Cases reported "Amnesia"

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11/35. Diencephalic amnesia.

    The anatomical basis and cognitive profile of diencephalic amnesia remain unclear. We report a two-part study. First, we studied 4 patients with bilateral medial thalamic infarctions using magnetic resonance imaging and comprehensive neuropsychological testing. All patients were followed for more than 1 year. Using a stereotactic method, we plotted the lesions in an atlas delineating the probable structure involved. Secondly, in 2 monkeys, using autoradiography, we traced the pathway from the amygdala to the dorsomedial nucleus, paying particular attention to the intrathalamic course of the amygdalothalamic projections. Our findings were (1) patients develop amnesia when infarctions are located anteriorly; (2) in patients with amnesia, the lesions can be small and strategically located, probably interfering with both hippocampal-related neural structures such as the mamillothalamic tract, and amygdala-related neural structures such as the ventroamygdalofugal pathway; and (3) a specific component of the latter is situated lateral but immediately adjacent to the mamillothalamic tract in the monkey, enabling both structures to be damaged bilaterally by small mirror image lesions. The amnesia is characterized by deficits in anterograde verbal and visual learning and in retrograde amnesia, but motor learning is preserved. We raise the possibility that bilateral diencephalic lesions may interfere particularly with temporal aspects of memory.
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ranking = 1
keywords = nucleus
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12/35. Observations during transient global amnesia. A behavioural and neuropsychological study of five cases.

    The clinical and behavioural features of 5 patients examined during transient global amnesia (TGA) are described. All underwent extensive neuropsychological testing during and sequentially after the attack. Our results show that in TGA there is a characteristic neuropsychological deficit which parallels that in the permanent amnesic syndrome. personality, complex cognition and problem solving, semantic knowledge, language and visuospatial function remained intact. Immediate memory was preserved. Longer-term verbal and nonverbal memory was severely disrupted in all cases. In contrast, the extent of retrograde amnesia was highly variable. A famous faces test showed an extensive deficit in 3 cases, with improvement in all cases following the attack. Analysis of group data confirmed the presence of a reversible temporal gradient, in that more distant memories were relatively spared. On a famous events test, recognition was normal across all decades, but dating of events from the 1960s and 1970s was consistently impaired. The Crovitz test of remote personal episodic memory was given to 3 subjects; all showed impaired uncued autobiographical memory and in contrast to normal controls, had a virtual absence of recent memories. During recovery from TGA there was progressive shrinkage of retrograde amnesia but a permanent short retrograde gap of around 1 h remained in all cases. Although subjectively normal within 24 h, all cases demonstrated persisting impairment of new learning for at least a week post-TGA. The relevance of the neuropsychological data to theories concerning the amnesic syndrome is discussed. We postulate a temporary deficit in retrieval of remote memories which appears to be dissociable from the anterograde amnesia.
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keywords = group
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13/35. Description of brain injury in the amnesic patient N.A. based on magnetic resonance imaging.

    N.A. has been amnesic since 1960 when at the age of 22 years he sustained a penetrating brain injury with a miniature fencing foil. The amnesia primarily affects verbal material and occurs in the absence of other detectable cognitive deficits. Previous CT scans demonstrated a lucency in the region of the left mediodorsal thalamic nucleus, but no additional damage was revealed. Beginning in 1986 when he was 48 years old, N.A. was evaluated with a series of magnetic resonance imaging (MR) studies. Three major areas of damage were identified. In the left thalamus there is a prominent 3- to 4-mm-wide linear lesion that approximates the position and orientation of the internal medullary lamina. The defect extends for approximately 20 mm anteroposteriorly and likely involves the rostral group of intralaminar nuclei (central medial, paracentral, central lateral, rhomboid, and reuniens nuclei), the caudal group of intralaminar nuclei (centrum medianum and parafascicular nuclei), the ventral aspect of the mediodorsal nucleus, and the ventral lateral and ventral anterior nuclei. It also likely interrupts the trajectories of the mammillothalamic tract and postcommissural fornix. The posterior hypothalamus is markedly disrupted and the mammillary nuclei appear to be missing bilaterally. Finally, the right anterior temporal lobe is damaged for a distance of about 3.5 cm from the pole to midway through the amygdaloid complex. This damage probably occurred during exploratory neurosurgery done at the time of N.A.'s injury. The hippocampal formation appears intact on both sides. A comparison of these findings with those from other patients with diencephalic amnesia suggests that amnesia can result when several diencephalic structures are damaged conjointly, including the internal medullary lamina, the intralaminar nuclei, the mediodorsal nucleus, and the mammillothalamic tract. Whether amnesia as severe as N.A.'s would result from selective damage to any one of these structures remains to be determined.
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ranking = 1261.8834707092
keywords = thalamic nucleus, nucleus, group
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14/35. Transient global amnesia follow-up: a neuropsychological investigation.

    A neuropsychological follow-up was made in a group of patients affected by transient global amnesia (TGA). The results suggest that TGA could leave some attentional and mnesic "fragility".
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keywords = group
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15/35. Location of lesions in Korsakoff's syndrome: neuropsychological and neuropathological data on two patients.

