Ataxic hemiparesis associated with transcortical motor aphasia

Two patients, ages 51 and 76 years, suddenly developed transcortical motor aphasia combined with pyramidal signs and ataxia of the right extremities that affected the leg more severely than the arm. Computed tomography revealed nonenhancing lucencies in the distribution territory of the left anterior cerebral artery involving the genu of the corpus callosum, white matter ventral to the left frontal horn, medial primary motor area, supplementary motor area, and superior part of the premotor area. It is postulated that aphasia, ataxia, and weakness resulted from involvement of the supplementary motor area and deep white matter, premotor, and primary motor areas, respectively. Anterior cerebral artery infarctions of the dominant hemisphere may result in transcortical motor aphasia associated with contralateral ataxic hemiparesis.     

Transcortical motor aphasia due to a right hemisphere lesion in a right-handed man

Abstract

A 67-year-old, right-handed male became aphasic following a right hemispheric infarction involving the frontal and parietal regions. The patient was evaluated by means of neurological, behavioural, and neuroradiological examinations. Behavioural investigations included Ianguage and nonverbal visuospatial and constructive evaluations. Language evaluation demonstrated transcortical motor aphasia and nonverbal tests showed left-sided visual neglect, left hemiakinesia, and constructional apraxia. Besides the information concerning crossed aphasia in a right-handed person, this case also supports the hypothesis that right-sided language representation does not affect right hemisphere dominance for visuospatial abilities.     

Clinical-anatomical correlation in a selective phonemic speech production impairment

Although phonemic paraphasias are common in aphasic disorders, including Broca's aphasia, conduction aphasia and transcortical motor aphasia, selective phonemic speech production impairment, or phonemic disintegration, is unusual. A patient with a selective phonemic speech production disorder underwent clinical, neuropsychological and structural neuroradiological assessment over a period of 6 years. The disorder was characterised by phonemic paraphasias (phonemic disintegration) with preserved comprehension and naming. Imaging showed a focal lesion in the white matter of the left precentral gyrus and, to a lesser extent, the posterior part of the left middle frontal gyrus, with overlying cortical atrophy. Biopsy of the lesion, after several years of observation, showed a calcified haemangioma. Clinical-anatomical correlation in this case suggests the importance of primary motor cortex of the inferior precentral (pre-Rolandic) gyrus and subjacent white matter in phoneme production, with sparing of the posterior inferior frontal gyrus (Broca's area).     

Homolateral ataxia and crural paresis: a crossed cerebral-cerebellar diaschisis.

A patient developed weakness of the right leg and homolateral ataxia of the arm, caused by a subcortical infarct in the area supplied by the anterior cerebral artery in the left paracentral region, demonstrated by CT and MRI. Cerebral blood flow studied by technetium-labelled hexamethyl-propylene-amine oxime using single photon emission computed tomography showed decreased blood flow in the left lateral frontal cortex and in the right cerebellar hemisphere ("crossed cerebral-cerebellar diaschisis"). The homolateral ataxia of the arm may be caused by decreased function of the right cerebellar hemisphere, because of a lesion of the corticopontine-cerebellar tracts, whereas crural hemiparesis is caused by a lesion of the upper part of the corona radiata.     

Transcortical sensory aphasia due to extensive infarction of left cerebral hemisphere]

We report a case of transcortical sensory aphasia occurred after extensive infarction of left cerebral hemisphere. A 68-year-old, right-handed man with atrial fibrillation suddenly developed cerebral embolism of left middle cerebral artery. He was treated conservatively, and the right hemiplegia, aphasia, apraxia in a slight degree and right hemispatial neglect in a slight degree consequently existed. MRI showed a large cortical and subcortical infarct lesion including the left Broca's area, central region, perisylvian area with Wernicke's area and temporal lobe. In contrast, neuropsychological evaluation using the Western Aphasia Battery (WAB) demonstrated transcortical sensory aphasia, e.g., fluency 8, auditory comprehension 1. repetition 10 and object naming 2.4. In addition to preserved repetition, both linguistic prosody and affective prosody were well preserved. Most cases with transcortical sensory aphasia are known to occur with the lesion including temporo-parieto-occipital junction of dominant hemisphere. Our patient and a few other reported cases of transcortical sensory aphasia had a lesion in perisylvian area including Wernicke's area. Therefore, it is possible that their minor hemisphere worked selectively for repetition. Furthermore, we suggest that this patient presented dissociative aphasia that all the process of repetition and the function of linguistic and emotional prosody were represented in the right hemisphere and the other functions including comprehension of word meanings were existed in the left hemisphere. We believe that our case of transcortical sensory aphasia with dissociative aphasia gives a suggestion about the mechanism and localization of repetition and prosody in the whole system of language.     

