First night effect analysis in a cohort of young children with autism spectrum disorder

Relationships between cortical, cardiac, and arousal-motor activities in the genesis of rhythmic masticatory muscle activity across sleep cycles in primary sleep bruxism children

STUDY OBJECTIVES

The present study aimed to clarify the physiological relationships between rhythmic masticatory muscle activity (RMMA) and cyclic changes in cortical, autonomic, and arousal-motor activities during sleep in sleep bruxism (SB) children.

METHODS

Polysomnographic recordings were performed on fifteen SB children (9 boys, 6 girls, 10.3 ± 2.5 years) and eighteen control children (5 boys, 13 girls, 10.7 ± 3.1 years) free from sleep and developmental disorders. Sleep and RMMA were scored by the standard rules. Sleep cycle was divided into NREM and REM sleep segments and the frequency of RMMA, transient arousal and movement, and cortical and cardiac activities were then quantitatively analyzed in relation to sleep cycles.

RESULTS

Neither sleep architecture nor sleep stage distribution of RMMA significantly differed between two groups. In sleep cycles, SB children showed more frequent RMMA in all segments than controls, while cyclic changes in cortical and autonomic activities did not significantly differ between two groups. In SB children, RMMA was the most frequent in the last NREM segment before REM sleep and was associated with increases in cortical beta activity and arousal; more than 70% of RMMA time-dependently occurred with cortical and motor arousals.

CONCLUSIONS

This is the first study to suggest that the potentiation of RMMA occurrence was associated with transient arousal under cyclic sleep processes in primary SB children.

The association between sleep and dual-task performance in preterm and full-term children: an exploratory study

OBJECTIVES

The present study explored associations between sleep and children's dual-task performance using cognitive-motor dual tasks (eg, walking and talking). Previous research with older adults indicated correlations between higher gait variability and unfavorable sleep continuity variables. Based on this research, as a first objective, we investigated similar correlations in a sample of children. Second, we explored correlations between dual-task performance and dimensions of sleep architecture. Third, we tested moderating effects of prematurity on these associations.

METHODS

In this study, 7-to 12-year-old children were tested in dual-task situations; of those, 39 were formerly preterm, and 59 were full-term born children. They were asked to walk and simultaneously perform different cognitive tasks. Gait was measured using an electronic walkway system. Sleep was measured using in-home sleep-electroencephalography.

RESULTS

After accounting for age and cognition, regression analyses revealed correlations between a higher number of awakenings after sleep onset and lower dual-task performance; concerning sleep architecture, analyses revealed correlations between a higher amount of rapid-eye-movement (REM) sleep and lower gait variability. Furthermore, associations between a higher amount of slow wave sleep (SWS) and children's higher cognitive performance were found. Moderation analyses indicated no effects of prematurity.

CONCLUSIONS

Our exploratory study suggests that a more disrupted sleep was related to children's poorer dual-task performance. Our findings support claims that REM sleep seems more related to performance in procedural tasks whereas SWS seems more related to performance in declarative tasks, suggesting that different sleep stages may support the processing of different performance types.

First-Night Effect on Sleep in Different Female Reproductive States

OBJECTIVES

In sleep laboratory studies, the new environment is generally considered to disturb sleep during the first night. However, older women have rarely been studied. Although menopause and hormone therapy affect sleep, their impact on the first-night effect is virtually unknown.

PARTICIPANTS

Four groups of women with no sleep laboratory experience: young on hormonal contraceptives (n = 11, 23.1 [0.5] years), perimenopausal (n = 15, 48.0 [0.4] years), postmenopausal without hormone therapy (HT; off-HT, n = 22, 63.4 [0.8] years) and postmenopausal with HT (n = 16, 63.1 [0.9] years).

PROCEDURE

A cross-sectional study.

METHODS

Polysomnography was performed over two consecutive nights and the first-night effect and group differences were evaluated. Questionnaire-based insomnia and sleepiness scores were correlated to sleep variables and their between-night changes.

RESULTS

Although sleep in young women was deeper and less fragmented than in the other groups, first-night effect was similar in all study groups. Total sleep time, sleep efficiency, and S1 and S2 sleep increased, and wake after sleep onset, awakenings per hour of sleep, S2 and REM latencies, and percentage of SWS decreased from the first to the second night. Perimenopausal women had more insomnia complaints than other women. Insomnia complaints were associated with more disturbed sleep but not with the first-night effect.

CONCLUSIONS

A first night in a sleep laboratory elicits a marked interference of sleep architecture in women of all ages, with a carryover effect of lighter sleep on the second study night. Menopausal state, HT use, or insomnia complaints do not modify this effect.

Spindle activity in young children with autism, developmental delay, or typical development

OBJECTIVE

To determine whether spindle activity differs in young children with and without autism.

METHODS

We investigated differences in spindle density, duration, and oscillatory features in 135 young children with autism, developmental delay without autism (DD), or typical development (TD) and secondarily assessed the dimensional relationship between spindle density and both cognitive ability and social functioning.

RESULTS

Compared to TD, both spindle density (Cohen d 0.93, 95% confidence interval [CI] 0.49-1.37) and duration (Cohen d 0.58, 95% CI 0.15-1.01) were significantly decreased in autism. Spindle density was also significantly reduced in autism compared to DD (Cohen d 0.61, 95% CI 0.13-1.09). Decreased spindle frequency in autism compared to both TD (Cohen d 0.47, 95% CI 0.04-0.90) and DD (Cohen d 0.58, 95% CI 0.10-1.06) did not survive correction. The DD group did not differ significantly from the TD group on any spindle parameter. These results, suggesting a relationship between spindle density and autism but not DD, were further illustrated in exploratory analyses, wherein nonverbal ratio IQ (RIQ) and the Vineland Socialization domain standard score were strongly correlated with spindle density in the full sample (r = 0.33, p ≤ 001 and r = 0.41, p ≤ 001, respectively) but not within group. After nonverbal RIQ was accounted for, the relationship between spindle density and Vineland Socialization remained statistically significant (r = 0.23, p < 0.01). However, Vineland Socialization scores accounted for the relationship between spindle density and nonverbal RIQ (r = 0.04, p = 0.67).

