrepant finding among cancer survivors with symptoms of insomnia. Future research is needed to validate appropriate sleep-wake assessment, and better understand factors that influence the discrepancy that exists between measures among this population. Clinical trials identifier: NCT03810365. Date of registration: January 14, 2019.

White matter microstructure and sleep-wake disturbances in individuals at ultra-high risk of psychosis.

White matter changes in individuals at ultra-high risk for psychosis (UHR) may be involved in the transition to psychosis. Sleep-wake disturbances commonly precede the first psychotic episode and predict development of psychosis. We examined associations between white matter microstructure and sleep-wake disturbances in UHR individuals compared to healthy controls (HC), as well as explored the confounding effect of medication, substance use, and level of psychopathology. Sixty-four UHR individuals and 35 HC underwent clinical interviews and diffusion weighted imaging. Group differences on global and callosal mean fractional anisotropy (FA) was tested using general linear modeling. Sleep-wake disturbances were evaluated using the subjective measures disturbed sleep index (DSI) and disturbed awakening index (AWI) from the Karolinska Sleep Questionnaire, supported by objective sleep measures from one-night actigraphy. The primary analyses comprised partial correlation analyses between global FA/callosal FA and sleep-wake measures. Secondary analyses investigated multivariate patterns of covariance between measures of sleep-wake disturbances and FA in 48 white matter regions of interest using partial least square correlations. Ultra-high risk for psychosis individuals displayed lower global FA (F = 14.56, p < 0.001) and lower callosal FA (F = 11.34, p = 0.001) compared to HC. Subjective sleep-wake disturbances were significantly higher among the UHR individuals (DSI: F = 27.59, p < 0.001, AWI: F = 36.42, p < 0.001). Lower callosal FA was correlated with increased wake after sleep onset (r = -0.34, p = 0.011) and increased sleep fragmentation index (r = -0.31, p = 0.019) in UHR individuals. Multivariate analyses identified a pattern of covariance in regional FA which were associated with DSI and AWI in UHR individuals (p = 0.028), but not in HC. Substance use, sleep medication and antipsychotic medication did not significantly confound these associations. The association with objective sleep-wake measures was sustained when controlling for level of depressive and UHR symptoms, but symptom level confounded the covariation between FA and subjective sleep-wake measures in the multivariate analyses. Compromised callosal microstructure in UHR individuals was related to objectively observed disruptions in sleep-wake functioning. Lower FA in ventrally located regions was associated with subjectively measured sleep-wake disturbances and was partly explained by psychopathology. These findings call for further investigation of sleep disturbances as a potential treatment target.

Associations between locus coeruleus integrity and nocturnal awakenings in the context of Alzheimer\u2019s disease plasma biomarkers: a 7T MRI study

BackgroundThe brainstem locus coeruleus (LC) constitutes the intersection of the initial pathophysiological processes of Alzheimer’s disease (AD) and sleep-wake dysregulation in the preclinical stages of the disease. However, the interplay between in vivo assessment of LC degeneration and AD-related sleep alterations remains unknown. Here, we sought to investigate whether MRI-assessed LC structural integrity relates to subjective sleep-wake measures in the context of AD plasma biomarkers, in cognitively unimpaired older individuals.MethodsSeventy-two cognitively unimpaired older individuals aged 50–85 years (mean age = 65.2 ± 8.2 years, 37 women, 21 APOE ε4 carriers) underwent high-resolution imaging of the LC at 7 Tesla, and LC structural integrity was quantified using a data-driven approach. Reports on habitual sleep quality and nocturnal awakenings were collected using sleep questionnaires. Plasma levels of total tau, p-tau181, Aβ40, and Aβ42 were measured using single-molecule array technology.ResultsIntensity-based cluster analyses indicated two distinct LC segments, with one covering the middle-to-caudal LC and displaying lower intensity compared to the middle-to-rostral cluster (t70 = −5.12, p < 0.0001). After correction for age, sex, depression, and APOE status, lower MRI signal intensity within the middle-to-caudal LC was associated with a higher number of self-reported nocturnal awakenings (F1,63 = 6.73, pFDR = 0.03). Furthermore, this association was mostly evident in individuals with elevated levels of total tau in the plasma (F1,61 = 4.26, p = 0.04).ConclusionOur findings provide in vivo evidence that worse LC structural integrity is associated with more frequent nocturnal awakenings in the context of neurodegeneration, in cognitively unimpaired older individuals. These results support the critical role of the LC for sleep-wake regulation in the preclinical stages of AD and hold promises for the identification of at-risk populations for preventive interventions.

