A study of right unilateral spatial neglect in left hemispheric lesions: the difference between right-handed and non-right-handed post-stroke patients -
Maeshima S, Shigeno K, Dohi N, Kajiwara T, Komai N. A study of right unilateral spatial neglect in left hemispheric lesions: the difference between right-handed and non-right-handed post-stroke patients. Acta Neurol Scand 1992: 85: 418-424. We report 20 cases of right unilateral spatial neglect caused by lesions in the left cerebral hemisphere. Differences in neuropsychological symptoms and lesion sites are discussed in connection with handedness. Of the right-handed patients, 6 had severe aphasia, 4 had Gerstmann’s syndrome, and 1 had pure agraphia, but unilateral spatial neglect in these cases disappeared after a number of months. Six of the non-right-handed patients had moderate-to-severe aphasia, while the other 3 cases had no aphasia at all. Eight of the 9 cases in this group continued to have right unilateral spatial neglect for more than 6 months. Lesion site as determined by CT differed as to hemisphere, but all fell into the common area previously mentioned in connection with such disorders: i.e.. the temporal, parietal and occipital lobes.
Unilateral spatial neglect refers to a condition in which the patient disregards objects located in one side of the patient’s field of perception (1-3). Brain (1) first reported on three cases of left unilateral spatial neglect and suggested that the condition was related to lesions in the right hemisphere. Since then, similar impairments in visual disorientation and hemi-inattention have been considered as symptoms of lesions in the non-dominant hemisphere. Left unilateral spatial neglect has also been noted in cases of crossed aphasia in the dextral where it is considered that lateralization of higher cortical function is incomplete (4). Such observations have led us to believe that strong laterality exists for the right hemisphere. Right unilateral spatial neglect is seen to appear occasionally in cases of left hemispheric lesions (5). There has also been extensive discussion of the qualitative differences between the two states. Zarit & Kahn (6) took note of the fact that many such lesions in the left hemisphere are accompanied by aphasia and dementia, making it impossible to conduct thorough testing. They also postulate that right hemispheric lesions occur far more frequently than indicated by the literature. Albert (7) also maintains that there is no difference in the frequency with which lesions occur in the right or left hemispheres, but that the more serious cases are generally found 418
S.Maeshima ’, K. Shigeno’, N. Dohi ’, T. Kajiwara’, N. Komai3
’
Departments of Rehabilitation Medicine, Fujita Health University, Hisai, Neurology, lzu Nirayama Rehabilitation Hospital, Shizuoka, Neurological Surgery, Wakayama Medical College, Japan
Key words: unilateral spatial neglect: cerebrovascular disorders; agnosia; left-hemisphere: cerebral dominance.
S. Maeshima, Department of Rehabilitation Medicine, Nanakuri-Sanatorium, Fujita Health University, 424-1, Oodori-cho. Hisai, 514-12 Mie, Japan. Accepted for publication November 14, 1991
in the right hemisphere. Meanwhile, Gainotti et al. (8) studied cases of lesions in the right hemisphere, pointing out that there is no appreciable difference between the hemisphere when it comes to omissions of portions of the figure at limited areas around the peripheries; however, in right hemispheric lesions there is a temporary tendency to leave figures incomplete. Caltagirone et al. (9) and Ogura et al. (10) studied patients with lesions of both the right and left hemispheres. By comparing drawings, they found that neither side is omitted in cases of right unilateral spatial neglect caused by left hemispheric lesions. There is, instead, distortion of the figure overall. However their study dealt mainly with righthanded cases. To date there are still few reports concerning patients who are left-handed or at least not fully right-handed. Kawahara et al. (11) completed a study of 100 cases of cerebral hemorrhage and stated that left-handedness was thought to be a factor in all five cases of right unilateral spatial neglect caused by left hemispheric lesions. Masure et al. (12) described that the hemispheric cerebral organization with respect to the mediation of visuospatial performance does not differ between right-handers and left-handers. Thus, many points remain to be clarified regarding the relation among handedness, hemispheric
Right unilateral spatial neglect dominance, lesion site and accompanying neuropsychological symptoms. Therefore, we investigated the correlation with handedness in 20 cases of right unilateral spatial neglect caused by lesions in the left hemisphere.
Figure copying. This entailed a picture of a flower and perspective drawing of a 3-D object. Controls were asked to perform tasks (b) (c) as well, and no anomalies were observed. Anosognosia and hemiasomatognosia
Subjects and methods
Subjects included 20 CVA patients (14 of cerebral hemorrhage and 6 of thrombosis) who, upon admission to this facility, showed signs of right unilateral spatial neglect in standard neuropsychologcal tests (details to follow). Lesions located in the left hemisphere in all cases were later confirmed with CT. There were 13 men and 7 women ranging in age from 31 to 77 years (mean: 60.8 years). The time from onset of the condition to admission varied from 2 weeks to 6 months (mean: 7.31 weeks). Handedness was determined using the Kertesz & Sheppard test (13). Nine of the 20 subjects were left-handed from birth. Eight had a family member who was lefthanded. Eight of these nine were ambidextrous, having been trained in childhood to perform certain tasks with the right hand, such as writing or using chopsticks. The remaining 11 cases were all righthanded (Table 1). In addition to neuropsychological examinations such as visual field (confrontation test), motor paralysis and sensory disturbance, the following neuropsychological tests were performed. Unilateral spatial neglect
The following diagnostic tests were conducted to judge the degree of unilateral spatial neglect: Line bisection test. The patient was asked to bisect a 20 cm line down on a standard letter-size (A4, 2Ox26cm) sheet of white paper. The same task given to 34 controls (1 1 men, 23 women; mean age: 57.9 & 13.24 years) revealed a standard mean error of only 2.00 2.10 mm. The standard for task failure was therefore set at an error of 1 6 . 5 mm or twice the mean error of the controls. Abnormalities were assessed, as follows: 6.5 mm to 13 mm as mild, 13mm to 19.5 mm as moderate, and more than 19.5 mm as severe. Cancellation task. Based on Albert’s method (7),we prepared a sheet of white A4 paper (20 x 26 cm) with 40 lines drawn thereon and asked patients to mark the lines. Oversight of less than one fourth of A4 paper was assessed as mildly abnormal, less than half left oversight as moderately abnormal and additional partial oversight of the right half as severely abnormal.
