Mild dementia or cognitive impairment: the Modified Mini-Mental State examination (3MS) as a screen for dementia.

OBJECTIVE: To examine the Modified Mini-Mental State Examination (3MS) as a screen for dementia.
METHOD: A group of 1092 elderly Edmonton community residents completed the 3MS and the Geriatric Mental State Examination (GMS). 3MS sensitivity and specificity were determined by comparing positive 3MS screens (score < or = 77) with those classified as GMS "organic" (severity level 3, equivalent to a clinical diagnosis). In the Canadian Study of Health and Aging (CSHA), 2914 subjects received the 3MS and a clinical examination. A group described as having "cognitive impairment but no dementia (CIND)" was identified.
RESULTS: In Edmonton, the 3MS showed 88% sensitivity, 90% specificity, 29% positive predictive value (PPV), and 99% negative predictive value (NPV). In the CSHA, 30% of subjects receiving both the 3MS and a clinical examination were classified as CIND. One-half of these were classified as having "age associated memory impairment (AAMI)" or as "unspecified."
CONCLUSIONS: The 3MS with a cutting score of 77/78 proved a reasonable screening instrument; 1 case in 3 screening "positive" has dementia, but few (0.64%) will be missed by screening "negative." CIND, accounting for 2 out of 3 cases screened positive by the 3MS in the Edmonton study, is a substantial, heterogeneous group that is not necessarily "predementia" but that in many cases merits further investigation.