Trajectory of insomnia symptoms in older adults with lung cancer: using mixed methods.

A knowledge gap exists in our understanding of the illness and insomnia symptom treatment trajectory in adults with inoperable non-small cell lung cancer (NSCLC). Compare valid and reliable sleep-wake measures for insomnia to interpretations of narrative descriptions of sleep to improve our comprehension of sleep-wake disturbances in adults with NSCLC. This study employed mixed methods (quantitative and qualitative) in a longitudinal design to study adults (n = 26) from ambulatory thoracic clinics. Valid and reliable surveys (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale), 7-day sleep diary, and actigraphy were obtained with interview narrative interpretations of sleep experiences in the context of lung cancer. Data collection occurred at four-time points: baseline (before chemotherapy), pre-second chemotherapy, pre-third chemotherapy, and 6months from baseline. Sleep measures were compared to interpretations from interview narratives to understand context of survey measures. Objective quantitative results were congruent with interview narrative interpretations that reflected participants' sleep-wake experiences. Objective sleep-wake measures for insomnia over-time described increasing sleep latency and decreasing sleep duration. The interview narratives provided context and insight into participants' subjective insomnia experiences. While participants' insomnia symptoms were present, they were resigned to endure insomnia, and the subjective measures reflected a more positive perception of sleep outcomes. A mixed methods approach provides a deeper understanding of sleep-wake disturbances and the differing quantitative objective and subjective results of sleep measures in the context of the participants' experience of the trajectory of insomnia symptoms before, during, and after lung cancer treatment.

Sleep assessment in a randomized trial of hyperbaric oxygen in U.S. service members with post concussive mild traumatic brain injury compared to normal controls

Study objectiveIn this exploratory, double-blind, longitudinal sham-controlled trial of hyperbaric oxygen (HBO2) for military personnel with post concussive mild traumatic brain injury (mTBI), self-reports and objective measures of sleep-wake disturbances were assessed and compared to normals. MethodsSelf-reports consisting of Pittsburg Sleep Quality Index (PSQI), sleep diary, screening for obstructive sleep apnea (OSA) risk, restless legs syndrome (RLS), cataplexy, and objective actigraphic measures of sleep-wake were obtained on 71 military personnel with mTBI [baseline, 13 weeks and six months post-randomization (post-intervention)], of which 35 met post-traumatic stress disorder (PTSD) criteria, and 75 healthy volunteers (baseline). Baseline between-group and follow-up changes from baseline overall and within subgroups were evaluated. Mild TBI was defined as consisting of head injury associated loss of consciousness (<24 h), post-traumatic amnesia, and neurological deficits. ResultsSleep quality by self-reports was markedly degraded in the mTBI group at baseline compared to a normative cohort; insomnia 87.3 versus 2.8%, OSA risk 70% versus 1.3%, RLS 32.4% versus and 2.7%. (all p-values <0.001), but actigraphy measures did not differentiate between groups. HBO2 compared to sham treatment improved self-reports of PSQI sleep measures, reports (five out of eight at 13-weeks and two out of eight at six-months). However, other sleep-wake measures were not different. ConclusionsPerceived sleep quality was markedly disrupted in mTBI military personnel and sleep-wake disturbances were prevalent compared to a normative cohort. HBO2 relative to sham improved some measures of sleep quality on the PSQI, but other measures of sleep were not significantly different.

