Sleep behaviour in children with language disorder

Sleep and language are intimately linked over childhood, as demonstrated by both in-lab studies and trajectories of change over developmental time. Despite this, objective sleep measurements have never been compared between children with developmental disorders of language and their language-typical peers. The aim of this two-study series was to assess an emergent hypothesis that children with poor structural language development may also exhibit poor sleep. In Study 1, 196 parents of 4-10 year old children completed the Children’s Sleep Habits Questionnaire and the Children’s Communication Checklist-2, including the parents of 61 children with reported language disorders. Parent-reported sleep behaviour and language ability showed a positive correlation, with children who scored more highly on the language measure showing better sleep-related behaviour. Interestingly, parental estimates of sleep duration showed the reverse pattern, with children who scored lower on the language measure being reported to go to bed earlier and sleep for longer. In Study 2, a subsample of 40 4-to-6 year old children from Study 1 gave objective measures of sleep with actigraphy and completed a battery of standardised language assessments. 20 of these children (the Language Disordered group) demonstrated clinically significant difficulties with language development, in contrast to the remaining 20 Typically Developing children. When we considered objective measures of sleep and language in this smaller sample a negative relationship emerged (consistent with parent estimates), whereby those children with language difficulties slept for longer and more efficiently than their language-typical peers. The parental perception of poor sleep-related behaviour in children with language difficulties may result from poor sleep in early childhood and from observed difficulties in sleep parameters that are not possible to assess with actigraphy, such as sleep-disordered breathing. We suggest that subjective and objective measures of children’s sleep be thoughts of as complementary.