Category fluency is also predominantly affected in Swiss Alzheimer's disease patients.

Abstract

To establish the comparative efficacy to differentiate between Swiss patients with dementia of the Alzheimer type (DAT) and elderly normal control subjects (NC) on two different verbal fluency tasks: category fluency and letter fluency. Fifty Swiss German DAT patients in the early stages of the disease and 50 matched normal control subjects were compared on letter and category fluency tasks. DAT patients exhibited an overproportional impairment on category fluency as compared with letter fluency. Receiver operating characteristic curves (ROC) showed that category fluency correctly classified a significantly higher number of DAT patients and NC subjects (84%) than letter fluency (70%). As similar findings have been described for English-speaking DAT patients, we conclude that deficiencies in category fluency are a general phenomenon, reflecting impaired structures of semantic knowledge occurring early in the course of Alzheimer's disease.