Rinsho Shinkeigaku (Clinical Neurology)

Original Article

A case of conduction aphasia due to small infarction in the left parietal lobe

Katsuhiko Ibayashi, M.D.

Department of Speech Pathology, Niigata Rehabilitation College

This is a report on the patient with conduction apahsia due to small infarction in the left parietal lobe. The patient is a right-handed man aged 74, who developed a speech disorder and mild paralysis of the right hand on November 13. 1996. A CT scan showed a small low-density in the supramarginal gyrus of the left parietal lobe. Standard Language Test of aphasia (SLTA) conducted at five days after admission to the hospital showed preserved auditory comprehension and phonemic paraphasic symptoms with respect to volitional speech, naming, reading aloud and repetition. Frequent self-correction was also observed while repetition was not remarkably impaired. A test at three months after the onset revealed generally fluent speech, while there still remained occasional phonemic paraphasia and self-correction for the speech disruption. Three years and four months later, most of the aphasic syndromes disappeared, although the patient claimed he still had difficulty in speaking.
This case suggests that conduction aphasia can be caused by a lesion, though small, located in arcuate fibers of the cerebrum. The characteristics are phonemic paraphasia with respect to general speech functions as well as self-correction toward target words. The indicated that lesions in the pathway connecting Broca's area and Wernicke's area causes difficulties in selecting accurate phonemes due to a malfunctioning interface between the two areas.

(CLINICA NEUROL, 42: 731|735, 2002)
key words: conduction aphasia, phonemic paraphasia, repetition, arcuate fasciculus, self-correction

(Received: 24-Feb-01)