Objective: To prospectively assess the relationship of hallucinations to sleep disorders in patients with Parkinson disease (PD) over 6 years.
Background: Several studies suggest an association between hallucinations and sleep disruption, but no longitudinal study has examined their progression and relationship, nor whether sleep alterations predict future hallucinations.
Methods: Eighty-nine PD patients were recruited to fill cells of normal sleep without hallucinations (n = 20); sleep fragmentation only (n = 20); vivid dreams/nightmares (n = 20); hallucinations with insight (n = 20); hallucinations without insight (n = 9). At baseline, 6 months, 18 months, 4 years, and 6 years, sleep disorders and hallucinations were assessed by standardized scales with the longitudinal data analyzed by generalized estimating equations and other nonparametric tests.
Results: At 6 years, we could account for all subjects (49 interviewed, 40 deceased or too ill for interview). Hallucination prevalence and severity increased over time (p < 0.0001). The odds of being a hallucinator increased by a factor of 1.39 at each successive time point. Sleep disorders, however, fluctuated widely among patients and time points, with no evidence of progression in severity (p = 0.73). The prevalence of sleep fragmentation did not differ between subjects with vs without hallucinations (OR = 1.43, p = 0.13). The presence of vivid dreams/nightmares, however, was highly correlated with the concurrent presence (OR = 2.32) and severity of hallucinations (OR = 3.02, both p < 0.0001). Vivid dreams/nightmares among non-hallucinators did not predict future development of hallucinations (OR = 0.94, p = 0.51).
Conclusions: Hallucinations and global sleep disorders follow different patterns of progression in Parkinson disease and are separate behavioral abnormalities. Sleep alterations are not necessarily harbingers of hallucinations.