"Crossed homonymous hemianopia" and "crossed left hemispatial neglect" in a case of Marchiafava-Bignami disease.

"Crossed homonymous hemianopia" and "crossed left hemispatial neglect" were observed in a woman with Marchiafava-Bignami disease. Two forms of "crossed homonymous hemianopia" were observed. Initially, Goldmann perimeter testing showed a left homonymous hemianopia with the right hand and vice versa. Later, confrontation tests showed a left homonymous hemianopia, whereas visual field testing using the Goldmann perimeter (kinetic quantitative perimeter) and the OCTOPUS (Interzeag AG, static automated perimeter) showed a right homonymous hemianopia with either hand. "Crossed left hemispatial neglect" was not seen with the left hand, but neglect of the left hemifield was seen with the right hand. CT and MRI showed a lesion occupying almost the entire corpus callosum. PET showed no significant differences between comparable areas of the left and right cerebral hemispheres. These findings indicate that both signs of interhemispheric disconnection were due to the callosal lesion. Moreover, the "crossed left hemispatial neglect" can be explained as being a consequence of the dominance of the right cerebral hemisphere for visuospatial recognition.     

Mixed alien hand syndrome coexisting with left-sided extinction secondary to a left corpus callosal lesion: a case report.

Alien hand syndrome (AHS) is actually two distinct syndromes with distinct clinical and anatomic features, that is, a frontal type and a callosal type. Frontal AHS occurs in the dominant hand; is associated with reflexive grasping, groping, and compulsive manipulation of tools. Callosal AHS is characterized primarily by intermanual conflict. We report a case of right frontal AHS and left callosal AHS (mixed AHS) secondary to ischemic stroke of the left corpus callosum (lesion extending from the genu to splenium) and right corpus callosum (minimal lesion in the splenium) in a 67-year-old male patient who also presented with left-sided tactile extinction. To our knowledge, rare reports have documented mixed AHS coexisting with nondominant side extinction secondary only to unilateral (left) callosal lesion, as in our case.     

Alexia without agraphia following biopsy of a left thalamic tumor

Alexia without agraphia is a rare disconnection syndrome characterized by the loss of reading ability with retention of writing and verbal comprehension. We report a patient who developed alexia without agraphia after undergoing a biopsy for a malignant glioma involving the left thalamus. A 15-year-old right-handed male presented with 3 days of severe headache, and vomiting, and 1 month of blurry vision in his right visual field. Magnetic resonance imaging of the brain disclosed a large exophytic mass originating in the left thalamus, with mass effect and hydrocephalus. The patient underwent biopsy of the left thalamic mass via a transcallosal approach. Postoperatively, the patient complained of inability to read or identify letters. Examination revealed alexia without agraphia. The syndrome of alexia without agraphia can be rarely caused after surgery. A transcallosal procedure through the splenium of the corpus callosum may disrupt the visual association fibers traveling from the right occipital cortex to the left angular gyrus. In our case the syndrome occurred because of a preexisting right homonymous hemianopia resulting from a left thalamic tumor.     

Callosal disconnection syndrome caused by left hemisphere infarction

A 49-year old right-handed taxi-driver experienced right upper limb weakness and global aphasia following internal carotid artery occlusion. Five months later, aphasia and hemiparesis had resolved but he complained of difficulties in his daily activities, termed "inner conflict". Specific testings disclosed typical features of a callosal syndrome: left unilateral ideomotor apraxia, left hand agraphia, left tactile dysnomia, right hand constructional difficulties, and left ear extinction on dichotic listening. Naming and recognition of tachistoscopically presented images or words was similar to that of classical split-brain studies. MRI showed a left-hemisphere periventricular increased signal involving the callosal outflow of the whole posterior half of the corpus callosum and partially destroying the splenium. Fibers from the anterior half of the body and the genu were spared. According to clinical and MRI findings in this case and other documented cases of callosal syndrome, localization of callosal transfer of various hemisphere functions is discussed. The relevance of callosal symptoms to the diagnosis of watershed infarcts is emphasized.     