All assessments were made by only one physician (SM) by Mori’s method (14). The examiner asked questions such as, “What feels funny?” “Is there anything wrong with your leg or hand?” “Can you move your right leg or hand?” (the examiner indicates the patient’s right leg or hand) “Is it hard to see things on the right side?” The patient’s responses were recorded. Patients who either were not aware of or who denied having visual problems were classified as anosognosic for visual field defect. Testing of this nature was not possible for the 11 cases with aphasia. Disregard for one side of the body (hemiasomatognosia) was observed by daily monitoring of patients in the hospital. For example, it was classified as abnormal if patients disregarded one side of the face or body while shaving, applying make-up, arranging hair or washing the face, etc. Aphasia
Aphasia was diagnosed using the SLTA (Standard Language Test for Aphasia) (15) which is the most widely used in Japan. Results were evaluated according to the scale devised by Hasegawa et al. (16) based on degrees of severity ranging from O j l O (most severe) to lOjl0 (mildest). Apraxia
By evaluating the patient’s performance on a standardized test of higher motor functions (17), we were able to judge attendant signs of apractognosia. Test involved buccofacial praxis such as clucking with the tongue and clearing the throat, ritual praxis such as bowing (in greeting), use of everyday objects including a comb and toothbrush, and dressing oneself. We evaluated each case for the above neuropsychological elements, then divided cases for comparison into a non-right-handed group, and a righthanded group. All cases were examined by CT, and the lesion site was classfied for correlations with handedness. Results Neurological symptoms
We investigated the neurological and neuropsychological findings of the patients. Initial neurological findings included, 18 cases of
419
56/M 7l/M 75/F 70/M 54/M 7 1/M 49/M 54/M 57/F 7 1/M 69/F 59/F 44/M 55/F 55/F 65/M 77/M 62/F 48/M 54/M
Age /Sex
LR LR LR LR LR LR LR L R R R R R R R R R R R
LR
t t t t t t t t -
PH
V FD: visual, field defect S I: sensory impairment
PH: Past history of corrective training FH: Family history of the left-haders
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1 2
No.
Handedness
-
t
-
t t t t t t t
FH
infarction infarction hemorrhage hemorrhage infarction infarction hemorrhage hemorrhage hemorrhage infarction infarction hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage
Etiology
t t t t t t
t t t t t t t t t t t
-
-
-
t t t t t t t t
I
S
t t t t t t t
-
V F D
-
-
-
-
severe severe severe moderate severe severe mild mild moderate severe severe severe severe mild severe
-
lower
severe severe severe moderate severe severe mild mild severe severe severe severe severe severe severe
-
upper
motor paresis
Neurological deficits
T: total aphasia B: Broca's syndrome W Wernicke's aphasia C: conduction aphasia G: Gerstmann's syndrome AG: agraphia NE: not examined for aphasia NP: no paresis NV: no visual field defect
7 wks 7 wks 7 wks 24 wks 12 wks 16 wks 7wks 20wks 7 wks 12 wks 2 wks 4 wks 3 wks 2 wks 8 wks Zwks 3wks 1 wks Zwks 0.5 wks
Duration after onset
Table 1, Clinical features and progress of the right unilateral spatial neglect
t
-
t t -
t t t
-
-
-
t t t t t t
-
-
t t t t t t t t
t
-
-
t t t
-
t t t t t t t t t t t t t t t t t t t t
A
C
t t t t t t t t t t t t t t t -
A
D
A: A A: A: H: V A:
B: line bisection L: cancellation task C: figure copying
L C F
bucco-facial apraxia ideomotor apraxia constructional apraxia dressing apraxia anosognosia for hemiparesis anosognosia for visual field defect Hemiasomatognosia
6/10 1/10 2/10 2/10
Oil0
6/10 3/10 2/10 Oil0
Oil0
1/10 2/10
-
-
I M A
-
B F A
BF IM C D A A H
T B W B T T C B T B G G G G AG
T T
Type of aphasia severity N
A
t N V t t t t N E N E NENE N E N E N E N E N E N E N E N E NENE N E N E N E N E NENE NENE N E N E N P t N P t N P t N P t N P t
H
A
Neuropsychological deficits
-
-
-
-
-
t t t t t t t t t
A
H
t t t t t t t t t t t t t t t t t t t t
B
L
t t t t t t + t t t t t t t t t t t t t
L
C
t t t t t t t t t t t t t t t t t t t t
C
F
remained 9 months post onset remained 9 months post onset remained 6 months post onset remained 6 months post onset remained 6 months post onset remained 9 months post onset relrlained 6 months post onset remained 9 months post onset disappeared within 3 months disappeared within 5 months disappeared within 2 months disappeared within 3 months disappeared within 2 months disappeared within 2 months disappeared within 6 months disappeared within 3 weeks disappeared within 4 weeks disappeared within 3 weeks disappeared within 4 weeks disappeared within 2 weeks
spatial neglect (observation period)
Prognosis of unilateral
g
P,
8' z
&
Right unilateral spatial neglect right homonymous hemianopsia, 15 cases of right hemiparesis involving the face, and 14 cases in which sensory impairment for the right side. Neuropsychological findings included, in addition to right unilateral spatial neglect, 12 cases of aphasia (four Broca, one Wernicke, one Conduction, and four Total aphasias), four cases of Gerstmann’s syndrome, and one case of pure agraphia. There were also ten cases of ideomotor apraxia, 14 cases of bucco-facial apraxia, 20 cases of constructional apraxia, and 15 cases with dficulty in dressing. The breakdown for anosognosia in the eight cases without aphasia was three cases of anosognosia for hemiplegia and eight cases of anosognosia for visual field defect. There were nine cases in hemiasomatognosia for the right side of the body was observed (Table 1). In studying the relationship between handedness and neurological symptoms, we discovered that 6 of the 11 cases in the right-handed group had severe aphasia, while four had Gerstmann’s syndrome and one had pure agraphia. The six cases with severe aphasia were also marked by severe hemiplegia, unilateral sensory dysfunction, hemianopsia, buccofacial apraxia, ideomotor apraxia, constructional apraxia and difficulty with dressing. There was no clearly defined paralysis or sensory impairments in the four cases with Gerstmann’s syndrome and one case with pure agraphia, but hemianopsia and anosognosia for visual field defect were observed. Three of these cases also showed signs of buccofacial apraxia and two of these cases showed ideomotor apraxia. All five cases had some constructional apraxia, but none of these patients had difficulty with dressing. Meanwhile, all nine cases in the non-right-handed group had hemiplegia, with unilateral sensory dysfunction in eight cases and hemianopsia in seven cases. Moderate-to-severe aphasia was present in six cases. No aphasia was observed in the other three cases. Of the six cases of aphasia, four showed bucco-facial apraxia, and two ideomotor apraxia. The three cases with no aphasia were marked by anosognosia for visual field defect and/or hemiplegia, but there was neither bucco-facial apraxia nor ideomotor apraxia. In all nine cases, we found unilateral personal neglect, constructional apraxia and difficulty with dressing.
