Shorter Sleep Latency Research Articles

Variations in habitual sleep and relational memory in 6-month-olds

ObjectivesAdequate sleep duration and good sleep quality are considered essential for development, especially during periods of major neurodevelopmental change. Still, relations between parent-reported habitual sleep and emerging cognitive abilities within the first year of life are not well studied. Here, we examined relations between habitual sleep measures and an aspect of cognitive functioning, relational memory, which emerges as early as 6 months of age, as compared to other abilities (ie, recognition memory and attentional orienting), both of which are considered to emerge earlier in development. ParticipantsParticipants were a subset of 267 healthy typically developing 6-month-olds taking part in the Growing Up in Singapore towards Healthy Outcomes cohort study. MeasurementsSleep duration, sleep latency, and number and duration of night awakenings were derived from the Brief Infant Sleep Questionnaire (BISQ). Short sleep was defined as <10 hours per day, categorized as “not recommended” based on the National Sleep Foundation recommendations. Associations between sleep variables and infants' performance on 2 relational memory tests (deferred imitation and relational binding) were examined independently using hierarchical (blockwise entry) linear regression. Associations between sleep and recognition memory and attentional orienting were also explored. ResultsHabitual short sleepers had poorer relational memory recall in the deferred imitation task compared with ‘typical’ sleepers (10-18 hours per day). Shorter sleep latency was related to a greater proportion of correct responses for certain aspects of relational binding. There were no associations between sleep and recognition memory or attention. ConclusionsOur findings suggest that habitual sleep duration and short sleep latency associate with 6-month-olds' relational memory, suggesting a preferential association with memory tasks that are sensitive to development during the second half of the first year.

Sleep and cognitive aging in the eighth decade of life.

We examined associations between self-reported sleep measures and cognitive level and change (age 70–76 years) in a longitudinal, same-year-of-birth cohort study (baseline N = 1091; longitudinal N = 664). We also leveraged GWAS summary data to ascertain whether polygenic scores (PGS) of chronotype and sleep duration related to self-reported sleep, and to cognitive level and change. Shorter sleep latency was associated with significantly higher levels of visuospatial ability, processing speed, and verbal memory (β ≥ |0.184|, SE ≤ 0.075, p ≤ 0.003). Longer daytime sleep duration was significantly associated slower processing speed (β = −0.085, SE = 0.027, p = 0.001), and with steeper 6-year decline in visuospatial reasoning (β = −0.009, SE = 0.003, p = 0.008), and processing speed (β = −0.009, SE = 0.002, p < 0.001). Only longitudinal associations between longer daytime sleeping and steeper cognitive declines survived correction for important health covariates and false discovery rate (FDR). PGS of chronotype and sleep duration were nominally associated with specific self-reported sleep characteristics for most SNP thresholds (standardized β range = |0.123 to 0.082|, p range = 0.003 to 0.046), but neither PGS predicted cognitive level or change following FDR. Daytime sleep duration is a potentially important correlate of cognitive decline in visuospatial reasoning and processing speed in older age, whereas cross-sectional associations are partially confounded by important health factors. A genetic propensity toward morningness and sleep duration were weakly, but consistently, related to self-reported sleep characteristics, and did not relate to cognitive level or change.

Actigraphy-based evaluation of sleep quality and physical activity in individuals with spinal cord injury.

