1/311. 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.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
2/311. Conduction aphasia elicited by stimulation of the left posterior superior temporal gyrus.OBJECTIVE: Disruption of fascicular tracts that connect Wernicke's to Broca's areas is the classic mechanism of conduction aphasia. Later work has emphasised cortical mechanisms. methods: To determine the distribution of language on dominant cortex, electrical cortical stimulation was performed using implanted subdural electrodes during brain mapping before epilepsy surgery. RESULTS: A transient, isolated deficit in repetition was elicited with stimulation of the posterior portion of the dominant superior temporal gyrus. CONCLUSION: This finding suggests that cortical dysfunction, not just white matter disruption, can induce conduction aphasia.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
3/311. Downbeat nystagmus caused by thiamine deficiency: an unusual presentation of CNS localization of large cell anaplastic CD 30-positive non-Hodgkin's lymphoma.A 24-year-old woman with a large cell anaplastic CD 30-positive T-cell non-Hodgkin's lymphoma (NHL) developed downbeat nystagmus, anisocoria, and oscillopsia. Prior to overt cerebral invasion by NHL, she had a thiamine deficiency with very low thiamine concentrations in the CSF, probably caused by protracted vomiting and increased vitamin B1 consumption by intrathecal tumor cells. We believe that her neurologic symptoms were caused -- at least partly -- by thiamine deficiency, as she reacted well to thiamine supplementation at the beginning of treatment.- - - - - - - - - - ranking = 83.762827654765keywords = cerebral (Clic here for more details about this article) |
4/311. stroke-associated stuttering.OBJECTIVE: To present patients with stuttering speech in association with stroke. DESIGN: Case series with follow-up for 5 years, or until the stuttering resolved. SETTING: University and community hospital neurology wards, and ambulatory neurology clinics. patients: Four patients who developed stuttering speech in association with an acute ischemic stroke. A 68-year-old man acutely developed stuttering with a large left middle cerebral artery distribution stroke. A 59-year-old man who had stuttered as a child began to stutter 2 months after a left temporal lobe infarction, as nonfluent aphasia was improving. Another childhood stutterer, a 59-year-old originally left-handed man developed severe but transient stuttering with a right parietal infarction. A 55-year-old man with a left occipital infarction had a right hemianopia and an acquired stutter, for which he was anosognosic. CONCLUSION: The clinical presentation of stroke-associated stuttering is variable, as are the locations of the implicated infarctions.- - - - - - - - - - ranking = 83.762827654765keywords = cerebral (Clic here for more details about this article) |
5/311. functional neuroimaging of speech perception in six normal and two aphasic subjects.This positron emission tomography study used a correlational design to investigate neural activity during speech perception in six normal subjects and two aphasic patients. The normal subjects listened either to speech or to signal-correlated noise equivalents; the latter were nonspeech stimuli, similar to speech in complexity but not perceived as speechlike. Regions common to the auditory processing of both types of stimuli were dissociated from those specific to spoken words. Increasing rates of presentation of both speech and nonspeech correlated with cerebral activity in bilateral transverse gyri and adjacent superior temporal cortex. Correlations specific to speech stimuli were located more anteriorly in both superior temporal sulci. The only asymmetry in normal subjects was a left lateralized response to speech in the posterior superior temporal sulcus, corresponding closely to structural asymmetry on the subjects' magnetic resonance images. Two patients, who had left temporal infarction but performed well on single word comprehension tasks, were also scanned while listening to speech. These cases showed right superior temporal activity correlating with increasing rates of hearing speech, but no significant left temporal activation. These findings together suggest that the dorsolateral temporal cortex of both hemispheres can be involved in prelexical processing of speech.- - - - - - - - - - ranking = 83.762827654765keywords = cerebral (Clic here for more details about this article) |
6/311. Global aphasia: an innovative assessment approach.OBJECTIVE: To provide an alternative language comprehension assessment strategy for patients unable to be tested with traditional verbally/behaviorally based methods. DESIGN: Event-related brain potentials were recorded from three midline scalp locations to visually and aurally computer-presented sentences, 50% of which were semantically appropriate and 50% semantically incongruous. SETTING: A rehabilitation hospital. PATIENT: A 21-year-old man with a traumatic brain injury. RESULTS: The patient exhibited brain response patterns to aurally presented congruous and incongruous sentences indicative of intact semantic processing capabilities. These findings resulted in reinstatement of individualized rehabilitative intervention, with a successful outcome. CONCLUSIONS: This innovative technique provides new opportunities for assessing intellectual function in noncommunicative patients who were patients previously unable to be tested.- - - - - - - - - - ranking = 3keywords = brain (Clic here for more details about this article) |