Napping and morningness-eveningness

Our main aim in this work was to investigate the difference in napping behavior in relation to morningness and eveningness. We assessed morningness, eveningness, habitual sleep-wake times and different measures of napping, namely, start time, end time and duration on both weekdays and weekend days. Napping start time did not differ between weekdays and weekends, but napping ended later on weekends. Morning affect positively and eveningness negatively were related to nap end on weekend, nap duration on weekdays/weekend, average nap duration, and midpoint of napping on free days (MNFc). Nap duration was related to morningness and eveningness, with evening-oriented people napping longer. Midpoint of sleep and midpoint of napping were also positively correlated. Further, longer naps do not seem to compensate for lack of sleep on weekdays. As a conclusion, we identified napping as a correlate of morningness, eveningness and midpoint of sleep.

Rest-activity rhythm and sleep characteristics associated with depression symptom severity in strained dementia caregivers.

Depression is associated with disturbances to sleep and the 24-h sleep-wake pattern (known as the rest-activity rhythm: RAR). However, there remains a need to identify the specific sleep/RAR correlates of depression symptom severity in population subgroups, such as strained dementia caregivers, who are at elevated risk for major depressive disorder. We assessed the cross-sectional associations of sleep/RARs with non-sleep depression symptom severity among 57 (mean age: 74years, standard deviation: 7.4) strained dementia caregivers who were currently without clinical depression. We derived sleep measures from polysomnography and actigraphy, modelled RARs using a sigmoidally transformed cosine curve and measured non-sleep depression symptom severity using the Hamilton Depression Rating Scale (HRDS) with sleep items removed. The following sleep-wake measures were associated with greater depression symptom severity (absolute Spearman's correlations ranged from 0.23 to 0.32): more time awake after sleep onset (WASO), higher RAR middle level (mesor), relatively shorter active periods (alpha), earlier evening settling time (down-mesor) and less steep RARs (beta). In multivariable analysis, high WASO and low RAR beta were associated independently with depression symptom severity. Predicted non-sleep HDRS means (95% confidence intervals) in caregivers with and without these characteristics were: normal WASO/beta=3.7 (2.3-5.0), high WASO/normal beta=5.5 (3.5-7.6), normal WASO/low beta=6.3 (3.6-8.9) and high WASO/low beta=8.1 (5.3-10.9). Thus, in our sample of strained caregivers, greater sleep fragmentation (WASO) and less sustained/sharply segregated resting and active periods (low RAR beta) correlate uniquely with depression symptom severity. Longitudinal studies are needed to establish whether these independent sleep-wake correlates of depression symptoms explain heightened depression risk in dementia caregivers.

Pineal volume and evening melatonin in young people with affective disorders.

Affective disorders in young people have been associated with disruptions in circadian rhythms, including abnormalities in secretion of the pineal hormone melatonin. Previous research reports relationships between pineal gland volumes, melatonin secretion, and sleep-wake cycles, but the relationship between these factors has not been explored in affective disorders. This study aimed to characterize these factors and explore associations with mood symptoms and functioning in a sample of young people with affective disorders. Pineal volume from magnetic resonance imaging and melatonin assay from evening dim-light saliva collection were evaluated in 50 individuals (15-30years old; 72% female) with bipolar, depressive, or anxiety disorders. Actigraphy monitoring was also conducted for approximately two weeks to derive sleep-wake measures. Pineal volume was associated with melatonin secretion across the evening, replicating previous findings in psychiatrically healthy individuals. Pineal volume was smaller in participants in which melatonin onset was not detected. Timing of melatonin secretion was related to sleep timing, but amount of melatonin and pineal volume were not related to any sleep-wake measures. A shorter phase angle between onset of melatonin secretion and sleep onset was associated with longer total sleep time. Lower melatonin levels were associated with poorer social and occupational functioning. Although pineal volume is not directly related to sleep disturbances or symptoms, melatonin may influence both sleep-wake cycles and functioning in the early stages of affective disorder. Causal links remain to be established, however, treatments that target circadian rhythms may be useful in improving functioning in young people with affective disorders.

