Hallucinations, sleep fragmentation, and altered dream phenomena in Parkinson's disease

In a series of consecutively randomized outpatients who had Parkinson's dis ease (PD), we examined the association of three behaviors: sleep fragmentat ion, altered dream phenomena, and hallucinations/illusions. Using a logline ar model methodology, we tested the independence of each behavior. Sixty-tw o percent of the subjects had sleep fragmentation, 48% had altered dream ph enomena, and 26% had hallucinations/illusions. Eighty-two percent of the pa tients with hallucinations/illusions experienced some form of sleep disorde r. The three phenomena were not independent. The interaction between sleep fragmentation and altered dream phenomena was strongly statistically signif icant. Likewise, a significant interaction existed between altered dream ph enomena and hallucinations/illusions. No interaction occurred between sleep fragmentation and hallucinations/illusions. Sleep fragmentation, altered d ream phenomena, and hallucinations/illusions in PD should be considered dis tinct but often overlapping behaviors. The close association between altere d dream phenomena and hallucinations suggests that therapeutic intervention s aimed at diminishing dream-related activities may have a specific positiv e impact on hallucinatory behavior.