1/56. The assessment of cognitive procedural learning in amnesia: why the tower of Hanoi has fallen down. The Tower of Hanoi has been widely accepted as an evaluation of cognitive procedural learning in amnesia but inconsistent findings have raised questions about the nature of the learning process involved in this task. This article presents the performance of a hippocampal amnesic, MS, who, showing poor learning across daily sessions of a formal evaluation, subsequently solved the puzzle through spontaneous use of a declarative-level strategy (the odd-even rule), suggesting that his primary approach to the task was the deployment of declarative solution-searching strategies. The presented data suggest normal learning within daily sessions, but subnormal learning across daily sessions due to the forgetting of acquired declarative information. It is suggested that tasks that are potentially solvable by an algorithm or rule, as is the Tower of Hanoi, be regarded as inappropriate for use in cognitive procedural assessments. ( info) |
2/56. An atypical neuropsychological profile of a korsakoff syndrome patient throughout the follow-up. The basis of amnesia in alcoholic Wernicke-korsakoff syndrome (WKS) has been generally associated with diencephalic lesions and more specifically with lesions of the anterior thalamic nuclei. These brain structures are considered to be involved in encoding/consolidation processes of episodic memory. However, frontal lobe damage responsible for executive function deficits has also been documented. The present report details the nature and extent of amnesia in an alcoholic patients with WKS and which appears to be mainly due to frontal lobe (executive) deficits. ( info) |
3/56. Memory disorder in Korsakoff's psychosis: a neuropathological and neuropsychological investigation of two cases. Neuropathological findings in the brains of two alcoholic patients with Korsakoff's psychosis are reported. Their memory defects had been studied in detail quantitatively over a period of nine years in one case and three years in the other, relevant details of which are presented. Both patients had had a relatively pure long-term memory impairment in the absence of other cognitive deficits and in the absence of a short-term memory impairment. Their retrograde amnesia for public events and famous faces had been measured and found to have extended backwards over at least twenty-five years. There was severe impairment in anterograde recognition memory for both verbal and non-verbal material. On a newly prepared memory quotient battery both patients had scored well below the bottom of the normal scale (less than 60, where 100 is the mean with a standard deviation of /- 15). Both patients had also shown the characteristic differential improvement in retention when tested by cued recall and also the characteristic 'prior learning effect', i.e. normal retention of one list of words when tested by cued recall but impaired retention of a second list sharing the same cues as the first list. There had been a slight but significant deterioration in intelligence in one of the patients in the two years prior to his death, although his IQ still fell within the normal range. The other patient remained undeteriorated until his death, and his IQ also was close to an estimated measure of his premorbid IQ. In the brains of both patients there was marked gliosis, shrinkage and discolouration bilaterally in the medial nuclei of the mammillary bodies. In addition there was a thin band of gliosis bilaterally between the wall of the third ventricle and the medial dorsal nucleus, the rostral limit lying anterior to the medial dorsal nucleus. In the patient with no intellectual deterioration these were the only pathological changes that were seen. In neither patient was there evident local loss of nerve cells, gliosis or any other qualitative evidence of abnormality in the hippocampi, the white matter of the temporal lobes or the greater part of the medial dorsal nuclei, although it is difficult to be certain whether there was any overlap between the band of gliosis and the most medial region of the medial dorsal nueleus and other adjacent thalamic nuclei. In the other patient there was also a small zone of softening in the cerebellum and an increase in astrocytes in other regions of the cerebral hemispheres, including the basal ganglia, amygdala, and brain-stem, but without noticeable loss of cells. The question of the minimal lesion for the alcoholic Korsakoff amnesic state, and some aspects of the related anatomy, is discussed in the context of other reports in the literature which are, however, difficult to assess in the absence of details of the specificity, severity and character of the memory disorders. ( info) |
4/56. The localization of memory. MRI showed severe lesions, thought to be specific for the Wernicke-korsakoff syndrome, in an alcohol dependent patient with an excellent memory. The morphological abnormalities thought to be typical of Wernicke-korsakoff syndrome might be features of chronic alcoholism and malnutrition. This contention has important implications for the localization of memory functions. Recent literature on the anatomical basis and mechanism of memory is reviewed. Memory probably resides in multifocal neural networks rather than in specific anatomical sites. ( info) |