right-handers, “mild” and “moderate” was null; and “severe”, 9, while among the cases of right-handers, “mild” was nil; “moderate”, 4; “severe”, 7. In cancellation task, among the cases of none-righthanders, “mild” was 1; “moderate”, 2; and “severe”, 6, while among the cases of right-handers, “mild” was 2; “moderate”, 4; “severe”, 5 . In figure copying, among the cases of none-right-handers, “mild” was null; “moderate”, 1; and “severe”, 8, while among the cases of right-handers, “mild” was 1;“moderate”, 4; “severe”, 6. On picture problems, they made marked omissions on the right side (Fig. la). The right-handers, conversely, disregarded the right side of figures to a lesser extent, and errors on picture tests for the most part were limited to distortions of the right side (Fig. lb). In 12 cases, symptoms of right unilateral spatial neglect disappeared within six months. In another eight cases, however, symptoms persisted for more than six months. In particular, the eight non-right-handed patients who had been trained in the past to use the right hand suffered from right unilateral spatial neglect well past six months. The other one patient who had not received such corrective training were free of symptoms within six months. By contrast, symptoms in the right-handed group disappeared within two weeks to six months after admission. Sex, age, etiology, handedness, focal lesion were compared between the group in which right unilateral spatial neglect disappeared (disappeared group)
!.lode1
Case 2
care 1
rare 7
Fig. l a . Figure copying by non-right-handed group
Qualitative differences and prognosis in unilateral spatial neglect
We investigated qualitative differences and prognosis in unilateral spatial neglect between handedness, sex, age and etiology. In comparison to the right-handed group, the nonright-handers exhibited a greater degree of unilateral neglect. In line bisection, among the cases of none-
case 10
Case 13
Cane 16
Fig. Ib. Figure copying by right-handed group
421
Maeshima et al. and the other group in which right unilateral spatial neglect remained (remained group) (Chi-square). While the number of non-right handers was significantly larger in the disappeared group than the remained group, there were no significant relations between sex, age, and etiology. As to responsible lesion, the number of non-right handers was also significantly larger i i the remained group than in the disappeared group, but there were no significant relation between responsible lesion. Prognosis in the other neurological symptoms
Anosognosia faded within two weeks to three months regardless of handedness or corrective training. All nine cases with right hemiasomatognosia belonged to the non-right-handed group. Hemiasomatognosia of the right side eventually disappeared in one case (Case 9) in which unilateral spatial neglect also irnproved. All six total aphasics did not improve apparently. Though their aphasic symptoms still remained, another six cases improved generally, regardless of handness or corrective training. Lesion site
Fig. 2 shows a superposition of CT images at initial examination. Extensive infarctions were seen in the area of the brain supplied by the left middle cerebral artery (five cases) and the area supplied by the left posterior and left middle cerebral arteries (one case). There were nine cases of hemorrhage in the left basal ganglia, and five of subcortical hemorrhage in the left parietal and occipital lobes. The nine cases in the non-right-handed group were broken down into four of cerebral infarction, all in the left temporal, parietal and occipital lobes or the area extending from the
f
C T lesion in non-right-handed group
CT lesion in right-handed group
Fig. 2. CT lesion in non-right-handed group (upper), in righthanded group (lower)
422
frontal lobe. Sites of cerebral hemorrhage in the other five cases were in the left putamen, capsula interna or thalamus, and the area extending from the parietal lobe (Fig. 2). In the right-handed group, there were two cases of infarction with lesions found in an extensive area extending from the left frontal lobe through the temporal, parietal and occipital lobes. Of another 9 cases of cerebral hemorrhage, 4 were found in a wide area centered on the left putamen, and the other 5 were of subcortical hemorrhage in the left parietal and occipital lobes (Fig. 2). As to focal lesion, the number of non-right handers was also significantly larger in the remained group than in the disappeared group, but there were no significant relations between handedness and focal lesion.
Discussion Nine of the 20 cases covered in our study were also not right-handed, indicating that handedness possibly affects changes in laterality pertaining to higher cortical function. In Cases 1, 2 and 3 , extensive lesions in the left hemisphere had damaged portions of the language centers; however, there was no aphasia, ideomotor apraxia or bucco-facial apraxia. The symptoms, including unilateral spatial neglect, personal neglect, and anosognosia, are those associated with the non-dominant hemisphere. As a consequence, we were led to assume that functions normally belonging to the dominant hemisphere in these three cases were operating from the right hemisphere and that certain visuo-spatial cognitive functions which are normally assigned to the non-dominant hemisphere were located in the left hemisphere. Cases 4-9 were marked by right unilateral spatial neglect, hemiasomatognosia and aphasia. In five of six cases there was also bucco-facial apraxia. The speculation in these six cases is that, in addition to language centers, the left hemisphere was also the site of certain functions associated with the nondominant hemisphere which relate to visuo-spatial perception, perception of physical space and control of bucco-facial praxis. Ideomotor apraxia seen in only two cases may indicate a strong probability that dominant hemispheric functions related to engrams of limb movements were relegated to the opposite side (right side). Also, despite the fact that all nine of these non-right-handed patients suffered from lesions in the left hemisphere, their mistakes in figure copying tasks were notably closer to errors of unilateral omission made by right-handed righthemispheric lesion cases rather than overall distortions. A review of prognosis in these cases of right unilateral spatial neglect shows that lesions were comparatively limited in Case 9 where symptoms disappeared after three months and recovery from aphasia
Right unilateral spatial neglect progressed simultaneously. Based on these observations, it does not seem unreasonable to assume that the part of the brain responsible for spatial neglect was not the site directly damaged by the lesion. However, symptoms also disappeared within several months despite the presence of extensive lesions throughout the right hemisphere. Perhaps this signifies that a lesser degree of strict lateralization of visual spatial functions makes it easier for the opposite hemisphere to take over tasks. In the eight cases where symptoms persevered for a longer period we also saw greater lateralization into the left hemisphere. This may be due from more direct damage occurring in the area of the cerebrum that controls these processes. Whatever the reason, it is of particular interest in terms of laterality of visuo-spatial perception to note that these were patients who had been constrained in childhood to use the right hand for activities such as holding chopsticks or writing. In three of nine cases there was no aphasia whatever, leading us to speculate that language function in these cases might reside in the right hemisphere. In summary, it seems probable that the lateralization of such higher cortical functions as visuo-spatial perception into the right and left hemispheres become precisely reversed in non-right-handed patients (mirror image), or that some areas overlap (anomalous patterns). In the 11 cases where left-handedness was not a factor, we found a consistent pattern of hemispheric dominance: aphasia was present in 6 cases, Gerstmann’s syndrome in 4, and pure agraphia in 1. Manifestations of right unilateral spatial neglect, mostly ideomotor apraxia and bucco-facial apraxia, disappeared within six months after onset. In these cases, it is thought that dominant-hemisphere functions such as language and limb praxis are sited as usual in the left hemisphere, and the temporary appearance of right unilateral spatial neglect is due to some other factor. However, the fact that even such righthanded patients are prone to occasional unilateral omissions implies that the accepted qualitative differences between the hemispheres are insufficient to explain all phenomena. We must also consider the possibility that lateralization of visuo-spatial function is not absolute. Four of the patients with Gerstmann’s syndrome and one of the patients with pure agraphia also suffered from right unilateral spatial neglect accompanied by hemianopsia and anosognosia for visual field defect: however, symptoms were temporary and disappeared in a few weeks. What is more, these symptoms were not accompanied by the classic signs of dysfunction in the non-dominant hemisphere such as personal neglect and difficulty with dressing. The pattern we have just described concurs well with the theory of sensory impairments proposed by Batterby et al. (18). In
other words, unilateral spatial neglect is a form of perceptual impairment that arises when elemental perceptual disorders such as hemianopsia are compounded by slight deterioration in attention and arousal functions. The six right-handed patients with severe aphasia also suffered from complications of hemianopsia, hemiplegia and sensory impairment. These observations lead us to believe that right unilateral spatial neglect might be caused by a similar mechanism. The difference is that symptoms persist for several months longer when the area affected by lesions is large and deterioration of arousal functions and inattention are long. This also suggests the possibility that the mechanism by which right unilateral spatial neglect appears in purely right-handed cases is different from that for cases in which lefthandedness is a factor. It has been reported that the severe cases of unilateral spatial neglect are more frequently seen in men than in women, and that laterality for visuo-spatial perception is hgher (19). In this study, there were no noticeable differences between sex, age, and etiology. The number of the cases in which right unilateral spatial neglect remained was much larger in men. This seemed to be because the number of non-right handers was larger in men among the subjects studied. Lesion sites thought to be responsible in cases of left unilateral spatial neglect include, in addition to the right temporo-parieto-occipital junction (20, 21), the right frontal lobe (22), the right occipital lobe (23), the right thalamus (24, 25), and right basal ganglia (26). Cases of right unilateral spatial neglect have been reported as being caused by lesions in the left temporo-parieto-occipital junction (1, 27), the left occipital lobe (20), the left basal ganglia (20) and the left frontal lobe (28), in addition to the frequentlymentioned left parietal and temporal regions. CT images of the 20 cases in this study showed that in 6 there were infarctions in the area supplied by the left middle cerebral artery, ranging extensively across the left temporal, parietal, occipital and frontal lobes. In another nine cases there was extensive hemorrhagmg in the area extending from the left basal ganglia through the capsula interna and thalamus. Also, in five cases there was subcortical hemorrhaging in the left parietal and occipital lobes. From these observations, we confirmed that although lesions may be seen in either hemisphere, the sites responsible for appearance of unilateral spatial neglect all fall in the parietal and occipital lobes, which are regions generally-cited in connection with such disorders. When we compared right-handers with nonright-handers, we found that lesions are more commonly located in the parietal and temporal lobes. Only in a few cases were lesions found to be restricted to a small area in the parietal and occipital lobes.
