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S Ishiai

Publications and source records attributed to S Ishiai.

At least 37 records · Page 2Linked to original sources
PubMed1996

Mechanisms of unilateral spatial neglect in copying a single object.

The present study examined 13 patients with typical left unilateral spatial neglect to explore the mechanisms of neglect in copying a single object. All patients identified the figure of a sunflower as a flower that had petals all around the central circle. Besides, in the free viewing of the flowers prepared by the examiner, 10 of the 13 patients could discriminate between the presence and absence of the left-sided petals. When copying the flower, however, they always left the left side unfinished without noticing the incompleteness. Whether perception in the left visual field was impaired or not was irrelevant to the performances in the copying and the free viewing of the flowers. We consider the mechanism of left unilateral spatial neglect in copying a flower as follows. Small leftward shift of attention may take place during the free observation of the stimulus flower. While copying, however, neglect patients pay attention exclusively to the right-sided petals they are drawing. The strong engagement of attention to the right side results in the lack of discovery of the left-sided omission. The close integration of attentional and premotor mechanisms seems to be crucial for the appearance of unilateral spatial neglect in copying a single object.

Aged↗
PubMed1995

Effects of cueing on visuospatial processing in unilateral spatial neglect.

Patients with typical left unilateral spatial neglect bisected lines after cueing to the left end-point, the fixation point being monitored with an eye camera. They persisted with the point of initial fixation made after cueing and placed the mark there without searching leftwards again. The rightward shift of fixation to the initial point of fixation thus determined the location of the subjective midpoint. We consider that rightward attentional bias increased the amplitude of this shift that was planned on the basis of the perception of the whole line while cueing. This hypothesis may explain smaller but obvious rightward bisection errors found in the cueing condition.

Aged↗
PubMed1995

Mutism developing after bilateral thalamo-capsular lesions by neuro-Behçet disease.

We described a 44-year old right-handed man showing mutism, left hemiplegia and pseudobulbar palsy after CT and MRI documented bilateral thalamo-capsular lesions by neuro-Behçet disease. Single photon emission tomography (SPECT) and Xenon CT revealed hypoperfusion of the bilateral frontal lobes. The pathophysiological mechanism of mutism was discussed and we postulate that mutism might occur as the result of frontal lobe dysfunction due to the disconnection of thalamocortical fiber from thalamus to frontal cortex and that it could be interpreted as an incomplete form of akinetic mutism.

Adult↗
PubMed1995

[Two case reports of Stanford type A acute aortic dissection complicated with thrombosed false lumen and saccular aneurysm formation].

We report two cases of successful surgical treatment for Stanford type A aortic dissection with thrombosed false lumen and saccular aneurysm formation. They were admitted to our clinic for severe anterior chest and back pain. Diagnosis was made as a Stanford type A dissection with thrombosed false lumen by chest CT, aortography and cardiac ultrasonography. Aortography showed ulcer like projection (ulp) in the ascending aorta, although flow in false lumen was not visualized. They were initially treated with antihypertensive drugs. Six and eight weeks later, although medical therapy was continued, a saccular aneurysm of the ascending aorta was found to be increased in size rapidly in both cases. Operation performed was the ascending aorta replacement with resection of the saccular aneurysm. The location of the ulp was found to be corresponded with the intimal tear at surgery. The postoperative courses were uneventful. Thus, careful medical follow up and surgical treatment were necessary in these cases. We believe that the ulp represents defect in the intima leading to the clotted false lumen and provides a possible sign of rupture in clinical course of aortic dissection.

Acute Disease↗
PubMed1995

[A case of infective endocarditis with subtotal rupture of the posterior papillary muscle].

We recently experienced a case of infective endocarditis with multiple embolic complications. The patient was a 21-year-old male who was admitted to our hospital with high fever and dyspnea. Echocardiography showed vegetation on the aortic valve, severe aortic regurgitation and mild mitral regurgitation. Abdominal echography revealed large splenic infarction. First we performed aortic valve replacement and splenectomy. But infective endocarditis developed after surgery, and echocardiography revealed severe mitral regurgitation, which has been a change for the worse. After treatment with antibiotics, mitral valve replacement (the second surgery) was performed. Intraoperative findings were confirmative of subtotal rupture of the posterior papillary muscle. Histological examination of the subtotal ruptured muscle revealed presence of coagulation necrosis. The patient is healthy without recurrence of infective endocarditis after the second surgery. It is exceedingly rare to experience a case of surgically treated subtotal papillary muscle rupture due to infective endocarditis.

Adult↗
PubMed1994

Preserved leftward movement in left unilateral spatial neglect due to frontal lesions.

Three patients with left unilateral spatial neglect after predominantly frontal lobe lesions were asked to extend a horizontal line leftwards to double its original length. In this line extension task, they readily executed movements in or towards the contralesional left space. They performed the task in the left and right hemispaces as well as in the midline. The mean extension lengths did not differ significantly among these three spatial conditions. These results suggest that directional hypokinesia takes little part in left unilateral spatial neglect due to frontal lobe lesions. It is considered that the patients could execute leftward movements as the task oriented their attention sufficiently to the left. Two of the three patients, like reported cases with frontal neglect, showed a typical exploratory deficit for the left space in the line cancellation test. Such a deficit found in the traditional tasks, however, does not mean the presence of directional hypokinesia. All three patients showed visual extinction on double simultaneous stimulation. An attentional mechanism seems to play a predominant part in unilateral spatial neglect due to frontal lesions.

