Sleep restores daytime deficits in procedural memory in children with attention-deficit/hyperactivity disorder

Sleep supports the consolidation of declarative and procedural memory. While prefrontal cortex (PFC) activity supports the consolidation of declarative memory during sleep, opposite effects of PFC activity are reported with respect to the consolidation of procedural memory during sleep. Patients with attention-deficit/hyperactivity disorder (ADHD) are characterised by a prefrontal hypoactivity. Therefore, we hypothesised that children with ADHD benefit from sleep with respect to procedural memory more than healthy children. Sixteen children with ADHD and 16 healthy controls (aged 9-12) participated in this study. A modification of the serial-reaction-time task was conducted. In the sleep condition, learning took place in the evening and retrieval after a night of sleep, whereas in the wake condition learning took place in the morning and retrieval in the evening without sleep. Children with ADHD showed an improvement in motor skills after sleep compared to the wake condition. Sleep-associated gain in reaction times was positively correlated with the amount of sleep stage 4 and REM-density in ADHD. As expected, sleep did not benefit motor performance in the group of healthy children. These data suggest that sleep in ADHD normalizes deficits in procedural memory observed during daytime. It is discussed whether in patients with ADHD attenuated prefrontal control enables sleep-dependent gains in motor skills by reducing the competitive interference between explicit and implicit components within a motor task.     

Prevalence and neurophysiological correlates of sleep disordered breathing in pediatric type 1 narcolepsy

Study objectivesTo investigate the prevalence and neurophysiological correlates of obstructive sleep disordered breathing (OSA) in type 1 narcolepsy (NT1) children and adolescents.MethodsThirty-eight, drug-naïve, NT1 children and adolescents and 21 age- and sex-balanced clinical controls underwent nocturnal polysomnography (PSG) and multiple sleep latency test (MSLT). According to the rules for pediatric population, an obstructive apnea-hypopnea index (Obstructive AHI) ≥ 1 (comprising obstructive and mixed events), defined comorbid OSA.ResultsNT1 children showed higher prevalence of overweight/obesity and severe nocturnal sleep disruption (lower sleep efficiency, and increased N1 sleep stage percentage) coupled with higher motor activity (periodic limb movement index [PLMi] and REM atonia index) compared to clinical controls. Sleep-related respiratory variables did not differ between NT1 and clinical controls (OSA prevalence of 13.2% and 4.8%, respectively). NT1 children with OSA were younger and showed lower N2 sleep stage percentage and higher PLMi than NT1 children without comorbid OSA. Overweight/obesity was not associated with OSA in NT1.ConclusionsDespite higher body mass index (BMI), OSA prevalence did not differ between children with NT1 and clinical controls. OSA in pediatric NT1 patients is a rare and mild comorbidity, further contributing to nocturnal sleep disruption without effects on daytime sleepiness.     

Poor sleep quality is associated with discordant peer relationships among adolescents with Autism Spectrum Disorder

BackgroundIndividuals with Autism Spectrum Disorder (ASD) experience impairments in social communication, and these deficits often make it difficult to form and maintain friendships with peers. Poor sleep quality and daytime sleepiness are common among adolescents with ASD, and consequences of poor sleep may make social interactions difficult. Connections between sleep quality and social relationships in ASD samples have been understudied; the current study addresses this gap.MethodParticipants were community samples of 19 adolescents with ASD and 10 neurotypical (NT) adolescents. Adolescents completed questionnaires about closeness and discord in relationships with a same-gender peer, and they reported on sleep-wake problems, daytime sleepiness, and internalizing problems. Adolescents also wore an actigraph for 7-nights.ResultsPearson correlations revealed significant associations between adolescents’ reports of sleep problems and discordant peer relationships; more sleep-wake problems and more daytime sleepiness were associated with more discord with peers in the sample with ASD, but not in the NT sample. The closeness aspect of peer relationships was not significantly associated with sleep quality. Internalizing problems did not mediate between sleep quality and discordant relationships.ConclusionsAdolescents’ reports of more sleep problems and daytime sleepiness, but not actigraph indicators of sleep quality, were directly associated with discordant peer relationships. Adolescents who are already challenged in social interactions due to ASD may be especially vulnerable to intense negativity in peer relationships when they also experience poorer nighttime sleep and more daytime sleepiness. NT adolescents may be better able to regulate social interactions despite poor sleep and feeling tired.     

