Screening of dementia in Chinese elderly adults by the clock drawing test and the time and change test.

OBJECTIVES To assess the usefulness, relative ease of administration, and patient acceptance of the clock drawing test as well as the time and change test for detecting dementia in Chinese elderly adults. DESIGN Prospective case-controlled study. SETTING Memory clinic and geriatric clinic of a district hospital, Hong Kong. PARTICIPANTS A convenient sample of 85 subjects aged 65 years or older attending the two clinics during the period from September 2002 to June 2003. MAIN OUTCOME MEASURES The clock drawing test scored according to Lam's method; the time and change test with modification to the making change task; and the Chinese version of the Mini-Mental State Examination. RESULTS Demented subjects were matched with non-demented ones with respect to age, sex, educational level, and co-morbidity status. The clock drawing test had a comparable sensitivity (89.4%) but a lower specificity (47.1%) when compared with that of the Chinese version of the Mini-Mental State Examination (96.0 and 76.5%, respectively). In contrast, the time and change test had a lower sensitivity (62.7%) but higher specificity (94.1%). Both tests took significantly less time to complete than the Chinese version of the Mini-Mental State Examination. All except four subjects completed the clock drawing test while all subjects accepted the time and change test well. CONCLUSIONS The Chinese version of the Mini-Mental State Examination is still the best among the three tests despite the longer time to completion. The clock drawing test may be a good alternative to the Mini-Mental State Examination as an effective screening test for dementia when time does not permit. The time and change test, although time-saving, is not suitable to be used alone because of its low sensitivity.