Hyperlexia in an adult patient with lesions in the left medial frontal lobe]

A 69-year-old right-handed woman developed a transcortical motor aphasia with hyperlexia following resection of a glioma in the left medial frontal lobe. Neurological examination revealed grasp reflex in the right hand and underutilization of the right upper extremity. An MRI demonstrated lesions in the left medial frontal lobe including the supplementary motor area and the anterior part of the cingulate gyrus, which extended to the anterior part of the body of corpus callosum. Neuropsychologically she was alert and cooperative. She demonstrated transcortical motor aphasia. Her verbal output began with echolalia. Furthermore hyperlexia was observed in daily activities and during examinations. During conversation she suddenly read words written on objects around her which were totally irrelevant to the talk. When she was walking in the ward with an examiner she read words written on a trash bag that passed by and signboards which indicated a name of a room. Her conversation while walking was intermingled with reading words, which was irrelevant to the conversation. She also read time on analog clocks, which were hung on a wall in a watch store. In a naming task, she read words written on objects first and named them upon repeated question about their names. When an examiner opened a newspaper in front of her without any instructions she began reading until the examiner prohibited it. Then she began reading again when an examiner turned the page, although she remembered that she should not read it aloud. She showed mild ideomotor apraxia of a left hand. Utilization behavior, imitation behavior, hypergraphia, or compulsive use of objects was not observed throughout the course. Hyperlexic tendency is a prominent feature of this patient's language output. Hyperlexia was often reported in children with pervasive developmental disorders including autism. There are only a few reports about hyperlexia in adults and some of them were related to diffuse brain dysfunction. Hyperlexia of our patient was associated with echolalia but not with the other "echo" phenomena, which may be because the lesion was unilateral on the left side. Dysfunction of the left supplementary motor area could lead to disinhibition of regulatory mechanism of verbal output in response to auditory and visual stimuli.     

Unilateral left paramedian infarction of thalamus and midbrain: a clinico-pathological study.

In a patient with a unilateral embolic infarct in the left posterior thalamo-subthalamic paramedian artery territory, neuropathological studies showed involvement of the intralaminar, dorsomedial, and internal part of the ventral posterior nuclei of the thalamus, of the rostral part of the mesencephalic reticular formation, and of the posterior commissure. The patient showed upgaze palsy for voluntary saccades, smooth pursuit and vestibulo-ocular movements, sustained downgaze, right-sided motor hemineglect and facio-brachial hypaesthesia, motor transcortical aphasia and anterograde amnesia. This case confirms that unilateral destruction of the posterior commissure, rostral interstitial nucleus of the MLF and interstitial nucleus of Cajal produces a non-dissociated upgaze palsy. Involvement of the nucleus of Cajal probably produced the sustained downward deviation of the eye, by causing predominance of downward vestibulo-ocular inputs. This case also shows that thalamic aphasia and anterograde amnesia may be related to a paramedian lesion of the thalamus, with special reference to involvement of the dorsomedial nucleus, in the absence of lesion of the pulvinar and mamillo-thalamic tract and of conspicuous involvement of the ventral lateral nucleus. Selective hemineglect for motor tasks may occur in infarction of the dominant thalamus, involving the intralaminar nuclei.     

Clinical aspects of premotor function

Observations on patients with frontal lesions including the premotor cortex but not the primary motor cortex as shown by CT scans have shown a slight or moderate weakness of the contralateral shoulder or hip muscles which remained as a permanent deficit. The second deficit was an incoordination between movements requiring temporal adjustment between proximal muscle activities of both sides (limb-kinetic apraxia). From the clinical examination there was no evidence for deficient sensory guidance of movement. Visual control of hand and finger movements was normal as long as the arm could be supported during the tasks. In contrast, gross abnormalities of visually guided reaching (visuomotor ataxia) or somesthetic movement control (tactile apraxia) are seen after parieto-occipital lesions. On the basis of clinical observations it is therefore more likely that sensory-motor integration and transformation already takes place at the posterior lobes, where corresponding disturbances are pronounced but are absent after frontal lobe lesions.     

Parietal kinetic ataxia without proprioceptive deficit.

A patient with acute onset "classic" cerebellar ataxia of the right arm without clinically detectable deep sensory loss is reported, in relation to an acute posterior parietal infarct. Wild back and forth swaying of the arm, giving away, or worsening by suppression of vision were not seen. The lesion involved area 5, parts of area 7, the angular gyrus, the middle and posterior parieto-occipital gyri, and posterior parts of the superior and middle temporal gyri. The paracentral lobule, commonly thought to be responsible for parietal ataxia, was spared. Thus posterior parietal lesions can mimick cerebellar ataxia, possibly by severing specific projections to the ventrolateral thalamic nuclei. On the basis of previous studies in primates, the superior parietal gyrus may play a major part in the ataxia presented by this patient.     

