A case of mixed transcortical aphasia with intact naming.

Altholgh Lichtheim recognized that Wernicke's 'reflex arch' (primary auditory area, to Wernicke's area, to Broca's area, to primary motor area) was important for repetition, he recognized that other areas of the brain (for example, area of concepts or semantic area) must be important in comprehension and voluntary speech. He suggested that Wernicke's area (phonemic area) not only projected to Broca's area (as Wernicke suggested) but that it also projected to the area of concepts. A lesion of this latter pathway or in the area of concepts would produce a syndrome where repetition was intact but comprehension was impaired (e.g. transcortical sensory aphasia). Lichtheim also thought that the area of concepts projected directly to Broca's area and that voluntary speech was mediated by this pathway. Although Lichtheim's model could explain the mechanism underlying transcortical aphasia, his schema could not explain anomic aphasia. Unlike Lichtheim's schema, Kussmaul's schema suggested that the area of concepts projects back to Wernicke's area before projecting to Broca's area. With this schema, a patient with a hypothetical lesion which interrupted the pathway from the area of concepts to Wernicke's area (but did not interrupt the pathway from Wernicke's area to the area of concepts) should be anomic, with normal comprehension and repetition. In order for this latter schema to be plausible there should also be a lesion which interrupts the pathway from Wernicke's area to the area of concepts but does not interrupt the pathway which goes from the area of concepts to Wernicke's area. A patient with this hypothetical lesion should comprehend poorly; however, in spite of poor comprehension, naming and repetition should be intact. We report a patient who demonstrates poor comprehension with intact naming and repetition. This patient could also read aloud but could not comprehend written language. Not only could this patient name objects but he could demonstrate their use. These observations suggest that comprehension of written language is mediated by a different pathway than the recognition of visually presented objects.     

Aphemia-like syndrome from a right supplementary motor area lesion

Lesions in the left supplementary motor area (SMA) can result in a transcortical motor aphasia with nonfluent spontaneous verbal output and relatively preserved repetition. Reading and writing are proportionally affected. We report a patient with an ischemic lesion in the right SMA. He had impaired articulation and normal repetition plus preserved reading and writing, consistent with an aphemia. This patient supports the dissociation of articulatory fluency and linguistic fluency and suggests that both SMAs affect the initiating of articulatory movements required to produce words whereas the left SMA also affects linguistic aspects of speech.     

Japanese crossed Wernicke's aphasia.

A right-handed Japanese man with no personal or family history of left-handedness developed severe Wernicke's aphasia, a mild constructional disorder, and slight left hemiparesis. MRI revealed infarction in the territory of the righ middle cerebral artery, including areas homologous to Broca's and Wernicke's areas. The cerebral blood flow in these areas remained diminished even after language activation. The most likely explanation is that language production occurred in the left Broca's area, while language comprehension occurred in the right Wernicke's area (a dissociated aphasia).     

Perceptual and acoustic correlates of affective prosody repetition in transcortical aphasias

Abstract

Perceptual judgements and acoustic analyses of affective prosody during sentence repetition were examined in four patients with transcortical aphasias and in two normal controls. Although all aphasic patients had a relative preservation of sentence repetition, perceptual ratings revealed that they repeated using correct affective intonation significantly less frequently than normal control subjects. Acoustic analysis revealed that patients with transcortical aphasias were unable to impart angry and happy intonation during repetition, producing flat intonation contours in most sentences. Restricted modulation of F0 and flat declinations of repeated utterances were found in patients with transcortical aphasias caused by lesions within the left perisylvian language area as well as outside this area. These findings suggest that repetition of affective prosody in transcortical aphasias is usually disrupted regardless of the intrahemispheric location (perisylvian or extraperisylvian) of the lesion, and that an adequate repetition of affective prosody may require bilateral, simultaneous hemispheric processing.     

Preserved oral reading in Wernicke's aphasia

In two patients with Wernicke's aphasia, both oral reading and reading comprehension were relatively preserved despite total destruction of Wernicke's area. The pattern of oral reading suggested an intact ability to derive phonology directly from print; the pattern of reading comprehension implied at least partial ability to interpret syntactic constructions. These features are not readily compatible with current notions of right hemisphere function and may suggest that undamaged left hemisphere structures mediated residual reading in these patients.     

Acute mixed transcortical aphasia with bihemispheric neurological deficits following diffuse cerebral dysfunction

A 78 year old man presented with acute mixed transcortical aphasia with intact naming and bilateral involvement of the motor systems following a left internal carotid artery stenosis. The CT scan showed hypodense areas in the border zones of the left hemisphere together with diffuse areas of ischaemia. Intact repetition the hallmark of transcortical aphasias and the exceptional preserved naming in this patient support the earlier findings that the contralateral hemisphere could mediate some aspects of language function. The patient also had bilateral motor abnormalities which could be explained on the occipito-parietal lesion. It is suggested that widespread hypofunction of the left hemisphere following cerebral ischaemia could give rise to bihemispheric neurological deficits which could be short lived and could possibly be attributed to bilateral cerebral blood flow changes that may occur with the hemispheric lesion.     

