Abstract
An 81-year-old man was referred to our psychiatry outpatient clinic for treatment of parasomnia. About 10 years previously, he had begun to experience visual hallucinations of small animals or persons during the night, and about 5 years later he had started to exhibit unusual nocturnal behavior such as speaking in a loud voice and falling out of bed. He had been treated by a physician at another clinic and prescribed medication including clonazepam, but this had not been effective for his parasomnia. Video polysomnography revealed severe obstructive sleep apnea syndrome (apnea hypopnea index 36.0/h) and REM sleep without atonia. A 123I-ioflupane SPECT revealed reduced dopamine transporter uptake in the bilateral basal ganglia, and 123I-MIBG scintigraphy demonstrated a reduced heart-to-mediastinum ratio, suggesting a probable diagnosis of dementia with Lewy bodies. We treated obstructive sleep apnea syndrome using continuous positive airway pressure therapy. In addition, we prescribed clonazepam for REM sleep behavior disorder and donepezil hydrochloride for the visual hallucinations due to dementia with Lewy bodies. This resulted in the disappearance of his nocturnal parasomnia symptoms. In this case, continuous positive airway pressure therapy may have improved the responsiveness of REM sleep behavior to clonazepam treatment. It is important to follow up this patient with careful monitoring in case of future cognitive decline.