7/311. Making sense out of jargon: a neurolinguistic and computational account of jargon aphasia.OBJECTIVE: To identify the cognitive and neuroanatomic bases of neologistic jargon aphasia with spared comprehension and production of written words. methods: Detailed analysis of performance across experiments of naming, reading, writing, repetition, and word/picture matching by a 68-year-old woman (J.B.N.) served to identify which cognitive mechanisms underlying naming and word comprehension were impaired. J.B.N.'s impairments were then simulated by selectively "lesioning" a computer model of word production that has semantic, word form, and subword phonologic levels of representation (described by Dell in 1986). RESULTS: In comprehension experiments, J.B.N. made far more errors with spoken word input than with written word or picture input (chi-square = 40-59; df = 1; p < 0.0001) despite intact auditory discrimination. In naming experiments (with picture, definition, or tactile input), J.B.N. made far more errors in spoken output relative to written output (chi-square = 14-56; df = 1; p < 0.0001). These selective impairments of spoken word processing were simulated by reducing connection strength between word-level and subword-level phonologic units but maintaining full connection strength between word-level and semantic units in Dell's model. The simulation yielded a distribution of error types that was nearly identical to that of J.B.N., and her CT and MRI scans showed a small subarachnoid hemorrhage in the left sylvian fissure without infarct. Cerebral angiogram showed focal vasospasm in sylvian branches of the left middle cerebral artery. CONCLUSION: Focal left perisylvian dysfunction can result in a highly selective "disconnection" between word-level and subword-level phonologic representations manifest as neologistic jargon aphasia with intact understanding and production of written words.- - - - - - - - - - ranking = 83.762827654765keywords = cerebral (Clic here for more details about this article) |
8/311. subclavian artery stenosis caused by non-specific arteritis (Takayasu disease): treatment with Palmaz stent.A 32-year old woman was admitted to the hospital with a sudden onset of right-sided hemiplegia and aphasia. Immediate angiographic examination revealed a severe form of type I takayasu arteritis with occlusion of all supra-aortic vessels, with the exception of the left subclavian artery which was, however, almost completely occluded 1 cm proximal to the origin of the left vertebral artery. Since the latter provided the entire blood supply to the brain tissues, an immediate attempt was undertaken to dilate the left subclavian artery; when this was unrewarding, stenting of the lesion was successfully accomplished with excellent primary and 6-month follow-up results.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
9/311. The relation of phoneme discrimination, lexical access, and short-term memory: A case study and interactive activation account.A brain-damaged patient (AP) is reported who had a strong tendency to identify nonwords as words on auditory lexical decision and to lexicalize nonwords in repetition, yet who showed a normal ability to perceive individual phonemes. It was initially hypothesized that these findings could be accounted for in terms of disrupted lexical phonological representations. This hypothesis was rejected on the basis of an interactive activation model of word recognition which revealed that modifications at the lexical level did not mimic the patient's pattern of results. Instead, it was found that increasing the rate of decay of activation at the phoneme level produced output that was consistent with the phoneme discrimination, lexical decision, and repetition results. This hypothesis of increased phoneme level decay led to the prediction that speech discrimination would decline with increased interstimulus interval and that short-term memory performance would be impaired. Both predictions were confirmed. The results of this study provide support for an interactive activation model of word recognition with feedback from the lexical to the phonemic level and for a close connection between the processes involved in word recognition and short-term memory.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
10/311. Management of penetrating injury to the petrous internal carotid artery: case report.We report the management of a penetrating foreign body injury to the neck with a length of fencing wire traversing the internal carotid artery within the petrous temporal bone and entering the middle cranial fossa. Discussion points include methods of haemorrhage control, as well as ligation versus repair or bypass as the definitive treatment.- - - - - - - - - - ranking = 20.807607147639keywords = haemorrhage (Clic here for more details about this article) |
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