Cross-sectional study. Sleep disturbances are frequently reported by individuals with spinal cord injury (SCI) and are associated both with poor quality of life and reduced ability to participate in rehabilitation and daily life activities. This study investigated sleep quality based on self-reports and actigraphy in individuals with SCI as compared to able-bodied. We also explored the relationship between sleep quality, physical activity, and neuropathic pain. Institute Guttmann, Neurorehabilitation Hospital, Badalona, Barcelona, Spain. Fourteen SCI patients (12 males, 43.10 ± 10.59 y.o.) and 10 healthy individuals (7 males, mean age 46.21 ± 12.58 y.o.) were enrolled in the study. Participants wore wrist actigraphs for 7 consecutive days to characterize their sleep-wake cycle, rest-activity circadian rhythm and physical activity. Sleep quality, chronotype, daytime sleepiness, neuropathic pain severity and interference were assessed based on questionnaires. SCI individuals reported poorer sleep quality compared to healthy individuals. Actigraphy-based sleep measurements revealed that patients woke up later, spent more time in bed and slept longer compared to the healthy controls but did not differ significantly in the estimated sleep efficacy and number of awakenings from the able-bodied controls. In individuals with SCI greater physical activity predicted higher sleep efficacy and less awakening episodes as well as shorter sleep latency and lower sleep disturbance. The actigraphy-based sleep estimates indicate that patients with SCI spent more time in bed and slept longer but their sleep efficacy was similar to able-bodied controls. Maintaining regular physical activity could improve pain control and sleep quality.

Nighttime sleep disorders in patients with daytime sleepiness in Parkinson s disease

Daytime sleepiness is one of the clinically significant non-motor manifestations of Parkinson's disease (PD). One of its insufficiently studied aspects is a relationship between daytime sleepiness and nighttime sleep disorders.Objective:to clarify the clinical characteristics of PD in patients with different types of daytime sleepiness and to estimate of the ratio of daytime sleepiness to clinical and polysomnographic characteristics of nighttime sleep in patients with advanced stages of PD.Patients and methods. The investigation included 110 patients (56 men and 54 women) (mean age, 63.78+0.6 years) with PD (Hoehn and Yahr stage 2.6+0.2; disease duration, 6.3+3.2 years) without dementia. All the patients received therapy with levodopa at a mean daily dose of 667.8 mg; 98 of them had the drug in combination with dopamine receptor agonists at a stable dose. The unified PD rating scale, the PD sleep scale (PDSS), and the Epworth sleepiness scale (ESS) were applied. Nocturnal polysomnography (PSG) and the multiple sleep latency test (MSLT) were performed.Results and discussion. There was daytime sleepiness in 44% of the patients: permanent sleepiness in 15%, sudden daytime sleep attacks (along with low daytime sleepiness (ESS) in 14%, and permanent drowsiness concurrent with sleep attacks in 15%. The PSG findings showed a decrease in sleep efficiency, an increase in the duration of the first stage of sleep, a reduction in the duration of the second and third sleep stages, an extension of rapid eye movement (REM) sleep latency, and frequent awakenings (sleep fragmentation). PSG also demonstrated REM sleep behavior disorders (RBD) in half of the examinees.Patients with sleep attacks differed from those with permanent drowsiness without sleep attacks with more severe sleep disorders (PDSS) and shorter sleep latency (MSLT). Patients with the RBD phenomenon had shorter sleep latency (MTLS) than those without this parasomnia. Patients with moderate or severe sleepiness (ESS scores of &gt;10) differed from those with milder drowsiness (ESS scores of 410) and a lower representation of the third sleep stage.Conclusion.There is evidence for the association of daytime sleepiness in PD with reduced efficiency, changes in the nighttime sleep pattern, and RBD.

Clinical characteristics of symptomatic narcolepsy or hypersomnia: an analysis of 182 consecutive cases with neurological disorders associated with hypersomnolence