Aged↗
PubMed1994

Improvement of left unilateral spatial neglect in a line extension task.

Patients with left unilateral spatial neglect following lesions that mainly involved the right parietal lobe performed a line extension task, extending a horizontal line leftward to double its original length. We examined line extension performances in the left and right hemispaces, as well as in the midline, to assess whether spatial conditions affected these performances. Whatever the severity of neglect found in the line bisection test, the line extension performances of the patients were almost accurate and comparable with those of normal controls across the three spatial conditions. The neglect patients executed movements in or toward the contralesional space as the task oriented their attention sufficiently to the left. The results suggest that the motor component, ie, directional hypokinesia, has little part in left unilateral spatial neglect due to right parietal lesions.

Adult↗
PubMed1994

[Visual memory in a case of topographical disorientation].

A 67-year-old, right-handed man was admitted to our hospital because of restricted field of vision. Neurological examination revealed left upper quadrantanopsia on confrontation. Axial and coronal T2 weighted MR images showed an increased signal intensity lesion that involved the right fusiform and lingual gyri. A small lesion was also noted in the white matter of the left cuneate gyrus. He was unable to describe the ground plan of his house or the well-known route he lived. No signs of unilateral spatial neglect, prosopangnosia, apraxia, and aphasia were found in specific tests. Wechsler Adult Intelligence Scale showed verbal IQ 126 and performance IQ 92. However, he scored poorly in the Benton Visual Retention Test (5 correct immediate recalls from 10 items). Recall from memory of Rey-Osterrieth's complex figure was severely impaired. Visual recall subtest of the Wechsler Memory Scale-Revised (WMS-R) scored 30 points when performed immediately, but zero after a 30 minutes delay. Visual paired associates learning from the WMS-R was also severely impaired. These findings suggest that visual memory is one of the important factors in the pathogenesis of topographical disorientation of this patient.

Aged↗
PubMed1994

[Surgical treatment of atherosclerotic vascular diseases associated with coronary artery disease].

Selective coronary angiography to determine the incidence of coronary artery disease (CAD) has been performed in the 38 patients with atherosclerotic vascular disease. significant CAD was demonstrated in 17 of 23 (73.8%) patients with angina pectoris or previous myocardial infarction, in 4/15 (26.7%) patients who had no clinical evidence of CAD. There were no early and late postoperative death in the 9 patients who underwent simultaneous coronary artery bypass graft and vascular operations or percutaneous coronary angioplasty, on the other hand, there were one early and four late death in the 11 patients who underwent only vascular procedure.

Aged↗
PubMed1993

Clock-drawing test and unilateral spatial neglect.

We investigated the ability of 25 patients with left unilateral spatial neglect to make a clock face by putting numbers inside a printed circle. Impairment seen in this clock-drawing test did not parallel neglect severity as judged by results of the line-cancellation and line-bisection tests, as well as the copying of a daisy. The score for clock drawing correlated highly with the verbal WAIS score. Most neglect patients with a verbal IQ of 87 or more could draw a clock face fairly well and used planning in placing the numbers 12, 3, 6, and 9 before the others. In clock drawing, verbal intelligence may compensate for left unilateral spatial neglect. We therefore recommend use of the line-cancellation and line-bisection tests, as well as the copying test, but do not recommend use of the clock-drawing test in the diagnosis of left unilateral spatial neglect.

Aged↗
PubMed1992

Leftward search in left unilateral spatial neglect.

The authors' previous study with an eye camera revealed that when asked to mark the centre of a line patients with left unilateral spatial neglect persist in fixating a point on its right part and place the subjective midpoint there without searching leftwards. The present study examined the patterns of leftward search of nine patients with left unilateral spatial neglect when they were required to search for the left endpoint of the line after the bisection. The patients could search leftwards beyond the subjective midpoint to place the mark at the subjective left endpoint. The initial fixation in this search always fell near the point located to the left of the subjective midpoint by the distance between the subjective midpoint and the right endpoint of the line. In patients with severe neglect the search further to the left of this point was laborious and fell short of the true left endpoint in about 80% of the trials. Our results suggest that when asked to bisect a line patients with left unilateral spatial neglect subjectively see the line as it extends equally to either side of the point where they are going to mark the subjective midpoint.

Aged↗
PubMed1990

Pure agraphia of kanji due to thrombosis of the Labbé vein.

