Cognitive test profile analysis for the identification of dementia of the Alzheimer type.

Two measures of profile similarity have been derived that offer complementary information about the classification of patients with diagnoses of probable dementia of the Alzheimer type (DAT). These measures were obtained for 31 probable DAT patients and 31 age- and education-matched controls using a set of six newly constructed cognitive scales designed to provide reliable measurement in both patient and control groups. A measure assessing similarity to the average performance of the controls provided perfect separation of the patient and control groups. A measure assessing similarity to the average performance of the probable DAT patients identified up to four atypical cases of probable DAT. One of these four cases has come to autopsy and was found to have Pick disease. The cognitive profiles of this Pick patient and an autopsy-confirmed DAT patient are compared to illustrate the potential advantages of using DAT patients as the reference group for profile analysis.