423
Maeshima et al. Right unilateral spatial neglect due to left hemisphere lesion was clinically investigated. The number of cases of right unilateral spatial neglect due to left hemisphere lesion was unexpectedly small, but it was also a fact that severe cases existed in which such neglect was persistent. To determine such cases, it is desirable to perform more in-depth investigation after confirming handedness (including family members). References 1. BRAINWR. Visual disorientation with Special reference to lesions ofthe right cerebral hemisphere. Brain 1941: 64: 2442722. 2. PATERSON A, ZANGWILL OL. Disorders of visual perception associated with lesions of the right cerebral hemisphere. Brain 1944: 67: 331-358. 3. MCFIE J, PIERCYMF, ZANGWILL OL. Visual-spatial agnosia associated with lesions of the right cerebral hemisphere. Brain 1950: 73: 167-190. MP, FISCHETTE MR, FISCHER RS. Crossed 4. ALEXANDER aphasias can be mirror image or anomalous. Brain 1989: 112: 953-973. 5. DENNY-BROWN D, MEYERJS, HORENSTEIN S. The significance of perceptual rivalry resulting from parietal lesion. Brain 1952: 75: 433-471. 6 . ZARITSH, KAHNRL. Impairment and adaptation in chronic disabilities: spatial inattention. J Nerv Ment Dis 1974: 159: 63-72. 7. ALBERTML. A simple test of visual neglect. Neurology 1973: 23: 658-664. 8. GAINOTTI G, TIACCIC. The relationships between disorders of visual perception and unilateral spatial neglect. Neuropsychologia 1971: 9: 451-458. 9. CALTAGIRONE C, MICELIG, GAINOTTI G. Distinctive features of unilateral spatial agnosia in right and left braindamaged patients. Eur Neurol 1977: 16: 121-126. 10. OGURAJ, YAMADORI A. On the hemispheric asymmetry of unilateral spatial neglect. Brain and Nerve (Tokyo) 1984: 36: 131-135. N, SATOK, SHIMADA T et al. The incidence 11. KAWAHARA and the recovery rate of unilateral spatial neglect in 100 cases with right or left putaminal hemorrhage: with special reference to the cerebral lateralization. Higher Brain Function Research (Tokyo) 1984: 4: 70-74.
424
12. MASUREMC. BENTONAL. Visuospatial performance in left-handed patients with unilateral brain lesions. Neuropsychologia 1983: 21: 179-181. 13. KERTESZ A. SHEPPARD A. The epidemiology of aphasia and cognitive impairment in stroke. Brain 1981: 104: 117-128. 4. MORIE. Anosognosia and hemiasomatognosia in stroke patient with right-hemisphere damage. Clin Neurol (Tokyo) 1982: 881-890. 5. Nirayama Conference. Standard language test of aphasia. Manual of directions. Tokyo, Homeido 1975. 6. HASEGAWAT, KISHIH, SHICENO K e t al.Three-dimensional structure in language test of aphasia. Folia phoniat 1985: 37: 246-258. 17. HASEGAWA T, ASAGAWA K, ABEK et al. Standardized test of higher motor functions. Higher Brain Function Research (Tokyo) 1985: 5: 865-886. WS, BENDERMB, POLLACKM, KAHNRL. 18. BATTERSBY Unilateral “spatial agnosia” (“inattention”) in patient with cerebral lesions. Brain 1956: 79: 68-93. 19. MCGLONEJ, KERTESZA. Sex differences in cerebral processing of visuospatial tasks. Cortex 1973: 9: 313-320. KM, VALENSTEIN E, WATSONRT. Localization 20. HEILMAN of neglect. In: Localization in Neuropsychology, edited by KERTESZA, New York, Academic Press, 1983: 471-492. 21. KUBOH. Unilateral spatial agnosia (neglect). Advances in N e u r o l o g d Sciences (Tokyo) 1980: 24: 598-609. 22. HEILMANN MH, VALENSTEIN E. Frontal lobe neglect in man. Neurology 1972: 22: 660-664. 23. KOBAYASHI S, YAMAGUCHI S, FUJIWARA S, TAZAKIY. Hemispatial agnosia (neglect) in cerebral infarction in the territory of posterior cerebral artery. Japanese Journal of Neuropsychology (Tokyo) 1986: 2: 41-47. 24. WATOSON RT, HEILMANKM. Thalamic neglect. Neurology 1979: 29: 690-694. 25. VALLARG, PERANID, CAPPA SF etal. Recovery from aphasia and neglect after subcortical stroke: neuropsychological and cerebral perfusion study. J Neurol Neurosurg Psychiat 1988: 51: 1269-1276. 26. FERROJM, KERTESZ A, BLACKSE. Subcortical neglect; quantitation, anatomy and recovery. Neurology 1987: 37: 1487-1492. GV. Reversed hemi27. DELISDC, KNIGHTRT, SIMPSON spheric organization in a left-hander. Neuropsychologia 1983: 21: 13-24. NF, KNIGHTRT. Right-sided neglect in a left28. DRONKERS hander: evidence for reversed hemispheric specialization of attention capacity. Neuropsychologia 1988: 27: 729-735.
