Nocturnal eating: sleep-related eating disorder or night eating syndrome? A videopolysomnographic study.

STUDY OBJECTIVES

To describe the clinical and videopolysomnographic characteristics of nocturnal eating episodes in sleep-related eating disorder.

DESIGN

Descriptive study of outpatients prospectively enrolled in 2 sleep centers.

SETTING

Videopolysomnographic recordings done in the sleep laboratory.

PATIENTS

Thirty-five consecutive drug-free patients with nocturnal eating.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Clinical interviews disclosed abnormal compulsory nocturnal eating episodes in all patients associated with a clinical report of sleepwalking (in 1), somniloquy (in 5), restless legs syndrome (in 8), and periodic limb movements during sleep (in 4). Videopolysomnography documented 45 episodes of nocturnal eating in 26 patients. Eating always occurred after complete awakenings from non-rapid eye movement sleep and only in 1 patient from REM sleep and was characterized by electroencephalographic alpha activity with no dissociated features of state-dependent sleep variables. Patients interviewed during the eating episodes were fully conscious and remembered the events the next day. Pathological periodic limb movements during sleep index was recorded in 22 and restless legs syndrome dyskinesias in 5 patients. Recurring chewing and swallowing movements during sleep were a feature in 29 patients, associated in about half of the events with electroencephalographic arousals.

CONCLUSIONS

In our patients, eating episodes occurred with normal consciousness and recall. Chewing or swallowing movements during sleep occurred frequently, resembling rhythmic masticatory-muscle activity in bruxism patients. The presence of periodic limb movements during sleep and chewing activity, the reported efficacy of dopaminergic medications, and the compulsory food-seeking behavior all argue for a dopaminergic dysfunction underlying the pathogenesis of sleep-related eating disorder.