Measures of Sleep–Wake Patterns and Risk of Mild Cognitive Impairment or Dementia in Older Women

Sleep disturbances are common in older adults. Little is known about the sleep of cognitively intact older adults and its relationship to subsequent cognitive impairment. The objective of this study was to examine the association between objective sleep-wake measures and risk of incident cognitive impairment. In this prospective cohort study encompassing four U.S. sites, 1,245 women (mean age: 82.6 years) without dementia participated in the Study of Osteoporotic Fractures and completed actigraphy at the baseline visit and comprehensive cognitive assessment at follow-up. The association between sleep-wake patterns measured by actigraphy and risk of incident mild cognitive impairment (MCI) and dementia was examined. A total of 473 women (38%) developed cognitive impairment during an average (SD) follow-up of 4.9 (0.6) years; 290 (23.3%) developed MCI and 183 (14.7%) developed dementia. After controlling for multiple potential confounders, women in the lowest quartile of average sleep efficiency (<74%) had a 1.5-fold higher odds of developing MCI or dementia compared with women in the highest quartile of sleep efficiency (>86%) (odds ratio: Q1 versus Q4 1.53; 95% CI: 1.07, 2.19; Wald χ(2) [1, N = 1,223] = 5.34 for p for trend = 0.03). Longer average sleep latency, but not total sleep time, was also associated with higher odds of developing cognitive impairment. Greater variability in both sleep efficiency and total sleep time was associated with an increased odds of developing MCI or dementia. Lower average sleep efficiency, longer average sleep latency, and greater variability in sleep efficiency and total sleep time are associated with increased odds of developing cognitive impairment. Further research is needed to explore the mechanisms underlying these associations.

Suppression of preoptic sleep-regulatory neuronal activity during corticotropin-releasing factor-induced sleep disturbance.

Corticotropin releasing factor (CRF) is implicated in sleep and arousal regulation. Exogenous CRF causes sleep suppression that is associated with activation of at least two important arousal systems: pontine noradrenergic and hypothalamic orexin/hypocretin neurons. It is not known whether CRF also impacts sleep-promoting neuronal systems. We hypothesized that CRF-mediated changes in wake and sleep involve decreased activity of hypothalamic sleep-regulatory neurons localized in the preoptic area. To test this hypothesis, we examined the effects of intracerebroventricular administration of CRF on sleep-wake measures and c-Fos expression in GABAergic neurons in the median preoptic nucleus (MnPN) and ventrolateral preoptic area (VLPO) in different experimental conditions. Administration of CRF (0.1 nmol) during baseline rest phase led to delayed sleep onset and decreases in total amount and mean duration of non-rapid eye movement (NREM) sleep. Administration of CRF during acute sleep deprivation (SD) resulted in suppression of recovery sleep and decreased c-Fos expression in MnPN/VLPO GABAergic neurons. Compared with vehicle controls, intracerebroventricular CRF potentiated disturbances of both NREM and REM sleep in rats exposed to a species-specific psychological stressor, the dirty cage of a male conspecific. The number of MnPN/VLPO GABAergic neurons expressing c-Fos was reduced in the CRF-treated group of dirty cage-exposed rats. These findings confirm the involvement of CRF in wake-sleep cycle regulation and suggest that increased CRF signaling in the brain 1) negatively affects homeostatic responses to sleep loss, 2) exacerbates stress-induced disturbances of sleep, and 3) suppresses the activity of sleep-regulatory neurons of the MnPN and VLPO.

Cross-cultural comparison of seven morningness and sleep-wake measures from Germany, India and Slovakia.