交叉性失语

右利手者右大脑半球病变所致的失语称为交叉性失语。交叉性失语少见。我科八年来共诊断八例（占我组失语症患者２５０例的２．８％），均为男性右利手者，头颅ＣＴ扫描均证实右大脑半球单发病灶，其中脑梗塞７例，脑出血１例。均于发病三个月内作失语检查。其中交叉性Ｂｒｏｃａ失语一例，交叉性传导性失语一例，交叉性Ｗｅｒｎｉｃｋｅ失语一例，交叉性经皮质运动性失语一例，交叉性经皮质感觉性失语三例，交叉性丘脑性失语一例。此８例各型交叉性失语之临床表现与右利手左大脑半球病变产生的各相应类型失语无根本不同。产生交叉性失语是患者的大脑半球语言中枢的逆转所致（不在左侧而在右侧大脑半球的对称部位），它与遗传有关。失语症类型与患者年龄和性别的关系有待进一步研究。     

Aphasia with a left frontal interhemispheric hematoma

We studied a patient with transcortical motor aphasia resulting from a traumatic interhemispheric left frontal hematoma. The aphasia was caused by compression exerted by the hematoma on the left supplementary motor area, which is known to have a function in speech. This cause of a transcortical motor aphasia has not been described earlier.     

Crossed aphasia: a PET follow up study of two cases.

Two cases of aphasia after right hemispheric stroke in right handed patients are described. The first patient had a severe mixed transcortical aphasia, apraxia and neglect after a lesion involving the right lenticular nucleus and periventricular white matter; aphasia was still present after three months. The second patient had a mild, transient fluent aphasia after a small right hemispheric periventricular lesion. Studies with [18F]FDG and positron emission tomography (PET) showed functional depression extending to the structurally unaffected left hemisphere in both patients in the acute stage. After three months, in the patient with persistent aphasia, metabolism was still reduced in the right hemisphere, with some recovery of hypometabolism on the left, while metabolic values had returned to normal in the patient with full language recovery. A close parallelism between glucose metabolism and clinical course in crossed aphasia is shown, as well as the presence of a functional involvement of the structurally unaffected left hemisphere in the acute stage.     

Optic ataxia: clinical-radiological correlations with the EMIscan.

After coronary by-pass surgery, a 47 year old, right-handed man developed Gerstmann's syndrome, a visual-spatial perceptual deficit, and a gross impairment of movememt under visual guidance ("optic ataxia"). Visual fields and extraocular movements were intact; he had a left hemiparesis. The EMIscan showed three lesions: a left parietal-occipital lesion; a posterior callosal lesion, and a right frontal lesion. It is hypothesized that optic ataxia in both visual fields requires bilateral lesions which, in the present case, were strategically placed so as to effectively disconnect motor cortex from visual input.     

Anatomic basis of transcortical motor aphasia

Analysis of language profiles and CT anatomy in transcortical motor aphasia (TCMA) suggests that the essential lesion is disruption of connections at sites between the supplementary motor area and the frontal perisylvian speech zone. If the lesion is extended, there may also be poor articulation (lesion deep to motor strip for face), impaired auditory comprehension (lesion in anterior head of caudate, anterior limb internal capsule, anterior putamen, and anterior portion of external capsule, claustrum, extreme capsule, and insula), or stuttering (lesion in pars opercularis and lower third of premotor region). This concept unifies disparate anatomic and psychophysiologic observations about three syndromes: classical TCMA, aphasia after left medial frontal infarction, and TCMA during recovery from Broca's aphasia.     

Bilateral crossed visuomotor ataxia--a case report

We observed a 55 y.o. right-handed woman, who was suspected of splenium tumor (glioblastoma?) by CT scan and presented bilateral crossed visuomotor ataxia proposed by Rondot et al. Left unilateral apraxia and agraphia were not found, but left unilateral hemialexia was evident by tachistoscopic examinations. In regard to bilateral crossed visuomotor ataxia, we suggested that at least there might be three possible hypotheses about its realization mechanism. (1) Callosal lesion might disconnect heterotopical fibers which runs from one occipital lobe to another frontal lobe. (2) Integrated information of visual and proprioceptive inputs in the parieto-occipital regions could not be transferred mutually to other side of the brain. (3) Functional dissociation between visual perception of "moving" and that of "position" might be the cause of this symptom. Former could be transferred via subcallosal pathway, but latter not transferred due to the callosal lesion. Hypothesis (1) could not explain, at least, "positive aspects" of this symptom, and which hypothesis is most probable might not be decided at present, because anatomical evidence and patho-plastic mechanism are not yet clarified.     