CONCLUSION

In a large cohort of young children with autism, spindle density was reduced compared to groups of age-matched children with DD or TD. Alterations in the maturational trajectory of spindles may provide valuable insight into the neurophysiologic differences related to behavior in disorders of neurodevelopment.

Individuals with Autism Spectrum Disorders Have Equal Success Rate But Require Longer Periods of Systematic Desensitization than Control Patients to Complete Ambulatory Polysomnography

STUDY OBJECTIVES

Polysomnography (PSG) is the gold standard for the assessment of sleep, yet the extensive apparatus required for monitoring with PSG can be difficult to tolerate, particularly in children. Clinical populations, such as those with anxiety or tactile sensitivity, may have even greater difficulty tolerating the PSG equipment. This study evaluated an innovative protocol for obtaining full PSG in individuals diagnosed autism spectrum disorders (ASD) or developmental delay (DD), as well as typically developing controls (TD). The primary aim was to assess whether this protocol was equally successful for obtaining PSG between these groups.

METHODS

One hundred sixty-one individuals were recruited for participation; 93 with a diagnosis of ASD, 23 with a diagnosis of DD, and 45 TD. The participants and families were instructed on a procedure of systematic desensitization to the ambulatory PSG equipment; PSG was performed in the home of the participant.

RESULTS

PSG was successfully attained in 144 (89.4%) participants. There was no difference in completion rate by diagnosis (p = 0.1), though younger age (p = 0.018) and duration of desensitization (p = 0.024) did predict PSG failure. Further, it was found that individuals with ASD took longer to desensitize to the equipment (16.08 d), than those with DD (8.04 d) or TD (0.98 d).

CONCLUSIONS

Systematic desensitization to PSG equipment, in combination with PSG completed in the home, allows for individuals with ASD to be equally successful in completing PSG, though they do take longer to acclimate to the equipment.

Sleep differences among children with autism spectrum disorders and typically developing peers: a meta-analysis

OBJECTIVE

Sleep problems such as difficulties in sleep initiation, nighttime awakening, and shortened sleep time are often subjectively reported in children with autism spectrum disorder (ASD). However, results of objective studies have been mixed. Our goal was to evaluate the existing data from objective measures using a systematic approach to identify and describe the differences in sleep parameters by comparing total sleep time (TST), sleep latency (SL), and sleep efficiency (SE) in children with ASD with those of typically developing (TD) peers.

METHODS

Studies that used objective measures such as actigraphy or polysomnography (PSG) to describe the sleep parameters of TST, SL, and SE in children with ASD compared with children with TD were identified. A meta-analysis was performed for the 10 studies that met inclusion criteria with evaluation of differences in means using random effects models. A total of 343 children with ASD and 221 children with TD were included. Assessments for sources of heterogeneity and publication bias were undertaken.

RESULTS

TST for children with ASD was on average 32.8 minutes less per day (95% confidence interval [CI]: 16.6-49.0 minutes) than their TD peers. Average SL was 10.9 minutes longer (95% CI: 6.7-15.0 minutes), and average SE was 1.9% less (95% CI: 0.7%-3.1%) than their TD peers. Notable heterogeneity was found within studies for TST, and mild heterogeneity was found for SE. Concurrent intellectual disability was a moderator of TST. Children with ASD and normal intelligence had a small and nonsignificant decrease in TST as compared with TD peers, whereas those with ASD and intellectual disability (ID) had a significant decrease in TST as compared with TD peers. The magnitude of the difference in mean SL and SE increased as compared with TD peers as age increased. Studies that used PSG and those that did not include children on medications were more likely to report mean decreases in SE.

CONCLUSIONS

Children with ASD have small but measurable objective differences in their sleep parameters that are consistent with subjective reporting. Children with ASD have shorter TST, longer SL periods, and decreased SE as compared with TD peers. Concurrent ID, medication use, method of data collection, and age of subjects significantly moderated these results. The decrease in TST in children with ASD and normal intelligence was not significant as compared with TD peers, suggesting that ID may help explain the shortened TST in children with ASD.

Sleep, plasticity and the pathophysiology of neurodevelopmental disorders: the potential roles of protein synthesis and other cellular processes

Sleep is important for neural plasticity, and plasticity underlies sleep-dependent memory consolidation. It is widely appreciated that protein synthesis plays an essential role in neural plasticity. Studies of sleep-dependent memory and sleep-dependent plasticity have begun to examine alterations in these functions in populations with neurological and psychiatric disorders. Such an approach acknowledges that disordered sleep may have functional consequences during wakefulness. Although neurodevelopmental disorders are not considered to be sleep disorders per se, recent data has revealed that sleep abnormalities are among the most prevalent and common symptoms and may contribute to the progression of these disorders. The main goal of this review is to highlight the role of disordered sleep in the pathology of neurodevelopmental disorders and to examine some potential mechanisms by which sleep-dependent plasticity may be altered. We will also briefly attempt to extend the same logic to the other end of the developmental spectrum and describe a potential role of disordered sleep in the pathology of neurodegenerative diseases. We conclude by discussing ongoing studies that might provide a more integrative approach to the study of sleep, plasticity, and neurodevelopmental disorders.