RESUMO
OBJECTIVE: To survey the prevalence of cognitive impairment in the elderly and to estimate the prevalence of dementia in the community dwelling Thai population. To assess the psychometric property of Thai Mental State Examination (TMSE). MATERIAL AND METHOD: We conducted a countrywide survey of 3,177 Thai elderly who were 60 years old and over from 1995 to 1997. Medical history and ability to carry out daily activities were taken by trained medical personnel. Thai Mental State Examination (TMSE) was used for cognitive study. Every elderly person involved in this study was examined by either an internist or a neurologist. Blood was taken for haematological and biochemical analysis. SPSS 6.0 was the main statistical analysis of the data. RESULTS: Three thousand one hundred and seventy seven elderly people were enrolled in this study, thirty eight point eight per cent were male and sixty one point two per cent were female. There was correlation between age, education and TMSE (r=-0.345, r=0.473, p<0.001). We found no correlation between TMSE, mean arterial blood pressure (BP), systolic BP, diastolic BP, haematocrit, cholesterol, triglyceride, blood sugar and syphilitic serology. Multiple cut off points of TMSE was proposed to utilise the twenty fifth percentile in each five yearly age interval. Those who were under the 25th percentile of TMSE and had impaired daily activities were diagnosed as dementia. The prevalence of dementia was 9.88 percentiles in our study. CONCLUSION: Dementia is a common problem in the Thai elderly. As treatment has become available for several etiologies of dementia, early detection and assessment of dementia with a cognitive screening test are essential. Public education to distinguish between dementia and old age needs to be emphasised.