Paired associate performance in the early detection of DAT

Subjects underwent longitudinal neuropsychological assessment in order to retrospectively determine which measures of cognitive function best predicted later development of dementia of the Alzheimer type (DAT). Three groups of subjects were studied: normal controls, patients with early DAT, and questionable dementia subjects (QD). All subjects were assessed using a battery of standard neuropsychological measures and two subtests from the Cambridge Neuropsychological Test Automated Battery (CANTAB), paired associate learning and delayed matching to sample. A structured interview was also used to elicit a profile of the subject's daily functioning. Subjects were assessed every 6 months for 2 years. At the 6 month assessment, almost half of the QD group exhibited significant deterioration in scores on the computerized paired associate learning subtest, while maintaining their scores on standard measures. At the conclusion of the study, all of this QD subgroup fulfilled the NINCDS–ADRDA criteria for probable DAT pertaining to significant cognitive and functional deterioration. Performance on the CANTAB paired associate learning subtest identified the onset of progressive memory deterioration in a subgroup of QD subjects. In almost all cases this was well before significant deterioration was noted on standard neuropsychological measures. Paired associate learning performance may therefore be a valuable tool for the early, preclinical detection and assessment of DAT. (JINS, 2002, 8, 58–71.)