Children's sleep problems are associated with poorer student–teacher relationship quality

ObjectiveChildren's sleep problems are associated with poorer student functioning in the school environment, including impairment in peer relationships; yet, no studies have examined sleep functioning in relation to the student–teacher relationship. The objective of this study was to examine whether child-rated total sleep problems or specific sleep problem domains (bedtime problems, nighttime problems, or daytime sleepiness) were associated with teacher-rated student–teacher closeness and conflict after controlling for student mental health symptoms known to be associated with both greater sleep problems and poorer student–teacher relationship quality. The study also examined whether age moderated the relation between sleep problems and student–teacher relationship quality.ParticipantsParticipants were 175 children (81 boys and 94 girls) in the first to sixth grades (age = 6–13 years) and their teachers.MethodsChildren completed the Sleep Self-Report. Teachers completed a measure of student mental health symptoms (ie, attention-deficit/hyperactivity disorder, oppositional defiant disorder, conduct disorder, and anxiety/depression) and a measure of their relational closeness and conflict with each student.ResultsTotal sleep problems were associated with greater student–teacher conflict, after controlling for child mental health symptoms and demographic factors. This association was moderated by age such that sleep problems were associated with conflict for younger children but not older children. Notably, daytime sleepiness specifically was associated with less student–teacher closeness.ConclusionsThis is the first study to demonstrate a relation between student sleep functioning and the student–teacher relationship. Results of the study suggest that sleep may be an important component of school-based screening and evaluation efforts, as sleep is an important malleable factor related to school success.     

The effects of Dexamethasone on sleep in young children with Acute Lymphoblastic Leukemia

PurposeCorticosteroids, which are a mainstay in the treatment of acute lymphoblastic leukemia (ALL), have a well-documented adverse effect on sleep. We sought to characterize the effects of dexamethasone on sleep over an entire 28-day treatment cycle using actigraphy, an objective measure of sleep.MethodsThe sleep of 25 children aged 2–9 years (mean 4.5 years) with ALL treated with dexamethasone were evaluated during maintenance chemotherapy using a within-subject experimental design, actigraphy, and standardized questionnaires to assess sleep, sleep problems, and fatigue.ResultsDuring the five days of dexamethasone treatment, sleep time increased during the night (535 vs. 498 min; p = 0.004) and daytime napping increased the following day (14 vs. 0 min; p = 0.002), and the number of wake episodes during the night was lower (14 vs. 20; p = ≤ 0.001). However, when assessed individually, sleep-onset time, efficiency, and wake after sleep onset during the night were unchanged during dexamethasone treatment; when the cumulative effect of all of these factors was assessed, there was a statistically and clinically significant increase in nighttime sleep duration during dexamethasone treatment.ConclusionsDuring the five days of treatment with dexamethasone, an increase in nighttime sleep as well as daytime napping was observed in young children with ALL. The increases in sleep duration return to baseline one day after the discontinuation of dexamethasone.     

