Rhythmic movement disorder in sleep persisting into childhood and adulthood.

STUDY OBJECTIVES

To evaluate the type, duration, and distribution of rhythmic movements in sleep stages in school-aged children and young adults; to find out if cases of rhythmic movement disorder persisting beyond infancy are associated with any daytime symptoms or psychopathology.

DESIGN

All participants underwent neurologic examination, biochemical screening, electroencephalography, neuroimaging, overnight videopolysomnography, and psychologic examination.

SETTING

Department of Neurology and Sleep Laboratory, 1st Medical Faculty, Charles University, Prague.

PATIENTS OR PARTICIPANTS

Ten subjects referred to the sleep disorders center because of rhythmic movement disorder. Five males, 5 females; age range, 7-24 years; mean age 14.7 +/- 5.69 years.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Biochemical screening, electroencephalogram, and neuroimaging were unremarkable in all cases. According to duration, 2 types of rhythmic movements were observed on polysomnography: longer episodes appeared in wakefulness and in non-rapid eye movement stage 1 sleep, while shorter episodes (2-80 seconds) occurred during non-rapid eye movement stage 2, non-rapid eye movement stage 3-4, and rapid eye movement sleep. According to sleep-stage distribution, we defined (a) rhythmic movements prevailing in the first half of the night and in the morning hours, usually associated with wakefulness or superficial sleep; (b) rhythmic movements occurring throughout the night in all sleep stages; (c) rhythmic movements prevailing in the second half of the night and mainly associated with rapid eye movement sleep. Psychologic examination showed symptoms of the attention-deficit/hyperactivity disorder in 6 cases.

CONCLUSIONS

According to our study, rhythmic movement disorder persisting beyond infancy may be connected with various daytime symptoms; a strong association between rhythmic movement disorder and attention-deficit/hyperactivity disorder was found in school-aged children. We speculate that pathogenetic mechanisms similar to those in attention-deficit/hyperactivity disorder are involved in rhythmic movement disorder or that symptoms of attention-deficit/hyperactivity disorder may be secondary to rhythmic movement disorder.