REM sleep behavior disorder in a patient with pontine stroke.

Rapid eye movement (REM) sleep behavior disorder (RBD) is frequently seen in patients with neurodegenerative diseases. It can also be seen in brainstem lesions involving the pons. However, RBD in patients with a pure pontine infarction has been rarely reported. A 68-year-old man had a two-month history of violent behavior during sleep. His nocturnal behavior was screaming, thrashing of arms, punching or kicking his spouse, and falling out of bed associated with nightmares of being attacked by what he described as, "terrible animals frightening me." No remarkable neurological signs were found. Brain MRI was performed on this patient and it revealed a lacunar ischemic infarct in the right paramedian pons. On the nocturnal polysomnography (PSG), there was phasic submental and limb electromyographic (EMG) tone and an absence of electroencephalographic (EEG) epileptiform activity during REM sleep. Hence, this patient was diagnosed with pontine infarction and RBD. Treatment with clonazepam 0.25mg nightly resulted in the disappearance of nocturnal events. This case with right pontine tegmental ischemic lesion provides evidence that the unilateral pontine lesion by itself is sufficient to cause RBD.