Material and Method: A cross sectional study in consecutive PD patients at the neurological clinic, MNRH between January and August 2011 was performed. The baseline characteristics such as age, sex, duration and severity of disease, education level, and medications were collected. Dementia was assessed according to Thai Mini Mental State Examinations (TMSE). The data were analyzed for determining the prevalence and factors that might correlate with dementia in patients with PD.

Results: One hundred forty three PD patients with mean age of 65.8±10.5 years and 49% males were enrolled in the present study. The prevalence of dementia was 35.0% in all subjects and 39.4% with education level adjustment. Dementia was found in any severity of PD. The advanced age and the later age at PD onset were the associated factors that had influenced on developing of dementia.

Conclusion: The prevalence of dementia in PD patients at MNRH with education level adjustment was 39.4% and could be found in any stage of disease. The advanced age and later age at PD onset were the significant associated factors for this condition. TMSE with cut-off score below 24 points was suitable for using to define dementia in Thai PD patients.

Keywords: Dementia, Thai Parkinson’s disease, Prevalence and associated factors