11/309. Pseudochoreoathetosis in four patients with hypesthetic ataxic hemiparesis in a thalamic lesion. Thalamic lesions give rise to a variety of clinical syndromes including choreoathetotic movements and ataxic hemiparesis as well as sensory deficits. We describe four patients exhibiting pseudochoreoathetosis, hypesthesia, and ataxic hemiparesis in the limbs contralateral to a thalamic lesion. Three of the four patients showed the involuntary movements within 10 days of stroke onset; the remaining patient was not seen until 4 years later. Three had infarction and the other one hemorrhage in the posterior and lateral thalamus. All the patients had both cerebellar and sensory ataxia. These cases suggest that failure to convey proprioceptive information be the basic pathophysiology of pseudochoreoathetosis. ( info) |
12/309. A combined pattern of movement disorders resulting from posterolateral thalamic lesions of a vascular nature: a syndrome with clinico-radiologic correlation. We report a series of seven patients in whom a combined pattern of complex movement disorders restricted to one upper extremity emerged as a result of posterolateral thalamic lesions of vascular origin. This disorder was mainly characterized by choreiform and dystonic movements associated with variable, rhythmic, alternating movements of low frequency (myorhythmia). All cases showed, on computed tomography scan and/or magnetic resonance imaging, focal lesions involving the posterolateral quadrant of the thalamus. review of similar cases reported with identical clinico-radiologic features allows us to conclude that it is possible to establish an accurate anatomoclinical correlation based on the clinical phenomenology, even before imaging studies are performed, in these cases. The opposite is not entirely possible, however, because lesions in the same quadrant of the thalamus are often associated with different patterns of abnormal movements or present without abnormal movements. ( info) |
13/309. CT and MRI in severe hypophosphataemia with central nervous system involvement. We report a 38-year-old woman with extreme hypophosphataemia in whom CT and MRI disclosed bilateral lesions within the basal ganglia, thalamus and occipital lobes. After adequate substitution of phosphate the lesions grossly resolved and the patient recovered. This case is the first to demonstrate that profound changes of serum phosphate may be associated with reversible brain lesions. ( info) |
14/309. 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. ( info) |
15/309. 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. ( info) |
16/309. Selective loss of vergence control secondary to bilateral paramedian thalamic infarction. The supranuclear pathways for vergence eye movements are poorly understood. The authors report a 57-year-old patient who presented with selective loss of vergence control and dissociation of light and near reaction. MRI showed a symmetric paramedian thalamic infarction without midbrain lesion. The findings suggest that this syndrome is due to an interruption of supranuclear fibers to midbrain vergence neurons. ( info) |
17/309. Correlation of clinical and neuroradiological findings in down-gaze palsy. BACKGROUND: Isolated down-gaze palsy is the least common pathology of vertical gaze. patients with low-gaze palsy may consult an ophthalmologist with difficulty in reading and this may be the only ocular finding of a central nervous system lesion. methods: A 43-year-old man with isolated down-gaze palsy was examined. The medical history of the patient revealed that he had had myocardial infarction. RESULT: magnetic resonance imaging disclosed an ischemic area at the right thalamus. CONCLUSION: Down-gaze palsy may be an important sign for the diagnosis of thalamic infarctions due to embolic syndrome. ( info) |
18/309. Bilateral basal ganglia-thalamic lesions subsequent to prolonged fetal bradycardia. We report two infants with bilateral basal ganglia-thalamic lesions subsequent to prolonged fetal bradycardia. Cardiotocogram revealed severe bradycardia lasting for more than 20 min in both. They demonstrated a significant encephalopathy, abnormal muscle tones and signs of brainstem injury. Clinical or electrical seizures were not observed in either of them. CT during early neonatal period demonstrated decreased tissue attenuation in basal ganglia and thalami in the absence of extensive cortical changes. Both of them developed severe mental retardation and quadriplegia. MRI in late infancy demonstrated abnormal high intensity areas in bilateral basal ganglia, thalami and around central sulci on T2-weighted image. Close correlation between prolonged fetal bradycardia and basal ganglia-thalamic lesion was suggested. ( info) |
19/309. Monocular central dazzle after thalamic infarcts. The authors observed a patient after he had ischemic strokes in both paramedian thalamic regions, which were more marked on the left side. Symptoms included dysphasia, vertical binocular diplopia, right-sided hemianopia, and a right-sided sensory and motor deficit, sparing the face. However, the most disturbing phenomenon was a painless, left monocular dazzle, which was the presenting symptom and also the only persisting symptom. This report shows that a thalamic lesion may be at the origin of central dazzle, and to the authors' knowledge, it is the first clinical observation of its monocular occurrence. It is conceivable that this dazzle was due to optic-trigeminal summation. ( info) |
20/309. Unilateral thalamic infarction and vertical gaze palsy: cause or coincidence? Although vertical gaze palsy (VGP) is commonly associated with lesions of the rostral mesencephalon, there is some evidence that VGP may also be caused by a unilateral thalamic lesion. The case of a 68-year-old man with persistent upward gaze palsy after a unilateral thalamic infarction, demonstrated on computed tomography and magnetic resonance imaging scans, is presented. Subsequent high-resolution magnetic resonance scanning, however, showed involvement of the rostral mesencephalon as well. The authors suggest that in previous patients with VGP ascribed to a unilateral thalamic infarction, a coexisting mesencephalic involvement may have been missed because of inappropriate imaging techniques. Strong evidence of unilateral thalamic infarction as a cause of VGP is still lacking. ( info) |