VISUOSPATIAL DYSGNOSIA D A V I D G. C O G A N , Bethesda,
The conscious awareness of one's phys ical relationship to his surroundings or one's estimate of spatial relationships among objects requires complex mental processing. Loss of these functions is generally termed visuospatial agnosia or topographic agnosia. I suggest that the term visuospatial dysgnosia more aptly incorporates the many and subtle varia tions of the syndrome. Rarely is it com plete or stereotypic. Included are the following: loss of way in customarily familiar surroundings or in routing (top ographic dysgnosia); impairment of draw ing designs such as circles, squares, triangles, clock-faces, and the like, or of the assembly of parts (constructional apraxia); difficulty in dressing (dressing apraxia); faulty pointing to objects in space (optic ataxia) or faulty saccadic fix ation (ocular motor apraxia); and rightleft confusion. Considerable clinical evidence since the observations of Hughling-Jackson a century ago 1 and the categorization of symptoms by Holmes 2 has suggested pre dominant localization of these functions in the general region of the nondominant parietum. The voluminous and contro versial literature on the subject, to gether with that of relevant observa tions on monkeys, has been extensively reviewed. 3 - 7 In the hope of obtaining further infor mation on the topography and etiology of dysgnosia I have reviewed the case histo-
From the Clinical Branch, National Eye Institute, National Institutes of Health, Department of Health Education and Welfare, Bethesda, Maryland. Reprint requests to David G. Cogan, M.D., Clini cal Branch, National Eye Institute, National Insti tutes of Health, Bethesda, MD 20014.
M.D.
Maryland
ries of 17 patients with either unilateral or bilateral lesions in whom this syndrome, in whole or in part, was a conspicuous or exclusive feature. All patients selected for review were otherwise alert and able to make meaningful judgments. Several cases have been previously described. 8,9 CASE REPORTS Case 1—A 60-year-old, right-handed man awoke one morning with a pounding headache in the right occipital region and intermittent paresthesias of the left hand. H e was found to have hypertension (228/130 mm Hg) and was given medication to lower pressure. While driving his car a few days later he suddenly became confused, lost his way in a cus tomarily familiar environment, and ran into a truck on his left side. Apparently the patient felt there was something wrong with his vision, and was on his way to consult his ophthalmologist. He walked to the garage, located his car without difficulty but climbed into the left rear seat by mistake. The attendant noted that he had difficulty locating the wheel and ignition. He was able to drive out of the garage without difficulty. However, he soon lost his way. He, therefore, stopped the car, hailed a taxi and gave the driver the address of the ophthalmologist's office but could not recognize any portion of the few blocks travelled. After a reassuring but perfunctory examination in which visual fields were not done he left the office, returned to his ear (how is not clear), and started home. This is when he had the accident with the truck coming from his left side. With a police escort he returned home in a taxi, but he was unable to direct the driver to his street or to pick out his own house until he was directly in front of it. During this time the patient had good insight into his disability. The spatial dysgnosia continued but he was able to continue his practice as a physician (except surgery), to prepare his income tax, to make appropriate (and successful) investments on the stock market, and to participate at a trustees' meet ing of a local university. I first saw this patient three weeks after the onset of his visual problem and found an almost complete left hemianopia. The eye movements, including the optokinetic response, were normal. Since he was such a good and reliable observer I asked him to document his observation in the form of a letter from which the following are excerpts: "I can see clearly in front of me the Copley Square Library and front of the Copley Plaza Hotel, but I cannot picture in my mind how I would walk or drive there."
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"If I go down to the garage, which is under my apartment building, I cannot find the door which takes me to the elevator of my apart ment." "I have gone to my son's place in . . . thousands of times but I cannot visualize or 'see' the streets which are necessary for me to reach my destina tion." "When I ride in a car . . . I am completely lost as to where I am." "If I leave the Medical Library, I cannot picture how I get to the Harvard Club." "I can picture the Harvard Stadium where I attended every football game for 25 years but my approach to the Harvard Stadium is blotted out in my memory." "I cannot for the life of me mentally visualize what is beyond the periphery of my sight." "My memory to reproduce mentally certain pic tures which have been projected into my brain by the sense of sight is now obliterated." Additionally, the patient was unable to diagram the rooms in his house. Examinations three and four months later showed partial resolution of the lower field defect but little change in the dysgnosia. He was not seen again, but died of myocardial infarc tion five years after the foregoing incident. Autopsy revealed a complete occlusion of the right posterior cerebral artery with infarction of the medial surface of the temporal and occipital lobes but sparing the dorsal parietum, the most anterior part of the hippo campus, the inferior temporal gyrus and the amyg dala. No lesion was found in the left cerebrum.
Comment—The testimony in this case is given in some detail because of the patient's informative insight into his dis ability and the discreteness of his dysgnosic symptomatology. The pathologic evidence suggests a localization of the lesion (an infarct) in the temporo-occipital area of the nondominant hemi sphere rather than in the parietal area. Case 2—A 24-year-old, right-handed woman had a meningioma of the right occipito-parietal region. Her symptoms included episodic colored phosphene, one major convulsion, asymmetrically ho monymous field defects in the left lower quadrant, and transient loss of familiarity of where she was. T h e optokinetic response was symmetric and Bell's reflex was not lateralized. Most of the tumor was removed surgically but the patient continued to have episodic flashes of colored lights although the visual fields were full.
Comment—In this patient loss of spa tial orientation was a transient manifesta tion of a meningioma in the nondominant parieto-occipital region. Case 3—A 69-year-old man had had rheumatic heart disease and an aortic valve replacement. He
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had previously lost the sight of the left eye from an embolic occlusion of the central retinal artery. Nine months before the present examination, he devel oped a left hemianopia of the right eye. The optoki netic response was symmetric in the two horizontal directions and closure of the eyes showed a normal Bell's reflex without lateralization. A conspicuous and persistent symptom, however, was an inability to localize objects in his seeing field. He regularly missed objects in pointing to them and made gross errors in trying to grasp them. Yet he identified objects in this field, recognized colors, and had normal visual acuity in the right eye. Computed tomography scan revealed a porencephalic translucency in the right occipital area com municating with the right lateral ventricle.
Comment—Because of the lack of path ologic corroboration this case does not permit sharp localization of the lesion but it does illustrate a spatial dysgnosia (prominent optic ataxia) with a lesion in the posterior portion of the nondominant hemisphere. The normal optokinetic re sponse and nonlateralized Bell's reflex suggests sparing of, at least, the dorsal parietum. Case 4—In this 56-year-old, right-handed woman the initial symptom was loss of way in customarily familiar surroundings. On one occasion she drove her car into the rear of another car. Examination disclosed a complete left homonymous hemianopia with defective optokinetic response on translation of the field toward the right. There was tactile extinc tion on the left and the electroencephalogram indi cated a focal abnormality in the temporoparietal region. Craniotomy disclosed a glioblastoma in this area.
Comment—This is a further illustration of a loss of "whereness" in a patient with a lesion (in this case a tumor) centering about the temporo-parietal region of the nondominant hemisphere. Case 5—This 52-year-old man suddenly found he was unable to find his way home. He summoned the police and had no difficulty in giving his address but could not direct them to his home. Shortly thereafter he developed left hemiparesis and was found to have a tumor of the septum pellucidum. The opto kinetic response was symmetric.
