Levodopa-induced sleepiness in the Parkinson variant of multiple system atrophy.

Recent observations suggest that levodopa can induce irresistible sleep onset in multiple system atrophy (MSA). Therefore, we assessed sleepiness during a levodopa challenge in 17 MSA compared with 23 Parkinson's disease (PD) patients using the Stanford Sleepiness Scale (SSS). SSS scores during the levodopa challenge compared with baseline were significantly increased in the MSA compared with the PD group. These findings suggest greater potential of levodopa to induce sleepiness in MSA compared with PD, which may be related to differences in basal ganglia and brainstem pathology between the two disorders.