| In order to support the concept that a lesion of the thalamus is sufficient to cause a korsakoff syndrome, we are presenting 5 patients, all of whom developed the syndrome after sustaining a left (dominant) thalamic infarction. Two patients had pure thalamic strokes followed by a permanent korsakoff syndrome. One of these patients was studied with neuropsychometric testing, as well as with a modern MRI scan. In 2 other patients, clinical and imaging data indicate that infarction was not limited to the thalamus. Another patient had bilateral thalamic infarcts but only a temporary korsakoff syndrome. Neuropathological data are needed to elucidate the exact anatomical substrate of dominant thalamic korsakoff syndrome. ( info) |
| A 47-year-old man began to suffer from progressive truncal ataxia and mental alterations typical of Wernicke-korsakoff syndrome. He showed confusional state, hallucinations, delirium of jealousy and a serious impairment of recent memory. The symptomatology lasted 13 months, but only in the last weeks was it complicated by myoclonias. Triphasic pseudoperiodic sharp-waves characterized the EEG-recordings only in the final stage. Macroscopic examination of the brain showed marked atrophy of the mammillary bodies and superior vermis. However, the histological features were consistent with Creutzfeldt-Jakob disease (CJD) with focal accentuation of the changes in the latter structures. This case supports the hypothesis that CJD-changes begin focally in the CNS and, subsequently, spread along neuronal pathways, probably via central axons. Only in the final stage does the pathological process involve most parts of the gray matter. A focal accentuation of the CJD process in the cerebello-mammillo-thalamic system caused in this case a Wernicke-Korsakoff-like syndrome. ( info) |
7/56. Memory for what it is and memory for what it means: a single case of Korsakoff's amnesia. A single case of Korsakoff's syndrome, showing classic circumscribed amnesia on traditional neuropsychological tests, performed a number of learning tasks previously used in primates to demonstrate the different anatomical basis of memory systems used to learn about the properties of objects or to learn about rules of responding. The patient (CJ) performed in a manner very similar to lesioned monkeys in that he could learn evaluative tasks (e.g. a red object is nice), but not rule based tasks (e.g. a red object means go left). In consequence CJ learned an object discrimination task in a manner qualitatively different from a group of non-amnesic controls. Although he could not learn rule based tasks, CJ could perform them once he had been given the rule. Detailed analysis of learning showed that CJ could choose the object he had chosen previously, but could not say where it had been or whether he had been rewarded. Furthermore he could recognise a word as familiar, while not remembering its source. We propose that he has a specific impairment in a memory system concerned with the representation of the signification of objects in particular contexts, while representation of the properties of objects remains intact. ( info) |
8/56. Hypothalamic histiocytosis X with diabetes insipidus and Korsakoff's syndrome--case report. A 54-year-old female presented with apparent isolated hypothalamic histiocytosis X associated with diabetes insipidus and Korsakoff's syndrome. Computed tomographic and magnetic resonance imaging demonstrated a single hypothalamic mass. A craniotomy for biopsy found granulation tissue of unknown cause. Further investigation discovered genital bleeding before admission. biopsy of the cervix uteri revealed histiocytosis X. Further studies showed the disease was restricted to the hypothalamus and the endometrium of the cervix uteri. Low-dose irradiation led to partial regression of the hypothalamic mass and improvement of Korsakoff's syndrome. Even when a diagnosis of isolated hypothalamic histiocytosis X is confirmed, the possibility of another histiocytosis X lesion in an unexpected region must be considered. ( info) |
9/56. Wernicke-korsakoff syndrome of nonalcoholic origin. We describe a patient who developed a severe loss of memory following intravenous feeding and intestinal surgery. The pattern of both anterograde and retrograde memory impairment and frontal pathology is shown to be comparable with that observed in patients with Wernicke-korsakoff syndrome of an alcoholic etiology. The data strengthen the view that the essential characteristics of the Wernicke-korsakoff syndrome are not dependent on a prior history of chronic alcoholism. Implications of these data for the interpretation of alcoholic Wernicke-korsakoff syndrome are considered. ( info) |
10/56. Treating organic abulia with bromocriptine and lisuride: four case studies. Abulia refers to an impairment of will, or the inability to initiate behaviour and action. There are reports of successful treatment of akinetic mutism, the most severe form of abulia, with bromocriptine. Four case studies are presented describing the successful treatment of abulia at a lesser severity than akinetic mutism with bromocriptine. Abulia was caused by brain damage due to alcohol in two cases, Wilson's disease and basal ganglia infarct in one each. Maximum bromocriptine dose varied from 25-70 mg. All improved considerably. Withdrawal or reduction of medication in three produced deterioration. The prescription of a neuroleptic drug had a similar effect in the fourth. One patient with a previous history developed a depressive relapse and so the drug was withdrawn and lisuride introduced. This produced a similar improvement. These cases highlight the value of identifying the syndrome of organic abulia and suggest that dopamine agonists may have a place in its treatment, though controlled studies are needed. ( info) |