Prader-Willi syndrome, excessive daytime sleepiness, and narcoleptic symptoms: a case report

Sleep abnormalities, including narcolepsy and cataplexy, are a common feature of Prader-Willi syndrome. Long-term treatment with the central nervous system stimulant modafinil has not been reported. In this case report we present a longitudinal perspective of sleep abnormalities in a nine-year-old Caucasian girl with Prader-Willi syndrome from age two to age nine, and detail the response to treatment with the central nervous system stimulant modafinil. Our patient presented at two years of age with hypersomnia and narcoleptic episodes with cataplectic features. Initial polysomnograph testing revealed adequate sleep efficiency, but increased sleep fragmentation especially during rapid eye movement sleep. The narcoleptic episodes continued and a repeat polysomnograph at age five years confirmed features consistent with narcolepsy. Further sleep studies at six years, including a multiple sleep latency test, demonstrated signs of excessive daytime sleepiness. Treatment with modafinil was initiated at age seven years six months due to persistent hypersomnia and narcoleptic symptoms. Two polysomnograph studies were performed following treatment with modafinil, at age eight years six months and nine years three months. These studies showed excellent sleep efficiency and improvement of rapid eye movement sleep parameters, supporting the beneficial effects of long-term modafinil therapy. Long-term modafinil therapy may ameliorate the sleep disturbances of Prader-Willi syndrome and should be the focus of future clinical trials.