Developmental differences in sleep's role for implicit off-line learning: comparing children with adults

Sleep crucially contributes to the off-line consolidation of memories. Although this view was confirmed in numerous studies in adults, it is not known whether it can be generalized to sleep during development. Here, we examined effects of sleep on implicit memory formation considered of particular relevance in children, because brain structures underlying implicit learning develop earlier in ontogeny than structures supporting explicit learning. Subjects were 7- to 11-year-old children (n = 14) and 20- to 30-year-old adults (n = 12) tested on a serial reaction time task before (learning) and after (retest) equal length retention periods of overnight sleep and daytime wakefulness. At learning, after eight training blocks, all subjects had acquired implicit knowledge of the probabilistic rules underlying the sequential stimulus materials, as indicated by a substantial difference in response time to grammatical versus nongrammatical trials in two test blocks that followed the training blocks. At learning, this response time difference was greater in children (48.49 +/- 6.08 msec) than adults (28.02 +/- 3.65 msec, p < .01), but did not differ between sleep and wake retention conditions in either age group. Consistent with previous studies, retesting in the adults revealed that the reaction time differences between grammatical and nongrammatical trials increased by 9.78 +/- 4.82 msec after sleep, but decreased by -12.76 +/- 5.49 msec after the wake retention period (p < .01). Contrary to this finding in adults, sleep in children did not lead to an increase, but to a decrease in the reaction time difference averaging -26.68 +/- 12.25 msec (p < .05), whereas across the wake retention interval the reaction time difference remained nearly unchanged. The sleep-dependent deterioration in measures of implicit sequence knowledge in children was in striking contrast to the gain of such knowledge in the adults during sleep (p < .01). Our findings indicate that the functional role of sleep in implicit memory consolidation depends on age. We speculate that the overnight decrease of implicit knowledge in children reflects a preferential effect of sleep toward the enhancement of explicit aspects of task performance that interferes with implicit performance gains.     

Subtypes of insomnia and the risk of chronic spinal pain: the HUNT study

ObjectiveTo examine the association between subtypes of insomnia and the risk of chronic spinal pain.MethodsThe study comprised 16,401 participants without chronic spinal pain at baseline who were followed for ∼11 years. People were categorized into ‘no insomnia symptoms’, ‘subthreshold insomnia’, and ‘insomnia’. Insomnia was defined according to the diagnostic classification system requiring both daytime and nighttime symptoms, and further categorized into subtypes based on nighttime symptoms (ie, sleep onset latency [SOL-insomnia], wake after sleep onset [WASO-insomnia], early morning awakening [EMA-insomnia], or combinations of these). Subthreshold insomnia comprised those with only daytime impairment or one or more nighttime symptoms. Chronic spinal pain was defined as pain in either ‘neck’, ‘low back’, or ‘upper back’, or a combination of these.ResultsIn multivariable regression analysis using people without insomnia as reference, people with subthreshold insomnia or insomnia had relative risks (RRs) of chronic spinal pain of 1.29 (95% confidence interval [CI] 1.21–1.38) and 1.50 (95% CI 1.34–1.68), respectively. The RRs for people with one nighttime symptom were 1.30 (95% CI 0.83–2.05) for WASO-insomnia, 1.32 (95% CI 1.06–1.65) for EMA-insomnia, and 1.70 (95% CI 1.32–2.18) for SOL-insomnia, respectively. Combinations of nighttime insomnia symptoms gave RRs from 1.45 (95% CI 1.08–1.94) for WASO + EMA-insomnia to 1.72 (95% CI 1.36–2.19) for all nighttime symptoms (SOL + WASO + EMA-insomnia).ConclusionsThese findings suggest that the risk of chronic spinal pain is highest among persons with insomnia subtypes characterized by sleep onset latency or among those having insomnia symptoms in all parts of the sleep period.     

