Evaluation of a Short Mental Test for the diagnosis of dementia

A Short Mental Test (SMT) composed of 26 items was evaluated for screening dementia, taking into account the effect of age and education. The relative contribution of individual items was assessed. The SMT was administered to healthy and demented subjects. Validity was established by a significant relationship between the total score on the SMT (as well as individual items) and the diagnosis established according to DSM-II R criteria. The best diagnostic accuracy (88.4%) was achieved using a cut-off score of 79 correct responses. The question that most successfully diagnosed dementia was subtraction of serial sevens. Subsequent ranking revealed the importance of items requiring abstraction and time orientation. Immediate recall and personal information were least helpful. Age negatively correlated with total scores, but affected recent memory, sentence repetition and proverb interpretation in the higher-schooled population only. Poor schooling evenly lessened general performance.