1/3. Persistent kluver-bucy syndrome after bilateral thalamic infarction.OBJECTIVE: To describe a patient who exhibited a partial kluver-bucy syndrome after small bilateral ischemic lesions in the thalami. BACKGROUND: Previously reported patients with kluver-bucy syndrome had very large, mostly bilateral lesions in the limbic system and could not provide sufficient information about its anatomo-functional correlate. METHOD: Behavioral assessments and clinical examinations, including magnetic resonance imaging and positron emission tomography, were conducted. RESULTS: The patient was severely amnestic, distractible, hyperoral, and affectively dyscontrolled, and she behaved socially inappropriately. magnetic resonance imaging showed bilateral infarctions in the territories of both thalamoperforating arteries, and positron emission tomography revealed bilaterally decreased fluorodeoxyglucose uptake in the anterior parts of the ventral thalami and, to a lesser extent, in the fronto-temporal cortices. CONCLUSIONS: This behavioral syndrome has not yet been reported with isolated diencephalic lesions, but it has been observed after bilateral temporal lobe lesions. The authors conjecture that this syndrome resulted from a disruption of the pathways connecting the dorsomedial thalami with the prefrontal cortices and with other limbic areas, systems essential for memory and the regulation of impulses and emotions.- - - - - - - - - - ranking = 1keywords = amnestic (Clic here for more details about this article) |
2/3. P300 abnormalities in patients with selective impairment of recent memory.We recorded auditory event-related potential (ERP) by using the standard oddball paradigm in seven amnestic patients. patients were divided into three groups according to brain CT or MRI findings. (1) Three patients with no detectable lesion, including two patients studied during the episode of transient global amnesia, showed a well-defined P300. (2) Three patients with detectable lesions in the mesial temporal lobes did not show any wave form corresponding to P300. In two of these three patients, the ERP wave form showed a significant change in accordance with the improvement of MRI findings. (3) One patient who had a hypothalamic lesion due to total resection of craniopharyngioma showed a low-amplitude P300. Although neuropsychological examinations showed selective and severe impairment of recent memory function in all of these patients, no significant relationship was found between the degree of memory disturbance and P300 abnormality. These results suggest that P300 is more affected by existence and extension of brain lesions, especially in the mesial temporal lobes, rather than degree of memory disturbance. However, these results do not necessarily suggest that the potential generated in the mesial temporal lobes is directly recorded as a component of the scalp-recorded P300.- - - - - - - - - - ranking = 1keywords = amnestic (Clic here for more details about this article) |
3/3. A case of concomitant impairment of operational signs and punctuation marks.A patient affected by amnestic aphasia, E.B., presented with a prevailing impairment in the use of operational signs and punctuation marks. His performance on tasks exploring his knowledge of these symbols is compared with that of two other patients suffering from similar aphasic disturbances. This comparison enables us to reject the hypothesis that E.B.'s defects arise from aphasia per se. A possible cognitive link between operational signs and punctuation marks is discussed.- - - - - - - - - - ranking = 1keywords = amnestic (Clic here for more details about this article) |