Impact of sleep disorders on sleep-dependent learning consolidation processes in children.

Summary Sleep plays a major role in the learning consolidation process. Subjects' performance in memory test retrieval is better when the learning and retrieval phases are separated by a period of sleep rather than by a period of wakefulness. The effects of sleep on these consolidation processes have been extensively studied in adults, notably with the help of specific sleep deprivation protocols. However, the use of these sleep deprivation protocols in children is not possible for ethical reasons. Our current knowledge of the effects of sleep on sleep-dependent learning consolidation processes is therefore very limited in children. Sleep disorders affect a significant proportion of children and have important daytime repercussions, particularly at the academic level. Surprisingly, although the majority of children with sleep disorders fail at school, the impact of these sleep disorders on the consolidation of sleep-dependent learning processes has very rarely been evaluated. The objective of this thesis project was therefore to evaluate the impact of sleep disorders on these consolidation processes. To achieve this goal, we selected 3 pathologies with specific sleep impairments: narcolepsy, obstructive sleep apnea syndrome (OSA) and benign centrotemporal spike epilepsy (BCSE). We subjected these groups of children and a group of age- and sex-matched control children to memory consolidation tests in which the learning phase was performed at night before bedtime and the retrieval phase in the morning after the post-learning night. In order to have the most complete vision possible of the impact of sleep disorders on learning consolidation processes, these memory consolidation tests involved declarative (verbal, visuo-spatial and emotional tasks) and non-declarative (procedural task) learning. We also measured the children's attentional abilities before learning and before retrieving the memory consolidation tests. Our results suggest that narcolepsy, OSA and PTSD would have a negative impact on the consolidation processes of sleep-dependent visual-spatial learning. On the other hand, these 3 pathologies do not seem to have an influence on these processes in the context of verbal, emotional and procedural learning. These results therefore suggest that aspects concerning the nocturnal consolidation of learning should be integrated into the neuropsychological evaluations that are taken into account in the diagnosis of children with these pathologies. Moreover, the pedagogical and reeducational follow-up of these children should be reconsidered.