The value of sleep deprivation as a diagnostic tool in adult sleepwalkers

Objective: Adult somnambulism can result in injury to the sleeper and to others. Attempts to induce sleepwalking episodes in the sleep laboratory have yielded mixed results.(1,2) Having shown that sleepwalkers have lower slow-wave activity power than control subjects,(3) the authors hypothesized that an enhanced pressure of the homeostatic process underlying sleep regulation could affect the disorder's characteristics even further. Therefore, the effects of 38 hours of sleep deprivation in adult sleepwalkers and control subjects were investigated. Methods: Ten adult somnambulistic patients and 10 sex- and age-matched control subjects were studied in the sleep laboratory. After a screening night, participants were monitored during 1) one night of baseline recording, and 2) one recovery night in which subjects slept ad libitum immediately after the sleep deprivation protocol. Behavioral manifestations were assessed for frequency and complexity using a 3-point scale of increasing complexity. Results: None of the control subjects had any behavioral manifestations on either of the two nights. Conversely, sleepwalkers showed a significant increase in the frequency and complexity of the somnambulistic episodes during the recovery night compared with baseline. Somnambulistic patients had a greater number of awakenings from slow-wave sleep than control subjects on both nights, but there was no significant increase during the recovery night. Conclusion: Sleep deprivation can be an effective tool for inducing somnambulistic episodes in the laboratory, thereby facilitating the diagnosis of sleepwalking.