Paroxysmal nocturnal dystonia presenting as excessive daytime somnolence.

We describe the clinical and electrophysiologic findings in seven patients referred for evaluation of excessive daytime somnolence. These patients had none of the usual causes of excessive daytime somnolence but during sleep exhibited stereotypic body movements, tachycardia, respiratory disturbances, somniloquy, and transient arousals in a repetitive fashion. These episodes induced fragmentation of sleep. The polysomnograms revealed an increase in wakefulness and stage I decreased rapid eye movement during sleep in addition to the episodes of abnormal body movements. No epileptiform features were present either in the electroencephalogram or in the nocturnal polysomnogram. Four of the seven patients were treated with anticonvulsants, with both subjective and objective improvement on subsequent follow-up polysomnograms. Because of the pronounced functional deficits associated with the sleep disorder in these patients, it is of great importance to recognize the disorder and treat it appropriately.