1/27. Dopaminergic dysfunction in midbrain dystonia: anatomoclinical study using 3-dimensional magnetic resonance imaging and fluorodopa F 18 positron emission tomography.OBJECTIVE: To determine the role of damage to neuronal systems, especially the dopaminergic system, in patients with symptomatic dystonia and mesencephalic lesions. DESIGN: Stereotaxic magnetic resonance imaging analysis and positron emission tomography after the administration of fluorodopa F 18. patients: Of a group of 48 patients with unilateral dystonia following a stroke, 7 patients with a well-defined midbrain lesion were selected. RESULTS: All patients had unilateral dystonic posture of an upper extremity and cerebellar dysmetria or hypotonia. Cerebellar tremor was present in 1 patient. Two patients had resting and postural tremor, which showed a marked improvement with treatment with levodopa. In patients with dystonia only, dopaminergic lesions were mostly confined to the ventromesial mesencephalon and red nucleus area, including the substantia nigra and nigrostriatal and cerebellothalamic fibers. dystonia was severe and did not resolve with time in patients with lesions involving the nigrostriatal pathway, and the degree of dopaminergic denervation revealed by positron emission tomography was correlated with the severity of dystonia. In patients with resting and postural tremor, lesions of the dopaminergic structures were larger and located more laterally and dorsally in the pars compacta, the perirubral and retrorubral areas, and extending to the central tegmental tract. CONCLUSIONS: Dopaminergic dysfunction plays a role in the occurrence and severity of midbrain dystonia, and additional lesions to dopaminergic neurons in the perirubral and retrorubral areas result in tremor that responds to levodopa treatment.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
2/27. Geniculate hemianopias: incongruous visual defects from partial involvement of the lateral geniculate nucleus.Quantitative perimetric studies in 4 patients with involvement of a lateral geniculate nucleus revealed strikingly incongruous defects in the corresponding homonymous fields of vision. The patterns of these hemianopias are analysed and correlated anatomically with established retinotopic projections on the six cellular laminae of the geniculate nucleus. Incongruous wedge-shaped field defects appear to be pathognomonic of focal disease in the dorsal crest of the geniculate nucleus. Other patterns typify lesions of the medical or lateral horns of the nucleus. On theoretical grounds monocular hemianopic defects should result from unilaminar geniculate lesions, but this perimetric sign awaits confirmation. In each case of geniculate disease where the retinal nerve fibre layer has been examined specifically for efidence of retrograde homonymous atrophy, typical hemiretinal signs were found to be present.- - - - - - - - - - ranking = 8keywords = nucleus (Clic here for more details about this article) |
3/27. Cerebrovascular accident after percutaneous rf thermocoagulation of the trigeminal ganglion. Case report.A case of cerebrovascular accident associated with percutaneous radiofrequency thermocoagulation of the trigeminal ganglion is presented in the hope of alerting other surgeons to this possible complication.- - - - - - - - - - ranking = 95.41695440809keywords = ganglion (Clic here for more details about this article) |
4/27. Non-Alzheimer non-Pick dementia with Fahr's syndrome.Five patients with non-Alzheimer non-Pick dementia combined with Fahr's syndrome were studied. Atypical clinical pictures emerged from an evaluation of these cases. Their symptoms and signs could be attributed neither to Alzheimer's disease nor to Pick's disease but to a partial mixture of both. The neuropathological changes were characteristic, and the common findings were as follows: 1) the absence of senile (neuritic) plaques, 2) the widespread presence of numerous neurofibrillary tangles throughout the neocortex, 3) a calcareous deposition of Fahr's type, 4) a circumscribed cerebral atrophy in the temporal or/and frontal lobes, 5) a moderate or severe demyelination and fibrous gliosis in the white matter of the atrophied areas and 6) a mild or moderate neuronal loss in the nucleus basalis of Meynert. These neuropathological changes were not due to Alzheimer's disease nor to Pick's disease. Similar cases reported previously were reviewed.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
5/27. Lacunar infarctions due to cholesterol emboli.BACKGROUND AND PURPOSE: hypertension is commonly considered the major cause of lacunar infarctions. However, in some cases, it has been suggested that lacunes could be caused by cerebral emboli from cardiac or carotid sources. cholesterol cerebral emboli have been rarely reported as a cause of lacunes. CASE DESCRIPTION: We describe a 79-year-old patient with a progressive multi-infarct dementia who developed transient motor aphasia and paresis of the right arm. Computed tomography showed lacunar infarcts in the right caudate nucleus, left thalamus, and left putamen, as well as an old right frontal infarction. Neuropathological examination demonstrated no prominent vascular hyalinosis, but did show multiple cholesterol emboli occluding small arteries around lacunar infarcts and leptomeningeal arteries near cortical infarcts. The cholesterol material presumably originated in the extended atheromatous changes along the aortic arch. CONCLUSIONS: Our report confirms that lacunes can be caused by cholesterol emboli in some patients. Small cerebral emboli should not be overlooked as a cause of lacunes.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
