Objective Measures of Pain Sensitivity in NREM Sleep Parasomnia

Non Rapid Eye Movement (NREM) sleep parasomnias (sleepwalking and sleep terrors) are frequent and disabling sleep disorders characterized by arousal specifically from slow wave sleep (SWS) with dissociated brain activity that may be related to lower nociceptive state. The investigators recently reported frequent subjective complaints of chronic pain, migraine and headache during wakefulness in adult sleepwalkers. They also described frequent analgesia during severe and injuring episodes, suggesting a relationship between dissociated brain activity and nociceptive dysregulation. However, this study did not included objective nociceptive measures and the retrospective assessment of perceived pain during parasomnia episodes over a lifetime span might also introduce a recall bias.

The aims of the present study are to measure objective pain sensitivity in patients with NREM parasomnias and matched controls during 1) parasomniac episodes, 2) light NREM sleep and SWS, and 3) wakefulness.

Fifteen adults with severe NREM parasomnia and 15 age and sex-matched controls will be recruited. A 25 hours (8 AM to 9 AM) sleep deprivation protocol followed by auditory stimulations during SWS will be used to trigger parasomniac episodes. Thermoalgic stimulations of graduate intensity will be applied during wakefulness (8 PM) to determine the nociceptive threshold. During the recovery sleep following the sleep deprivation, the investigators will apply repeated subthreshold thermoalgic stimulations in NREM stage 2, SWS and triggered parasomniac episodes and report the behavioural/neurophysiologic nociceptive responses.

The investigators hypothesized a lower nociceptive threshold during wakefulness in sleepwalkers and a decrease of the arousabiliy during SWS and parasomniac episodes. This study may help to better understand the etiology and mechanisms underlying the clinical enigma of the nociceptive dysregulation in NREM sleep parasomnias.