Symptomatic narcolepsy is characterized as low orexin (hypocretin) levels (≤ 110 pg/ml) due to neurological diseases. However, we have experienced the cases that show symptoms similar to narcolepsy, complaining of pathological sleepiness even in cases with intermediate orexin levels (110–200 pg/ml). Therefore, we reevaluated the previously reported cases to make the concept of disease to the group in which the orexin concentration is intermediate. Although orexin-deficient symptomatic narcolepsy has been reported worldwide, facilities that are capable of measuring orexin are still limited. Currently, our laboratory handles with almost all the CSF samples from Asian countries for determining orexin levels. We measured over 2500 cases including 182 cases suspected of symptomatic narcolepsy/hypersomnolence. Therefore, we subdivided these cases into three groups according to CSF orexin levels, low orexin group (≤ 110 pg/ml), intermediate orexin group (110–200 pg/ml), and normal orexin group (> 200 pg/ml). We defined “symptomatic hypersomnia” for hypersomnolence cases with intermediate CSF orexin levels. MSLT was recommended but not necessary. Short sleep latency (< 8 min) without SOREMPs should be observed on MSLT when performed. We compared symptoms (excessive daytime sleepiness and cataplexy) and objective measures (mean sleep latency and number of SOREMPs in MSLT) among the three groups, attempting to characterize the “symptomatic hypersomnia” group. Among the 182 cases with clinical hypersomnolence, there were 32 cases of symptomatic narcolepsy (16%) and 14 cases of symptomatic hypersomnia (8%). Causative diseases of symptomatic narcolepsy cases consist of immune-mediated demyelinating disorders (34%) and neurodegenerations (19%), whereas those of symptomatic hypersomnia are immune-mediated demyelinating disorders (43%) and encephalopathies (14%). Significant differences were not found between orexin levels and the existence of cataplexy, SOREMPs, and short sleep latency among three hypersomnolence groups. From these results, we found that it is difficult to estimate orexin concentration from subjective symptoms and PSG/MSLT findings. We identified that 32 symptomatic narcolepsy and 14 cases of symptomatic hypersomnolence with intermediate CSF orexin levels. We proposed these latter cases as a novel category of “symptomatic hypersomnia”. Currently, symptomatic hypersomnia cases with intermediate orexin levels or short sleep latency (< 8 min) without SOREMPs were not classified as a specific entity. However, symptomatic hypersomnia had similar severity of hypersomnolence symptoms to symptomatic narcolepsy. Therefore, these cases including equivalent pathophysiology are enough to make a comparable category as “symptomatic hypersomnia”. Since it is difficult to estimate the orexin concentration from subjective symptoms and physiological findings (PSG/MSLT), further studies for the characterization of “symptomatic hypersomnia” and understanding its pathophysiology are necessary.

Autonomic cardiac activity in adults with short and long sleep onset latency.

Autonomic cardiac activity during sleep has been widely studied. Research has mostly focused on cardiac activity between different sleep stages and wakefulness as well as between normal and pathological sleep. This work investigates autonomic activity changes during sleep onset in healthy subjects with long and short sleep onset latency (SOL). Polysomnography (PSG) and electrocardiography (ECG) were simultaneously recorded in 186 healthy subjects during a single night. Autonomic activity was assessed based on frequency domain analysis of RR intervals and results show that the analysis of RR intervals differs significantly between the short SOL and the long SOL groups. We found that the spectral power in the low frequency band (LF) was significantly higher in the long SOL group compared to the short SOL group in the first 10 minutes in bed intended to sleep. There was no significant difference for LF and the spectral power in the high frequency band (HF) 10 minutes before and after sleep onset between the two groups. Only in the short SOL group there was a significant increase in HF from the first 10 minutes in bed intended to sleep to 10 minutes before SO, while LF decreased significantly in both groups. The effect of time (5.5-min bin) on the heart rate variability (HRV) features around sleep onset showed that both LF and HF differed significantly during the period surrounding sleep onset only in the short SOL group.

The inappropriate occurrence of rapid eye movement sleep in narcolepsy is not due to a defect in homeostatic regulation of rapid eye movement sleep.

