The Clock Drawing Test: utility for dementia detection in multiethnic elders

Abstract

Background: Disproportionate increases in dementia morbidity in ethnic minorities challenge established screening methodologies because of language and culture barriers, varying access to health services, and a relative paucity of cross-cultural data validating their use. Simple screening techniques adapted to a range of health and social service settings would accelerate dementia detection and social and health services planning for demented minority elders.

Methods: The effectiveness of the Clock Drawing Test (CDT) for dementia detection was compared with that of the Mini-Mental State Examination (MMSE) and the Cognitive Abilities Screening Instrument (CASI) in community-dwelling elders of diverse linguistic, ethnic, and educational backgrounds. Subjects (N = 295) were tested at home in their native languages (English, n = 141; another language, n = 154). An informant-based clinical dementia history and functional severity index derived from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) protocols were used to classify subjects as probably demented (n = 170), and probably not demented (n = 125).

Results: All tests were significantly affected by education (p < .001) but not by primary language (p > .05). Sensitivities and specificities for probable dementia were 82% and 92%, respectively, for the CDT; 92% and 92% for the MMSE; and 93% and 97% for the CASI for subjects completing each test. However, in poorly educated non-English speakers, the CDT detected demented subjects with higher sensitivity than the two longer instruments (sensitivity and specificity 85% and 94% for the CDT, 46% and 100% for the MMSE, and 75% and 95% for the CASI). Moreover less information was lost due to noncompletion of the CDT than the MMSE or CASI (severe dementia or refusal: CDT 8%, MMSE 12%, and CASI 16%).

Conclusions: Overall, the CDT may be as effective as the MMSE or CASI as a first-level dementia screen for clinical use in multiethnic, multilingual samples of older adults. Its brevity (1-5 minutes), minimal language requirements, high acceptability, and lack of dependence on specialized testing materials are well adapted for screening of non-English-speaking elderly persons in settings where bilingual interpreters are not readily available and screening time is at a premium.