Risk Factors in Developing Hallucinations in Parkinson’s Disease

OBJECTIVE: Hal lucinations are frequent non-motor symptoms of Parkinson’s disease (PD). METHODS: In this study, it was aimed to investigate the possible risk factors on the emergence of hallucinations in PD. RESULTS: Seventy hallucinating PD patients (Group 1) and non-hallucinating 60 PD patients as control group (Group 2) were enrolled in the study. The mean age at onset of hallucinations in Group 1 were matched with the mean age of patients at their last available visit in Group 2. Between these two groups, the age at onset of first PD symptom, duration of PD, Hoehn-Yahr (H&Y) staging, Unified PD Rating Scale (UPDRS) scores, duration and mean dosage of levodopa and other antiparkinsonian drugs, the presence of wearing-off phenomenon, dyskinesia and rapid eye movement sleep behaviour disorder (RBD) were evaluated. CONCLUSION: The mean age at onset of PD symptoms in hallucinators was higher than those of non-hallucinators (p=0.02). Although the daily activity and motor parts of UPDRS and H&Y scores did not differ between two groups, the UPDRS part I scores were significantly higher in patients with hallucinations, as expected (p=0.0001). The mean duration of PD, duration and daily doses of dopaminergic drugs did not show any differences between the groups. Similarly, motor complications developed in both groups with no statistical difference. However, RBD was more frequently encountered among hallucinators than non-hallucinators (p=0.007). Conclusions: Hallucinations could develop during the course of PD, and late onset of first PD symptom is associated with the emergence of hallucinations, as well as RBD frequently found to accompany the hallucinations in PD. However, the duration and severity of PD along with the duration and dosage of antiparkinsonian drugs do not have a role in the appearance of hallucinations. As data in the literature are inconclusive, it has been suggested that the emergence of hallucinations in PD, which has been thought to be multifactorial, may be influenced by many factors, including especially the cognitive state