Morningness-eveningness or circadian typology can be viewed as an interesting aspect of individual differences. Morningness-eveningness is a preference for a given time of day for physical or mental performance, but also reflects aspects of affect. Here, we used seven different measures to assess differences in morningness-eveningness between Germany, Slovakia and India. The hypothesis was that Indians should be earliest chronotypes, followed by Slovakia and then Germany, because of higher temperatures in India, and the fact that Slovakia is located farther east compared to Germany. We applied the Composite Scale of Morningness (CSM), the Circadian Energy Scale (CIRENS), the CAEN Chronotype Questionnaire (CCQ), and habitual sleep-wake variables to calculate sleep duration, midpoint of sleep and social jetlag. Sample sizes were N = 300 (Germany), N = 482 (Slovakia) and N = 409 (India). Country had the strongest influence on morningness-eveningness. Germans were latest chronotypes and differed in all seven measures from Indians but differed from Slovakians only in the energy level at the evening and midpoint of sleep. Slovakians and Indians differed in all measures but the energy level (CIRENS). Women scored higher on the CSM, lower on CIRENS, lower on the morningness-eveningness (ME) scale, but higher on distinctness (DI) scale. Women slept longer and had an earlier midpoint of sleep.

Women would like their Partners to be more Synchronized with them in their Sleep-Wake Rhythm

Men sleep shorter and go to bed and get up later than women, thus they are later chronotypes. This difference between the sexes is most pronounced between puberty and menopause indicating the possibility that morningness is subject to sexual dimorphism related to reproductive aspects. The objective of the study was to compare the sleep-wake behavior of women with their actual partners and with their preferred partners. As a hypothesis, we expect some assortment in mating concerning chronotype (with the actual partner), but we also expect a higher synchronization with a preferred ideal partner. 167 women were analyzed in this study (mean age: 23.0 ± 2.57 (SD) years). Mated women were earlier chronotypes than their partners (t = -2.051, p = .042, d = .34) but the difference was small (11:02 min ± 1:04 min). The results of the present study showed women preferring a partner synchronized to their own sleep-wake-rhythm more than their actual partners were. The above result was true either for single facets of the sleep-wake rhythm (e.g. bed time, sleep onset) or for midpoint of sleep on free days - an indicator of actual chronotype: women's and their partners' correlation of midpoint of sleep was lower (r = .513) than women's and their ideal partners' correlation (r = .855). Amongst various sleep-wake measures, women particularly preferred a partner going to bed at the same time. Assortative mating according to sleep-wake rhythm exists, but women for long-term pair-bonds would like their partners far more synchronized.

Six-Month Sleep–Wake Organization and Stability in Preschool-Age Children With Autism, Developmental Delay, and Typical Development

This study examined sleep–wake patterns in 3 matched comparison groups of preschool-aged children: children with autism (AUT), children with developmental delay (DD) without AUT, and children who are developing typically (TYP). Sleep was assessed via actigraphy and parent-report diaries for 7 consecutive 24-hr periods across 3 time points: at enrollment (n = 194), 3 months later (n = 179), and 6 months after enrollment (n = 173). At each recording period, children in the AUT group slept less per 24-hr period, on average, and were less likely to awaken at night than children in the other two groups. In contrast, children in the DD group had more frequent and longer duration nighttime awakenings than children in the AUT group. Overall, children in the 2 neurodevelopmentally disordered groups demonstrated more night-to-night variability in their sleep–wake measures than children in the TYP group.

Spatial memory performance associated with measures of immune function in elderly female rhesus macaques

We recently reported that in aged female rhesus macaques, spatial learning and memory correlates with circadian sleep-wake measures and hippocampal muscarinic type 1 (M 1) receptor binding. To investigate if spatial memory also correlates with measures of immune function, we assessed the magnitude of the adaptive immune response to vaccination in the same old female rhesus macaques. Cognitively characterized animals were classified as good spatial performers (GSP) or poor spatial performers (PSP) based on performance in the Spatial Foodport maze. The GSP group had higher frequency of CD8, but not CD4, interferon-γ (IFN-γ) producing cells following vaccination compared to the PSP group, suggesting a stronger CD8 T cell response in the GSP group. In addition, the number of CD-8 IFN-γ positive cells correlated with measures of sleep quality. Interestingly, the PSP group had a significantly higher antibody titer compared to the GSP group, and antibody titer negatively correlated with day-time activity. Thus, in aged female rhesus macaques, superior cognitive performance is correlated with a more robust CD8 T cell response but a reduced antibody response to vaccination.

