Dementia in Thai patients with Parkinson's disease: analysis of 132 patients

A cross-sectional design study was done at Siriraj Hospital from 1990 to 1994 to determine the prevalence of dementia in Thai patients with Parkinson's disease. There were 81 males and 51 females with a male to female sex ratio of 1.59:1. One hundred and thirty two patients with Parkinson's disease were enrolled in this study. The mean duration of illness was 3.5 (S.D. 3.53) years. All patients were screened for depression by using the Thai Geriatric Depression Scale and patients with Alzheimer's disease or stroke were excluded from the study. The Thai Mental State Examination (TMSE) is a standard test used in this study to identify dementia in Thai patients with Parkinson's disease. Thirty four patients (25.76 per cent) scored TMSE below 23 points (cut-off point for dementia) and were considered as having dementia. Twenty four patients (18.18 per cent) scored below 20 points and were considered as having severe dementia, 12 patients (9.09 per cent) scored between 20-22 points (classified as mild to moderate dementia). Thirty seven patients (28.03 per cent) were in the borderline group as they had TMSE scores between 23-25 points. Fifty nine patients (44.70 per cent) were determined as nondemented as their TMSE scores were over 25 points. The items of cognitive function tests in TMSE which were severely impaired in the demented group were recall, attention and calculation whereas registration was relatively unaffected. Orientation and language were moderately impaired in the demented group. Dementia in Thai patients with Parkinson's disease is a significant problem for long term care of patients because of its high prevalence (one-fourth of all patients) and nearly one-fifth had severe dementia. Prompt recognition and proper management of dementia are required for family members and medical personnel to handle patients with Parkinson's disease.