Sensory alien hand syndrome: case report and review of the literature

An 81 year old right handed woman developed a left alienhand syndrome characterised by involuntary movements of choking and hitting the face, neck, and shoulder. The patient showed multiple disorders of primary sensation, sensory processing, hemispatial attention, and visual association, as well as a combination of sensory,optic, and cerebellar ataxia (triple ataxia) of the left arm in theabsence of motor neglect or hemiparesis. Imaging studies disclosedsubacute infarction in the right thalamus, hippocampus, inferiortemporal lobes, splenium of corpus callosum, and occipital lobe due toright posterior cerebral artery occlusion. This rare syndrome should beconsidered as a "sensory" or "posterior" form of thealien hand syndrome, to be distinguished from the"motor" or "anterior" form described more commonly.

     

Opticosensory ataxia and alien hand syndrome after posterior cerebral artery territory infarction

A right-handed woman developed left homonymous hemianopia and left hemianesthesia from infarction due to right posterior cerebral artery occlusion. Ataxia of the left arm and leg was severe and was not improved by vision. The patient often interpreted spontaneous movements of the left arm as alien in origin. The ataxia may have been caused by a combination of sensory ataxia, resulting from right thalamic infarction, and crossed-optic ataxia, resulting from posterior disconnection of the hemispheres due to right temporo-occipital infarction. This opticosensory ataxia was associated with a new form of "alien hand" syndrome.     

Alien hand syndrome in left posterior stroke

Alien hand syndrome is a rare neurological disorder characterized by involuntary and uncontrollable motor behaviour, usually of an arm or hand. The patient perceives the affected limb as alien, and may personify it. The case of a 61-year-old right-handed woman who developed right posterior AHS after ischaemic stroke in the left posterior cerebral artery territory is reported. Neuroimaging studies disclosed no frontal or parietal involvement, while a posterior thalamic lesion was detected. A possible role of the thalamus in the genesis of AHS is discussed.     

Impaired reading in patients with right hemianopia

A left occipital stroke may result in alexia for two reasons, which may coexist depending on the distribution of the lesion. A lesion of the left lateroventral prestriate cortex or its afferents impairs word recognition ("pure" alexia). If the left primary visual cortex or its afferents are destroyed, resulting in a complete right homonymous hemianopia, rightward saccades during text reading are disrupted ("hemianopic" alexia). By using functional imaging, we showed two separate but interdependent systems involved in reading. The first, subserving word recognition, involved the representation of foveal vision in the left and right primary visual cortex and the ventral prestriate cortex. The second system, responsible for the planning and execution of reading saccades, consisted of the representation of right parafoveal vision in the left visual cortex, the bilateral posterior parietal cortex (left > right), and the frontal eye fields (right > left). Disruption of this distributed neural system was demonstrated in patients with severe right homonymous hemianopia, commensurate with their inability to perform normal reading eye movements. Text reading, before processes involved in comprehension, requires the integration of perceptual and motor processes. We have demonstrated these distributed neural systems in normal readers and have shown how a right homonymous hemianopia disrupts the motor preparation of reading saccades during text reading.     

Changes in sensory inattention, directional motor neglect and "release" of the fixation reflex following a unilateral frontal lesion: a case report

We recorded eye movements to and away from visual stimuli from a patient with left-sided neglect following a right frontal infarct in order to determine (a) whether and to what extent his neglect was due to sensory inattention and directional motor neglect and (b) whether he had difficulty suppressing inappropriate eye movements to visual stimuli ("release" of visual grasp) as his sensory inattention declined. In the first testing session, conducted 5 days following his stroke, he often failed to move his eyes when a stimulus on the left required a rightward eye movement, but he consistently moved his eyes to a stimulus on the right. Thus, he showed contralateral but not ipsilateral sensory inattention. Initially, he also was impaired in making leftward eye movements when right stimuli were presented. Thus, he also showed a directional motor neglect. In subsequent tests, his left-sided sensory inattention as defined above decreased, and was no longer present three weeks following his stroke, nor in a follow-up test conducted almost 6 months following this stroke. In contrast, his directional motor neglect, as defined above, was still present in the follow-up test. As his left-sided sensory inattention declined, his tendency to move his eyes incorrectly to stimuli on the left side (the side contralateral to his lesion) when these stimuli required eye movements to the right became stronger ("release" of visual grasp); he continued to show this strong tendency in the test conducted almost 6 months following his stroke.     

