A Case of Prevailing Deficit of Nonliving Categories or a Case of Prevailing Sparing of Living Categories?

Abstract

We describe a new case of semantic deficit in which nonliving categories are disproportionately impaired. PL, a woman affected by progressive degeneration of the left temporal lobe, was examined twice, at a distance of 1 year. The deficit was first apparent on naming and on a verbal semantic questionnaire, but a year later nonliving categories were disproportionately affected also on verbal comprehension (word/picture matching task). Body parts and musical instruments were also investigated: the former was the best preserved category, whereas the latter was the most severely affected. Considering all categories, functional and perceptual information was not differently affected, but there was a trend toward a worse score for nonliving category functional questions. Discussing the current hypotheses on the genesis of category dissociations, we conclude that nonliving categories might not be a true domain, and that their impairment could simply derive from the relative sparing of the domains of the living categories, for which separate cognitive and anatomical representations can be better postulated. Finally, we discuss the problems raised by published cases in an attempt to find a consistent anatomical substrate for category dissociations.