A case is described of a 56 year old Japanese male with pure agraphia of kanji (the Japanese morphograms) due to haemorrhagic infarction of the left temporal lobe caused by the rare condition of cortical vein thrombosis of Labbé. Writing kanji was severely impaired without disturbed consciousness, aphasia or apraxia. On the other hand, writing kana (the Japanese syllabograms), and reading kanji and kana were almost intact. This suggests that the process of writing kanji involves a different pathway from that of reading kanji in the left temporal lobe. Pure agraphia of kanji is considered to be similar to lexical agraphia in Indo-European languages, in that the writing system with a poor or irregular phoneme-grapheme transformation is impaired by the left temporal lesion. This case indicates the necessity for considering thrombosis of the Labbé vein when a subcortical haematoma is detected in a temporal lobe on computed tomography of the brain.

Agraphia↗
PubMed1990

Improvement of unilateral spatial neglect with numbering.

We examined 8 patients with moderate to severe left unilateral spatial neglect by means of a series of line cancellation tasks. We asked the patients to cross out lines in the 1st trial, to number lines in the 2nd trial, and again to cross out lines in the 3rd trial. In the 2nd trial with numbering, all the patients showed improvement of left unilateral spatial neglect. Numbering involved the successive use of increasing numbers. This process seemed to motivate the patients to continue searching for another line, even at the point when they would be satisfied that they had completed the task if they used simple crossing-out. Insufficient motivation for visuospatial searching may play an important role in unilateral spatial neglect observed in cancellation tasks.

Aged↗
PubMed1989

Visuospatial processes of line bisection and the mechanisms underlying unilateral spatial neglect.

Patients with unilateral spatial neglect fail to report or respond to stimuli contralateral to the lesion which usually involves the right parietal lobe. When asked to mark the centre of a horizontal line, these patients place the mark to the right of the true midpoint. It has been considered that they neglect the left part of the line and bisect the perceived line segment. We investigated the eye-fixation patterns of hemianopic patients with or without unilateral spatial neglect during the bisection of lines, using an eye camera. Hemianopic patients without unilateral spatial neglect saw the whole lines, searching to the endpoint on the hemianopic side, and bisected it correctly. In contrast, left hemianopics with unilateral spatial neglect never searched to the left hemianopic side. Once they fixated a certain point on the right part of the line, they persisted with this point and marked the subjective midpoint there. Taking left homonymous hemianopia into account, the subjective midpoint appeared to be marked, not at the centre of the line segment perceived in the seeing right visual field, but at the leftmost point of it. However, they could appreciate the deviation of the subjective midpoint in the right visual field when forced to fixate the left endpoint of the line. These findings suggest that the left hemisphere has the ability to estimate the midpoint of the line through the right visual field and that visuospatial disorder in the line bisection test is attributable to the pathological change in the right hemisphere. The results are interpreted to mean that left hemianopic patients with unilateral spatial neglect see a totalized image of a line extending equally to either side of the point where they are going to mark the subjective midpoint. We considered that the right hemisphere completes the line, using the visual input relating to the right part of the line perceived by the left hemisphere.

Adult↗
PubMed1989

[A technique of end-to-side anastomosis of a prosthetic graft to the ascending aorta: reinforcement of the anastomosis with wrapping of the ascending aorta].

In temporary, permanent or extra-anatomic bypass grafting to the side of the ascending aorta, a technique of prosthetic fabric wrapping of the ascending aorta associated with reinforcement of the anastomosis is devised as a simple and useful method for aortic surgery. With this technique, dislodgement of the vascular forceps can be prevented completely, and the ascending aortic wall may be protected from injuries owing to the vascular forceps.

Anastomosis, Surgical↗
PubMed1989

[The surgical treatment of ruptured thoracic aortic aneurysm with use of permanent bypass].

Two surgical cases with ruptured thoracic aortic aneurysm were reviewed. Case 1 was a 74-year-old female, and Case 2 was a 77-year-old female. In both cases, chest X-ray examination revealed a mass like shadow in the left superior mediastinum, and aortography demonstrated a ruptured saccular aneurysm distal to the left subclavian artery. Midsternotomy and an incision over the third left intercostal space were made to approach the aneurysm. Since inflammatory adhesion was marked in the perianeurysmal area, a permanent bypass was placed between the ascending and descending aorta followed by exclusion of the aneurysm. One of the two cases was alive, but the other case was died due to bleeding from the area of permanent aortic clamp.

Aged↗
PubMed1989

[Intramyocardial hemangioma of the right ventricle with successful resection--report of a case and review of the literature].

A 62-year-old man developed symptoms of heart failure. Echocardiography showed a dense mass arising from the free wall of the right ventricle and occupying about 75% of the right ventricular cavity. Selective coronary angiography demonstrated intense neovascularization of a cardiac neoplasm arising in the distribution of the right coronary artery. Under cardiopulmonary bypass the tumor was resected completely and the defect of the ventricular wall was repaired with Gore-tex (EPTFE) patch (area 7.5 X 5.0 cm). The size of the resected tumor was 10.0 X 9.5 X 3.4 cm and weighed 170 g. Histological examination of the tumor disclosed cavernous hemangioma. The post operative course was uneventful and the patient has remained asymptomatic after the surgery. To our knowledge, only 23 cases of intramyocardial or intracavital hemangioma were reported in the world literature and this may be the first report in Japan.

Heart Neoplasms↗