Narcolepsy type 1 is a disabling disorder with four primary symptoms: excessive-daytime-sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis. The later three symptoms together with a short rapid eye movement (REM) sleep latency have suggested impairment in REM sleep homeostatic regulation with an enhanced propensity for (i.e. tendency to enter) REM sleep. To test this hypothesis, we challenged REM sleep homeostatic regulation in a recognized model of narcolepsy, the orexin knock-out (Orex-KO) mice and their wild-type (WT) littermates. We first performed 48 hr of REM sleep deprivation using the classic small-platforms-over-water method. We found that narcoleptic mice are similarly REM sleep deprived to WT mice. Although they had shorter sleep latency, Orex-KO mice recovered similarly to WT during the following 10 hr of recovery. Interestingly, Orex-KO mice also had cataplexy episodes immediately after REM sleep deprivation, anticipating REM sleep rebound, at a time of day when cataplexy does not occur in baseline condition. We then evaluated REM sleep propensity using our new automated method of deprivation that performs a specific and efficient REM sleep deprivation. We showed that REM sleep propensity is similar during light phase in Orex-KO and WT mice. However, during the dark phase, REM sleep propensity was not suppressed in Orex-KO mice when hypocretin/orexin neuropeptides are normally released. Altogether our data suggest that in addition to the well-known wake-promoting role of hypocretin/orexin, these neuropeptides would also suppress REM sleep. Therefore, hypocretin/orexin deficiency would facilitate the occurrence of REM sleep at any time of day in an opportunistic manner as seen in human narcolepsy.

The link between maternal sleep and permissive parenting during late adolescence.

Utilizing a multi-method design, the present study examined the association between maternal sleep, assessed via actigraphy and self-reports, and permissive parenting (e.g. lax, inconsistent discipline) during adolescence, as well as the extent to which this association differed by mothers' race/ethnicity and socioeconomic status. The sample was comprised of 234 mothers (M age=41.76years, SD=6.25; 67% European-American, 31% African-American, 2% other race/ethnicities) and 237 adolescents (113 boys, 124 girls; M age=15.80years, SD=0.80; 66% European-American, 34% African-American). Mothers' sleep duration (actual sleep minutes) and quality (sleep efficiency, latency, long wake episodes) were assessed using actigraphy. Mothers also reported on their sleep problems and adolescents reported on mothers' permissive parenting behaviours. Results revealed that actigraphy-based longer sleep duration and shorter sleep latency were associated with lower levels of permissive parenting. Further, mothers' race/ethnicity and socioeconomic status moderated the association between actigraphy-based sleep quality (i.e. sleep efficiency, long wake episodes) and permissive parenting. Specifically, a negative association between sleep efficiency and permissive parenting was evident only for African-American mothers. In addition, a positive association between more frequent night wakings and permissive parenting was evident only for mothers from lower socioeconomic status households. The findings highlight the benefits of longer and higher-quality sleep for reducing the risk of permissive parenting, especially among ethnic minority mothers and mothers from lower socioeconomic status households.

Randomised study found that improved nutritional intake was associated with better sleep patterns in prepubertal children who were both short and lean.

Nutrition and sleep are prerequisites for linear growth and we addressed the under-researched role of sleep in this equation. This was a prospective randomised, double-blinded, placebo-controlled study of nutritional supplements in 164 healthy lean, short, prepubertal children with 83 in the supplement group and 81 in the placebo group. From November 2010 to November 2013, we focussed on children aged three to nine years referred for specialist growth assessments to the Schneider Children's Medical Center, Israel. Progress was assessed using anthropometric measurements, sleep questionnaires and three-day food diaries at baseline and after the six-month intervention. Children in the supplement group who took at least 50% of the recommended dose had shorter sleep latency than those who did not (p = 0.046). Children who fell asleep in less than 15 minutes had significantly improved standard deviation scores for weight (0.25 ± 0.34 versus 0.07 ± 0.36, p = 0.044) and height (0.09 ± 0.13 versus 0.03 ± 0.13, p = 0.057) than those who took longer to fall asleep. Positive correlations were found between mean sleep duration and caloric and macronutrient intake per kilogram. Adequate nutritional intake was associated with better sleep patterns and may enhance linear growth.

