Objective and subjective sleep characteristics across severity subgroups in children with autism spectrum disorder

Background Sleep disturbances are common in children with autism spectrum disorder (ASD), yet the relationship between objective sleep characteristics and ASD severity remains unclear. We examined polysomnography‐derived and caregiver‐reported sleep characteristics in children with ASD and typically developing children (TDC), with additional analyses across ASD severity subgroups. Methods We included 111 children aged 3–13 years: 81 with ASD and 30 TDC. Participants underwent home PSG, and second‐night PSG data were used for the primary analyses. Caregiver‐reported sleep behaviors were assessed with the Children's Sleep Habits Questionnaire. Children with ASD were classified by Childhood Autism Rating Scale scores into mild (M‐ASD, n = 36) or moderate‐to‐severe (MS‐ASD, n = 45) subgroups. Group comparisons used age‐ and sex‐adjusted analysis of covariance with correction for multiple comparisons. Exploratory logistic regression and receiver operating characteristic analyses were conducted in the ASD group. Results Compared with TDC, children with ASD showed poorer sleep continuity, including lower sleep efficiency and longer sleep latency, with greater wake after sleep onset in the primary model. Sleep‐architecture differences were not significant after correction. Across severity subgroups, sleep‐continuity difficulties were present in both ASD subgroups, whereas increased wake after sleep onset and greater caregiver‐reported bedtime difficulties were most evident in MS‐ASD. Bedtime resistance, sleep onset delay, and sleep anxiety differed across severity subgroups. Exploratory ASD‐only analyses suggested that selected PSG and caregiver‐reported variables may provide complementary information for characterizing differences between M‐ASD and MS‐ASD. Conclusions Children with ASD showed poorer sleep continuity than TDC, and children with MS‐ASD had more pronounced caregiver‐reported bedtime difficulties. Objective and caregiver‐reported sleep measures may provide complementary information for characterizing sleep phenotypes across ASD severity.