Development & Validation of the 10/66 Dementia Diagnostic Algorithm

Background: There is a need for more research into dementia in developing countries. Exploring variations in disease frequency in international collaborations using harmonised procedures may also enhance our understanding of aetiology. However, methodological problems need first to be addressed, particularly development of culture- and education-fair diagnostic procedures.

Methods: The 10/66 Dementia Research Group interviewed 2885 persons aged 60 and over in 25 centres in India, China and South East Asia, Latin America and the Caribbean and Africa; 729 people with dementia, and three groups free of dementia; 702 with depression, 694 with high education and 760 with low education. Experienced local clinicians diagnosed dementia (DSM IV dementia and Clinical Dementia Rating mild or moderate) and depression (Montgomery Asberg Depression Rating Scale 18 or over). The Geriatric Mental State (a structured clinical interview assessing dementia, depression and psychosis syndromes), the Community Screening Instrument for Dementia (cognitive test, and informant interview) and the modified CERAD 10 word list-learning task were then administered by an interviewer, masked to case status.

Findings: Each of the four assessments that we tested independently predicted dementia diagnosis. In a split half procedure, a diagnostic algorithm derived from all four elements in one half of the sample performed better than any of them individually. Applied to the other half of the sample it identified 94% of dementia cases with false positive rates of 15%, 3% and 6% in the depression, high education and low education groups.

Conclusions: The 10/66 Dementia Diagnosis provides a sound basis for culture and education-fair dementia diagnosis in clinical and population-based research, supported by translations of its constituent measures into many languages, covering the majority of the peoples of the developing world.

10/66 Publications

1. Prince M. Methodological issues for population-based research into dementia in developing countries. A position paper from the 10/66 Dementia Research Group. International Journal of Geriatric Psychiatry. 15(1): 21-30, 2000
2. Prince M, Acosta D, Chiu H, Scazufca M, Varghese M, 10/66 Dementia Research Group. Dementia diagnosis in developing countries: A cross-cultural validation study. Lancet. 361(9361): 909-17, March 2003
3. Prince M, Acosta D, Chiu H, Copeland J, Dewey M, Scazufca M, Varghese M. Effects of education and culture on the validity of the Geriatric Mental State and its AGECAT algorithm. The British Journal of Psychiatry. 185: 429-436, November 2004
4. Shen-Ing Liu, Martin Prince, Ming-Jang Chiu, Ta-Fu Chen, Yi-Wen Sun, Ping-Keung Yip, M.. Validity and Reliability of a Taiwan Chinese Version of The Community Screening Instrument for Dementia. American Journal of Geriatric Psychiatry 13:7 581-588, 2005
5. Chan TS, Lam LC, Chiu HF, Prince M. Validity and applicability of the Chinese version of community screening instrument for dementia. Dementia and Geriatric Cognitive Disorders. 15(1): 10-8, 2003
6. Kim JM, Stewart R, Prince M, Shin IS, Yoon JS. Diagnosing dementia in a developing nation: An evaluation of the GMS-AGECAT algorithm in an older Korean population. International Journal of Geriatric Psychiatry. 18(4): 331-6, April 2003