Comment—This patient's chief symp tom was loss of the sense of "whereness." His lesions appear to have begun in the midline structures of the third ventricle and to have extended into the nondomi nant hemisphere.
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Case 6—This 52-year-old right-handed man de veloped intermittent headaches over a period of several months. He then found he was bumping into objects on his left side, tended to drive his car on the middle of the road, and made mistakes in typewrit ing. He could no longer direct his wife's driving because he had "lost my visual recognition." He could not untangle an extension cord or garden hose. As a civil engineer he found it particularly difficult to judge distances and to assess perspectives in a blue print. He lost his ability to make geometric sketches and other architectural figures. He could not reassemble the parts of his daughter's bicycle. Examination showed complete left hemianopia and confirmed the constructional apraxia. He had great difficulty in assembling the parts of a flashlight or in drawing simple figures. He could not draw a cube or bisect a line. It all seemed like "a ball of wax." He had no other neurologic signs but he did have papilledema. Arteriography disclosed a large tumor which on biopsy was found to be a glioblastoma. Subsequently the patient developed dressing apraxia, which was noted first by inability with his necktie but later in putting arms in the sleeves. Reading and calculations were, however, intact. He then became progressively disoriented, had terrify ing hallucinations, developed left hemiplegia with neglect of the left side, and died. Autopsy showed extensive involvement of the entire right hemi sphere with extension into the pons. There was no evident involvement of the left hemisphere.
Comment—The spatial dysgnosia in this case is of especial interest because of the patient's occupation which required an unusual ability to appreciate spatial relationships. The isolated hemianopia pointed to a unilateral lesion in the parie tal region of the nondominant hemi sphere but a co-existent involvement of the corpus callosum cannot be denied in view of the known infiltrative habit of glioblastomas. This may indeed account for the profoundness of the patient's dysgnosia. Case 7—This 61-year-old, right-handed man relat ed a history of intermittent aching of the right eye of approximately two years' duration, relieved by shak ing his head. Five weeks before the present exami nation he suddenly developed a left-sided visual field defect and did not know where he was while driving his car although he had travelled this route many times. On getting home eventually, he was unable to negotiate his car into the parking lot. That evening he had difficulty finding the door to the bathroom in his house. The next morning, however, he was well oriented and had no further spatial dysgnosia but he continued to have a partial upper left quadranopia. The optokinetic response was
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symmetric and Bell's reflex showed no lateralization.
Comment—This patient with a pre sumed transient ischemic attack had a lapse of his spatial orientation. Judging by the fields and the intact optokinetic response the lesion was presumably in the temporoparietal region of the nondominant hemisphere. Case 8—This 64-year-old, right-handed man's ini tial symptom was loss of way in familiar territory. This was first evident on driving his car home from the office and in sailing his boat in well-known waters. The disability increased so that he mixed up rooms in his house. Nevertheless, he was alert in other fields and continued to perform surgery. He volunteered in jest: "I can still do an appendectomy if I can find my way to the hospital." Other difficulties consisted of mild dressing apraxia as evident in putting shoes on the wrong foot and in being unable to find the proper pant-leg. Examination disclosed a left homonymous hemi anopia with sparing of the central area. He had good insight and tested psychometrically as "high aver age." He was able to read well but could not draw a simple map, diagram the position of organs in the abdomen, or the floor plan of his house, and made left-sided errors in inserting the numbers in a clockface or drawing the petals on a daisy. In attempting to bisect a line he indicated a substantially smaller left side. Pneumoencephalography disclosed a cerebral tumor in the lower parietal region on the right. Biopsy indicated glioblastoma multiforme.
Comment—This patient illustrated at the onset an almost pure loss of a sense of "whereness," which contrasted with his mental intactness in other fields. The le sion was situated primarily in the nondominant hemisphere but, owing to the infiltrative nature of the tumor, some in volvement of the corpus callosum cannot be excluded. Case 9—This patient, a 37-year-old, right-handed woman, telephoned her husband to report that she was unwell. During the conversation she noted that her speech became "nasal" and " o d d " but she had no difficulty in selecting words. She felt dizzy and had a mild midfrontal headache. Her left leg felt "tingly" and the headache became severe. When the family physician arrived she was unable to identify his face. Results of neurologic examination at that time were reported to be negative. Neuro-ophthalmic examination four days later disclosed a left hemianopia, most dense in the upper quadrant. She was confused about her position in
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familiar territory ("cannot encompass a panorama"); she made errors in selecting the proper door to take in exiting from a room; and in driving with her husband she was lost at formerly familiar intersec tions. The optokinetic response was symmetric and the Bell's reflex showed no lateralization. The visual acuity was normal.
Comment—This patient with an un confirmed but presumably vascular le sion had the sudden onset of brain stem signs (dysarthria, vertigo) and spatial dysgnosia. The visual fields and intact optokinetic response pointed to a lesion in the occipito-temporal region of the nondominant hemisphere. Case 10—This patient was a 50-year-old woman whose initial symptoms were inability to find her way about a neighborhood in which she had lived for 25 years and tendency to drive her car on the lefthand side of the road. The duration of the symptoms was about six weeks at the time of the first examina tion. The neurologic abnormalities were a left homonymous hemianopia, left facial weakness, and astereognosia of the left hand. Angiography revealed a mass in the right temporal lobe. This was partially resected and found to be a glioblastoma multiforme extending upward to the angular and supramarginal gyri. The ocular motor functions were not recorded preoperatively but five months after the surgery she did show deviation of the eyes to the left on closure of the eyelids but still no asymmetry of the optoki netic response. At death, 14 months after surgery, the brain showed diffuse tumor of the right hemi sphere but no involvement of the left hemisphere.
Comment—This patient with a glio blastoma in the right temporal lobe had symptoms of loss of way in a formerly familiar neighborhood and disorientation in driving a car. The visual fields showed a complete left homonymous hemianopia and a spasticity of the eyes to the left on forced closure of the eyelids but the opto kinetic response was symmetric even at an advanced stage of the disease. Case 11—This 32-year-old man had a partial pneumonectomy for chronic aspergillosis. During surgery the systolic blood pressure fell to between 30 and 40 mm Hg on two occasions. In the next few days he appeared to be blind as he groped for ob jects although he denied any visual defect. He was also profoundly amnesic. Two weeks after surgery he was still amnesic and confabulated freely to cir cumvent his memory defect. No field defect was evi dent on confrontation. He readily identified ob jects (comb, keys, coins, and the like) and colors but was unable to localize the objects in space. Thus he handed me a pencil at some distance from my
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outstretched hand. He was unable to draw a square, triangle, or clock-face although he wrote legibly (at an angle across the page). He was unable to read; indeed, he could not tell whether the book which he held in his hand was right-side-up or upside-down. Computed tomography scan showed biparietal le sions compatible with infarcts. During the next two weeks the patient's memory and testing ability improved. It was then apparent that he had right-left confusion, finger agnosia, acalculia, alexia without agraphia, a partial right homonymous hemianopia, continued constructional apraxia, and inability to recognize faces (even his own face on the TV monitor). By six weeks after surgery his memory had im proved greatly but he still had a homonymous hemianopic defect in the lower right field, was unable to draw a clock-face or diagram a house, car, or sailboat. His visual acuity was at least 6/12 (20/40) and he had recovered his ability to dial the telephone.
