Risk factors for visual hallucinations in patients with Parkinson's disease.

Aim: Parkinson's disease (PD) patients frequently present visual hallucinations (VHs) that have been associated with depression, old age, and cognitive impairment. Sleep abnormalities are also related to these factors. The aim of this study is to evaluate risk factors, particularly sleep alterations, associated with VHs in PD.

Methods: This is a cross-sectional evaluation of consecutive patients from a Movement Disorder's clinics. Patients were clinically evaluated, and behavioral questionnaires were applied in a face-to-face interview.

Results: Among 100 PD patients (67% male, mean age  =  65.0 ± 10.4), VHs were present in 28% of cases; individuals with VHs had worse sleep quality (Pittsburgh Sleep Questionnaire Index) and more severe sleep disturbances [Parkinson's Disease Sleep Scale (PDSS)]. Logistic regression analysis showed that vivid dreams and Unified Parkinson's Disease Rating Scale (UPDRS) I scores (i.e., mentation, behavior, and mood symptoms) are independently associated with VHs. Our data show that the presence of vivid dreams is associated with VHs in PD and reaffirm that VHs are linked to cognitive impairment.

Conclusions: Investigating vivid dreams may help the identification of VHs in PD. Identifying vivid dreams can be hard considering that patients may fail to report symptoms for the fear of the stigma associated with psychosis and dementia.