Left unilateral apraxia

A 32-year-old right-handed man suffered a traffic accident with head injury, resulting in loss of spontaneity, right hemiparesis, severe aphasia, and unilateral apraxia, which was noticed on his non-paralyzed left hand. An MRI scan conducted 11 months after onset revealed a large lesion in the left frontal lobe, a small lesion in the right frontal lobe and a striking thinning of the trunk of the corpus callosum with remarkable dilatation of the lateral ventricles. An IMP-SPECT scan, performed 1 year after onset, showed a diffuse hypoperfusion extending to the left temporo-parietal area further than the MRI verified abnormal density areas. The patient's praxic abilities were precisely evaluated 1 year after onset. The performance on the object use task was characterized by content errors. For example, when using a match with his left hand, he always treated with it like a cigarette. The right hand performance of this task was clumsy due to his right hemiparesis but successful. The performance on his left hand did not improved even when the patient was given visual examples. The term "ideational apraxia" proposed by Liepmann, which was characterized by content errors, implies a conceptual deficit. Morlaas defined ideational apraxia as a agnosia of usage. Ideational apraxia has been so far investigated mainly on patients with these difficulties in both hands. On the other hand, left unilateral apraxia has been explained by callosal disconnection. Liepmann and Maas thought that a lesion of the corpus callosum would prevent the space-time engrams in the left hemisphere from reaching the right sensorimotor area necessary to carry out the skilled act with the left hand, thereby inducing apraxia.(ABSTRACT TRUNCATED AT 250 WORDS)     

Atypical conduction aphasia. A disconnection syndrome

Conduction aphasia was originally proposed to result from separation of the posterior language comprehension area and the anterior motor speech area of the left hemisphere. The arcuate fasciculus has been the most frequently suggested site of such a disconnection, but the syndrome has been reported in cases in which the abnormality involved the dominant Wernicke's area. This challenges the arcuate fasciculus theory, and it has been suggested that a cortical lesion, not a disconnection, is the crucial factor. Three new cases in which the lesion does not lie in the arcuate fasciculus are reported, two in left-handed patients with left temporoparietal lesions and one in a right-handed patient with a right temporoparietal infarct, a "crossed" aphasia. While atypical, these cases offer evidence that disconnection of the circuit linking language comprehension to motor speech output, not damage to a specific cortical region, underlies the syndrome of conduction aphasia.     

Impairments of procedures for implementing complex language are due to disruption of frontal attention processes.

Production of complex discourse-lengthy, open-ended utterances and narratives-requires intact basic language operations, but it also requires a series of learned procedures for construction of complex, goal-directed communications. The progression of clinical disorders from transcortical motor aphasia to dynamic aphasia to discourse impairments represents a progression of procedural deficits from basic morpho-syntax to complex grammatical structures to narrative and a progression of lesions from posterior frontal to polar and/or lateral frontal to medial frontal. Two cases of impaired utilization of language exemplify the range of impairments from clearly aphasic agrammatic, nonfluency to less and less "aphasic" and more and more executive impairments from transcortical motor aphasia to dynamic aphasia to narrative discourse disorder. The clinical phenomenology of these disorders gradually comes to be more accurately defined in the terminology of executive deficits than that of aphasia. The executive deficits are, in turn, based on impairments in various components of attention. Specific impairments in energizing attention and setting response criteria associated, respectively, with lesions in superior medial and left ventrolateral frontal regions may cause defective recruitment of the procedures of complex language assembly.     

Unilateral neglect and constructional apraxia in a right-handed artist with a left posterior lesion

A rapidly growing tumor in the left posterior parietal lobe of a right-handed, 72 year old artist resulted in bilateral neglect and constructional apraxia that were greater on the right side of his painting than on the left. These changes indicate that a left posterior parietal lesion alters visuospatial perception and constructional ability on both sides of a painting with the contralateral hemispace more impaired than the ipsilateral hemispace. Primitivization of emotional expressions on human faces also occurred.     

Transcortical sensory aphasia following a left frontal lobe infarction probably due to anomalously represented language areas

A 57-year-old right-handed man presented with speech disturbance 1 day prior to his admission. The standardized aphasia test batteries showed transcortical sensory aphasia. MRI revealed a left frontal and insular infarct. Positron emission tomography scans also revealed a glucose hypometabolism in the same region as the infarcted area on MRI. Repeated aphasia testing showed that his aphasia only partially improved.