Comment—This patient who evidently suffered anoxic episodes during surgery had computed tomographic scan evi dence of biparietal lesions. His conse quent symptoms consisted of a complex mix of Gerstmann's syndrome, prosopagnosia, alexia without agraphia, and spatial dysgnosia. Case 12—This 63-year-old woman has been fol lowed up for several years because of the presump tive diagnosis of Alzheimer's disease. A computed tomography scan had shown bilateral cortical atro phy. The onset, approximately five years previously, was characterized by memory impairment, which progressed to dressing apraxia, loss of way in famil iar environments, neglect of food on the left side of the plate, and progressive left hemianopia. The optokinetic response was relatively poor on rotation to the patient's right and the eyes showed spasticity of gaze to the right on closure of the eyelids. The visual acuity was 6/7.5 (20/25). The recognition of objects was highly variable but recognition of color was always accurate and often the patient used color as a mnemonic for identifying objects and places. A persistent symptom was inability to find her way about. This was evident by getting lost out of doors in a customarily familiar territory or in finding the appropriate rooms in her house. She would frequently start out in the wrong direction. She had difficulty finding the door to the car and usually ended up trying to get into the car in front of the door on the right side. She was unable to find objects that she nevertheless identified and showed erro neous reaching for objects that she could see and identify. She frequently failed to fixate on an object of attention, claiming that she "cannot see because the eye-balls move around in the head." She was able to write out simple dictation but was unable to read, even individual words. She could not draw a clock-face or follow the diagram of a simple maze.
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Yet she was able to write well. When her visual recognition failed she impulsively tried to feel ob jects and had much better tactile recognition than visual recognition. She also frequently failed to recognize persons by sight but could do so by sound and touch. On one occasion she recognized her husband only by feeling his beard. She did not recognize her own face on the TV monitor. During a recent visit she was unable to estimate the relative or absolute distance of objects from her. She repeatedly b u m p e d into objects even in her seeing field. When asked to bisect a horizontal line she drew a vertical line considerably to the right of the horizontal line and did not recognize the dis crepancy. She was unable to arrange books in front of her by order of size. Despite these incapacitating and socially embar rassing difficulties the patient was in excellent audi tory rapport with the examiner, had good insight into her difficulty, even joking about some of her misadventures, and volunteered that she hoped we might turn up something of use to others if not to herself.
Comment—This patient with bilateral diffuse cerebral disease (Alzheimer's dis ease) had symptoms that were predomi nantly visual. In the initial stages of the disease she had consulted numerous oph thalmologists. The visual symptoms in cluded visual anomia and moderate mem ory impairment. Most particularly her symptoms centered about a loss of the "sense of whereness," dressing apraxia, and appreciation for distances. These symptoms contrasted with the intactness of auditory and tactile appreciation and with her insight. The hemianopia, opto kinetic response, and spasticity of gaze suggested a lesion predominantly in the parietal lobes of both sides. Case 13—This patient was a 57-year-old woman with presumed Alzheimer's disease. Her major com plaint was an inability to read, which waxed and waned. She could see individual letters but was unable to synthesize them together in meaningful words or sentences. She had seen "millions of doctors" and had received three new pairs of glasses without benefit. At one clinic she was told she had hysteria. In addition to the reading problem she had lost her way in the neighborhood several times, had dressing apraxia, and was unable to set the table correctly at home. On examination she was found to have some memory impairment, right-left confu sion, and dyslexia without agraphia. She also had some object agnosia which she attempted to circum vent by palpating objects. She said she could recog nize objects by touch better with her eyes closed
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than with them open. Her visual acuity was 6/9 (20/30) and she had good color perception. The visual fields were full. Pneumoencephalography showed cortical atrophy.
Comment—Although this patient's major complaint was dyslexia, caused presumably by dominant hemisphere in volvement, she also had spatial dysgnosia compatible with nondominant hemi sphere involvement. Case 14—This patient was a 26-year-old, lefthanded woman whose initial relevant symptom was transient unsteadiness (ataxia) of the left hand. This ataxia partially cleared but was followed by slurring of speech, recurrent weakness of the left leg, and internuclear ophthalmoplegia. Multiple sclerosis was diagnosed. T h e patient then developed visual difficulty and on examination was found unable to localize objects on the left side. She had no hemi anopia and could identify objects and recognize their colors in both fields but was unable to locate them on the left side. She would often indicate their position by pointing to the wrong side. When asked to point to her left knee, leg, or ear she either had no idea where it was or pointed to the right side. She would make gross errors in grasping for objects on the left and sometimes reach on the right. In con versing with persons at the bedside she would frequently fixate on a person on one side while ad dressing the person on the opposite side. When asked to indicate riiy position at the foot of her bed she frequently pointed to the head of the bed with out being aware of the inconsistency. Similarly, when asked to close her eyes and point to objects in her room such as the window, flower vase, and the like, she would project them as often to the wrong side as to the correct side.
Comment—This left-handed woman with presumed multiple sclerosis showed a spatial dysgnosia that was predominant ly lateralized and sometimes expressed as a fnirror-image projection. The site of the lesion or lesions was uncertain but was probably bilateral although asymmetric. Case 15—This patient was an 18-year-old, lefthanded girl who developed difficulty in gait and left-sided hemianopia with loss of the optokinetic response on movement of tHe field to the patient's right. No diagnosis was established at this time. The patient was again seen at age 26 years because she became lost in familiar surroundings. She observed that the "familiar had become unfamiliar" and she had to depend on auditory or tactile clues for orien tation. By way of illustration she described how she had become lost on her customary trip to school and was only re-oriented by the sound of a train at a nearby station. Or again she had learned which was her apartment floor by counting the number of steps required to reach her proper landing. The patient
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was alert and had intelligently developed clever mnemonics to bypass her problem of dysgnosia. She volunteered that not only sounds but touch and smells had become extremely important to her. On examination the patient now showed in addi tion to the left hemianopia a partial right upper quadranopia indicating a bilateral lesion. Her gait had recently worsened, and was particularly bad after a hot bath. Multiple sclerosis was diagnosed. One year later the patient developed central scotomas and for the first time was unable to read. Following this she developed optic atrophy.
Comment—This patient in whom spa tial dysgnosia became a prominent symp tom of multiple sclerosis, illustrates the mnemonics for bypassing the visual de fect. Case 16—A 57-year-old man with biparietal mestastatic carcinoma (thyroid) had headaches and "blurring of vision." The initial symptom was a tendency to drive his car on the left hand side of the road. This was followed by difficulty in dressing and feeding himself, overshooting the mark on reaching for objects, and right-left confusion. On examination he was unable to draw simple diagrams and he was found to have a complete left homonymous hemi anopia. Visual acuity was at least 6/60 (20/200). Following excision of two nodules in the right parietum he developed anomia and right-sided sei zures. A radioactive iodine ( 131 I) scan indicated a lesion in the left parietum. He then developed an aggravation of his dressing apraxia, he could not orient himself on getting into bed or sitting in a chair, and made erroneous attempts to grasp an object that he could nevertheless see and identify. He was alexic and often unable to tell whether reading matter was right-side up or upside down but he recognized colors accurately.