Gender differences in nighttime sleep and daytime napping as predictors of mortality in older adults: The Rancho Bernardo Study

ObjectiveMany studies suggest optimal sleep duration for survival is 7–8 h/night. We report the gender-specific independent association of all-cause mortality with nighttime sleep and daytime nap duration in older adults who were followed for up to 19 years.MethodsBetween 1984 and 1987, 2001 community-dwelling, mostly retired, adults (1112 women), age 60–96 years, answered questions about health, mood, medications, life-style, daytime napping, and nighttime sleep duration. Vital status was confirmed for 96% through July 2001.ResultsAt baseline, men reported significantly longer nighttime sleep and daytime napping than women. In both men and women, nighttime sleep <6 h was associated with depressed mood and sleep-related medication, and ⩾9 h was associated with more alcohol consumption. Napping ⩾30 min was associated with prevalent depressed mood, coronary heart disease, and cancer. Of the group, 61% died over the next 19 years, at an average age of 85.6 years. Mortality risk was lowest among those sleeping 7–7.9 h/night in both men and women. Multiple-adjusted analyses showed that increased mortality was associated with nighttime sleep ⩾9 h in women (HR 1.51: 95% CI = 1.05–2.18), and with daytime napping ⩾30 min in men (HR 1.28: 95% CI, 1.00–1.64).ConclusionsMechanisms for these differences are unknown.     

Characteristics of sleep in children with autism spectrum disorders from the Simons Simplex Collection

BackgroundAn estimated 40–80% of children with ASD have sleep problems, including bedtime behavior problems, difficulty falling asleep and staying asleep, decreased sleep time, and daytime sleepiness. This study aimed to examine the relationship between sleep problems and characteristics of children with ASD in a large, nationwide sample.MethodsThis secondary analysis of children 4- to 18-years explored 11 sleep problems using the Simons Simplex Collection Sleep Interview (SSCSI). The SSCSI includes nighttime problems, daytime problems, and sleep duration problems subscales. Chi square, Kruskal-Wallis and Mann- Whitney U tests were performed to detect differences between age groups, sexes, and sleep problem groups (none/minimal, mild, moderate/severe). Odds ratios for variables associated with sleep problems were assessed using baseline and adjacent category logistic regression. Two-way interaction effects were included in regression models, and stratified analyses were performed for age groups.ResultsApproximately 41% of children were categorized as having mild or moderate/severe sleep problems. The most commonly reported SSCSI items were in the nighttime problems subscale; difficulty falling asleep was the most frequently reported item. Mean sleep duration was approximately 9 h, although more than one-quarter slept less than the hours recommended for their age. Increased odds of sleep problems were most frequently associated with gastrointestinal distress (GID) and non-verbal IQ (NVIQ), followed by male sex and age. ADOS severity score is likely not associated with sleep problems in this sample.ConclusionsThis study advances our understanding of sleep in ASD by showing that GID, NVIQ, sex, and age increased the odds of sleep problems in children with ASD. These results reinforce that healthcare professionals should screen for sleep problems in children with ASD and suggest future lines of inquiry.     

Daytime symptoms of restless legs syndrome – clinical characteristics and rotigotine effectiveness

ObjectiveTo elucidate the prevalence and clinical characteristics of daytime restless legs syndrome (RLS) among patients with idiopathic RLS and investigate the effectiveness of rotigotine for daytime RLS.MethodsIn 256 enrolled RLS patients, we investigated factors associated with the presence of RLS symptoms throughout the day. We also assessed the duration of daytime RLS symptoms at hourly intervals, time of initial symptom onset during the day, and associations between duration of daytime and nighttime RLS symptoms. In addition, we compared changes in duration and frequency of RLS symptoms during daytime and nighttime after randomly assigning patients to a 13-week treatment with rotigotine, a dopamine agonist patch with 24-hour action, or placebo.ResultsEighty-one (31.6%) patients had daytime RLS symptoms. Only the International Restless Legs Syndrome Study Group rating scale total score was significantly associated with the presence of daytime RLS symptoms (p < 0.01) on multiple logistic regression analysis. Daytime RLS symptom onset was at 6 a.m. in 44.4% of patients; symptom duration increased significantly toward nighttime. There was a significant positive association between duration of daytime and nighttime RLS symptoms (p < 0.0001) and a greater statistically significant reduction of daytime RLS symptom duration with rotigotine treatment than with placebo (p = 0.03).ConclusionsDaytime symptoms are frequent in patients with RLS and may be associated with increased severity of the disorder and prolonged nighttime RLS symptoms. Rotigotine could become an important treatment choice for daytime symptoms.     