Sensory aprosodia with left hemiparesis from subcortical infarction. Right hemisphere analogue of sensory-type aphasia with right hemiparesis?

We report a case of sensory aprosodia with left hemiparesis following an ischemic infarction of the right thalamus and posterior limb of the internal capsule. Bedside evaluation, confirmed by special quantitative tests, demonstrated normal spontaneous affective prosody and gesturing with marked impairment of affective repetition and comprehension of affective prosody and gestures. A left hemiparesis with sensory loss was also present. This combination of deficits appears to represent the right-side analog to the unusual syndrome of Wernicke-type aphasia with right hemiparesis occasionally observed following left subcortical injury, thus providing further support for the hypothesis that the functional-anatomic organization of affective language in the right hemisphere mirrors that of propositional language in the left.     

Repetition of affective prosody in mixed transcortical aphasia

Two patients with mixed transcortical aphasia could repeat propositional speech but not affective prosody. These findings suggest that the intact perisylvian region responsible for propositional speech does not mediate effective prosody. We propose that affective prosody is incorporated into propositional speech by means of an interhemispheric mechanism and that the failure of these patients to repeat affective prosody was caused by a disconnection of the left perisylvian structures from the right hemisphere structures thought to mediate affective prosody.     

Recovery from wernicke's aphasia: A positron emission tomographic study

Changes in the organization of the brain after recovery from aphasia were investigated by measuring increases in regional cerebral blood flow (rCBF) during repetition of pseudowords and during verb generation. Six right-handed patients who had recovered from Wernicke's aphasia caused by an infarction destroying the left posterior perisylvian language zone were compared with 6 healthy, right-handed volunteers. In the control subjects, strong rCBF increases were found in the left hemisphere in the posterior part of the superior and middle temporal gyrus (Wernicke's area), and during the generation task in lateral prefrontal cortex (LPFC) and in inferior frontal gyrus (Broca's area). There were some weak right hemisphere increases in superior temporal gyrus and inferior premotor cortex. In the patients, rCBF increases were preserved in the frontal areas. There was clear right hemisphere activation in superior temporal gyrus and inferior premotor and lateral prefrontal cortices, homotopic to the left hemisphere language zones. Increased left frontal and right perisylvian activity in patients with persisting destruction of Wernicke's area emphasizes redistribution of activity within the framework of a preexisting, parallel processing and bilateral network as the central mechanism in functional reorganization of the language system after stroke.     

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 in left-handers: lesion site, lesion side, and hemispheric asymmetries on CT

Language in left-handed aphasics with left (n = 27) or right (n = 4) hemisphere lesion was examined. Left occipital CT asymmetry was the most common asymmetry and could not be used to predict handedness or which hemisphere, if damaged, would produce aphasia. When left hemisphere lesion sites were matched between eight left-handed and eight right-handed aphasics, there were no significant group differences on language measures. Two nonfluent cases with good comprehension and large right frontal, parietal, and temporal lesions appeared to have "Broca's area" in the right hemisphere, but "Wernicke's area" in the left. Results suggest separate hemispheric loci for handedness, speech output, and/or comprehension dominance in some left-handers.     

Mechanism of repetition in transcortical sensory aphasia.

A typical case of transcortical sensory aphasia (TSA) is presented, in which the Wada test suggests that it is the right hemisphere which enables the patient to repeat orally. It is supposed that one of the mechanisms of preserved repetition in TSA is linked to an exceptional ability for repetition of the right hemisphere, which may help to explain why cases of TSA are so rare.     

Pure word deafness due to left hemisphere damage.

We report the case of a 55 year-old right-handed man who presented with a long lasting pure word deafness following left thalamic bleeding. There was no sign of aphasia. The auditory deficit was specific for language, while recognition of music and environmental sounds was normal. CT, MRI and PET examinations showed that the lesion was anatomically and functionally confined to the left cerebral hemisphere, mainly the white matter of the temporal and parietal lobes. Wernicke's area was largely preserved. It is proposed that pure word deafness was consequent to the isolation of Wernicke's area from incoming auditory information due to the interruption both of the association fibers from the right auditory area traveling across the corpus callosum and of the left auditory radiations.     

原发性进行性失语的临床、影像及语言特征

目的 探讨原发性进行性失语（PPA）的临床、影像及语言特征.方法 PPA患者7例,其中语义性痴呆（SD）6例,进行性非流利性失语（PNFA）1例,收集患者的人口学资料、病史,进行头MRI检查,采用汉语失语成套测验进行语言评估.结果 患者平均发病年龄56岁,均缓慢起病,以语言表达、命名障碍为首发症状.MRI示左侧颞极萎缩为主,病程长的患者左侧额叶和顶叶、右侧颞叶也明显萎缩.语言评估发现所有患者的自发语言、复述、命名、听理解、阅读和书写均不同程度损害.SD患者言语流利,复述、朗读能力下降相对较轻,命名、复杂语句的理解能力损害突出.PNFA言语顿挫吃力,患者列名能力明显下降,但命名相对保存完好.结论 PPA多为老年前期发病,语言障碍为最早、最突出的症状.MRI特征性的改变为额叶和颞极萎缩,左侧为著.其中SD表现为命名性失语和经皮质感觉性失语,PNFA表现为经皮质运动性失语的特征.     

