Two cases with the mildest form of Broca's aphasia were studied neuropshychologically and neurologically. In case 1, a 58-year-old right-handed man had dysarthria, literal paraphasia, and literal paragraphia because of development of glioma. Comprehension was excellent. There were the right central and hypoglossal paresis and abolition of gag reflex. The site of lesion confirmed by computerized tomography and operation was in the lower part of the left precentral gyrus. A month after the resection of the tumor, only paragraphia improved. In case 2, a 58-year-old right-handed man developed the essentially same neurological and linguistic symptoms as those of case 1. Computerized tomography demonstrated a small hematoma probably restricted in the left inferior precentral gyrus. Three months later, the symptoms subsided except for slight dysarthria and dysgraphia. On the basis of literature and our two cases, it may be concluded that the left inferior precentral gyrus plays an important role not only in articulation but also in writing, and that this area is a more critical zone for Broca's aphasia than the foot of the left third frontal gyrus.
As it become appreciated that the disruption restricted to the third frontal gyrus does not produce Broca's aphasia, the lesion localization responsible for the occurrence of Broca's aphasia is, again, coming into question. Besides, articulatory disorder, the prominent feature of Broca's aphasia, varies both in quality and in quantity, e. g. from phonetic disintegration syndrome to anarthria, therefore, it seems to be inadequate to expect single lesion. We compared the location of the lesion of the cases who became Broca's aphasia (7 cases) and who did not become Broca's aphasia (4 cases of no aphasia and 6 cases of anomic aphasia) by the infarction which centered frontal lobe, insula, and lenticular zone, where has been regarded to be associated with Broca's aphasia. We also compared the variety of the nature of the articulatory disorder and the difference of the lesion. As a result, association of the symptoms and the location of lesions thought to be as follows, phonetic disintegration syndrome and anterior central gyrus, phonemic paraphasia and posterior insula or posterior part of the peri-Rolandic area, anomia and white matter of the deep portion of the third frontal gyrus and centrum semiovale. It was suggested that Broca's aphasia is produced by the disruption overlapping these areas, i. e. Broca's aphasia characteristic of phonetic disintegration syndrome is associated with the infarction of the white matter of the deep portion of the third frontal gyrus, centrum semiovale, and anterior central gyrus, Broca's aphasia characteristic of both phonetic disintegration syndrome and phonemic paraphasia is produced by the lesion extended further to posterior insula or the posterior part of the peri-Rolandic area.
Word association test which consisted of 108 stimulus words, was undertaken in 27 aphasic patients (6 Wernicke's aphasics, 10 Broca's aphasics and 11 anomics). The data were compared with that of normal subjects8). The results were as follows : 1) There was a tendency for aphasics to give association word whose part of speech was the same as that of stimulus words. 2) Anomics was the top group that coincided with normal subjects8) in association words, followed by Broca's aphasics and Wernicke's aphasics. 3) Aphasics had a tendency to give the association words that were antonymous to the stimulus words. And the frequency of antonymous words was higher in aphasics than in normal subjects. 4) The unconventional responses appeared in aphasics. Examples of these were : association words whose sound or letter resembles that of stimulus word ; association words making a reference to the experience of subject himself. 5) It was suggested that aphasics, once got a pattern of response, were apt to repeat the pattern in word association.
A case of cortical deafness resulting from CVA due to Moyamoya disease was reported. Patient, a 32 year-old left-handed woman, suddenly became deaf without aphasia. CT scan revealed old infarction in the right fronto-temporo-parietal area and fresh hemorrhage in the left putamen and auditory radiation. Pure tone audiometry showed severe hearing loss of 80 dB in both ears. In Békésy audiometry, excursion of the graph were extremely wide. During recovery period, we observed that her auditory perception was improved by repetitive auditory stimuli or by stimuli of other sensory modality. Under circumstances where she could predict the occurrence of sound or voice, she was often able to hear them. These phenomena were confirmed by the following experimental results. Audiometry by method of limits revealed that ascending limens were higher than the descending ones by approximately 10 dB in both ears. When flashes were given simultaneously with tone stimuli, thresholds became lower as compared with the condition without flash. From the clinical observations and experimental results, we presumed that the active process of auditory perception would be disturbed in the mechanism of cortical deafness.
Current research on thalamic lesions, especially on the speech and mental function leaves many questions still unsettled. We report here a case of aphasia and reduced mental function resulting from bilateral thalamic infarction. A 65-year-old man who had suffered from atrial flutter, suddenly presented neurological signs characterized by disorientation and aphasia, and he was confirmed to have bilateral small infarction of the anterior thalamic by CT scans. Three months later, the aphasia improved but severe disturbance of recent memory and reduced mental activity remained. One year after the onset, his verbal IQ improved to nearly 90 and his activity of daily life was moderate. However, marked reduction of recent memory, character change, and disorientation of place, time and person still persisted. Even two years after the onset, his mental function was proved to be unchanged by examinations, which seemed to show the difficulty in amelioration of recent memory and mental function in the case of bilateral thalamic lesions. We supposed that the mental deterioration was attributed to the reduced fiber connection between the frontal cortex and bilateral thalamic, and that the transient aphasia was due to the affection of the left thalamus and its surrounding portion.
The associations of clinical evaluation tasks of minor hemisphere symptoms, including unilateral spatial agnosia (USA), spatial agnosias and constructional apraxia, were analysed. Subjects were 77 right hemisphere damaged patients due to CVA. They showed either left homonemous hemianopia or left visual extinction. Three tasks, line bisection, counting marbles and finding two points, were highly associated. Then it was acknowledged that these three tasks constitutes Guttman type scale. Patients of severe grades, i. e. those showed left side neglect in counting marbles and in finding two points, were also showed various spatial disorders. Intellectual decline and emotional disturbances did not highly associated with USA severity scale. About 80 % of USA patients had lesions in parietal lobe. Age, etiology and duration from onset of CVA had certain effects on prognosis of USA grades.