Dominant posterior-variant alien hand syndrome after acute left parietal infarction

Alien hand syndrome (AHS) is a complex clinical disorder in which patients develop a sense of estrangement from, and loss of volitional control of, an affected limb and non-purposeful complex motor actions of the same limb. Several forms of AHS exist, including frontal, callosal, and posterior types with a series of different associated neuroanatomical lesions and clinical symptoms. Most commonly, the lesions associated with AHS occur in the frontal lobes and corpus callosum. Rarely, lesions in the parietal lobes may be associated with AHS, and most often occur within the non-dominant hemisphere. We describe a 57-year-old patient who developed symptoms of posterior AHS after an acute infarction in the left (presumably dominant) parietal lobe. A review of the different clinical features of AHS and the underlying mechanisms is also presented.     

Hemianopic line bisection error in a patient with Alzheimer’s disease

Visual symptoms are frequently observed in posterior cortical atrophy compared to typical amnestic Alzheimer’s disease (AD). We report the case of a patient with amnestic AD with long-lasting homonymous hemianopia. A 62-year-old woman, who was diagnosed in amnestic AD, complained of visual disturbance. She had left homonymous hemianopia in the perimetry test and left tactile extinction. Regardless of posture, retinotopically leftward error was observed on 21 cm line bisection test. Brain single photon emission computerized tomography (SPECT) showed bilateral temporoparietal hypoperfusion, which was more severe to the right than left side. This case suggested that long-lasting hemianopia could occur in the patient with amnestic AD and that hemianopic line bisection error might be compensatory mechanism.     

Hemianopia, hemianesthesia, and spatial neglect: a study with evoked potentials.

We recorded somatosensory or visual evoked potentials (SEPs, VEPs) to stimuli contralateral and ipsilateral to the lesion in three right-brain-damaged patients with left spatial hemineglect and in three left-brain-damaged patients without evidence of neglect, as assessed by visual exploratory tasks. All patients had contralateral homonymous hemianopia or hemianesthesia. The three neglect patients showed normal SEPs or VEPs to stimuli delivered to the left half-field or to the left hand, without conscious perception and verbal report of the stimulation. By contrast, the three left-brain-damaged patients without neglect showed no recognizable cortical evoked response to contralateral visual or somatosensory stimuli. In all patients, the cortical evoked responses to ipsilateral stimulation were normal. In patients with spatial hemineglect, hemianopia and hemianesthesia may be manifestations of the neglect syndrome (visual and somatosensory hemi-inattention), rather than representing primary sensory deficit. Visual and somatosensory hemi-inattention may be due to defective access to the neural processes subserving conscious perception by information that has undergone early sensory processing.     

Chronic encapsulated intracerebral hematoma in thalamus with incongruous right homonymous hemianopia: a case report]

We presented a patient with chronic encapsulated intracerebral hematoma. This 49-year-old woman suffered from visual disturbance, and slowly progressive right hemiparesis, sensory disturbance of the right extremities and incongruous right homonymous hemianopia over 2 months. Computed tomography scanning showed high density area and ring enhancement, and magnetic resonance imaging revealed mixed intensity on T1 and T2-weighted images in her left thalamus and internal capsule. Angiographic studies revealed no vascular anomaly or tumor stain. The pathologic pictures indicated well-encapsulated hematoma containing fresh and old hematomas in the left thalamus. Most reported cases of this disease had hematomas in the subcortex and no cases had similar visual disturbance. This report was prepared because this condition is uncommon and may remain unrecognized.     

