Cases reported "Thalamic Diseases"

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1/40. A case of thalamic syndrome: somatosensory influences on visual orientation.

    The ability to set a straight line to the perceived gravitational vertical (subjective visual vertical, SVV) was investigated in a 21 year old woman with long standing left hemihypaesthesia due to a posterior thalamic infarct. The putative structures involved were the somatosensory and vestibular thalamus (VPL, VPM) and associative (pulvinar) thalamus. The SVV was normal when seated upright. When lying on her right side, line settings deviated about 17 degrees to the right, which is the normal A-effect. When lying on the hypaesthetic side the mean SVV remained close to true vertical-that is, the A-effect was absent, and there was a large increase in variability of the SVV settings. The findings support the view that the body tilt-induced bias of the SVV (A-effect) is largely mediated by somatosensory afferents. The finding that the A-effect was absent only when lying on the hypaesthetic side suggests that, during body tilt, the somatosensory system participates in visuogravitational orientation.
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keywords = visual
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2/40. Attentional grasp in far extrapersonal space after thalamic infarction.

    Studies of animals and humans with focal brain damage suggest that attention in near and far extrapersonal space may be mediated by anatomically separate systems. Thalamic lesions have been associated with spatial neglect, but whether asymmetric attention specific to near or far space occur after thalamic damage has not been explored. It is also unclear if thalamic injury can induce contralesional defective response inhibition.We tested a woman with a left thalamic infarction who reported that, when driving, she had a tendency to veer towards people or objects on the right side of the road. Our patient and four controls performed a line bisection task with a laser pointer in near and far extrapersonal space. The experimenter marked each bisection either from the right of the presented line (right-distractor, RD) or the left (left-distractor, LD). RD and LD trials were pseudo-randomized.Our patient performed similarly to controls (mean -0.7 mm, controls -0.6 mm) on the line bisection task in near space. In far space she erred significantly rightward compared to her performance in near space (p<0.001). Controls performed similarly in near and far space. The experimenter position did not affect our patient's performance on near line bisections, nor did controls demonstrate a distractor effect for the near condition. In the far condition, however, our patient showed a significant distractor effect (LD -3.3 mm, RD 35.3 mm, p<0.001). Controls also demonstrated a distractor effect in the far condition (LD -6.4 mm, RD 0.7 mm, p<0.01), though of much smaller magnitude. Our results suggest that frontal-thalamic systems regulating visual attention may be disrupted by thalamic infarction. Such damage may produce an attentional grasp specific to far extrapersonal space.
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keywords = visual
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3/40. Thalamic degeneration with negative prion protein immunostaining.

    A 34-year-old woman presented with an insidious 5-year history of cognitive decline and apathy, associated with hypersomnia, ataxia, and dysarthria. magnetic resonance imaging of the brain showed cortical and subcortical atrophy. At autopsy we found abnormalities in the subcortical grey matter and brainstem, with a relatively preserved cerebral cortex. The thalami showed symmetrical neuronal loss and astrocytosis, particularly severe in the dorsal medial nucleus, followed by the lateral nuclei group. Prion protein immunostaining was negative, and there was no spongiform change. No mutations were detected in the prion protein gene.
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ranking = 7.1525252305855
keywords = cortex
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4/40. Apraxic agraphia due to thalamic infarction.

    The authors report a patient of pure apraxic agraphia with normal praxis due to left thalamic infarction. 15O-gas-PET showed reduced oxygen metabolism in the left thalamus and the left dorsolateral premotor area, while MRI and 11C-fulumazenil-PET showed no remarkable lesions in the frontal cortex. The patient's word imaging remained normal. The authors hypothesize that thalamic destruction causes pure apraxic agraphia by exerting a remote effect on left dorsolateral premotor area and blocking somewhere between graphemic area and motor programming.
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keywords = cortex
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5/40. Acquired aphasia in children after surgical resection of left-thalamic tumors.

    Five children (three males, two females; four right-, one left-handed; age range 6 to 14 years) who developed aphasia after gross-total excision of left predominantly thalamic tumors are reported. Three patients had Broca aphasia, one had mixed transcortical aphasia, and one patient had conduction aphasia. In the months after surgery, three children improved while receiving radiation and/or chemotherapy, although none recovered completely. Two patients with malignant tumors developed worsening aphasia when the tumor recurred, and later died. Two of three patients tested had visuospatial difficulties in addition to language deficits. attention and executive functioning were affected in three of three patients tested. memory, verbal and/or visual functioning, were affected in four of four patients tested. Both patients who were tested showed transient right hemineglect. Two of two patients tested were probably apraxic. The wide range of deficits in these children highlights the importance of the thalamus and other subcortical structures in developing cognition.
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keywords = visual
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6/40. Reversal of thalamic hand syndrome by long-term motor cortex stimulation.

    The authors describe a case of complete recovery from the so-called "thalamic hand" syndrome following chronic motor cortex stimulation in a 64-year-old man suffering from poststroke thalamic central pain. As of the 2-year follow-up examination, the patient's dystonia and pain are still controlled by electrical stimulation. It is speculated that a common mechanism in which the thalamocortical circuit loops are rendered out of balance may sustain hand dystonia and central pain in this case of thalamic syndrome. To the authors' knowledge this is the first reported case of its kind.
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ranking = 35.762626152927
keywords = cortex
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7/40. Right medial thalamic lesion causes isolated retrograde amnesia.

