Sleepwalking: More Often Neurological Than Psychiatric
Abstract & Commentary
By Charles P. Pollack, MD Dr. Pollack is Professor, Clinical Neurology, Weill College of Medicine. Dr. Pollack is a stockholder and on the speaker's bureau for Cephalon.
Synopsis: Successful treatment of SDB, which is frequently associated with chronic sleepwalking, controlled the syndrome in young adults.
Source: Guilleminault C, et al. Adult Chronic Sleepwalking and Its Treatment Based on Polysomnography. Brain. 2005;128:1062-1069.
Sleepwalking (somnambulism) is an abnormal liberation of motor activity during slow-wave sleep Because of the association with stage 3-4 sleep, episodes usually occur during the first few hours of sleep. There is little or no awareness or recall by the sleeper. Diagnosis may be made after excluding REM-Sleep Behavior Disorder, night eating and epilepsy. A sleep recording (polysomnogram) will often reveal brief arousals during sleep-wave sleep, which are not necessarily associated with gross motor activity. Most often, the patient is a child, but sleepwalking may persist into or even appear during adulthood. Surveys have shown that it affects 2% to 5% of the adult population. Serious injuries have occurred while sleepwalking, as well as acts of violence. It can usually be suppressed or rendered innocuous with small doses of benzodiazepines (lorazepam, diazepam).
In this study, fifty young adult sleepwalkers and 50 non-sleepwalkers underwent detailed diagnostic evaluation, including interview of bed partners, sleep-deprived and non-deprived EEGs (sleepwalkers only) and polysomnography (PSG). PSG included esophageal pressure, which is needed for recognizing the upper airway resistance syndrome (UARS). Patients with UARS show increases of esophageal pressure (respiratory effort) during sleep but, unlike obstructive sleep apnea syndrome (OSAS), little change of airflow or oxygen saturation, and episodes do not necessarily terminate with EEG arousal. Daytime somnolence is therefore minimal. Injuries to self or others during sleepwalking were reported by 30% of the study subjects. In all, 42 of the 50 patients were found to have sleep-disordered breathing (SDB): UARS in 76%, OSAS in 24%. All were treated with nasal CPAP and followed up at 6 months. Forty-two subjects were compliant with nasal CPAP treatment which they used for 5.8 hours a night. Their apneas and hypopneas essentially disappeared, as did sleepwalking. By contrast, those who were noncompliant with CPAP (< 2 hours of nightly use) continued to sleepwalk, as did those who were followed by a psychiatrist and treated with drugs and/or psychotherapy. Noncompliant subjects were offered upper airway surgery; this also successfully controlled sleepwalking.
Sleepwalking is usually considered a problem of the middle childhood years, but it has long been known to occasionally persist into adulthood. It is surprisingly common in adults and is often associated with psychiatric disorders. In the current issue of Brain, however, Guilleminault and colleagues show that sleepwalking is more often associated with sleep disorders (sleep-disordered breathing). Both obstructive sleep apnea (OSAS) and upper airway resistance (UARS) are best treated by nasal CPAP, which is also fully effective against sleepwalking as long as the patient remains compliant. Clinical experience with OSAS has shown that compliance is highest when symptoms (loud snoring, daytime somnolence) have been eliminated by CPAP. These symptoms are not typical of UARS, however, perhaps explaining why CPAP compliance and thus control of sleepwalking was limited in the UARS patients of this study. For that matter, the mechanism by which UARS promotes sleepwalking is unclear. The authors speculate that it may partially induce wakefulness. This seems reasonable, as it has long been known that forcibly sitting a sleepwalker up in bed, thereby disturbing the continuity of sleep, can initiate a full sleepwalking episode.
This paper makes clear that adult sleepwalking is often secondary to other sleep disorders, mainly disturbances of breathing that can and should be controlled with nasal CPAP. Upper airway surgery was also effective in controlling sleepwalking in subjects who did not comply with nightly CPAP. Psychiatric management with either medication or psychotherapy was not effective. Additional measures to reduce the risk of injury include: removal of potentially dangerous objects from the bedroom, clearing the floor of obstructions, locking doors and windows and placing the mattress on the floor.