Comment—In this patient with pro found spatial dysgnosia the major clinical symptom pointed to a lesion in the nondominant parietal region but minor symptoms and 131 I scan indicated a lesion in the dominant parietal region as well. Case 17—This patient was a 31-year-old woman who had been born four months prematurely and weighed only 907.2 g at birth. She had never been able to read, write, or recognize people but she comprehended speech so well that she could pro gress through school and was a Ph.D. candidate in speech therapy. Her conspicuous symptoms were an almost total inability to navigate by visual cues and erroneous reaching for objects. She depended heavily on auditory and tactile information and acted as a blind person. Nevertheless her visual acuity was 6/9 (20/30), as determined by laborious deciphering of letters. The fundi and pupillary reflexes were normal. The visual fields were difficult to assess but there appeared to be a bilateral defect. Additionally, there were bilateral pyramidal tract signs and ocular
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motor disturbapces suggesting cerebral diplegia and ocular motor apraxia.
Comment—This patient with bilateral cerebral lesions of obscure, but presum ably developmental, origin had spatial dysgnosia despite an intact sensorium in other spheres. DISCUSSION
The results of this study agree with those of others, in indicating that unilat eral lesions in the nondominant hemi sphere may impair the sense of "whereness." The patients became lost in famil iar territory; they showed erroneous reaching for objects which they could nevertheless identify; they failed in de sign drawing; and they were prone to auto accidents. This series further suggests that the responsible lesion involved the area bordering the occipito-temporoparietal region rather than the whole pari etum as often assumed. This is suggested by the tendency for the hemianopic de fect, when partial, to be in the upper left field and by the usual sparing of the optokinetic response and the symmetric Bell's reflex which are affected with su perior parietal lesions. Bilateral lesions, on the other hand, produce more complex and more pro found dysgnosic signs, often confounded with other visuocognitive disturbances. Spatial dysgnosia then may or may not be the presenting symptom depending on the site of the lesion. In the present series of bilateral lesions the other symptoms included object anomia, alexia, dressing apraxia, right-left-confusion, prosopagnosia, and memory impairment in addi tion to the strictly spatial dysgnosia. Many of these symptoms related to in volvement of the dominant hemisphere as well as that of the nondominant hemi sphere. Color recognition was usually well pre served even when the lesions were bilat eral and though they caused severe spatial dysgnosia. The auditory and tactile dis-
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criminations were also well preserved so that the patients relied heavily on these senses for orientation. It is tempting to suggest that the right occipito-temporoparietal or angular gyrus region of the human brain is the visuospatial counterpart of the visuoverbal representation in the left angular gyrus region. But as Battersby and associ ate 10 have pointed out, this may be spe cious for the profound communicative disorder occurring with the left-sided le sions may be masking a visuospatial dis order. In the case of right-sided lesions we may simply be witnessing a distur bance in spatial judgment unadulterated by other visual symptoms. This possi ble bilateral representation, nevertheless, does not lessen the practical importance of overt visuospatial dysgnosia in the localization of right-sided lesions. The symptoms of patients with visuo spatial dysgnosia overlap with those of Balint's syndrome ("psychic paralysis of gaze and visual inattention"). The ocular motor defect in both has been termed optic ataxia. The conditions may, howev er, be distinctive both phenotypically and topologically. Whereas in pure visuospa tial dysgnosia the patient is unable to localize an object either by pointing with his hands or fixating with his eyes (a true optic ataxia), in pure Balint's syndrome he is unable to move his eyes voluntar ily toward an excentric object of regard while, nevertheless, retaining full random movements (a true ocular motor apraxia). The lesion in predominant visuospatial dysgnosia is in the angular gyrus region of the nondominant hemisphere and is often unilateral, whereas that in Balint's syndrome is in the superior parietal re gion and is bilateral. CONCLUSIONS
1. Spatial dysgnosia may be a present ing or prominent sign in brain disease. It has relevance to ophthalmology. 2. The lesion for predominent visuo
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spatial dysgnosia appears to be in the nondominant hemisphere, most particu larly in the area comprising the junction of the occipito-temporoparietal regions. 3. With lesions limited to this area pa tients may have a specific loss of the sense of "whereness" of themselves' in relation to the environment and in the relation ship of objects to each other. 4. Visuospatial disturbances resulting from lesions in the dominant hemisphere may be masked by other gnostic symp toms. 5. With the more extensive lesions, most especially those involving similar areas in both hemispheres, the patients have not only spatial disturbances but other cognitive disturbances associated with vision. 6. Spatial dysgnosia may occur with any of several etiologies. In the present series these included: tumors, vascular accidents, Alzheimer's disease, multiple sclerosis, and developmental aberrations. SUMMARY
Spatial dysgnosia may occur in patients with various forms of brain disease, in cluding tumors, vascular accidents, Alzheimer's disease, multiple sclerosis, and developmental aberrations. Patients with lesion in the nondominant hemi sphere, particularly at the junction of the occipito-temporoparietal regions, may manifest predominantly visuospatial dysgnosia—a loss of the sense of "where ness" in the relation of himself to his environment and in the relation of objects to each other. Visuospatial disturbances caused by lesions in the dominant hemi sphere may be masked by other gnostic symptoms. Patients with more extensive lesions, especially those involving similar areas in both hemispheres, may also ex hibit other cognitive disturbances associ ated with vision. ACKNOWLEDGMENT
Henry Webster, M.D., provided notes on Case 1.
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REFERENCES 1. Jackson, J. H.: Case of large cerebral tumor without optic neuritis and with left hemiplegia and imperception. In Taylor, J. (ed.): Selected Writings of John Hughlings Jackson, vol. 2. London, Hodder and Stoughton, p. 146, 1932. 2. Holmes, C : Disturbances of visual orientation. Br. J. Ophthalmol. 2:449, 1918. 3. Critchley, M.: The Parietal Lobes. London, Arnold, 1953, pp. 326-355. 4. Walsh, F., and Hoyt, W.: Clinical Neuroophthalmology. Baltimore, Williams and Wilkins, 1969, pp. 104-107. 5. Benton, A. L.: Disorders of spatial orientation. In Vinken, J. L., and Bryn, G. N. (eds.): Handbook of Clinical Neurology, vol. 3. Amsterdam, North Hol land Publishing Co., 1969, pp. 212-228.
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6. Kinsbourne, M.: Lateralization of human cere bral function. In Goldensohn, E . S., and Appel, E. H. (eds.): Scientific Approaches to Clinical Neu rology, vol. 1. Philadelphia, Lea and Febiger, 1977, pp. 628-636. 7. Hecaen, H., and Albert, M. L.: Human Neuropsychology. New York, John Wiley and Sons, 1978, pp. 213-231. 8. Cogan, D. G.: Ophthalmic manifestation of bilateral non-occipital cerebral lesions. Br. J. Oph thalmol. 49:281, 1965. 9. : Hemianopia and associated symptoms due to parietotemporal lobe lesions. Am. J. Ophthalmol. 50:1056, 1960. 10. Battersby, W. S., Wagman, I. H., Karp, E., and Bender, M. B.: Neural limitations of visual excitability. Alterations produced by cerebral le sions. Arch. Neurol. 3:24, 1960.
