Category-specific naming and comprehension impairment: a double dissociation.

We describe 2 neurologically impaired patients with lesions involving primarily the left temporal lobe, whose production and comprehension of words in the semantic category of animals were disproportionately spared in 1 case and disproportionately impaired in the other, in comparison to performance with other common categories. This double dissociation provides neurally based evidence for the view that lexical-semantic information is organized categorically.