Increased proportion of farm animal names generated by patients with Alzheimer's disease: What does it mean?

Binetti et al. (1995) reported that patients with Alzheimer's disease (AD) produced fewer semantic clusters than controls on the Animals Fluency task; of the clusters produced, 80% involved farm animals for the patients with AD compared to 40% for controls. In the present study we replicated the fin ding of Binetti et al.; however, the differential distribution of animal na mes by subcategory for the patients and controls could be accounted for by differences in the overall output and by assuming that word generation was strictly determined by prototypicality of the animal names. Thus, the incre ased proportion of farm animal names produced by patients with AD can be ac counted for simply by postulating impaired access to semantic memory rather than degraded representations, the idea favored by Binetti et al.