Impaired sleep-related consolidation of declarative memories in idiopathic focal epilepsies of childhood

ObjectiveDeclarative memory is consolidated during sleep in healthy children. We tested the hypothesis that consolidation processes are impaired in idiopathic focal epilepsies (IFE) of childhood in association with frequent interictal epileptiform discharges (IEDs) during sleep.MethodsA verbal (word-pair association) and a nonverbal (2D object location) declarative memory task were administrated to 15 children with IFEs and 8 control children 6–12 years of age. Patients had either centrotemporal (11 patients) or occipital (4 patients) IEDs. All but 3 patients had a history of unprovoked seizures, and 6 of them were treated with valproate (VPA). The learning procedure (location of object pairs presented on a grid; association of word pairs) was executed in the evening. Retrieval was tested immediately after learning and on the next morning after a night of sleep. Participants were tested twice, once in natural home conditions and one month later in the unfamiliar conditions of the sleep unit under EEG monitoring.ResultsOvernight recall performance was lower in children with IFE than in control children on both tasks (ps < 0.05). Performance in home conditions was similar to that in hospital conditions. Higher spike–wave index (SWI) during nonrapid eye movement (NREM) sleep was associated with poorer performance in the nonverbal task (p < 0.05). Valproate treatment was not associated with overnight recall performance for both tasks (ps > 0.05).ConclusionMemory consolidation is impaired in IFE of childhood. The association between higher SWI during NREM sleep and poorer nonverbal declarative memory consolidation supports the hypothesis that interictal epileptic activity could disrupt sleep memory consolidation.     

Polysomnographic predictors of sleep,motor and cognitive dysfunction progression in Parkinson's disease: a longitudinal study

ObjectiveTo assess the predictive value of polysomnographic (PSG) data in the prospective assessment of cognitive, motor, daytime and nighttime sleep dysfunction in Parkinson's Disease (PD) patients.MethodsPD patients were assessed at baseline with video-PSG and with cognitive (MoCA), Sleep (SCOPA-Sleep Nighttime and Daytime scores) and Motor (UPDRSIII) function scales at both baseline and four years later. Linear regression analysis was used to assess the relation between PSG variables at baseline and change in symptoms scores.ResultsWe included a total of 25 patients, 12 with rapid eye movement (REM) sleep behavior disorder (RBD) (in 8 PSG was inconclusive, due to lack of REM sleep). MoCA scores decreased significantly at follow-up, while SCOPA-Sleep Daytime and SCOPA-Sleep Nighttime and UPDRSIII did not vary. Lower N3 percentage at baseline was significantly associated with MoCA decrease. Higher Periodic Limb Movements in Sleep index (PLMS) and the presence of RBD were significantly associated with SCOPA daytime score increase. Higher global severity of RBD, tonic RSWA and total number of motor events during REM sleep were associated with SCOPA Nighttime score increase.ConclusionsThe present work suggests that PSG data could be useful for predicting PD cognitive and sleep dysfunction progression. Reduced SWS could predict deterioration of cognitive function, while baseline PLMS could be useful to predict worsening of daytime sleep dysfunction. Severity of RBD could be used for estimating nighttime sleep symptoms progression.     