The conscious awareness of one's phys ical relationship to his surroundings or one's estimate of spatial relationships among objects requires complex mental processing. Loss of these functions is generally termed visuospatial agnosia or topographic agnosia. I suggest that the term visuospatial dysgnosia more aptly incorporates the many and subtle varia tions of the syndrome. Rarely is it com plete or stereotypic. Included are the following: loss of way in customarily familiar surroundings or in routing (top ographic dysgnosia); impairment of draw ing designs such as circles, squares, triangles, clock-faces, and the like, or of the assembly of parts (constructional apraxia); difficulty in dressing (dressing apraxia); faulty pointing to objects in space (optic ataxia) or faulty saccadic fix ation (ocular motor apraxia); and rightleft confusion. Considerable clinical evidence since the observations of Hughling-Jackson a century ago 1 and the categorization of symptoms by Holmes 2 has suggested pre dominant localization of these functions in the general region of the nondominant parietum. The voluminous and contro versial literature on the subject, to gether with that of relevant observa tions on monkeys, has been extensively reviewed. 3 - 7 In the hope of obtaining further infor mation on the topography and etiology of dysgnosia I have reviewed the case histo-
From the Clinical Branch, National Eye Institute, National Institutes of Health, Department of Health Education and Welfare, Bethesda, Maryland. Reprint requests to David G. Cogan, M.D., Clini cal Branch, National Eye Institute, National Insti tutes of Health, Bethesda, MD 20014.
M.D.
Maryland
ries of 17 patients with either unilateral or bilateral lesions in whom this syndrome, in whole or in part, was a conspicuous or exclusive feature. All patients selected for review were otherwise alert and able to make meaningful judgments. Several cases have been previously described. 8,9 CASE REPORTS Case 1—A 60-year-old, right-handed man awoke one morning with a pounding headache in the right occipital region and intermittent paresthesias of the left hand. H e was found to have hypertension (228/130 mm Hg) and was given medication to lower pressure. While driving his car a few days later he suddenly became confused, lost his way in a cus tomarily familiar environment, and ran into a truck on his left side. Apparently the patient felt there was something wrong with his vision, and was on his way to consult his ophthalmologist. He walked to the garage, located his car without difficulty but climbed into the left rear seat by mistake. The attendant noted that he had difficulty locating the wheel and ignition. He was able to drive out of the garage without difficulty. However, he soon lost his way. He, therefore, stopped the car, hailed a taxi and gave the driver the address of the ophthalmologist's office but could not recognize any portion of the few blocks travelled. After a reassuring but perfunctory examination in which visual fields were not done he left the office, returned to his ear (how is not clear), and started home. This is when he had the accident with the truck coming from his left side. With a police escort he returned home in a taxi, but he was unable to direct the driver to his street or to pick out his own house until he was directly in front of it. During this time the patient had good insight into his disability. The spatial dysgnosia continued but he was able to continue his practice as a physician (except surgery), to prepare his income tax, to make appropriate (and successful) investments on the stock market, and to participate at a trustees' meet ing of a local university. I first saw this patient three weeks after the onset of his visual problem and found an almost complete left hemianopia. The eye movements, including the optokinetic response, were normal. Since he was such a good and reliable observer I asked him to document his observation in the form of a letter from which the following are excerpts: "I can see clearly in front of me the Copley Square Library and front of the Copley Plaza Hotel, but I cannot picture in my mind how I would walk or drive there."
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"If I go down to the garage, which is under my apartment building, I cannot find the door which takes me to the elevator of my apart ment." "I have gone to my son's place in . . . thousands of times but I cannot visualize or 'see' the streets which are necessary for me to reach my destina tion." "When I ride in a car . . . I am completely lost as to where I am." "If I leave the Medical Library, I cannot picture how I get to the Harvard Club." "I can picture the Harvard Stadium where I attended every football game for 25 years but my approach to the Harvard Stadium is blotted out in my memory." "I cannot for the life of me mentally visualize what is beyond the periphery of my sight." "My memory to reproduce mentally certain pic tures which have been projected into my brain by the sense of sight is now obliterated." Additionally, the patient was unable to diagram the rooms in his house. Examinations three and four months later showed partial resolution of the lower field defect but little change in the dysgnosia. He was not seen again, but died of myocardial infarc tion five years after the foregoing incident. Autopsy revealed a complete occlusion of the right posterior cerebral artery with infarction of the medial surface of the temporal and occipital lobes but sparing the dorsal parietum, the most anterior part of the hippo campus, the inferior temporal gyrus and the amyg dala. No lesion was found in the left cerebrum.
Comment—The testimony in this case is given in some detail because of the patient's informative insight into his dis ability and the discreteness of his dysgnosic symptomatology. The pathologic evidence suggests a localization of the lesion (an infarct) in the temporo-occipital area of the nondominant hemi sphere rather than in the parietal area. Case 2—A 24-year-old, right-handed woman had a meningioma of the right occipito-parietal region. Her symptoms included episodic colored phosphene, one major convulsion, asymmetrically ho monymous field defects in the left lower quadrant, and transient loss of familiarity of where she was. T h e optokinetic response was symmetric and Bell's reflex was not lateralized. Most of the tumor was removed surgically but the patient continued to have episodic flashes of colored lights although the visual fields were full.
Comment—In this patient loss of spa tial orientation was a transient manifesta tion of a meningioma in the nondominant parieto-occipital region. Case 3—A 69-year-old man had had rheumatic heart disease and an aortic valve replacement. He
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had previously lost the sight of the left eye from an embolic occlusion of the central retinal artery. Nine months before the present examination, he devel oped a left hemianopia of the right eye. The optoki netic response was symmetric in the two horizontal directions and closure of the eyes showed a normal Bell's reflex without lateralization. A conspicuous and persistent symptom, however, was an inability to localize objects in his seeing field. He regularly missed objects in pointing to them and made gross errors in trying to grasp them. Yet he identified objects in this field, recognized colors, and had normal visual acuity in the right eye. Computed tomography scan revealed a porencephalic translucency in the right occipital area com municating with the right lateral ventricle.
Comment—Because of the lack of path ologic corroboration this case does not permit sharp localization of the lesion but it does illustrate a spatial dysgnosia (prominent optic ataxia) with a lesion in the posterior portion of the nondominant hemisphere. The normal optokinetic re sponse and nonlateralized Bell's reflex suggests sparing of, at least, the dorsal parietum. Case 4—In this 56-year-old, right-handed woman the initial symptom was loss of way in customarily familiar surroundings. On one occasion she drove her car into the rear of another car. Examination disclosed a complete left homonymous hemianopia with defective optokinetic response on translation of the field toward the right. There was tactile extinc tion on the left and the electroencephalogram indi cated a focal abnormality in the temporoparietal region. Craniotomy disclosed a glioblastoma in this area.
Comment—This is a further illustration of a loss of "whereness" in a patient with a lesion (in this case a tumor) centering about the temporo-parietal region of the nondominant hemisphere. Case 5—This 52-year-old man suddenly found he was unable to find his way home. He summoned the police and had no difficulty in giving his address but could not direct them to his home. Shortly thereafter he developed left hemiparesis and was found to have a tumor of the septum pellucidum. The opto kinetic response was symmetric.
