Abstract
We reported a peculiar speech symptom obsereved in a patient with transcortical sensory aphasia following head trauma. His speech was fluent but contaminated by a lot of irrelevant verbal paraphasias. Naming and word comprehension were severely impaired. His paraphasias, although irrelevant to the target words, were semantically associated with each other. This kind of speech symptom was considered to correspond to the iterative pattern of semantic variation, which was described by Hadano in his report of semantic jargon aphasia. We considered that word comprehension disorder and relative intactness of lexical items, in addition to heightened impulse to produce verbal output, play an important role in the pathogenesis of irrelevant paraphasias. Output of a series of irrelevant paraphasias belonging to the same semantic category would be explained in terms of semantic perseveration. Because of a severe lexical-semantic impairment, in out patient, once a semantic field was activated, another semantic field could not be activated properly. Therefore, he had to select only words within the semantic field under improperly persistent excitement, which would result in this unique speech symptom.