Effect of melatonin on sleep disorders in a monkey model of Parkinson's disease

ObjectivesTo evaluate and compare the effects of melatonin and levodopa (L-dopa) on sleep disorders in a monkey model of Parkinson's disease.Materials and methodsThe daytime and nighttime sleep patterns of four macaques that were rendered parkinsonian by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were recorded using polysomnography in four conditions: at baseline, during the parkinsonian condition; after administration of L-dopa, and after administration of a combination of melatonin with L-dopa.ResultsIt was confirmed that MPTP intoxication induces sleep disorders, with sleep episodes during daytime and sleep fragmentation at nighttime. L-dopa treatment significantly reduced the awake time during the night and tended to improve all other sleep parameters, albeit not significantly. In comparison to the parkinsonian condition, combined treatment with melatonin and L-dopa significantly increased total sleep time and sleep efficiency, and reduced the time spent awake during the night in all animals. A significant decrease in sleep latencies was also observed in three out of four animals. Compared with L-dopa alone, combined treatment with melatonin and L-dopa significantly improved all these sleep parameters in two animals. On the other hand, combined treatment had no effect on sleep architecture and daytime sleep.ConclusionThese data demonstrated, for the first time, objective improvement on sleep parameters of melatonin treatment in MPTP-intoxicated monkeys, showing that melatonin treatment has a real therapeutic potential to treat sleep disturbances in people with Parkinson's disease.     

Association between nighttime sleep duration,midday naps,and glycemic levels in Japanese patients with type 2 diabetes

ObjectivesTo clarify the relationship between nighttime sleep duration, midday naps, and glycemic control in Japanese patients diagnosed with type 2 diabetes (n = 355) or impaired glucose tolerance (n = 43).MethodsA total of 398 patients completed a self-administered questionnaire on sleep duration/quality and were divided into five groups according to their self-reported nighttime sleep duration: <5 h, 5–6 h, 6–7 h, 7–8 h, and >8 h. Each group was further divided into two subgroups each according to the presence or absence of midday naps. Poor glycemic control was defined as HbA1c ≥ 7.0%.ResultsShort nighttime sleep (<5 h), poor sleep induction, daytime sleepiness, and low sleep satisfaction were associated with high HbA1c levels. HbA1c was higher in the short nighttime sleep/no nap group than in non-nappers with different nighttime sleep duration, whereas the short nighttime sleep/nap group showed similar HbA1c levels to the other nap subgroups. In multivariate logistic regression models, after adjusting for a number of potential confounders, short (<5 h) nighttime sleep without nap was significantly associated with poor glycemic control compared with 6–7 h nighttime sleep without nap (OR [95% CI]: 7.14 [2.20–23.20]). However, taking naps reduced this risk for poor glycemic control in short sleepers. Other risk factors for poor glycemic control were low sleep satisfaction (1.73 [1.10–2.70]) and poor sleep induction (1.69 [1.14–2.50]).ConclusionsPoor sleep quality and quantity could aggravate glycemic control in type 2 diabetes. Midday naps could mitigate the deleterious effects of short nighttime sleep on glycemic control.Clinical trials registrationUMIN 000017887.     

Actigraphic assessment of sleep/wake behavior in central disorders of hypersomnolence

ObjectiveTo evaluate the reliability of actigraphy to distinguish the features of estimated daytime and nighttime sleep between patients with central disorders of hypersomnolence and healthy controls.MethodsThirty-nine drug-naïve patients with Narcolepsy Type 1, twenty-four drug-naïve patients with Idiopathic Hypersomnia, and thirty age- and sex- matched healthy controls underwent seven days of actigraphic and self-report monitoring of sleep/wake behavior. The following variables were examined: estimated time in bed (eTIB), estimated total sleep time, estimated sleep latency (eSOL), estimated sleep efficiency, estimated wake after sleep onset, number of estimated awakenings (eAwk), number of estimated awakenings longer than 5 minutes, estimated sleep motor activity (eSMA), number of estimated naps, mean duration of the longest estimated nap (eNapD), and daytime motor activity.ResultsAll actigraphic parameters significantly differentiated the three groups, except eTIB and eSOL. A discriminant score computed combining actigraphic parameters from nighttime (eSMA, eAwk) and daytime (eNapD) periods showed a wide area under the curve (0.935) and a good balance between positive (95%) and negative predictive (87%) values in Narcolepsy Type 1 cases.ConclusionActigraphy provided a reliable objective measurement of sleep quality and daytime napping behavior able to distinguish central disorders of hypersomnolence and in particular Narcolepsy Type 1. The nycthemeral profile, combined with a careful clinical evaluation, may be an ecological information, useful to track disease course.     

