69 patients with aphasia caused by left cerebral infarction were examined by Token Test of Differential Diagnosis for Aphasia. All cases were also examined by computed tomography (CT) in order to find the locus and extent of the cerebral damage. The major results obtained from the statistical analysis included the following:
1) The temporal lobe was shown to be involved in performing most of the 56 subjects.
2) The frontal lobe was shown to be closely related to such subjects that are supposed to be evaluate speech production processes, e. g., “degultition”, “movement of the soft palate”, “repetition of one-syllable words”, “phonemic errors”and“fluency”. The parietal-frontal lobes, on the other hand, appeared to be closely related to“repetition of sentences”.
3) The subjects with same input and output modalities but with different levels of language processing seemd to require participation of different areas of the brain. For instance, the subtest for “auditory recognition of the spoken words” showed a close relationship to the temporal lobe and the anterior part of the frontal lobe, while “auditory comprehension of spoken sentences” was closely related to the temporal lobe and the anterior part of the occipital lobe.
4) On the other hand, involvement of different areas of the brain was not indicated for some subtests in which input and output modalities and/or levels of language processing are clearly different, e. g., “reading kanji” and “reading kana”.
Implications for the findings and suggestion for further study were discussed.
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