A Comparison of Sleep Patterns and Behaviour in Children with Autism, Other Developmental Disabilities, and Typically Developing Children

Background: Sleep problems are common in developmental disabilities including autism, and Down (DS), Prader-Willi (PWS), and fragile-X syndromes and children with familial intellectual disability (FID). However, few researchers compare the sleep of children with autism with specific developmental disorders, instead using mixed comparison groups. Additionally while disruptive behaviour has been shown to be related to reported sleep problems the impact of both daytime and nighttime behaviour on sleep patterns is generally not considered. Objectives: 1) To examine 24-hour sleep patterns of children with autism DS, PWS and FID, and typically developing (TD) children; (2) To elucidate how 24-hour sleep patterns related to behaviour patterns across this period. Methods: Participants represented 115 (75%) children between 3 and 16 years of age (M=7.9, SD=3.0 years) previously reported in Cotton and Richdale (2006) and were all from three earlier studies conducted by one or both authors. 34 children had autism, 12 had DS, 12 had PWS, 24 had FID, and 33 children were TD. The groups did not differ on age and all groups had more males than females with a 3:1 ratio in the autism group. Fourteen-day sleep diary data covering daytime and nightime sleep and behaviour were examined. Parents also provided qualitative information in the diaries. Given the uneven and sometimes small group sizes non-parametric analyses were conducted: Kruskal-Wallis H statistic for group comparisons (p <.05), Mann-Whitney-U for multiple pair-wise comparisons (p <.05) and Spearman's Rho for all correlations (p ≤ .01). Results: Group comparisons showed significant differences for daytime behaviours with children with autism showing the most difficult daytime and bedtime behaviour, more energetic and excited daytime behaviour and less daytime and bedtime sleepiness. Multiple pairwise comparisons variously showed significant differences with the DS, FID and TD groups, with the autism group being significantly less sleepy at bedtime than all other groups. Children with autism napped less than the PWS and DS groups. They fell asleep later, spent longer awake if they woke, slept less at night and over 24 hours, and had poorer sleep quality than all other groups. With the exception of night sleep, multiple pairwise comparisons variously showed significant differences between the autism and the PWS, FID and TD groups. Children with autism were more likely to be woken in the morning than all the other groups and the PWS comparison was significant. There were a large number of significant associations between behaviours and sleep patterns in the autism group compared to the other groups. In particular these associations suggested that higher levels of daytime activity and poor behaviour were associated with poor sleep quality in children with autism as opposed to the other groups. Conclusions: Comparison of sleep and behaviour patterns in autism, DS, PWS, FID and TD children indicates that there are some sleep characteristics that differentiate these disorders. In autism sleep patterns are generally more problematic, sleep quality is poorer and unlike the other disorders, poor sleep quality is related to over-active behaviours and disturbed sleep. Implications will be discussed.