The effect of sleep on motor skill learning in young badminton players aged 6–9 years

The objective of this study was to examine the effect of sleep on the acquisition of motor skills in young badminton players. Thirteen badminton players, aged 6–9 years (8.0 ± 0.3 years; mean ± SE), practiced the shuttle bouncing drill, and a skill none of the players had prior experience with. After practice sessions, shuttle bouncing performance was immediately tested and then retested 1 week later. We evaluated sleep parameters for 7 consecutive days using actigraphy. Using the median value of sleep efficiency, subjects were divided into two groups: good sleepers and poor sleepers. Good sleepers had shorter sleep latency (p < 0.05), longer wake after sleep onset (p < 0.001), longer total sleep time (p < 0.005), and higher sleep efficiency (p < 0.001) than the poor sleepers. Interestingly, improvement in shuttle bouncing performance was significantly greater in the good sleeper group than that in the poor sleeper group (p < 0.05). In addition, we found that changes in the shuttle bouncing performance positively correlated with sleep efficiency (β = 0.765, p < 0.01) and total sleep time (β = 0.588, p < 0.05) after adjusting for their badminton career. These data suggest that sleep may affect the acquisition of motor skills in young players.

Sleep onset latency on overnight PSG is complementary to epworth sleepiness score for predicting shorter mean MSLT sleep latency and OSA severity

Sleep onset latency on overnight PSG is complementary to epworth sleepiness score for predicting shorter mean MSLT sleep latency and OSA severity

Sleep macrostructure is modulated by positive and negative social experience in adult pet dogs.

The effects of emotionally valenced events on sleep physiology are well studied in humans and laboratory rodents. However, little is known about these effects in other species, despite the fact that several sleep characteristics differ across species and thus limit the generalizability of such findings. Here we studied the effect of positive and negative social experiences on sleep macrostructure in dogs, a species proven to be a good model of human social cognition. A non-invasive polysomnography method was used to collect data from pet dogs (n = 16) participating in 3-hour-long sleep occasions. Before sleep, dogs were exposed to emotionally positive or negative social interactions (PSI or NSI) in a within-subject design. PSI consisted of petting and ball play, while NSI was a mixture of separation, threatening approach and still face test. Sleep macrostructure was markedly different between pre-treatment conditions, with a shorter sleep latency after NSI and a redistribution of the time spent in the different sleep stages. Dogs' behaviour during pre-treatments was related to the macrostructural difference between the two occasions, and was further modulated by individual variability in personality. This result provides the first direct evidence that emotional stimuli affect subsequent sleep physiology in dogs.

P 133 Differentiating hypo- and hyperaroused fatigue in major depression and in the context of organic diseases

Introduction Fatigue is a core symptom in patients with major depressive disorder (MDD), and a common symptom in organic diseases involving inflammatory and immunological processes. From a clinical perspective, fatigue in depression is a state with high inner tension and prolonged sleep onset latencies, whereas fatigue in the context of organic diseases describes an anergic state with excessive sleepiness and short sleep latencies. Given that these two states are diametrically opposed in the arousal dimension, it has been proposed to differentiate two subtypes of fatigue ( Hegerl et al., 2013 , Hegerl and Ulke, 2016 ): hyperaroused fatigue (typical for depression) and hypoaroused fatigue (typical in the context of organic diseases). Due to the striking heterogeneity of MDD and frequent occurrence of depressive symptoms in organic diseases, we sought to examine whether both fatigue subtypes can be found within a sample of depressed patients (study 1) and within a sample of subjects with inflammatory-immunological diseases and cancer (study 2). In the first study, we hypothesized that in MDD fatigue with unstable arousal regulation is associated with higher sleepiness scores and more atypical symptoms (e.g. short sleep onset latency) than fatigue with stable arousal regulation. In the second study, we hypothesized that in the context of organic diseases fatigue with stable arousal regulation is associated with higher depression and lower sleepiness scores than fatigue with labile arousal regulation. Methods Sample Study 1: MDD-Patients with clinically relevant fatigue (N = 102). Sample Study 2: Subjects with clinically relevant fatigue in the context of inflammatory-immunological diseases and cancer (N = 127). Arousal regulation was assessed based on 20-min resting-EEG using automatic EEG-vigilance stage classification with the Vigilance Algorithm Leipzig (VIGALL 2.1). Subjects were separated into groups according to their arousal regulation. Results Study 1: According to our hypothesis, fatigue subtypes in the context of MDD differ in regard to daytime sleepiness (ESS: p Conclusions An unstable arousal regulation in MDD-Patients with clinically relevant fatigue could influence the treatment strategy. Stable arousal regulation in persons with clinically relevant fatigue in the context of organic diseases can be an indication of a comorbid depression, which has to be treated according to guidelines.