Maeshima S, Shigeno K, Dohi N, Kajiwara T, Komai N. A study of right unilateral spatial neglect in left hemispheric lesions: the difference between right-handed and non-right-handed post-stroke patients. Acta Neurol Scand 1992: 85: 418-424. We report 20 cases of right unilateral spatial neglect caused by lesions in the left cerebral hemisphere. Differences in neuropsychological symptoms and lesion sites are discussed in connection with handedness. Of the right-handed patients, 6 had severe aphasia, 4 had Gerstmann’s syndrome, and 1 had pure agraphia, but unilateral spatial neglect in these cases disappeared after a number of months. Six of the non-right-handed patients had moderate-to-severe aphasia, while the other 3 cases had no aphasia at all. Eight of the 9 cases in this group continued to have right unilateral spatial neglect for more than 6 months. Lesion site as determined by CT differed as to hemisphere, but all fell into the common area previously mentioned in connection with such disorders: i.e.. the temporal, parietal and occipital lobes.
Unilateral spatial neglect refers to a condition in which the patient disregards objects located in one side of the patient’s field of perception (1-3). Brain (1) first reported on three cases of left unilateral spatial neglect and suggested that the condition was related to lesions in the right hemisphere. Since then, similar impairments in visual disorientation and hemi-inattention have been considered as symptoms of lesions in the non-dominant hemisphere. Left unilateral spatial neglect has also been noted in cases of crossed aphasia in the dextral where it is considered that lateralization of higher cortical function is incomplete (4). Such observations have led us to believe that strong laterality exists for the right hemisphere. Right unilateral spatial neglect is seen to appear occasionally in cases of left hemispheric lesions (5). There has also been extensive discussion of the qualitative differences between the two states. Zarit & Kahn (6) took note of the fact that many such lesions in the left hemisphere are accompanied by aphasia and dementia, making it impossible to conduct thorough testing. They also postulate that right hemispheric lesions occur far more frequently than indicated by the literature. Albert (7) also maintains that there is no difference in the frequency with which lesions occur in the right or left hemispheres, but that the more serious cases are generally found 418
S.Maeshima ’, K. Shigeno’, N. Dohi ’, T. Kajiwara’, N. Komai3
’
Departments of Rehabilitation Medicine, Fujita Health University, Hisai, Neurology, lzu Nirayama Rehabilitation Hospital, Shizuoka, Neurological Surgery, Wakayama Medical College, Japan
Key words: unilateral spatial neglect: cerebrovascular disorders; agnosia; left-hemisphere: cerebral dominance.
S. Maeshima, Department of Rehabilitation Medicine, Nanakuri-Sanatorium, Fujita Health University, 424-1, Oodori-cho. Hisai, 514-12 Mie, Japan. Accepted for publication November 14, 1991
in the right hemisphere. Meanwhile, Gainotti et al. (8) studied cases of lesions in the right hemisphere, pointing out that there is no appreciable difference between the hemisphere when it comes to omissions of portions of the figure at limited areas around the peripheries; however, in right hemispheric lesions there is a temporary tendency to leave figures incomplete. Caltagirone et al. (9) and Ogura et al. (10) studied patients with lesions of both the right and left hemispheres. By comparing drawings, they found that neither side is omitted in cases of right unilateral spatial neglect caused by left hemispheric lesions. There is, instead, distortion of the figure overall. However their study dealt mainly with righthanded cases. To date there are still few reports concerning patients who are left-handed or at least not fully right-handed. Kawahara et al. (11) completed a study of 100 cases of cerebral hemorrhage and stated that left-handedness was thought to be a factor in all five cases of right unilateral spatial neglect caused by left hemispheric lesions. Masure et al. (12) described that the hemispheric cerebral organization with respect to the mediation of visuospatial performance does not differ between right-handers and left-handers. Thus, many points remain to be clarified regarding the relation among handedness, hemispheric
Right unilateral spatial neglect dominance, lesion site and accompanying neuropsychological symptoms. Therefore, we investigated the correlation with handedness in 20 cases of right unilateral spatial neglect caused by lesions in the left hemisphere.
Figure copying. This entailed a picture of a flower and perspective drawing of a 3-D object. Controls were asked to perform tasks (b) (c) as well, and no anomalies were observed. Anosognosia and hemiasomatognosia
Subjects and methods
Subjects included 20 CVA patients (14 of cerebral hemorrhage and 6 of thrombosis) who, upon admission to this facility, showed signs of right unilateral spatial neglect in standard neuropsychologcal tests (details to follow). Lesions located in the left hemisphere in all cases were later confirmed with CT. There were 13 men and 7 women ranging in age from 31 to 77 years (mean: 60.8 years). The time from onset of the condition to admission varied from 2 weeks to 6 months (mean: 7.31 weeks). Handedness was determined using the Kertesz & Sheppard test (13). Nine of the 20 subjects were left-handed from birth. Eight had a family member who was lefthanded. Eight of these nine were ambidextrous, having been trained in childhood to perform certain tasks with the right hand, such as writing or using chopsticks. The remaining 11 cases were all righthanded (Table 1). In addition to neuropsychological examinations such as visual field (confrontation test), motor paralysis and sensory disturbance, the following neuropsychological tests were performed. Unilateral spatial neglect
The following diagnostic tests were conducted to judge the degree of unilateral spatial neglect: Line bisection test. The patient was asked to bisect a 20 cm line down on a standard letter-size (A4, 2Ox26cm) sheet of white paper. The same task given to 34 controls (1 1 men, 23 women; mean age: 57.9 & 13.24 years) revealed a standard mean error of only 2.00 2.10 mm. The standard for task failure was therefore set at an error of 1 6 . 5 mm or twice the mean error of the controls. Abnormalities were assessed, as follows: 6.5 mm to 13 mm as mild, 13mm to 19.5 mm as moderate, and more than 19.5 mm as severe. Cancellation task. Based on Albert’s method (7),we prepared a sheet of white A4 paper (20 x 26 cm) with 40 lines drawn thereon and asked patients to mark the lines. Oversight of less than one fourth of A4 paper was assessed as mildly abnormal, less than half left oversight as moderately abnormal and additional partial oversight of the right half as severely abnormal.