Two cases of cerebral embolism showing global aphasia without hemiparesis]

We report two cases of typical global aphasia without hemiparesis due to cerebral embolism. Case 1 was a 65-year-old right-handed man with a history of old myocardial infarction. No spontaneous speech was noted by his family. Neurological examination upon admission revealed confusional state, global aphasia, conjugate deviation to the left and slight drift of the outstretched right limbs. The right hemiparesis rapidly recovered after admission. CT scan performed on the second hospital day showed discrete low density areas in the left posterior frontal lobe and left temporo-parietal regions. The extent and severity of his global aphasia were unchanged. The second case was an 82-year-old right-handed man with a history of atrial fibrillation. He was admitted to our hospital one hour after he was found unable to speak. Neurological examination upon admission revealed global aphasia, conjugate deviation to the left and suspected right homonymous hemianopia by confrontation. There was no sign of hemiparesis. CT scan showed extensive low density area in the left temporo-parietal regions. In both cases, cerebral angiography failed to demonstrate any occlusion of intra- and extra-cranial blood vessels. IMP-SPECT showed a depression of cerebral blood flow in the left anterior and posterior watershed areas in case 1 and 2. In the literature, there have been 20 cases of global aphasia without hemiparesis including our two cases. In many cases, the initial symptom was inability or difficulty in speaking.(ABSTRACT TRUNCATED AT 250 WORDS)     

Visual search training for a case of homonymous field defect with multiple visual dysfunctions]

A 72-year-old right handed man developed right homonymous hemianopia without macular sparing, left homonymous lower quadranopia with macular sparing, cerebral amblyopia, cerebral achromatopsia, impaired form vision, and mild right hemispatial neglect, after multiple cerebral infarctions, involving bilateral occipital cortices. His intelligence and memory were deteriorated moderately. He failed to notice objects located in the affected visual field, because of his severely impaired visual search. When ordinary lighting was used, he showed severe right-sided omissions on the line cancellation test. However, omissions were less marked under the brighter lighting. By using a modified method of Kerkhoff and Vianen (1994), he was trained to make saccadic eye movements toward affected regions to find a target and to search and point at targets arranged randomly. As the sensitivity for contrast of isoluminante red and green stimuli was preserved well at high spatial frequencies despite the decreaced contrast sensitivity for brightness, we used green targets as the training stimuli. After the training, search field and pointing range that could be covered by the patient increased in size for both green and white targets, and daily activities improved. Moreover, after the training, he no longer showed discrepancy in line cancellation performances between ordinary and brighter lighting conditions. In the follow up period, the search field and the performance on the line cancellation test were maintained, while the performance of pointing targets array declined. The family members complained of mild re-deterioration of daily activities. Then, the training for searching and pointing re-introduced at home. After the training, his pointing performance and daily activities, evaluated by questionnaires to his family members, improved again. In conclusion, it was suggested that disordered visual search after a homonymous field defect can be treated effectively, even if multiple visual dysfunctions were associated.     

Proximal posterior cerebral artery occlusion simulating middle cerebral artery occlusion

We describe 12 cases of acute stroke in which clinical features of proximal posterior cerebral artery occlusion simulated the clinical syndrome of middle cerebral artery occlusion. The majority of patients developed contralateral hemiparesis, homonymous hemianopia, hemispatial neglect, and sensory loss or sensory inattention. All 8 patients with dominant hemisphere lesions were aphasic. Accurate diagnosis in each case was achieved only after a head CT, showing occipital lobe, thalamic, and inferomesial temporal lobe infarction. "Cortical" signs are probably explained by thalamic involvement. Recognition of this syndrome has implications for management and prognosis.     