Effects of Cataract Opacity and Surgery on Sleep Quality

This study aimed to identify the type of cataract opacity associated with subjective sleep quality for cataract patients. A total of 180 consecutive patients (average age 74.2 years) underwent cataract surgery with implantation of an ultraviolet-blocking or blue light-blocking intraocular lens. The participants' subjective sleep quality was evaluated using the Pittsburgh sleep quality index (PSQI) before and at 2 months after surgery. Patients were divided into two groups for analysis: normal sleepers (preoperative PSQI ≤5) and poor sleepers (preoperative PSQI ≥6). The preoperative and postoperative PSQI scores were 2.8 ± 1.5 and 3.2 ± 2.0, respectively, for normal sleepers (n = 99), and 8.5 ± 2.9 and 7.4 ± 3.3, respectively, for poor sleepers (n = 81). The improvement in PSQI was significant in poor sleepers (p < 0.0001, Wilcoxon's test) with measured values of 0.22 ± 0.96 hours extension in sleep duration and 0.16 ± 0.62 hours shortening in sleep latency. Patients with posterior subcapsular cataract (PSC) and nuclear opacity showed the greatest improvement in PSQI score, with regression analysis identifying PSC as having a significant effect on improvement in PSQI. Significant correlations were found between the subjective sleep and cataract opacity in cataract patients. Ophthalmic personnel should therefore be aware that cataract patients with PSC have a greater potential for disability and predictable benefits from surgery in vision and subjective sleep.

The short and long of adolescent sleep: the unique impact of day length

Study objectivesVariation in day length is proposed to impact sleep, yet it is unknown whether this is above the influence of behavioural factors. Day length, sleep hygiene, and parent-set bedtime were simultaneously explored, to investigate the relative importance of each on adolescents’ sleep. MethodsAn online survey was distributed in four countries at varying latitudes/longitudes (Australia, The Netherlands, Canada, Norway). ResultsOverall, 711 (242 male; age M = 15.7 ± 1.6, range = 12–19 yrs) adolescents contributed data. Hierarchical regression analyses showed good sleep hygiene was associated with earlier bedtime, shorter sleep latency, and longer sleep (β = −0.34; −0.30; 0.32, p < 0.05, respectively). Shorter day length predicted later bedtime (β = 0.11, p = 0.009), decreased sleep latency (β = −0.21, p < 0.001), and total sleep (β = −0.14, p = 0.001). Longer day length predicted earlier bedtimes (β = −0.11, p = 0.004), and longer sleep (β = 0.10, p = 0.011). ConclusionsSleep hygiene had the most clinical relevance for improving sleep, thus should be considered when implementing adolescent sleep interventions, particularly as small negative effects of shorter day length may be minimised through sleep hygiene techniques.

Comparative effectiveness of electro-acupuncture versus gabapentin for sleep disturbances in breast cancer survivors with hot flashes: a randomized trial.