Sleep phenotypes in infants and toddlers with neurogenetic syndromes

BackgroundAlthough sleep problems are well characterized in preschool- and school-age children with neurogenetic syndromes, little is known regarding the early emergence of these problems in infancy and toddlerhood. To inform syndrome-specific profiles and targets for intervention, we compared parent-reported sleep problems in infants and toddlers with Angelman syndrome (AS), Williams syndrome (WS), and Prader–Willi syndrome (PWS) with patterns observed among same-aged typically developing (TD) controls.MethodsMothers of 80 children (18 AS, 19 WS, 19 PWS, and 24 TD) completed the Brief Infant Sleep Questionnaire. Primary dependent variables included (1) sleep onset latency, (2) total sleep duration, (3) daytime and nighttime sleep duration, and (4) sleep problem severity, as measured by both maternal impression and National Sleep Foundation guidelines.ResultsSleep problems are relatively common in children with neurogenetic syndromes, with 41% of mothers reporting problematic sleep and 29% of children exhibiting abnormal sleep durations as per national guidelines. Across genetic subgroups, problems are most severe in children with AS and WS, particularly in relation to nighttime sleep duration. Although atypical sleep is characteristically reported in each syndrome later in development, infants and toddlers with PWS exhibited largely typical patterns, potentially indicating delayed onset of sleep problems in concordance with other medical features of PWS.ConclusionsOur findings suggest that sleep problems in neurogenetic syndromes emerge as early as infancy and toddlerhood, with variable profiles across genetic subgroups. This work underscores the importance of early sleep screenings as part of routine medical care of neurosyndromic populations and the need for targeted, syndrome-sensitive treatment.     

Objectively measured sleep duration and hyperglycemia in pregnancy

ObjectiveOur primary purpose was to assess the impact of objectively measured nighttime sleep duration on gestational glucose tolerance. We additionally examined associations of objectively measured daytime sleep duration and nap frequency on maternal glycemic control.MethodsSixty-three urban, low-income, pregnant women wore wrist actigraphs for an average of 6 full days in mid-pregnancy prior to screening for hyperglycemia using the 1-h oral glucose tolerance test (OGTT). Correlations of nighttime and daytime sleep durations with 1-h OGTT values were analyzed. Multivariable logistic regression was used to evaluate independent associations between sleep parameters and hyperglycemia, defined as 1-h OGTT values ⩾130 mg/dL.ResultsMean nighttime sleep duration was 6.9 ± 0.9 h which was inversely correlated with 1-h OGTT values (r = −0.28, P = .03). Shorter nighttime sleep was associated with hyperglycemia, even after controlling for age and body mass index (adjusted odds ratio [OR], 0.2 [95% confidence interval {CI}, 0.1–0.8]). There were no associations of daytime sleep duration and nap frequency with 1-h OGTT values or hyperglycemia.ConclusionsUsing objective measures of maternal sleep time, we found that women with shorter nighttime sleep durations had an increased risk for gestational hyperglycemia. Larger prospective studies are needed to confirm our negative daytime sleep findings.     