Sleep/Wake Patterns Derived from Activity Monitoring and Maternal Report for Healthy 1- to 5-Year-Old Children

To describe behavioral sleep/wake patterns of young children from actigraphy and mothers' reports, assess age-group and sex differences, describe daytime napping, and investigate the impact of family demographic variables on sleep-wake measures. Cross-sectional sample of children wore actigraphs for 1 week; mothers kept concurrent diaries. Children studied in their homes. 169 normal healthy children in 7 age groups (12, 18, 24, 30, 36, 48, and 60 months old); 84 boys and 85 girls. N/A. Nocturnal sleep/wake measures estimated from activity recordings using a validated algorithm; mothers' reports of nocturnal sleep/wake patterns and daytime naps obtained from concurrent diaries. Bedtimes and sleep start times were earliest and time in bed and sleep period times were longest for 12-month-old children. Rise time, sleep end time, and nocturnal sleep minutes did not differ across age groups. Actigraphic estimates indicated that children aged 1 to 5 years slept an average of 8.7 hours at night. Actigraph-based nocturnal wake minutes and wake bouts were higher than maternal diary reports for all age groups. Daytime naps decreased monotonically across age groups and accounted for most of the difference in 24-hour total sleep over age groups. Children in families with lower socioeconomic status had later rise times, longer time in bed, more nocturnal wake minutes and bouts, and more night-to-night variability in bedtime and sleep period time. Children with longer naps slept less at night. Individual differences in sleep/wake measures reflect characteristics of children, parents, or parent-child interactions.

Sleep patterns and sleep disruptions in school-age children.

This study assessed the sleep patterns, sleep disruptions, and sleepiness of school-age children. Sleep patterns of 140 children (72 boys and 68 girls; 2nd-, 4th-, and 6th-grade students) were evaluated with activity monitors (actigraphs). In addition, the children and their parents completed complementary sleep questionnaires and daily reports. The findings reflected significant age differences, indicating that older children have more delayed sleep onset times and increased reported daytime sleepiness. Girls were found to spend more time in sleep and to have an increased percentage of motionless sleep. Fragmented sleep was found in 18% of the children. No age differences were found in any of the sleep quality measures. Scores on objective sleep measures were associated with subjective reports of sleepiness. Family stress, parental age, and parental education were related to the child's sleep-wake measures.

Comparison of Cognitive-Behavioral Therapy and Clonazepam for Treating Periodic Limb Movement Disorder

Many patients with periodic limb movement disorder (PLMD) display inadequate sleep hygiene, and others decline conventional pharmacologic intervention for their form of sleep disturbance. Nonetheless, the use of nonpharmacologic therapies with PLMD remains unexplored. The current study was designed to compare the short-term treatment effects of a cognitive-behavioral therapy (CBT) and conventional pharmacotherapy (clonazepam) among a group of insomniacs with PLMD. The 16 subjects participating in this study first underwent baseline assessment procedures, including completion of a sleep log for 2 weeks, an ambulatory polysomnogram (APSG) and an Insomnia Symptom Questionnaire (ISQ). They then were randomized either to CBT (n = 8) or standard clonazepam therapy (n = 8). Subjects maintained sleep logs throughout a 4-week treatment and then completed a second APSG and ISQ. Comparison of pre- and post-treatment data suggested that the two treatments led to equal improvements in sleep log measures of sleep-wake times and ISQ measures of subjective sleep concerns. Patients treated with CBT showed a decrease in daytime napping, whereas the clonazepam group reported increased napping. Conversely, those treated with clonazepam showed larger declines in periodic limb movement-arousals per hour of sleep than did the CBT group. Post-treatment interviews suggested that both CBT and clonazepam therapies were generally well tolerated by study participants. It is concluded that both treatments may be useful for PLMD but that the two treatments may have contrasting effects across selected measures of improvement. Additional research is needed to examine the long-term efficacy of CBT as a primary or adjunctive treatment for varying levels of PLMD severity.