A category-specific naming impairment after temporal lobectomy.

Unilateral temporal lobectomy patients and normal control subjects were tested in a speeded naming task with pictures of living and nonliving things that were equated for name frequency, familiarity, and visual complexity. Although right temporal lobectomy patients and normal subjects performed equally well with the living relative to nonliving things, left temporal lobectomy patients were disproportionately impaired at naming nonliving things. This result has several implications: First, it supports the existence of category-specific naming impairments. In particular, it undermines the proposal that living-nonliving dissociations are artifactual, resulting from the greater difficulty of living things. Second, it demonstrates an asymmetry in the neural representation of nonliving things, in favor of the left hemisphere. Third, it casts doubt on the hypothesis that the anterior temporal cortices are convergence zones that are particularly necessary for the naming of living things.