Comment—This patient's chief symp tom was loss of the sense of "whereness." His lesions appear to have begun in the midline structures of the third ventricle and to have extended into the nondomi nant hemisphere.
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Case 6—This 52-year-old right-handed man de veloped intermittent headaches over a period of several months. He then found he was bumping into objects on his left side, tended to drive his car on the middle of the road, and made mistakes in typewrit ing. He could no longer direct his wife's driving because he had "lost my visual recognition." He could not untangle an extension cord or garden hose. As a civil engineer he found it particularly difficult to judge distances and to assess perspectives in a blue print. He lost his ability to make geometric sketches and other architectural figures. He could not reassemble the parts of his daughter's bicycle. Examination showed complete left hemianopia and confirmed the constructional apraxia. He had great difficulty in assembling the parts of a flashlight or in drawing simple figures. He could not draw a cube or bisect a line. It all seemed like "a ball of wax." He had no other neurologic signs but he did have papilledema. Arteriography disclosed a large tumor which on biopsy was found to be a glioblastoma. Subsequently the patient developed dressing apraxia, which was noted first by inability with his necktie but later in putting arms in the sleeves. Reading and calculations were, however, intact. He then became progressively disoriented, had terrify ing hallucinations, developed left hemiplegia with neglect of the left side, and died. Autopsy showed extensive involvement of the entire right hemi sphere with extension into the pons. There was no evident involvement of the left hemisphere.
Comment—The spatial dysgnosia in this case is of especial interest because of the patient's occupation which required an unusual ability to appreciate spatial relationships. The isolated hemianopia pointed to a unilateral lesion in the parie tal region of the nondominant hemi sphere but a co-existent involvement of the corpus callosum cannot be denied in view of the known infiltrative habit of glioblastomas. This may indeed account for the profoundness of the patient's dysgnosia. Case 7—This 61-year-old, right-handed man relat ed a history of intermittent aching of the right eye of approximately two years' duration, relieved by shak ing his head. Five weeks before the present exami nation he suddenly developed a left-sided visual field defect and did not know where he was while driving his car although he had travelled this route many times. On getting home eventually, he was unable to negotiate his car into the parking lot. That evening he had difficulty finding the door to the bathroom in his house. The next morning, however, he was well oriented and had no further spatial dysgnosia but he continued to have a partial upper left quadranopia. The optokinetic response was
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symmetric and Bell's reflex showed no lateralization.
Comment—This patient with a pre sumed transient ischemic attack had a lapse of his spatial orientation. Judging by the fields and the intact optokinetic response the lesion was presumably in the temporoparietal region of the nondominant hemisphere. Case 8—This 64-year-old, right-handed man's ini tial symptom was loss of way in familiar territory. This was first evident on driving his car home from the office and in sailing his boat in well-known waters. The disability increased so that he mixed up rooms in his house. Nevertheless, he was alert in other fields and continued to perform surgery. He volunteered in jest: "I can still do an appendectomy if I can find my way to the hospital." Other difficulties consisted of mild dressing apraxia as evident in putting shoes on the wrong foot and in being unable to find the proper pant-leg. Examination disclosed a left homonymous hemi anopia with sparing of the central area. He had good insight and tested psychometrically as "high aver age." He was able to read well but could not draw a simple map, diagram the position of organs in the abdomen, or the floor plan of his house, and made left-sided errors in inserting the numbers in a clockface or drawing the petals on a daisy. In attempting to bisect a line he indicated a substantially smaller left side. Pneumoencephalography disclosed a cerebral tumor in the lower parietal region on the right. Biopsy indicated glioblastoma multiforme.
Comment—This patient illustrated at the onset an almost pure loss of a sense of "whereness," which contrasted with his mental intactness in other fields. The le sion was situated primarily in the nondominant hemisphere but, owing to the infiltrative nature of the tumor, some in volvement of the corpus callosum cannot be excluded. Case 9—This patient, a 37-year-old, right-handed woman, telephoned her husband to report that she was unwell. During the conversation she noted that her speech became "nasal" and " o d d " but she had no difficulty in selecting words. She felt dizzy and had a mild midfrontal headache. Her left leg felt "tingly" and the headache became severe. When the family physician arrived she was unable to identify his face. Results of neurologic examination at that time were reported to be negative. Neuro-ophthalmic examination four days later disclosed a left hemianopia, most dense in the upper quadrant. She was confused about her position in
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familiar territory ("cannot encompass a panorama"); she made errors in selecting the proper door to take in exiting from a room; and in driving with her husband she was lost at formerly familiar intersec tions. The optokinetic response was symmetric and the Bell's reflex showed no lateralization. The visual acuity was normal.
Comment—This patient with an un confirmed but presumably vascular le sion had the sudden onset of brain stem signs (dysarthria, vertigo) and spatial dysgnosia. The visual fields and intact optokinetic response pointed to a lesion in the occipito-temporal region of the nondominant hemisphere. Case 10—This patient was a 50-year-old woman whose initial symptoms were inability to find her way about a neighborhood in which she had lived for 25 years and tendency to drive her car on the lefthand side of the road. The duration of the symptoms was about six weeks at the time of the first examina tion. The neurologic abnormalities were a left homonymous hemianopia, left facial weakness, and astereognosia of the left hand. Angiography revealed a mass in the right temporal lobe. This was partially resected and found to be a glioblastoma multiforme extending upward to the angular and supramarginal gyri. The ocular motor functions were not recorded preoperatively but five months after the surgery she did show deviation of the eyes to the left on closure of the eyelids but still no asymmetry of the optoki netic response. At death, 14 months after surgery, the brain showed diffuse tumor of the right hemi sphere but no involvement of the left hemisphere.
Comment—This patient with a glio blastoma in the right temporal lobe had symptoms of loss of way in a formerly familiar neighborhood and disorientation in driving a car. The visual fields showed a complete left homonymous hemianopia and a spasticity of the eyes to the left on forced closure of the eyelids but the opto kinetic response was symmetric even at an advanced stage of the disease. Case 11—This 32-year-old man had a partial pneumonectomy for chronic aspergillosis. During surgery the systolic blood pressure fell to between 30 and 40 mm Hg on two occasions. In the next few days he appeared to be blind as he groped for ob jects although he denied any visual defect. He was also profoundly amnesic. Two weeks after surgery he was still amnesic and confabulated freely to cir cumvent his memory defect. No field defect was evi dent on confrontation. He readily identified ob jects (comb, keys, coins, and the like) and colors but was unable to localize the objects in space. Thus he handed me a pencil at some distance from my
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outstretched hand. He was unable to draw a square, triangle, or clock-face although he wrote legibly (at an angle across the page). He was unable to read; indeed, he could not tell whether the book which he held in his hand was right-side-up or upside-down. Computed tomography scan showed biparietal le sions compatible with infarcts. During the next two weeks the patient's memory and testing ability improved. It was then apparent that he had right-left confusion, finger agnosia, acalculia, alexia without agraphia, a partial right homonymous hemianopia, continued constructional apraxia, and inability to recognize faces (even his own face on the TV monitor). By six weeks after surgery his memory had im proved greatly but he still had a homonymous hemianopic defect in the lower right field, was unable to draw a clock-face or diagram a house, car, or sailboat. His visual acuity was at least 6/12 (20/40) and he had recovered his ability to dial the telephone.
