TRANSCORTICAL SENSORY APHASIA - DISSOCIATION BETWEEN NAMING AND COMPREHENSION

Although anemia in transcortical sensory aphasia (TSA) is usually desc ribed as a semantically based deficit (naming and recognition are equa lly affected), dissociations in naming performance have occasionally b een reported. We report a two-part study: in Study 1 the pattern of pr eserved and impaired language abilities was examined in five patients with TSA and intact object naming; in Study 2 the neural mechanism(s) underlying preserved visual confrontation naming in TSA was examined. Demographic factors, severity of language deficits, lesion volume and location, and cerebral asymmetries of patients with TSA and intact nam ing (TSA-intact) (n=6) were compared with those of patients with TSA a nd impaired naming (TSA-impaired) (n=6), anemic aphasia (Anemia) (n=6) , and left hemisphere damage without aphasia (Control). The results of Study 1 revealed that all five patients had a relative preservation o f oral production (spontaneous speech, repetition, naming and reading aloud), but impaired auditory and written (sentence-level) comprehensi on. Object/picture naming was significantly better than auditory compr ehension of the same targets, and naming was also preserved in tactile and auditory (verbal definitions and non-verbal sounds) modalites, bu t written naming was impaired. In four patients oral reading showed a pattern of phonological dyslexia. The results of Study 2 failed to dem onstrate significant differences between the groups with preserved nam ing (TSA-intact and control) and those with impaired naming (TSA-impai red and anemia) in non-language variables that might explain the selec tive preservation or impairment of naming. These results are discussed in terms of the functional and anatomical independence of the neural systems responsible for object naming and comprehension.