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

OBJECTIVES: 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.
MATERIAL AND METHODS: 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.
RESULTS: 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%).
CONCLUSION: 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.