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Relationship of dementia and visual hallucinations in tremor and non-tremor dominant Parkinson's disease

Therapy adherence issues in Parkinson's disease

15 December 2012
Rana AQ, Vaid HM, Edun A, Dogu O, Rana MA

Objectives: Both visual hallucinations and cognitive dysfunction are experienced by a significant number of patients with Parkinson's disease. There were three main objectives of this study: (1) to determine if there is a difference in the prevalence of dementia in patients with tremor versus non-tremor dominant Parkinson's; (2) to determine if there is a difference of prevalence of visual hallucinations in patients with tremor and non-tremor dominant Parkinson's disease; and (3) to determine if there is a relationship between visual hallucinations and dementia in Parkinson's disease patients.

Background: Dementia and visual hallucinations are common non-motor symptoms of Parkinson's disease that affect a significant number of patients. Previous research has shown that visual hallucinations may be predictive of future onset of dementia. We wanted to compare the prevalence of these non-motor symptoms in tremor vs. non-tremor dominant Parkinson's disease, although previous research has shown that dementia may be more common in the akinetic rigid variant of Parkinson's disease without tremor. Visual hallucinations have not yet been studied in this way.

Methods: We performed a retrospective chart analysis on 314 patients with Parkinson's disease in this study. Patients meeting the inclusion criteria were stratified into several categories based on the presence or absence of tremor dominant PD, akinetic rigid dominant PD, dementia and visual hallucinations. Nonparametric tests were used for performing statistical analyses. The Chi Squared test was used for the analysis of categorical variables.

Results: Patients without tremor had a higher prevalence of dementia (29%) than those with tremor (14%). There was no difference in visual hallucinations in tremor versus non-tremor patients, although there was a significant trend between tremor and visual hallucinations in female patients. A significant correlation was found between dementia and visual hallucinations in the sample, however further investigation showed this was largely associated with female Parkinson's disease patients.