"Left unilateral agraphia with right hemiparesis" after occlusion of the left middle cerebral artery]

This paper presented a case of a right-handed male who showed a right hemiplegia without aphasia and apraxia. He lost the ability to write with the left hand. A 56-year-old right-handed man, who had a daughter of left-handedness, was sent to our hospital with a homonymous hemianopsia, facial weakness, spastic hemiparesis and sensory disturbance in the right side. CT scan revealed an infarction in the territory of the left middle cerebral artery. On a month after the onset, he was alert and oriented. His speech was normal and verbal comprehension was intact. Although he neglected the right side of the page, he could read and comprehend it correctly. In contrast with his normal abilities to speak, comprehend, and read, difficulties in writing were prominent. Spontaneous writing with the left hand was extremely poor, and he even had difficulty writing his own name. His dictation was also poor, but his writing improved with copying letters. Agraphia had seen even after USN was recovered. Analysis of this case suggested the presence of the dominance for speech, comprehension, and praxis in the intact right hemisphere, and writing center in the damaged left hemisphere.     

A case of topographic disorientation without right occipital lesion]

A 73-year-old right-handed man developed topographical disorientation, left homonymous hemiianopsia, left visuospatial neglect and mild visual memory disturbance following the right hemispheric infarction. The visual agnosia is very similar to agnosia for streets because he could not identify familiar buildings and streets even though he could remember their way. He did not have prosopagnosia. His brain MRI demonstrated infarction at the right anterior choroidal artery area, including right thalamus, caudate tail and optic radiation. SPECT showed the mild decrease of rCBF at the right temporoparietal cortex. His topographic disorientation faded and finally disappeared about 3 weeks after its onset. Our case is atypical because of sparing the posterior part of the right parahippocampal gyrus where plays an important role in the development of agnosia for streets.     

Callosal disconnection and limb-kinetic apraxia

According to Liepmann, patients with limb-kinetic apraxia (LKA) have a loss of upper limb deftness–dexterity. Prior studies have revealed in right-handed patients that, whereas injury of the left hemisphere induces an ipsilesional LKA, injury to the right hemisphere does not induce an ipsilesional LKA. There are at least two possible means by which the left hemisphere may influence the deftness of the left hand, either by callosal connections or by ipsilesional corticospinal projections. The purpose of this study was to learn whether a patient with a focal lesion of the corpus callosum had a callosal disconnection LKA. This 57-year-old right-handed man had a memory impairment, and upon brain imaging, was found to have a septum pellucidum cyst, which was causing mild ventricular obstruction to the occipital and temporal horns. He underwent an endoscopic-assisted fenestration of the septum pellucidum. Postoperative imaging revealed a lesion of the mesial portion of his corpus callosum and an assessment of praxis revealed that he had both a limb-kinetic and ideomotor apraxia of his left but not his right hand. The observation that this man had a callosal disconnection LKA of his left hand suggests that in some people it is the left hemisphere’s premotor or motor cortex that enables the right hemisphere’s motor system to program deft movements of the left hand.     

Hypertensive basal ganglionic hemorrhage with hemianopsia as the sole symptom--report of 2 cases

The majority of patients with sudden onset of homonymous hemianopia are caused by occlusion of the posterior cerebral artery. Apart from a subcortical hemorrhage in the occipital lobe, no previous cases of the hypertensive intracerebral hemorrhage presenting isolated homonymous hemianopia have been reported. Since the introduction of computed tomography (CT), the authors have experienced two cases of hypertensive basal ganglionic hemorrhage (including a thalamic hemorrhage) showing homonymous hemianopia alone as the neurological manifestation. Both patients (age 40 and 45) are right-handed male with known hypertension. The CT scans demonstrated a hematoma laterally and posteriorly along the thalamus on the left side. The cerebral angiography were unremarkable. The authors discussed the mechanism presenting homonymous hemianopia without association of pyramidal signs. These two cases described above are unique, hypertensive basal ganglionic hemorrhage, presenting a localized damage in the optic peduncle with sparing the pyramidal tract. In addition, they are worthwhile to be paid attention, because of showing homonymous hemianopia as a single, neurological manifestation, as well as being able to be diagnosed only by CT.