Functional Imagery of Sleepwalking

Sleepwalking (also called somnambulism) is a disorder in which only SWS is disrupted. This NREM parasomnia is characterized by inappropriate motor behaviors, usually initiated during arousal from SWS, that induce psychological distress and alter quality of life, leading to fatigue, excessive daytime sleepiness, and objectively impaired vigilance in the morning.

The pathophysiology of sleepwalking remains poorly understood. Sleepwalkers had difficulty maintaining stable, consolidated sleep and experienced more arousals and microarousals, specifically from SWS, leading to increased NREM instability, especially during the first sleep cycles. The brain is partially awake, resulting in behavioral manifestations, and partially in NREM sleep, resulting in no conscious awareness of actions.

A Single Photonic Emission Computed Tomography (SPECT) study of one sleepwalking episode found increased activation in the posterior cingulate cortex and cerebellum, with deactivation in the frontoparietal associative cortices. Data from intracerebral EEGs during confusional arousals confirmed both local arousal of the motor and cingulate cortices and increased delta activity in the frontoparietal associative cortices.

The investigators thus proposed a controlled study of SPECT imagery in 24 sleepwalkers (12 SPECT during a SW episode and 12 SPECT during slow wave sleep and 24 during wakefulness) and 12 controls (during slow wave sleep and wakefulness). SW episodes will be elicited by sleep deprivation condition associated with forced arousal (auditory stimulus).

The comparative analyses of SPECT acquisitions between different states (wakefulness, slow wave sleep and SW) and populations (sleepwalkers versus controls) will provide new insights about the complex pathophysiology of SW episodes.