Comparison of current levels of performance and scores based on change as diagnostic discriminators among the elderly.

Elderly in residential care were classified as probably 'normal' and probably 'organic' by a community screening questionnaire. Performance on a test of verbal learning was assessed at baseline and after two years. The initial and follow-up scores on this test, the changes shown during follow-up and the discrepancies between follow-up score and predicted follow-up performance (estimated from baseline score) were related to this classification. Against expectation, scores based on change did not discriminate better than current levels of performance at baseline or follow-up.