Western instruments for assessing cognitive impairment perform badly in less developed countries, producing many false positives. This occurs because many items require literacy and a reasonable level of education. A cognitive impairment screening test for use in less developed countries with high levels of illiteracy and low educational attainment is needed. The development of such an instrument was attempted. An initial instrument was derived from a review of existing instruments, selecting those items not requiring reading and writing ability. The 36 items obtained were then used with elderly people aged 60+ years who had no evidence of psychiatric, behavioural or psychological disturbance. Subjects were drawn from rural and urban clinical settings and a random sample from a Bangkok slum. Thirteen items showed no relationship with educational attainment and were then considered by an expert panel for utility and domain of cognition covered. The revised instrument, the Chula Mental Test (CMT), was then applied to 212 residents of an old people's home in Bangkok. The validity of the CMT was tested by comparison with a neurologist's independent diagnosis of dementia. Comparisons were made with the Mini-Mental State Examination and the Abbreviated Mental Test. The CMT at its optimal threshold had the best combination of sensitivity (100%) and specificity (90%) for detection of dementia. Test-retest repeatability and internal consistency were high. Translated versions of the CMT may have value in other south and southeast Asian countries.
KEY woms-cognitive impairment; aged; assessment; measurement; developing countries In many less developed countries of south and southeast Asia, ageing is accelerating and will lead to very large numbers of older people. It is anticipated that increased burdens of chronic degenerative disease will occur, in particular dementia syndromes. Quantifying the burden of cognitive impairment and estimating the rate of dementia syndromes are necessary tasks in defining health policy.
Cognition screening tests are useful tools for both epidemiological surveys and clinical assess-