ON THE STATUS OF OBJECT CONCEPTS IN APHASIA

While verbal comprehension is often impaired in aphasia due to left he mispheric damage, the status of nonverbal conceptual knowledge of obje cts remains controversial. We tested 16 aphasic subjects for their com prehension of concrete single words. Eight showed significant impairme nt on word-to-picture matching, when distracters were semantically and not just perceptually confusable. These 8 also made errors in answeri ng verbal probe questions concerning the same items. When tested on a nonverbal pictorial version of the same probe questions, however, 3 of these 8 improved their performance to the level of normal controls. T he other 5 showed continuing impairment in indicating responses to pic torial probes. These 5 showed no evidence of generalized intellectual impairment, and it is concluded that they demonstrated a comprehension deficit not limited to the verbal domain. Unlike the other aphasic pa tients, these latter 5 also had CT scan lesions extending into the pos terior left temporal lobe (involving Brodmann's areas 22, 21, and 37). They were also more impaired in terms of general aphasia severity. It is suggested that a nonverbal (as well as verbal) semantic memory def icit occurs in a subgroup of patients with single word comprehension d isturbance due to aphasia, and this may reflect general severity of la nguage impairment as well as damage to certain localized brain regions . (C) 1997 Academic Press.