Dissociations among daytime sleepiness,nighttime sleep,and cognitive status in Parkinson's disease

BackgroundDaytime and nighttime sleep disturbances and cognitive impairment occur frequently in Parkinson's disease (PD), but little is known about the interdependence of these non-motor complications. Thus, we examined the relationships among excessive daytime sleepiness, nighttime sleep quality and cognitive impairment in PD, including severity and specific cognitive deficits.MethodsNinety-three PD patients underwent clinical and neuropsychological evaluations including the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI). Patients were classified as having normal cognition (PD-NC), mild cognitive impairment (PD-MCI), or dementia (PDD) using recently proposed Movement Disorder Society PD-MCI and PDD criteria. Relationships between the sleep and cognitive measures and PD cognitive groups were examined.ResultsThe PD cohort included PD-NC (n = 28), PD-MCI (n = 40), and PDD (n = 25) patients. ESS scores, as a measure of daytime sleepiness, were significantly worse (p = 0.005) in cognitively impaired PD patients, particularly PDD patients. ESS scores correlated significantly with Mini-Mental State Examination scores and also with cognitive domain scores for attention/working memory, executive function, memory, and visuospatial function. In contrast, PSQI scores, as a measure of nighttime sleep quality, neither differed among cognitive groups nor correlated with any cognitive measures.ConclusionsDaytime sleepiness in PD, but not nighttime sleep problems, is associated with cognitive impairment in PD, especially in the setting of dementia, and attention/working memory, executive function, memory, and visuospatial deficits. The presence of nighttime sleep problems is pervasive across the PD cognitive spectrum, from normal cognition to dementia, and is not independently associated with cognitive impairment or deficits in cognitive domains.     

Sleep patterns and their age-related changes in elementary-school children

ObjectivesThis study aimed to evaluate children’s bedtime, wake-up time, total sleep duration (TSD), sleep latency, and daytime napping by age and gender. Its secondary aim was to compare sleep duration among demographic and lifestyle factors.MethodsWe performed a cross-sectional study of 3639 children in Daegu, Korea, comparing bedtimes, wake-up times, TSDs, daytime naps, and sleep latency according to age and gender, as well as comparing sleep duration according to the children’s demographic and lifestyle factors.ResultsBedtime and TSD varied significantly by age. But wake-up time differences were not as large, as the differences in bedtimes and TSDs. There were no gender differences in any sleep parameters. The percentage of the children who took naps decreased until age 9 and began increasing again at age 10. Children who lived in apartments got less sleep than did those living in other types of housing. Extracurricular academic activities, duration and timing of television-watching, and computer playing were also related to the children’s sleep duration.ConclusionsOlder children sleep less than younger children; the main reason is late bedtimes. Late bedtimes may be due to socio-cultural factors, high levels of nighttime and recreational activities, and/or excessive academic activities.     

Ethnic-specific associations of sleep duration and daytime napping with prevalent type 2 diabetes in postmenopausal women

ObjectiveThe objective of this study was to evaluate ethnic differences in the associations of nighttime sleep and daytime napping durations with prevalent type 2 diabetes.MethodsSamples of White (n = 908), Filipina (n = 330), and Black (n = 371) community-dwelling, postmenopausal women aged 50–86 years were evaluated with cross-sectional data obtained during 1992–1999 including self-reported duration of nighttime sleep and daytime napping, behaviors, medical history, and medication use. The prevalence of type 2 diabetes was evaluated with a 2-h 75-g oral glucose tolerance test.ResultsOverall, 10.9% of White, 37.8% of Filipina, and 17.8% of Black women had type 2 diabetes. Average sleep durations were 7.3, 6.3, and 6.6 h and napping durations were 16.8, 31.7, and 25.9 min for White, Filipina, and Black women, respectively. Sleep duration showed a significant (p < 0.01) nonlinear association with type 2 diabetes in Filipina women, with increased odds of diabetes at both low and high sleep durations independent of age, body mass index (BMI), triglyceride to high-density lipoprotein (HDL) ratio, hypertension, and daytime napping duration. Daytime napping duration was associated with type 2 diabetes only among White women; those napping ≥ 30 min/day had 74% (95% confidence interval (CI) = 10%, 175%) higher odds of diabetes compared to non-nappers independent of covariates including nighttime sleep duration.ConclusionsResults suggest ethnic-specific associations of nighttime sleep and daytime napping durations with type 2 diabetes.