Comment—This patient who evidently suffered anoxic episodes during surgery had computed tomographic scan evi dence of biparietal lesions. His conse quent symptoms consisted of a complex mix of Gerstmann's syndrome, prosopagnosia, alexia without agraphia, and spatial dysgnosia. Case 12—This 63-year-old woman has been fol lowed up for several years because of the presump tive diagnosis of Alzheimer's disease. A computed tomography scan had shown bilateral cortical atro phy. The onset, approximately five years previously, was characterized by memory impairment, which progressed to dressing apraxia, loss of way in famil iar environments, neglect of food on the left side of the plate, and progressive left hemianopia. The optokinetic response was relatively poor on rotation to the patient's right and the eyes showed spasticity of gaze to the right on closure of the eyelids. The visual acuity was 6/7.5 (20/25). The recognition of objects was highly variable but recognition of color was always accurate and often the patient used color as a mnemonic for identifying objects and places. A persistent symptom was inability to find her way about. This was evident by getting lost out of doors in a customarily familiar territory or in finding the appropriate rooms in her house. She would frequently start out in the wrong direction. She had difficulty finding the door to the car and usually ended up trying to get into the car in front of the door on the right side. She was unable to find objects that she nevertheless identified and showed erro neous reaching for objects that she could see and identify. She frequently failed to fixate on an object of attention, claiming that she "cannot see because the eye-balls move around in the head." She was able to write out simple dictation but was unable to read, even individual words. She could not draw a clock-face or follow the diagram of a simple maze.
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Yet she was able to write well. When her visual recognition failed she impulsively tried to feel ob jects and had much better tactile recognition than visual recognition. She also frequently failed to recognize persons by sight but could do so by sound and touch. On one occasion she recognized her husband only by feeling his beard. She did not recognize her own face on the TV monitor. During a recent visit she was unable to estimate the relative or absolute distance of objects from her. She repeatedly b u m p e d into objects even in her seeing field. When asked to bisect a horizontal line she drew a vertical line considerably to the right of the horizontal line and did not recognize the dis crepancy. She was unable to arrange books in front of her by order of size. Despite these incapacitating and socially embar rassing difficulties the patient was in excellent audi tory rapport with the examiner, had good insight into her difficulty, even joking about some of her misadventures, and volunteered that she hoped we might turn up something of use to others if not to herself.
Comment—This patient with bilateral diffuse cerebral disease (Alzheimer's dis ease) had symptoms that were predomi nantly visual. In the initial stages of the disease she had consulted numerous oph thalmologists. The visual symptoms in cluded visual anomia and moderate mem ory impairment. Most particularly her symptoms centered about a loss of the "sense of whereness," dressing apraxia, and appreciation for distances. These symptoms contrasted with the intactness of auditory and tactile appreciation and with her insight. The hemianopia, opto kinetic response, and spasticity of gaze suggested a lesion predominantly in the parietal lobes of both sides. Case 13—This patient was a 57-year-old woman with presumed Alzheimer's disease. Her major com plaint was an inability to read, which waxed and waned. She could see individual letters but was unable to synthesize them together in meaningful words or sentences. She had seen "millions of doctors" and had received three new pairs of glasses without benefit. At one clinic she was told she had hysteria. In addition to the reading problem she had lost her way in the neighborhood several times, had dressing apraxia, and was unable to set the table correctly at home. On examination she was found to have some memory impairment, right-left confu sion, and dyslexia without agraphia. She also had some object agnosia which she attempted to circum vent by palpating objects. She said she could recog nize objects by touch better with her eyes closed
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than with them open. Her visual acuity was 6/9 (20/30) and she had good color perception. The visual fields were full. Pneumoencephalography showed cortical atrophy.
Comment—Although this patient's major complaint was dyslexia, caused presumably by dominant hemisphere in volvement, she also had spatial dysgnosia compatible with nondominant hemi sphere involvement. Case 14—This patient was a 26-year-old, lefthanded woman whose initial relevant symptom was transient unsteadiness (ataxia) of the left hand. This ataxia partially cleared but was followed by slurring of speech, recurrent weakness of the left leg, and internuclear ophthalmoplegia. Multiple sclerosis was diagnosed. T h e patient then developed visual difficulty and on examination was found unable to localize objects on the left side. She had no hemi anopia and could identify objects and recognize their colors in both fields but was unable to locate them on the left side. She would often indicate their position by pointing to the wrong side. When asked to point to her left knee, leg, or ear she either had no idea where it was or pointed to the right side. She would make gross errors in grasping for objects on the left and sometimes reach on the right. In con versing with persons at the bedside she would frequently fixate on a person on one side while ad dressing the person on the opposite side. When asked to indicate riiy position at the foot of her bed she frequently pointed to the head of the bed with out being aware of the inconsistency. Similarly, when asked to close her eyes and point to objects in her room such as the window, flower vase, and the like, she would project them as often to the wrong side as to the correct side.
Comment—This left-handed woman with presumed multiple sclerosis showed a spatial dysgnosia that was predominant ly lateralized and sometimes expressed as a fnirror-image projection. The site of the lesion or lesions was uncertain but was probably bilateral although asymmetric. Case 15—This patient was an 18-year-old, lefthanded girl who developed difficulty in gait and left-sided hemianopia with loss of the optokinetic response on movement of tHe field to the patient's right. No diagnosis was established at this time. The patient was again seen at age 26 years because she became lost in familiar surroundings. She observed that the "familiar had become unfamiliar" and she had to depend on auditory or tactile clues for orien tation. By way of illustration she described how she had become lost on her customary trip to school and was only re-oriented by the sound of a train at a nearby station. Or again she had learned which was her apartment floor by counting the number of steps required to reach her proper landing. The patient
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was alert and had intelligently developed clever mnemonics to bypass her problem of dysgnosia. She volunteered that not only sounds but touch and smells had become extremely important to her. On examination the patient now showed in addi tion to the left hemianopia a partial right upper quadranopia indicating a bilateral lesion. Her gait had recently worsened, and was particularly bad after a hot bath. Multiple sclerosis was diagnosed. One year later the patient developed central scotomas and for the first time was unable to read. Following this she developed optic atrophy.
Comment—This patient in whom spa tial dysgnosia became a prominent symp tom of multiple sclerosis, illustrates the mnemonics for bypassing the visual de fect. Case 16—A 57-year-old man with biparietal mestastatic carcinoma (thyroid) had headaches and "blurring of vision." The initial symptom was a tendency to drive his car on the left hand side of the road. This was followed by difficulty in dressing and feeding himself, overshooting the mark on reaching for objects, and right-left confusion. On examination he was unable to draw simple diagrams and he was found to have a complete left homonymous hemi anopia. Visual acuity was at least 6/60 (20/200). Following excision of two nodules in the right parietum he developed anomia and right-sided sei zures. A radioactive iodine ( 131 I) scan indicated a lesion in the left parietum. He then developed an aggravation of his dressing apraxia, he could not orient himself on getting into bed or sitting in a chair, and made erroneous attempts to grasp an object that he could nevertheless see and identify. He was alexic and often unable to tell whether reading matter was right-side up or upside down but he recognized colors accurately.