    Psychometric and neuropathological findings on two Korsakoff amnesics are described. Both patients showed anterograde and retrograde amnesia, poor performance on the Peterson short-term memory task, on the wisconsin card sort test and on certain visuo-spatial tasks. Patient J.W. performed consistently worse on tests of anterograde, but not retrograde amnesia, whereas patient B.C. showed more perseverative difficulties and, unlike J.W., his measured intelligence seemed to have declined from its premorbid level. Both patients showed marked neuronal loss from the medial mammillary bodies and a narrow band of gliosis in the medial thalamus, adjacent to the wall of the third ventricle, a region known as the paratenial nucleus. Only B.C. showed visible signs of cortical atrophy. Morphometric measures did, however, reveal reduced nucleolar volumes in layers III and V of the frontal cortex, with B.C. also showing more marked neuronal loss from these layers. B.C. also showed neuronal loss from the CA1 region of the hippocampus and reduced nucleolar volumes in the septum. Significantly, both patients had normal neuronal numbers and nucleolar volumes in the nucleus basalis of Meynert. J.W. only showed greater dysfunction than B.C. in one region: the locus caeruleus. This finding was related to his more severe amnesia.
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ranking = 2
keywords = nucleus
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16/35. Transient global amnesia precipitated by emotion in an adolescent.

    Transient global amnesia has been reported to be precipitated by intense emotion in adult patients. Transient global amnesia is uncommon in the pediatric age group. We report the unusual occurrence of this syndrome, apparently precipitated on two occasions by emotion, in an adolescent who had earlier in life suffered a left temporal and occipital lobe embolic infarction from congenital heart disease. Transient global amnesia following intense emotion may be a cause of some confusional states in children and adolescents.
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ranking = 0.00083373981589614
keywords = group
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17/35. Astereognosis as a presenting symptom in cervical meningioma.

    Three unusual cases with astereognosis caused by cervical meningioma are presented. Astereognosis of subcortical origin has been reported several times. According to these reports, the causative lesion was confined to the area extending between the lower brain stem and the fourth cervical vertebra, thus suggesting that a sensory centre for stereognosis could be confined within these well defined anatomical limits, and that therefore a lesion in this area could lead to astereognosis. It is assumed in this paper that the lesion involves the sensory system of the Nucleus Cervicalis Lateralis. Fibres from the spinothalamic tract, a specialized sensory pathway, ascend from the palms of the hands to this nucleus. From this nucleus arise fibres which decussate and reach the Ventral Posterolateral Nucleus of the thalamus. It is likely that a lesion of the nucleus itself or its related sensory tracts may cause astereognosis.
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ranking = 3
keywords = nucleus
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18/35. Transient global amnesia and stroke.

    Four patients who experienced isolated transient global amnesia had computed tomographic evidence for a cerebral infarct (3 cases) or hemorrhage (1 case). The medial part of the temporal lobe was involved in 2 patients (left in 1, right in 1), the left lentiform nucleus in 1 patient, and the left thalamus in 1 left-handed patient. These findings suggest that transient global amnesia may be associated with stroke in some cases, but it has no localizing value within the temporodiencephalic structures. No cerebrovascular events occurred over a 1-to 5-year follow-up, suggesting that transient global amnesia with infarction or hemorrhage is not a strong predictor of further stroke.
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ranking = 1
keywords = nucleus
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19/35. amnesia following thalamic hemorrhage. Another stroke syndrome.

    The clinical manifestations of thalamic hemorrhage frequently comprise hemiparesis, hemianesthesia, and oculomotor abnormalities. Since the advent of computed tomography, an amnestic syndrome following thalamic hemorrhage has been recognized, but the thalamic structures involved and the mechanism of amnesia have remained uncertain. We report a patient with sudden memory dysfunction following hemorrhage into the anterior nucleus of the left thalamus that was shown neuropathologically to disrupt the mamillothalamic fasciculus, one of the principal components of the limbic system. It is considered that the amnestic syndrome following thalamic (anterior nucleus) hemorrhage is due to interruption of the mamillothalamic fasciculus.
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ranking = 2
keywords = nucleus
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20/35. amnesia can facilitate memory performance: evidence from a patient with dissociated retrograde amnesia.

    A case is reported of a patient who experienced numerous episodes of transient global amnesia (TGA) during which anterograde amnesia was less prominent than usual, and who developed a permanent selective retrograde amnesia. On formal testing, he performed well on traditional verbal memory tests, but showed marked retrograde amnesia for verbal material, including items on a famous voices recognition test. He was administered a paired-associate learning test where the names of famous personalities for which he was amnesic were associated with incongruous activities (e.g. John Newcombe-singing). Our patient performed better on this task than a group of five matched control subjects. Our observations indicate that in the organization of human memory retrograde amnesia may be fractionated from anterograde amnesia and that in certain situations specific types of amnesia can produce a facilitation effect compared to the performance of control subjects.
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ranking = 0.00083373981589614
keywords = group
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