All assessments were made by only one physician (SM) by Mori’s method (14). The examiner asked questions such as, “What feels funny?” “Is there anything wrong with your leg or hand?” “Can you move your right leg or hand?” (the examiner indicates the patient’s right leg or hand) “Is it hard to see things on the right side?” The patient’s responses were recorded. Patients who either were not aware of or who denied having visual problems were classified as anosognosic for visual field defect. Testing of this nature was not possible for the 11 cases with aphasia. Disregard for one side of the body (hemiasomatognosia) was observed by daily monitoring of patients in the hospital. For example, it was classified as abnormal if patients disregarded one side of the face or body while shaving, applying make-up, arranging hair or washing the face, etc. Aphasia
Aphasia was diagnosed using the SLTA (Standard Language Test for Aphasia) (15) which is the most widely used in Japan. Results were evaluated according to the scale devised by Hasegawa et al. (16) based on degrees of severity ranging from O j l O (most severe) to lOjl0 (mildest). Apraxia
By evaluating the patient’s performance on a standardized test of higher motor functions (17), we were able to judge attendant signs of apractognosia. Test involved buccofacial praxis such as clucking with the tongue and clearing the throat, ritual praxis such as bowing (in greeting), use of everyday objects including a comb and toothbrush, and dressing oneself. We evaluated each case for the above neuropsychological elements, then divided cases for comparison into a non-right-handed group, and a righthanded group. All cases were examined by CT, and the lesion site was classfied for correlations with handedness. Results Neurological symptoms
We investigated the neurological and neuropsychological findings of the patients. Initial neurological findings included, 18 cases of
419
56/M 7l/M 75/F 70/M 54/M 7 1/M 49/M 54/M 57/F 7 1/M 69/F 59/F 44/M 55/F 55/F 65/M 77/M 62/F 48/M 54/M
Age /Sex
LR LR LR LR LR LR LR L R R R R R R R R R R R
LR
t t t t t t t t -
PH
V FD: visual, field defect S I: sensory impairment
PH: Past history of corrective training FH: Family history of the left-haders
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
1 2
No.
Handedness
-
t
-
t t t t t t t
FH
infarction infarction hemorrhage hemorrhage infarction infarction hemorrhage hemorrhage hemorrhage infarction infarction hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage hemorrhage
Etiology
t t t t t t
t t t t t t t t t t t
-
-
-
t t t t t t t t
I
S
t t t t t t t
-
V F D
-
-
-
-
severe severe severe moderate severe severe mild mild moderate severe severe severe severe mild severe
-
lower
severe severe severe moderate severe severe mild mild severe severe severe severe severe severe severe
-
upper
motor paresis
Neurological deficits
T: total aphasia B: Broca's syndrome W Wernicke's aphasia C: conduction aphasia G: Gerstmann's syndrome AG: agraphia NE: not examined for aphasia NP: no paresis NV: no visual field defect
7 wks 7 wks 7 wks 24 wks 12 wks 16 wks 7wks 20wks 7 wks 12 wks 2 wks 4 wks 3 wks 2 wks 8 wks Zwks 3wks 1 wks Zwks 0.5 wks
Duration after onset
Table 1, Clinical features and progress of the right unilateral spatial neglect
t
-
t t -
t t t
-
-
-
t t t t t t
-
-
t t t t t t t t
t
-
-
t t t
-
t t t t t t t t t t t t t t t t t t t t
A
C
t t t t t t t t t t t t t t t -
A
D
A: A A: A: H: V A:
B: line bisection L: cancellation task C: figure copying
L C F
bucco-facial apraxia ideomotor apraxia constructional apraxia dressing apraxia anosognosia for hemiparesis anosognosia for visual field defect Hemiasomatognosia
6/10 1/10 2/10 2/10
Oil0
6/10 3/10 2/10 Oil0
Oil0
1/10 2/10
-
-
I M A
-
B F A
BF IM C D A A H
T B W B T T C B T B G G G G AG
T T
Type of aphasia severity N
A
t N V t t t t N E N E NENE N E N E N E N E N E N E N E N E NENE N E N E N E N E NENE NENE N E N E N P t N P t N P t N P t N P t
H
A
Neuropsychological deficits
-
-
-
-
-
t t t t t t t t t
A
H
t t t t t t t t t t t t t t t t t t t t
B
L
t t t t t t + t t t t t t t t t t t t t
L
C
t t t t t t t t t t t t t t t t t t t t
C
F
remained 9 months post onset remained 9 months post onset remained 6 months post onset remained 6 months post onset remained 6 months post onset remained 9 months post onset relrlained 6 months post onset remained 9 months post onset disappeared within 3 months disappeared within 5 months disappeared within 2 months disappeared within 3 months disappeared within 2 months disappeared within 2 months disappeared within 6 months disappeared within 3 weeks disappeared within 4 weeks disappeared within 3 weeks disappeared within 4 weeks disappeared within 2 weeks
spatial neglect (observation period)
Prognosis of unilateral
g
P,
8' z
&
Right unilateral spatial neglect right homonymous hemianopsia, 15 cases of right hemiparesis involving the face, and 14 cases in which sensory impairment for the right side. Neuropsychological findings included, in addition to right unilateral spatial neglect, 12 cases of aphasia (four Broca, one Wernicke, one Conduction, and four Total aphasias), four cases of Gerstmann’s syndrome, and one case of pure agraphia. There were also ten cases of ideomotor apraxia, 14 cases of bucco-facial apraxia, 20 cases of constructional apraxia, and 15 cases with dficulty in dressing. The breakdown for anosognosia in the eight cases without aphasia was three cases of anosognosia for hemiplegia and eight cases of anosognosia for visual field defect. There were nine cases in hemiasomatognosia for the right side of the body was observed (Table 1). In studying the relationship between handedness and neurological symptoms, we discovered that 6 of the 11 cases in the right-handed group had severe aphasia, while four had Gerstmann’s syndrome and one had pure agraphia. The six cases with severe aphasia were also marked by severe hemiplegia, unilateral sensory dysfunction, hemianopsia, buccofacial apraxia, ideomotor apraxia, constructional apraxia and difficulty with dressing. There was no clearly defined paralysis or sensory impairments in the four cases with Gerstmann’s syndrome and one case with pure agraphia, but hemianopsia and anosognosia for visual field defect were observed. Three of these cases also showed signs of buccofacial apraxia and two of these cases showed ideomotor apraxia. All five cases had some constructional apraxia, but none of these patients had difficulty with dressing. Meanwhile, all nine cases in the non-right-handed group had hemiplegia, with unilateral sensory dysfunction in eight cases and hemianopsia in seven cases. Moderate-to-severe aphasia was present in six cases. No aphasia was observed in the other three cases. Of the six cases of aphasia, four showed bucco-facial apraxia, and two ideomotor apraxia. The three cases with no aphasia were marked by anosognosia for visual field defect and/or hemiplegia, but there was neither bucco-facial apraxia nor ideomotor apraxia. In all nine cases, we found unilateral personal neglect, constructional apraxia and difficulty with dressing.
