Mental and Neural Correlates of NREM Parasomnias in Children

Without the regular ebb and flow of consciousness during sleep, it would be easy to overlook that consciousness is not a constant, but rather depends on the way our brain is functioning. The understanding that sleep and wakefulness can be locally regulated offers additional insights into a continuum of intermediate states, ranging from full consciousness, as experienced when awake, to complete unconsciousness.

This study leverages these insights by investigating NREM parasomnias, where features of sleep and wakefulness appear to coexist in different brain areas for extended periods of time. Affected individuals can talk, walk, engage in sexual acts, and even drive, all while in a state of partial or near-total disconnection from their surroundings. Although diagnostic criteria describe these episodes as automatic behaviors without conscious experiences, growing evidence from adults suggests otherwise. When questioned immediately after parasomnia episodes, 50-80% of subjects report dream-like or hallucinatory experiences where external stimuli blend with internally generated imagery.

NREM parasomnias are significantly more prevalent in children, yet paradoxically, far fewer studies have focused on pediatric cases than on adults. The limited retrospective evidence available suggests that children are less likely to remember their episodes or associated mental content. This raises fundamental questions: Is this due to a lower likelihood of children waking after episodes and thus forgetting them, or are children less frequently conscious during episodes due to factors related to brain and dream maturation? Furthermore, what are the neurophysiological correlates of parasomnia episodes in children, and what distinguishes episodes with conscious experiences from those without?

This study aims to answer these questions by examining 50 children during spontaneous and provoked parasomnia episodes recorded over two nights using high-density EEG. Children will be interviewed using a semi-structured questionnaire immediately after their episodes to assess subjective experiences. On the second night, auditory stimuli, a known trigger for these episodes, will be used to induce parasomnia episodes. Pre-existing datasets, collected by the applicant and collaborators, will also be analyzed to identify EEG patterns that may predict the likelihood parasomnia episodes. A pilot closed-loop test will further serve as a proof of concept for these predictions.

By studying these phenomena in children, this project aims to deepen our understanding of consciousness and its neurobiological underpinnings and to uncover how conscious experiences and brain maturation intersect. Clinically, the study has the potential to justify a revision of current diagnostic criteria. Moreover, the use of targeted auditory stimulation to increase the likelihood of capturing episodes in a laboratory setting may enhance clinical diagnostic practices. Ultimately, a better understanding of cortical dynamics preceding and during parasomnia episodes could inform the understanding of underlying neural circuits and the development of treatment strategies.