Prevalence of dementia in an urban slum population in thailand: Validity of screening methods

Abstract

SUMMARYA randomly selected sample of 500 subjects over 60 years old and their relatives were studied using standardized methods for assessment of cognitive impairment. The prevalence of DSM-111-R dementia was 1.8% (95% confidence intervals 0.6-3%), and the majority of cases had a probable diagnosis of Alzheimer's disease. The sensitivity and specificity of the field survey version of the Mini-Mental State Examination (MMSE) for a diagnosis of dementia using a threshold of 21 were 100% and 53% respectively. This was associated with a positive predictive value of dementia, given a low score, of only 3%. A high prevalence of low MMSE scores was found: 23% of men and 50% of women had scores below 21, and there were strong relationships between low scores and age. Strong associations between low MMSE scores and no education were found, and weaker associations with female sex, deafness and poor sight. The MMSE is markedly affected by educational level, which together with its low positive predictive value for dementia in this population makes it a poor screening or research tool. A Behaviour Rating Scale score had a higher specificity leading to fewer false positives, but only achieved a sensitivity of 67%. In populations with low levels of education it is recommended that behavioural disabilities scales should be developed as a means of screening for dementia syndromes.

Investigações epidemiológicas sobre demência nos países em desenvolvimento

“…Sete estudos populacionais sobre o assunto, realizados recentemente em países em desenvolvimento, 2,14,19,21,23,26,32 com metodologias adequadas para seus contextos culturais, apresentaram resultados consistentes de prevalências de demência ajustadas por idade inferiores às encontradas nos estudos realizados na Europa, 6 tanto para pessoas com 60 anos ou mais (variação entre os estudos: 1,3% a 5,3%), como para pessoas com 65 anos ou mais (variação entre os estudos: 1,7% a 5,2%). Três destes estudos foram realizados na Índia, 2,23,26 dois na China, 19,32 um na Tailândia 21 e um na Nigéria.…”

Methodological issues for population-based research into dementia in developing countries. A position paper from the 10/66 Dementia Research Group

“…In the preceding consensus statement (10/66 Dementia Research Group, 1998) we listed seven published population-based prevalence surveys from the developing world, three from India (Shaji et al, 1996;Rajkumar et al, 1997;, two from China (Li et al, 1989;Zhang et al, 1990) and one each from Thailand (Phanthumchinda et al, 1991) and Nigeria (Hendrie et al, 1995). This is not an exhaustive list, but does represent all recent methodologically robust and comparable studies.…”

Care arrangements for people with dementia in developing countries

“…We can infer, given the dearth of health and welfare services for older people that families and other informal caregivers are the mainstay of support (Li et al, 1989;Phanthumchinda et al, 1991;Shaji et al, 1996). However, we also know little of the impacts upon these caregivers and their local communities.…”