right-handers, “mild” and “moderate” was null; and “severe”, 9, while among the cases of right-handers, “mild” was nil; “moderate”, 4; “severe”, 7. In cancellation task, among the cases of none-righthanders, “mild” was 1; “moderate”, 2; and “severe”, 6, while among the cases of right-handers, “mild” was 2; “moderate”, 4; “severe”, 5 . In figure copying, among the cases of none-right-handers, “mild” was null; “moderate”, 1; and “severe”, 8, while among the cases of right-handers, “mild” was 1;“moderate”, 4; “severe”, 6. On picture problems, they made marked omissions on the right side (Fig. la). The right-handers, conversely, disregarded the right side of figures to a lesser extent, and errors on picture tests for the most part were limited to distortions of the right side (Fig. lb). In 12 cases, symptoms of right unilateral spatial neglect disappeared within six months. In another eight cases, however, symptoms persisted for more than six months. In particular, the eight non-right-handed patients who had been trained in the past to use the right hand suffered from right unilateral spatial neglect well past six months. The other one patient who had not received such corrective training were free of symptoms within six months. By contrast, symptoms in the right-handed group disappeared within two weeks to six months after admission. Sex, age, etiology, handedness, focal lesion were compared between the group in which right unilateral spatial neglect disappeared (disappeared group)
!.lode1
Case 2
care 1
rare 7
Fig. l a . Figure copying by non-right-handed group
Qualitative differences and prognosis in unilateral spatial neglect
We investigated qualitative differences and prognosis in unilateral spatial neglect between handedness, sex, age and etiology. In comparison to the right-handed group, the nonright-handers exhibited a greater degree of unilateral neglect. In line bisection, among the cases of none-
case 10
Case 13
Cane 16
Fig. Ib. Figure copying by right-handed group
421
Maeshima et al. and the other group in which right unilateral spatial neglect remained (remained group) (Chi-square). While the number of non-right handers was significantly larger in the disappeared group than the remained group, there were no significant relations between sex, age, and etiology. As to responsible lesion, the number of non-right handers was also significantly larger i i the remained group than in the disappeared group, but there were no significant relation between responsible lesion. Prognosis in the other neurological symptoms
Anosognosia faded within two weeks to three months regardless of handedness or corrective training. All nine cases with right hemiasomatognosia belonged to the non-right-handed group. Hemiasomatognosia of the right side eventually disappeared in one case (Case 9) in which unilateral spatial neglect also irnproved. All six total aphasics did not improve apparently. Though their aphasic symptoms still remained, another six cases improved generally, regardless of handness or corrective training. Lesion site
Fig. 2 shows a superposition of CT images at initial examination. Extensive infarctions were seen in the area of the brain supplied by the left middle cerebral artery (five cases) and the area supplied by the left posterior and left middle cerebral arteries (one case). There were nine cases of hemorrhage in the left basal ganglia, and five of subcortical hemorrhage in the left parietal and occipital lobes. The nine cases in the non-right-handed group were broken down into four of cerebral infarction, all in the left temporal, parietal and occipital lobes or the area extending from the
f
C T lesion in non-right-handed group
CT lesion in right-handed group
Fig. 2. CT lesion in non-right-handed group (upper), in righthanded group (lower)
422
frontal lobe. Sites of cerebral hemorrhage in the other five cases were in the left putamen, capsula interna or thalamus, and the area extending from the parietal lobe (Fig. 2). In the right-handed group, there were two cases of infarction with lesions found in an extensive area extending from the left frontal lobe through the temporal, parietal and occipital lobes. Of another 9 cases of cerebral hemorrhage, 4 were found in a wide area centered on the left putamen, and the other 5 were of subcortical hemorrhage in the left parietal and occipital lobes (Fig. 2). As to focal lesion, the number of non-right handers was also significantly larger in the remained group than in the disappeared group, but there were no significant relations between handedness and focal lesion.
Discussion Nine of the 20 cases covered in our study were also not right-handed, indicating that handedness possibly affects changes in laterality pertaining to higher cortical function. In Cases 1, 2 and 3 , extensive lesions in the left hemisphere had damaged portions of the language centers; however, there was no aphasia, ideomotor apraxia or bucco-facial apraxia. The symptoms, including unilateral spatial neglect, personal neglect, and anosognosia, are those associated with the non-dominant hemisphere. As a consequence, we were led to assume that functions normally belonging to the dominant hemisphere in these three cases were operating from the right hemisphere and that certain visuo-spatial cognitive functions which are normally assigned to the non-dominant hemisphere were located in the left hemisphere. Cases 4-9 were marked by right unilateral spatial neglect, hemiasomatognosia and aphasia. In five of six cases there was also bucco-facial apraxia. The speculation in these six cases is that, in addition to language centers, the left hemisphere was also the site of certain functions associated with the nondominant hemisphere which relate to visuo-spatial perception, perception of physical space and control of bucco-facial praxis. Ideomotor apraxia seen in only two cases may indicate a strong probability that dominant hemispheric functions related to engrams of limb movements were relegated to the opposite side (right side). Also, despite the fact that all nine of these non-right-handed patients suffered from lesions in the left hemisphere, their mistakes in figure copying tasks were notably closer to errors of unilateral omission made by right-handed righthemispheric lesion cases rather than overall distortions. A review of prognosis in these cases of right unilateral spatial neglect shows that lesions were comparatively limited in Case 9 where symptoms disappeared after three months and recovery from aphasia
Right unilateral spatial neglect progressed simultaneously. Based on these observations, it does not seem unreasonable to assume that the part of the brain responsible for spatial neglect was not the site directly damaged by the lesion. However, symptoms also disappeared within several months despite the presence of extensive lesions throughout the right hemisphere. Perhaps this signifies that a lesser degree of strict lateralization of visual spatial functions makes it easier for the opposite hemisphere to take over tasks. In the eight cases where symptoms persevered for a longer period we also saw greater lateralization into the left hemisphere. This may be due from more direct damage occurring in the area of the cerebrum that controls these processes. Whatever the reason, it is of particular interest in terms of laterality of visuo-spatial perception to note that these were patients who had been constrained in childhood to use the right hand for activities such as holding chopsticks or writing. In three of nine cases there was no aphasia whatever, leading us to speculate that language function in these cases might reside in the right hemisphere. In summary, it seems probable that the lateralization of such higher cortical functions as visuo-spatial perception into the right and left hemispheres become precisely reversed in non-right-handed patients (mirror image), or that some areas overlap (anomalous patterns). In the 11 cases where left-handedness was not a factor, we found a consistent pattern of hemispheric dominance: aphasia was present in 6 cases, Gerstmann’s syndrome in 4, and pure agraphia in 1. Manifestations of right unilateral spatial neglect, mostly ideomotor apraxia and bucco-facial apraxia, disappeared within six months after onset. In these cases, it is thought that dominant-hemisphere functions such as language and limb praxis are sited as usual in the left hemisphere, and the temporary appearance of right unilateral spatial neglect is due to some other factor. However, the fact that even such righthanded patients are prone to occasional unilateral omissions implies that the accepted qualitative differences between the hemispheres are insufficient to explain all phenomena. We must also consider the possibility that lateralization of visuo-spatial function is not absolute. Four of the patients with Gerstmann’s syndrome and one of the patients with pure agraphia also suffered from right unilateral spatial neglect accompanied by hemianopsia and anosognosia for visual field defect: however, symptoms were temporary and disappeared in a few weeks. What is more, these symptoms were not accompanied by the classic signs of dysfunction in the non-dominant hemisphere such as personal neglect and difficulty with dressing. The pattern we have just described concurs well with the theory of sensory impairments proposed by Batterby et al. (18). In
other words, unilateral spatial neglect is a form of perceptual impairment that arises when elemental perceptual disorders such as hemianopsia are compounded by slight deterioration in attention and arousal functions. The six right-handed patients with severe aphasia also suffered from complications of hemianopsia, hemiplegia and sensory impairment. These observations lead us to believe that right unilateral spatial neglect might be caused by a similar mechanism. The difference is that symptoms persist for several months longer when the area affected by lesions is large and deterioration of arousal functions and inattention are long. This also suggests the possibility that the mechanism by which right unilateral spatial neglect appears in purely right-handed cases is different from that for cases in which lefthandedness is a factor. It has been reported that the severe cases of unilateral spatial neglect are more frequently seen in men than in women, and that laterality for visuo-spatial perception is hgher (19). In this study, there were no noticeable differences between sex, age, and etiology. The number of the cases in which right unilateral spatial neglect remained was much larger in men. This seemed to be because the number of non-right handers was larger in men among the subjects studied. Lesion sites thought to be responsible in cases of left unilateral spatial neglect include, in addition to the right temporo-parieto-occipital junction (20, 21), the right frontal lobe (22), the right occipital lobe (23), the right thalamus (24, 25), and right basal ganglia (26). Cases of right unilateral spatial neglect have been reported as being caused by lesions in the left temporo-parieto-occipital junction (1, 27), the left occipital lobe (20), the left basal ganglia (20) and the left frontal lobe (28), in addition to the frequentlymentioned left parietal and temporal regions. CT images of the 20 cases in this study showed that in 6 there were infarctions in the area supplied by the left middle cerebral artery, ranging extensively across the left temporal, parietal, occipital and frontal lobes. In another nine cases there was extensive hemorrhagmg in the area extending from the left basal ganglia through the capsula interna and thalamus. Also, in five cases there was subcortical hemorrhaging in the left parietal and occipital lobes. From these observations, we confirmed that although lesions may be seen in either hemisphere, the sites responsible for appearance of unilateral spatial neglect all fall in the parietal and occipital lobes, which are regions generally-cited in connection with such disorders. When we compared right-handers with nonright-handers, we found that lesions are more commonly located in the parietal and temporal lobes. Only in a few cases were lesions found to be restricted to a small area in the parietal and occipital lobes.