    Pervasive retrograde amnesia without anterograde memory impairment has rarely been described as a consequence of circumscribed brain damage. We report this phenomenon in a 33 yr-old, right-handed man (JG) in association with the extension in the right thalamus of a previously small, bilateral thalamic lesion. JG presented with a dense amnesia for autobiographical material more than a few years old, with some sparing of recent memories. Furthermore, he was completely unable to recognise famous people or world events. Many other aspects of semantic knowledge were intact and there was no evidence of general intellectual impairment, executive dysfunction or loss of visual imagery. magnetic resonance imaging revealed an acute lesion in the right thalamus and two small, symmetrical, bilateral non-acute thalamic lesions. Follow-up neuropsychological assessment indicated a stable pattern of impaired retrograde and spared anterograde memory over 18 months and psychiatric assessments yielded no evidence of confabulation, malingering or other symptoms to suggest psychogenic amnesia. JG's profile indicates that the division of declarative memory into just two categories - episodic and semantic - is inadequate. Rather, his case adds to the growing body evidence to suggest that world knowledge pertaining to people and events is stored or accessed similarly to autobiographical information and differently from other types of more general factual knowledge. We hypothesize that the right mediodorsal thalamic nucleus and immediately surrounding regions comprise the central processing mechanism referred to by McClelland (Revue Neurologique, 150 (1994) 570) and Markowitsch (brain research review, 21 (1995) 117) as responsible for inducing and co-ordinating the recall of these sorts of cortically stored memory engrams.
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ranking = 0.2
keywords = visual
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8/40. Development of selective verbal memory impairment secondary to a left thalamic infarct: a longitudinal case study.

    A 68 year old man suffered an acute dysphasic episode with persistent memory disturbance while taking part as a control in a longitudinal magnetic resonance imaging (MRI) study. A small new left thalamic infarct involving the mamillo-thalamic tract could be demonstrated on volumetric MRI, coinciding with the development of a selective verbal memory impairment. This suggests that lateralisation of cognitive processing of visual and verbal material exists at the thalamic as well as the cortical level. High resolution volumetric MRI may be helpful in demonstrating small subcortical infarcts that may not be seen using computed tomography or conventional MRI.
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keywords = visual
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9/40. Endoscopic removal of thalamic hematoma: a technical note.

    OBJECT: To minimize invasiveness, an endoscopic surgical technique under stereotactic guidance is described for removal of thalamic hematoma. SURGICAL TECHNIQUE: A burr hole is placed at a point 3 cm above the glabella and 3 cm lateral from the midline. A transcortical transventricular puncture is performed with a stainless steel tube under stereotactic guidance. The tube is mounted to a metal holder. Through this tube, a rod-lens working channel endoscope and surgical instruments are inserted for visualization of the thalamus and evacuation of the hematoma. Compared with the endoscopic approach through the shortest distance of viable brain tissue, this technique allows removal of the hematoma in the ventricular space and thalamus simultaneously. The case of one patient with thalamic hemorrhage and obstructive hydrocephalus, caused by an intraventricular blood clot, is reported for surgical demonstration. CONCLUSION: An endoscopic technique for removal of thalamic hematoma with the aid of stereotactic guidance, which allows precise targeting of the lesion, is reported.
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ranking = 0.2
keywords = visual
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10/40. Increased regional cerebral blood flow in the contralateral thalamus after successful motor cortex stimulation in a patient with poststroke pain.

    The mechanisms underlying poststroke pain have not been clearly identified. Although motor cortex stimulation (MCS) sometimes reduces poststroke pain successfully, the exact mechanism is not yet known. For further investigation of the neural pathways involved in the processing of poststroke pain and in pain reduction by MCS, the authors used positron emission tomography (PET) scanning to determine significant changes in regional cerebral blood flow (rCBF). This 58-year-old right-handed man suffered from right-sided poststroke pain for which he underwent implantation of a stimulation electrode in the right motor cortex. After 30 minutes of stimulation, his pain was remarkably reduced (visual analog scale scores decreased 8 to 1) and he felt warmth in his left arm. The rCBF was studied using PET scanning with 15O-labeled water when the patient was in the following states: before MCS (painful condition, no stimulation) and after successful MCS (painless condition, no stimulation). The images were analyzed using statistical parametric mapping software. State-dependent differences in global blood flow were covaried using analysis of covariance. Comparisons of the patient's rCBF in the painful condition with that in the painless condition revealed significant rCBF increases in the left rectus gyrus (BA11), left superior frontal lobe (BA9), left anterior cingulate gyms (BA32), and the left thalamus (p < 0.05, corrected). On the other hand, there were significant decreases in rCBF in the right superior temporal gyrus (BA22, p < 0.01, corrected) and the left middle occipital gyrus (BA19, p < 0.05, corrected). The efficacy of MCS was mainly related to increased synaptic activity in the thalamus, whereas the activations in the rectus gyrus, anterior cingulate gyrus, and superior frontal cortex as well as the inactivation of the superior temporal lobe may be related to emotional processes. This is the first report in which the contralateral thalamus was significantly activated and pain relief was achieved using MCS.
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ranking = 50.067676614098
keywords = cortex
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