The critical role of Wernicke's area in sentence repetition

The anatomical correlates of persistent deficits in sentence repetition were studied in a group of 32 right-handed patients with fluent aphasia caused by left hemisphere ischemic stroke. Patients whose ability to repeat remained impaired by 6 months after onset almost without exception had damage to Wernicke's area. Furthermore, all patients with damage to Wernicke's area had impaired repetition 6 months after onset. The most consistent lesion correlating with chronic impairment of repetition, therefore, was one destroying parts or all of Wernicke's area. Lesions outside of this area typically resulted in milder impairment of repetition that resolved within a few months. Only 5 patients had no repetition impairment when tested early (1 month after onset). These patients all had lesions anterior to the rolandic fissure, some including Broca's area.     

Language-related brain function during word repetition in post-stroke aphasics

We compared fMRI findings (using SPM99) obtained with repetition task in normal subjects with those of two patients with Broca's and Wernicke's aphasia who received speech therapy and showed complete recovery. Both aphasic patients with left hemisphere damage who showed complete recovery exhibited activation of only the compensatory area in the right hemisphere during the repetition task. Recovery from Broca's aphasia involves reorganization and neuromodulation between the external temporopolar area and the anterior superior temporal area of the superior temporal gyrus, putamen and the inferior frontal gyrus, while that from Wernicke's aphasia involves reorganization and neuromodulation between the superior temporal gyrus of the temporal region, the posterior supramarginal gyrus and inferior parietal lobule of the parietal region.     

Perisylvian language networks of the human brain

Early anatomically based models of language consisted of an arcuate tract connecting Broca's speech and Wernicke's comprehension centers; a lesion of the tract resulted in conduction aphasia. However, the heterogeneous clinical presentations of conduction aphasia suggest a greater complexity of perisylvian anatomical connections than allowed for in the classical anatomical model. This article re-explores perisylvian language connectivity using in vivo diffusion tensor magnetic resonance imaging tractography. Diffusion tensor magnetic resonance imaging data from 11 right-handed healthy male subjects were averaged, and the arcuate fasciculus of the left hemisphere reconstructed from this data using an interactive dissection technique. Beyond the classical arcuate pathway connecting Broca's and Wernicke's areas directly, we show a previously undescribed, indirect pathway passing through inferior parietal cortex. The indirect pathway runs parallel and lateral to the classical arcuate fasciculus and is composed of an anterior segment connecting Broca's territory with the inferior parietal lobe and a posterior segment connecting the inferior parietal lobe to Wernicke's territory. This model of two parallel pathways helps explain the diverse clinical presentations of conduction aphasia. The anatomical findings are also relevant to the evolution of language, provide a framework for Lichtheim's symptom-based neurological model of aphasia, and constrain, anatomically, contemporary connectionist accounts of language.     

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.     

Dissociated crossed aphasia: a challenging language representation disorder

A monolingual strongly right-handed woman developed a left hemiparesis and severe motor aphasia following a right middle cerebral artery infraction, whereas comprehension was entirely intact. She had a history of a transient cerebrovascular event characterized by right hemiparesis and fluent sensory aphasia. This case suggests a transhemispheric pattern of language organization in which the Broca area resides in the right hemisphere, whereas the Wernicke area is in the left.     

Transcortical sensory aphasia: Dissociation between naming and comprehension

Abstract

Although anomia in transcortical sensory aphasia (TSA) is usually described as a semantically based deficit (naming and recognition are equally affected), dissociations in naming performance have occasionally been reported. We report a two-part study: in Study 1 the pattern of preserved and impaired language abilities was examined in five patients with TSA and intact object naming; in Study 2 the neural mechanism(s) underlying preserved visual confrontation naming in TSA was examined. Demographic factors, severity of language deficits, lesion volume and location, and cerebral asymmetries of patients with TSA and intact naming (TSA-intact) (n = 6) were compared with those of patients with TSA and impaired naming (TSA-impaired) (n = 6), anomic aphasia (Anomia) (n = 6), and left hemisphere damage without aphasia (Control). The results of Study 1 revealed that all five patients had a relative preservation of oral production (spontaneous speech, repetition, naming and reading aloud), but impaired auditory and written (sentence-level) comprehension. Object/picture naming was significantly better than auditory comprehension of the same targets, and naming was also preserved in tactile and auditory (verbal definitions and non-verbal sounds) modalites, but written naming was impaired. In four patients oral reading showed a pattern of phonological dyslexia. The results of Study 2 failed to demonstrate significant differences between the groups with preserved naming (TSA-intact and control) and those with impaired naming (TSA-impaired and anomia) in non-language variables that might explain the selective preservation or impairment of naming. These results are discussed in terms of the functional and anatomical independence of the neural systems responsible for object naming and comprehension.