Sleep disturbance is a major consequence of hot flashes among breast cancer survivors. This study evaluated the effects of electro-acupuncture (EA) versus gabapentin (GP) for sleep disturbances among breast cancer survivors experiencing daily hot flashes. We analyzed data from a randomized controlled trial involving 58 breast cancer survivors experiencing bothersome hot flashes at least two times per day. Participants were randomly assigned to receive 8 weeks of EA or daily GP (total dose of 900 mg/d). The primary outcome was change in the total Pittsburgh Sleep Quality Index (PSQI) score between groups at week 8. Secondary outcomes include specific PSQI domains. By the end of treatment at week 8, the mean reduction in PSQI total score was significantly greater in the EA group than the GP group (-2.6 vs -0.8, P = 0.044). The EA also had improved sleep latency (-0.5 vs 0.1, P = 0.041) and sleep efficiency (-0.6 vs 0.0, P = 0.05) compared with the GP group. By week 8, the EA group had improved sleep duration, less sleep disturbance, shorter sleep latency, decreased daytime dysfunction, improved sleep efficiency, and better sleep quality (P < 0.05 for all) compared with baseline, whereas the GP group improved in duration and sleep quality only (P < 0.05). Among women experiencing hot flashes, the effects of EA are comparable with GP for improving sleep quality, specifically in the areas of sleep latency and efficiency. Larger randomized controlled trials with longer follow-ups are needed to confirm this preliminary finding.

Relationship between parent knowledge of child sleep, and child sleep practices and problems: A pilot study in a children's hospital cohort.

To describe parent reports of sleep practices, and examine associations with parent knowledge of child sleep, and whether children's sleep practices differ between parents who underestimated, overestimated or accurately estimated children's sleep needs. Parents of children aged 2-12 years (n = 115) attending hospital inpatient or day wards were approached and asked to report child sleep routines, sleep problems, parent education, household income and parent knowledge of child sleep via questionnaire. Younger age was associated with earlier bedtimes and wake times, shorter sleep latencies, longer sleep durations and greater sleep problems (P < 0.05). Parents from higher income homes reported earlier bedtimes and wake times, shorter sleep latencies and fewer sleep problems (P < 0.05). Parents with higher education reported shorter sleep latencies (P < 0.05). Parents with greater knowledge about child sleep reported earlier weekday and weekend bedtimes (r s ≥ 0.26) and wake times (r s ≥ 0.21) and greater consistency between their child's weekend and weekday sleep routines (P < 0.05). In comparison with parents who correctly estimated their child's sleep needs: parents who underestimated reported later weekday bedtimes (on average, 46 min), and longer sleep latencies (17 min); parents who overestimated reported longer sleep latencies (22 min). These findings remained significant when controlling for child age (P < 0.05). Parents with increased sleep knowledge, higher incomes and higher levels of education were more likely to report earlier bedtimes, wake times and more consistent sleep routines for their children.

Abstract WP159: Effects of Gender on Sleep Alterations After Stroke

Introduction: Stroke in women tends to lead to greater disabilities and increased likelihood of institutionalization compared to men. We explored if sleep disturbances following stroke are influenced by gender. We also evaluated if levels of thyroid hormone (TSH, T3, T4), which are associated to functional outcome are influenced by gender. Methods: Sleep was evaluated via polysomnography in stroke 33 patients (men: n=20; women: n=13; M age = 54). Functional outcome was assessed with the Supervision Rating Rating Scale (SRS) and the Mayo-Portland Adaptability Inventory 4 (MPAI). Patients were also evaluated for hormonal alterations. Sleep values were also compared with age-matched published normative data from uninjured adults. Results: Women performed worse on the MPAI Ability Index and Adjustment index compared to men (p&lt;0.05). Women also showed more disability according the SRS (p&lt;0.05). Ability Index and sleep efficiency was correlated for all (p&lt;0.01). Both male and female stroke patients had a higher percent time in Stage 2 (M: 61.5 and 66.7, respectively) compared to normative data (45.7). Moreover, 88% of stroke survivors did not did not reach Stage 3. Women showed lower sleep efficiency, spent less percent of time in REM and had a higher percent wake after sleep onset compared to normative data. Women also had lower T3 levels compared to men (p&lt;0.01). Incidence of apnea was higher in men compared to women (p&lt;0.05). Men tended to have more central apnea (p=0.08). Men had more spontaneous arousals during sleep and reported more daytime sleepiness compared to women (p&lt;0.05). Accordingly, Epworth scores were correlated with low levels of participation in the MPAI for men (p&lt;0.03). Comparisons to normative data showed that men have a shorter sleep-latency (M: 8.3 vs 15.8). Conclusions: Whereas apnea is more predominant in men, alterations in sleep architecture appear to be more marked in women. Women also have lower levels of T3. Sleep alterations after stroke are associated with functional deficits. These findings have implications for cognitive processing, as Stage III and REM are important for memory consolidation.

