Hypothesis on the nature of comprehension deficit in a patient with transcortical mixed aphasia with preserved naming.
Patients with poor comprehension and preserved naming have been occasionally described. Such patients, who are affected by transcortical aphasia, have been taken as evidence of the possibility of naming an object while bypassing the semantic system. We describe a patient affected with mixed transcortical aphasia who presented a clear dissociation between ability in naming and difficulties in performing word-picture matching tasks. The pattern is explained by the existence of covert compulsory automatic naming that interferes with less automatic procedures involved in word-picture matching. In fact, when we tried to oppose automatic naming by using, in word-picture matching tasks, pictures difficult to name, the comprehension improved. This finding excludes a semantic deficit at the basis of poor comprehension of our patient. We suggest that the dissociation between naming and comprehension could be an expression of a computational limitation within the processes involved in word-picture matching, due to the competition for limited processing resources by automatically activated hyperactive naming.
Silveri
M C
MC
Neuropsychology Service, Catholic University, Rome, Italy.
Colosimo
C
C
D001037:Aphasia / Q000175:diagnosis / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011859:Radiography; D015899:Tomography, Emission-Computed, Single-Photon; D014705:Verbal Behavior