Prospective longitudinal assessment of hallucinations in Parkinson’s disease. Goetz CG, Pappert EJ, Raman R, Stemer AB. Neurology 2001;57:2078–2082

Abstract

Hallucinations, predominantly visual hallucinations, are a common complication of long-term Parkinson’s disease (PD) and its therapy. The two primary contexts in which hallucinations occur in PD are, occasionally, as part of a drug-induced toxic delirium or complication of a superimposed medical illness, and, more commonly, as a late complication of antiparkinsonian medication treatment. This prospective study assessed the evolution of hallucinations over four years in a stratified sample of patients with PD. Using a modified version of the Unified PD Rating Scale (UPDRS) Thought Disorder question, the authors stratified patients into five baseline behavioral groups. They recruited up to 20 patients for each group to participate in sequential interviews at baseline and six, 18, and 48 months. UPDRS motor examinations and Mini Mental State Examinations (MMSE) were obtained at baseline and 48 months. Based on the design stratification, 60 patients had no hallucinations at baseline (20 with no behavioral problems, 20 with sleep fragmentation, 20 with altered dream phenomena). Twenty-nine patients had hallucinations (20 with retained insight and nine with loss of insight). At 48 months, the authors could account for all but two subjects (98% retrieval). In four years, the presence of hallucinations increased (33% at baseline, 44% at 18 months, and 63% at 48 months, P < 0.0001). The presence of frequent hallucinations (at least three times weekly) also increased (P = 0.0002). Having hallucinations at baseline or at any given assessment was a strong predictor at all follow-up evaluations of continued hallucinations (P < 0.0001). Hallucinations were not associated with increased mortality. Among the 60 subjects without hallucinations at baseline, time was the only significant factor influencing the development of hallucinations over 48 months. Baseline age, PD duration, sex, medications, and UPDRS or MMSE scores did not influence the incidence of hallucinations. This prospective, longitudinal study documents the persistent and progressive nature of hallucinations in PD patients on chronic dopaminergic therapy. The consistent association of hallucinations with combined levodopa/agonist therapy suggests that these drugs may play a role in the pathophysiology of hallucinations.—Nancy J. Newman