Comment—In this patient with pro found spatial dysgnosia the major clinical symptom pointed to a lesion in the nondominant parietal region but minor symptoms and 131 I scan indicated a lesion in the dominant parietal region as well. Case 17—This patient was a 31-year-old woman who had been born four months prematurely and weighed only 907.2 g at birth. She had never been able to read, write, or recognize people but she comprehended speech so well that she could pro gress through school and was a Ph.D. candidate in speech therapy. Her conspicuous symptoms were an almost total inability to navigate by visual cues and erroneous reaching for objects. She depended heavily on auditory and tactile information and acted as a blind person. Nevertheless her visual acuity was 6/9 (20/30), as determined by laborious deciphering of letters. The fundi and pupillary reflexes were normal. The visual fields were difficult to assess but there appeared to be a bilateral defect. Additionally, there were bilateral pyramidal tract signs and ocular
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motor disturbapces suggesting cerebral diplegia and ocular motor apraxia.
Comment—This patient with bilateral cerebral lesions of obscure, but presum ably developmental, origin had spatial dysgnosia despite an intact sensorium in other spheres. DISCUSSION
The results of this study agree with those of others, in indicating that unilat eral lesions in the nondominant hemi sphere may impair the sense of "whereness." The patients became lost in famil iar territory; they showed erroneous reaching for objects which they could nevertheless identify; they failed in de sign drawing; and they were prone to auto accidents. This series further suggests that the responsible lesion involved the area bordering the occipito-temporoparietal region rather than the whole pari etum as often assumed. This is suggested by the tendency for the hemianopic de fect, when partial, to be in the upper left field and by the usual sparing of the optokinetic response and the symmetric Bell's reflex which are affected with su perior parietal lesions. Bilateral lesions, on the other hand, produce more complex and more pro found dysgnosic signs, often confounded with other visuocognitive disturbances. Spatial dysgnosia then may or may not be the presenting symptom depending on the site of the lesion. In the present series of bilateral lesions the other symptoms included object anomia, alexia, dressing apraxia, right-left-confusion, prosopagnosia, and memory impairment in addi tion to the strictly spatial dysgnosia. Many of these symptoms related to in volvement of the dominant hemisphere as well as that of the nondominant hemi sphere. Color recognition was usually well pre served even when the lesions were bilat eral and though they caused severe spatial dysgnosia. The auditory and tactile dis-
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criminations were also well preserved so that the patients relied heavily on these senses for orientation. It is tempting to suggest that the right occipito-temporoparietal or angular gyrus region of the human brain is the visuospatial counterpart of the visuoverbal representation in the left angular gyrus region. But as Battersby and associ ate 10 have pointed out, this may be spe cious for the profound communicative disorder occurring with the left-sided le sions may be masking a visuospatial dis order. In the case of right-sided lesions we may simply be witnessing a distur bance in spatial judgment unadulterated by other visual symptoms. This possi ble bilateral representation, nevertheless, does not lessen the practical importance of overt visuospatial dysgnosia in the localization of right-sided lesions. The symptoms of patients with visuo spatial dysgnosia overlap with those of Balint's syndrome ("psychic paralysis of gaze and visual inattention"). The ocular motor defect in both has been termed optic ataxia. The conditions may, howev er, be distinctive both phenotypically and topologically. Whereas in pure visuospa tial dysgnosia the patient is unable to localize an object either by pointing with his hands or fixating with his eyes (a true optic ataxia), in pure Balint's syndrome he is unable to move his eyes voluntar ily toward an excentric object of regard while, nevertheless, retaining full random movements (a true ocular motor apraxia). The lesion in predominant visuospatial dysgnosia is in the angular gyrus region of the nondominant hemisphere and is often unilateral, whereas that in Balint's syndrome is in the superior parietal re gion and is bilateral. CONCLUSIONS
1. Spatial dysgnosia may be a present ing or prominent sign in brain disease. It has relevance to ophthalmology. 2. The lesion for predominent visuo
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spatial dysgnosia appears to be in the nondominant hemisphere, most particu larly in the area comprising the junction of the occipito-temporoparietal regions. 3. With lesions limited to this area pa tients may have a specific loss of the sense of "whereness" of themselves' in relation to the environment and in the relation ship of objects to each other. 4. Visuospatial disturbances resulting from lesions in the dominant hemisphere may be masked by other gnostic symp toms. 5. With the more extensive lesions, most especially those involving similar areas in both hemispheres, the patients have not only spatial disturbances but other cognitive disturbances associated with vision. 6. Spatial dysgnosia may occur with any of several etiologies. In the present series these included: tumors, vascular accidents, Alzheimer's disease, multiple sclerosis, and developmental aberrations. SUMMARY
Spatial dysgnosia may occur in patients with various forms of brain disease, in cluding tumors, vascular accidents, Alzheimer's disease, multiple sclerosis, and developmental aberrations. Patients with lesion in the nondominant hemi sphere, particularly at the junction of the occipito-temporoparietal regions, may manifest predominantly visuospatial dysgnosia—a loss of the sense of "where ness" in the relation of himself to his environment and in the relation of objects to each other. Visuospatial disturbances caused by lesions in the dominant hemi sphere may be masked by other gnostic symptoms. Patients with more extensive lesions, especially those involving similar areas in both hemispheres, may also ex hibit other cognitive disturbances associ ated with vision. ACKNOWLEDGMENT
Henry Webster, M.D., provided notes on Case 1.
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REFERENCES 1. Jackson, J. H.: Case of large cerebral tumor without optic neuritis and with left hemiplegia and imperception. In Taylor, J. (ed.): Selected Writings of John Hughlings Jackson, vol. 2. London, Hodder and Stoughton, p. 146, 1932. 2. Holmes, C : Disturbances of visual orientation. Br. J. Ophthalmol. 2:449, 1918. 3. Critchley, M.: The Parietal Lobes. London, Arnold, 1953, pp. 326-355. 4. Walsh, F., and Hoyt, W.: Clinical Neuroophthalmology. Baltimore, Williams and Wilkins, 1969, pp. 104-107. 5. Benton, A. L.: Disorders of spatial orientation. In Vinken, J. L., and Bryn, G. N. (eds.): Handbook of Clinical Neurology, vol. 3. Amsterdam, North Hol land Publishing Co., 1969, pp. 212-228.
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6. Kinsbourne, M.: Lateralization of human cere bral function. In Goldensohn, E . S., and Appel, E. H. (eds.): Scientific Approaches to Clinical Neu rology, vol. 1. Philadelphia, Lea and Febiger, 1977, pp. 628-636. 7. Hecaen, H., and Albert, M. L.: Human Neuropsychology. New York, John Wiley and Sons, 1978, pp. 213-231. 8. Cogan, D. G.: Ophthalmic manifestation of bilateral non-occipital cerebral lesions. Br. J. Oph thalmol. 49:281, 1965. 9. : Hemianopia and associated symptoms due to parietotemporal lobe lesions. Am. J. Ophthalmol. 50:1056, 1960. 10. Battersby, W. S., Wagman, I. H., Karp, E., and Bender, M. B.: Neural limitations of visual excitability. Alterations produced by cerebral le sions. Arch. Neurol. 3:24, 1960.