423
Maeshima et al. Right unilateral spatial neglect due to left hemisphere lesion was clinically investigated. The number of cases of right unilateral spatial neglect due to left hemisphere lesion was unexpectedly small, but it was also a fact that severe cases existed in which such neglect was persistent. To determine such cases, it is desirable to perform more in-depth investigation after confirming handedness (including family members). References 1. BRAINWR. Visual disorientation with Special reference to lesions ofthe right cerebral hemisphere. Brain 1941: 64: 2442722. 2. PATERSON A, ZANGWILL OL. Disorders of visual perception associated with lesions of the right cerebral hemisphere. Brain 1944: 67: 331-358. 3. MCFIE J, PIERCYMF, ZANGWILL OL. Visual-spatial agnosia associated with lesions of the right cerebral hemisphere. Brain 1950: 73: 167-190. MP, FISCHETTE MR, FISCHER RS. Crossed 4. ALEXANDER aphasias can be mirror image or anomalous. Brain 1989: 112: 953-973. 5. DENNY-BROWN D, MEYERJS, HORENSTEIN S. The significance of perceptual rivalry resulting from parietal lesion. Brain 1952: 75: 433-471. 6 . ZARITSH, KAHNRL. Impairment and adaptation in chronic disabilities: spatial inattention. J Nerv Ment Dis 1974: 159: 63-72. 7. ALBERTML. A simple test of visual neglect. Neurology 1973: 23: 658-664. 8. GAINOTTI G, TIACCIC. The relationships between disorders of visual perception and unilateral spatial neglect. Neuropsychologia 1971: 9: 451-458. 9. CALTAGIRONE C, MICELIG, GAINOTTI G. Distinctive features of unilateral spatial agnosia in right and left braindamaged patients. Eur Neurol 1977: 16: 121-126. 10. OGURAJ, YAMADORI A. On the hemispheric asymmetry of unilateral spatial neglect. Brain and Nerve (Tokyo) 1984: 36: 131-135. N, SATOK, SHIMADA T et al. The incidence 11. KAWAHARA and the recovery rate of unilateral spatial neglect in 100 cases with right or left putaminal hemorrhage: with special reference to the cerebral lateralization. Higher Brain Function Research (Tokyo) 1984: 4: 70-74.
424
12. MASUREMC. BENTONAL. Visuospatial performance in left-handed patients with unilateral brain lesions. Neuropsychologia 1983: 21: 179-181. 13. KERTESZ A. SHEPPARD A. The epidemiology of aphasia and cognitive impairment in stroke. Brain 1981: 104: 117-128. 4. MORIE. Anosognosia and hemiasomatognosia in stroke patient with right-hemisphere damage. Clin Neurol (Tokyo) 1982: 881-890. 5. Nirayama Conference. Standard language test of aphasia. Manual of directions. Tokyo, Homeido 1975. 6. HASEGAWAT, KISHIH, SHICENO K e t al.Three-dimensional structure in language test of aphasia. Folia phoniat 1985: 37: 246-258. 17. HASEGAWA T, ASAGAWA K, ABEK et al. Standardized test of higher motor functions. Higher Brain Function Research (Tokyo) 1985: 5: 865-886. WS, BENDERMB, POLLACKM, KAHNRL. 18. BATTERSBY Unilateral “spatial agnosia” (“inattention”) in patient with cerebral lesions. Brain 1956: 79: 68-93. 19. MCGLONEJ, KERTESZA. Sex differences in cerebral processing of visuospatial tasks. Cortex 1973: 9: 313-320. KM, VALENSTEIN E, WATSONRT. Localization 20. HEILMAN of neglect. In: Localization in Neuropsychology, edited by KERTESZA, New York, Academic Press, 1983: 471-492. 21. KUBOH. Unilateral spatial agnosia (neglect). Advances in N e u r o l o g d Sciences (Tokyo) 1980: 24: 598-609. 22. HEILMANN MH, VALENSTEIN E. Frontal lobe neglect in man. Neurology 1972: 22: 660-664. 23. KOBAYASHI S, YAMAGUCHI S, FUJIWARA S, TAZAKIY. Hemispatial agnosia (neglect) in cerebral infarction in the territory of posterior cerebral artery. Japanese Journal of Neuropsychology (Tokyo) 1986: 2: 41-47. 24. WATOSON RT, HEILMANKM. Thalamic neglect. Neurology 1979: 29: 690-694. 25. VALLARG, PERANID, CAPPA SF etal. Recovery from aphasia and neglect after subcortical stroke: neuropsychological and cerebral perfusion study. J Neurol Neurosurg Psychiat 1988: 51: 1269-1276. 26. FERROJM, KERTESZ A, BLACKSE. Subcortical neglect; quantitation, anatomy and recovery. Neurology 1987: 37: 1487-1492. GV. Reversed hemi27. DELISDC, KNIGHTRT, SIMPSON spheric organization in a left-hander. Neuropsychologia 1983: 21: 13-24. NF, KNIGHTRT. Right-sided neglect in a left28. DRONKERS hander: evidence for reversed hemispheric specialization of attention capacity. Neuropsychologia 1988: 27: 729-735.
