Improvement of semantic categorization through procedural learning in Alzheimer's disease.

This paper studies the procedural learning of semantic categorization in 20 patients with mild Alzheimer's disease (AD). We investigated if the AD group was able to develop semantic skill using a cognitive procedural task, developed in our laboratory, by applying a manual and serial reaction time paradigm to semantic categorization. The AD group had markedly lower scores than the normal group on semantic categorization and had longer reaction times than the control subjects. Nevertheless, we observed an improvement of semantic categorization reaction times over time with practice, even with new verbal material to categorize, in both the AD and control groups. These results support the notion that AD patients are able to acquire semantic skill without awareness simply by repeated exposure, although their semantic accuracy will not reach normal levels.