The relationship between sleep apnea, metabolic dysfunction and inflammation: The gender influence

Obstructive sleep apnea (OSA) has been associated with increased risk of cardiovascular morbidity and mortality. Although inflammatory markers may mediate this association, it is unknown the influence of gender in this mechanism. Thus, we aimed to evaluate the interaction effects between OSA and gender on metabolic and inflammatory profile in a population sample. This study is part of EPISONO cohort, in which 1042 participants underwent polysomnography, answered questionnaires, and had their blood collected for analysis of fasting glucose, total cholesterol and fractions, leptin, ghrelin, liver transaminases, tumor necrosis factor (TNF)-α, interleukin (IL)-6, and C-reactive protein. The results showed that men with OSA had higher leptin levels, shorter sleep latency and lower N3 sleep stage compared to men control (CTRL). They also presented higher apnea index and number of central apneas compared to both CTRL men and OSA women. In women, OSA was related to longer REM sleep latency, higher apnea-hypopnea index (AHI) during REM sleep and increased TNF-α levels compared to CTRL women. A multivariate model showed that male gender, ghrelin and total cholesterol were negatively associated with TNF-α, while IL-6, triglycerides and hypopnea index were positively associated (R2=0.21). Additionally, gender (men), body mass index, ghrelin, apnea index and smoking were positive predictors of leptin levels (R2=0.55). Of note, postmenopause was associated with changes observed in both TNF-α and AHI during REM sleep in women with OSA. Taken together, our study suggests that OSA consequences may differ between genders and this could indicate a need for different OSA management in women according to their reproductive life’s stage.

Sleep physiology in toddlers: Effects of missing a nap on subsequent night sleep

The shift from a biphasic to a monophasic sleep schedule is a fundamental milestone in early childhood. This transition, however, may result in periods of acute sleep loss as children may nap on some but not all days. Although data indicating the behavioral consequences of nap deprivation in young children are accumulating, little is known about changes to sleep neurophysiology following daytime sleep loss. This study addresses this gap in knowledge by examining the effects of acute nap deprivation on subsequent nighttime sleep electroencephalographic (EEG) parameters in toddlers. Healthy children (n=25; 11 males; ages 30–36 months) followed a strict sleep schedule for ≥5 days before sleep EEG recordings performed on 2 non-consecutive days: one after 13h of prior wakefulness and another at the same clock time but preceded by a daytime nap. Total slow-wave energy (SWE) was computed as cumulative slow-wave activity (SWA; EEG power in 0.75–4.5Hz range) over time. Nap and subsequent night SWE were added and compared to SWE of the night after a missed nap. During the night following a missed nap, children fell asleep faster (11.9±8.7 min versus 37.3±22.1min;d=1.6, p=0.01), slept longer (10.1±0.7 h versus 9.6±0.6h; d=0.7, p<0.01) and exhibited greater SWA (133.3±37.5% versus 93.0±4.7%; d=0.9, p<0.01) compared to a night after a daytime nap. SWE for combined nap and subsequent night sleep did not significantly differ from the night following nap deprivation (12141.1±3872.9 μV²*h versus 11,588±3270.8 μV²*h; d=0.6, p=0.12). However, compared to a night following a missed nap, children experienced greater time in bed (13.0±0.8 h versus 10.9±0.5 h; d=3.1, p<0.01) and total sleep time (11.2±0.8 h versus 10.1±0.7 h; d=1.4, p<0.01). Shorter sleep latency, longer sleep duration, and increased SWA in the night following a missed nap indicate that toddlers experience a physiologically meaningful homeostatic challenge after prolonged wakefulness. Whether toddlers fully recover from missing a daytime nap in the subsequent night necessitates further examination of daytime functioning.