6/27. language disturbances from paramedian thalamic infarcts: a CT method for lesion location.The authors describe the case of three patients suffering from language disorder secondary to mesencephalo-thalamic infarcts. One of them showed the clinical features of transcortical motor aphasia, while the other two presented the typical pattern of the so-called "thalamic aphasia". The CT-stereotaxic method for lesion localization disclosed that the dorso-medial was the mostly involved thalamic nucleus in each case. Since this nucleus is connected both with Broca's and Wernike's areas, the authors suggest that the more or less extensive involvement of the fibres connecting these structures may be responsible for the different aphasic features presented in these cases.- - - - - - - - - - ranking = 2keywords = nucleus (Clic here for more details about this article) |
7/27. Focal capsular vascular lesions can selectively deafferent the prerolandic or the parietal cortex: somatosensory evoked potentials evidence.Four patients with a unilateral focal vascular accident involving the internal capsule (but not the cortex) were studied electrophysiologically. Averaged somatosensory evoked potentials (SEPs) to electrical stimulation of the median nerve on the left or the right side were analyzed. In the 3 patients with hemiparesis and normal somatic sensation, the precentral P22 and N30 SEP components were lost, whereas the parietal components were preserved. In another patient with clinical somatosensory loss unaccompanied by any central motor impairment, the precentral SEP components were preserved, whereas the parietal SEP components were lost. Thus, a small capsular lesion can eliminate distinct cortical SEP components by selectively involving either the axons of the thalamic VPLc nucleus going to parietal receiving cortex or the axons of thalamic VPLo going to motor area 4. These findings extend to subcortical lesions the diagnostic value of SEPs in patients with dissociated clinical motor and sensory signs.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
8/27. A case of unilateral opercular syndrome associated with a subcortical lesion.A patient who developed a unilateral opercular syndrome following a cerebrovascular accident is described. Computed tomography showed that the lesion did not affect the opercular cortex, but involved deep white matter and the head of the caudate nucleus of the left hemisphere. Persistent hypophonia and transient aphasia were associated. Comparison with previous cases is discussed.- - - - - - - - - - ranking = 1keywords = nucleus (Clic here for more details about this article) |
9/27. Late-onset post-hemiplegic hemidystonia: CT and angiographic findings.A 27-year-old woman is described who suffered an acute left hemiplegia at the age of three years and 20 years later she noted the onset of unilateral left limb dystonic movements. Her cranial CT scan showed an area of low density, consistent with longstanding infarction, in the right lentiform nucleus. cerebral angiography demonstrated aneurysmal dilatation of the terminal portion of the right internal carotid artery, minor irregularity of the lenticulostriate branches of the right middle cerebral artery (suggestive of Moya Moya disease) and occlusion of the right anterior cerebral artery. The dystonic movements improved with levodopa therapy. Clinico-radiological correlation in this case supports recent evidence for a disruption of pathways between the caudate nucleus, lentiform nucleus and thalamus in the pathophysiology of hemidystonia.- - - - - - - - - - ranking = 3keywords = nucleus (Clic here for more details about this article) |
10/27. magnetic resonance imaging stereotactic thalamotomy: report of a case with comparison to computed tomography.The anatomical location of the thalamic target (ventrolateral nucleus) during stereotactic thalamotomy for a movement disorder was determined using magnetic resonance imaging (MRI) to define the anterior and posterior commissures and the intercommissural plane. Precise targeting was confirmed by intraoperative stereotactic computed tomography (CT), electrophysiological stimulation, and a gratifying postoperative response (disappearance of contralateral tremor and rigidity). The use of a MRI- and CT-compatible stereotactic coordinate frame allowed multiplanar imaging with excellent spatial and contrast resolution, visualization of the source of the tremor (prior embolic stroke affecting the dentatorubrothalamic pathway), and correction for the more medial location of the internal capsule in this patient. Location did not vary among target sites seen with MRI and CT imaging techniques. In this patient MRI during stereotactic thalamotomy supplemented CT and the electrophysiological technique that we conventionally use to define the ventrolateral nucleus. Although the importance of possible magnetic susceptibility imaging artifacts remains to be elucidated, stereotactic MRI may prove sufficiently accurate in the future to replace other imaging techniques used during functional neurosurgery.- - - - - - - - - - ranking = 2keywords = nucleus (Clic here for more details about this article) |
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