Hallucinations and sleep-wake cycle in PD: a 24-hour continuous polysomnographic study.

Twenty-four-hour ambulatory polysomnography was performed in 20 patients with PD who were having visual hallucinations (12 men and 8 women, mean age 70 +/- 6 years). Visual hallucinations were clearly related to daytime NREM sleep or nocturnal REM sleep in 33% of the instances. The data reinforce the hypothesis that neural mechanisms implicated in generating sleep and, in particular, in dream imagery play a role in the occurrence of visual hallucinations in PD.