1/305. A case of amnestic syndrome caused by a subcortical haematoma in the right occipital lobe.A case of an amnestic syndrome caused by a subcortical haematoma in the right occipital lobe is reported. A 62-year-old right-handed man presented with a sudden onset of headache to the hospital. On admission, he had a left homonymous hemianopsia, disorientation and recent memory disturbance, but had normal remote memory and digit span. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a subcortical haematoma in the right occipital lobe. These findings suggest that the patient's amnesia was caused by a lesion of the retrosplenial region in the non-dominant hemisphere.- - - - - - - - - - ranking = 1keywords = memory (Clic here for more details about this article) |
2/305. Recovery from anterograde and retrograde amnesia after percutaneous drainage of a cystic craniopharyngioma.A case is reported of a cystic craniopharyngioma involving the floor and walls of the third ventricle. Pronounced anterograde and retrograde amnesia were documented preoperatively by formal testing. Rapid improvement in both new learning capacity and remote memory occurred after percutaneous twist drill drainage of the cystic portion of the tumour. The relevance of these observations to the amnesic syndrome and its neuropathological basis is discussed.- - - - - - - - - - ranking = 0.5keywords = memory (Clic here for more details about this article) |
3/305. Contributions of prefrontal cortex to recognition memory: electrophysiological and behavioral evidence.To clarify the involvement of prefrontal cortex in episodic memory, behavioral and event-related potential (ERP) measures of recognition were examined in patients with dorsolateral prefrontal lesions. In controls, recognition accuracy and the ERP old-new effect declined with increasing retention intervals. Although frontal patients showed a higher false-alarm rate to new words, their hit rate to old words and ERP old-new effect were intact, suggesting that recognition processes were not fundamentally altered by prefrontal damage. The opposite behavioral pattern was observed in patients with hippocampal lesions: a normal false-alarm rate and a precipitous decline in hit rate at long lags. The intact ERP effect and the change in response bias during recognition suggest that frontal patients exhibited a deficit in strategic processing or postretrieval monitoring, in contrast to the more purely mnemonic deficit shown by hippocampal patients.- - - - - - - - - - ranking = 2.5keywords = memory (Clic here for more details about this article) |
4/305. Retrograde temporal order amnesia resulting from damage to the fornix.Some amnesic patients show an impairment of temporal order memory that cannot be accounted for by content memory deficits. The performance of an amnesic patient on memory tasks assessing the patient's content and temporal memories for remotely acquired material is described, after a lesion including the bilateral anterior fornix and adjacent anterior thalamus. The patient displayed a deficit in the temporal order tasks for remotely acquired information. Neither frontal cognitive deficits nor recognition deficits can account for this patient's poor temporal memory. This retrograde temporal order memory impairment without content memory deficits were not seen in previously reported thalamic amnesic patients. Accordingly, the present patient's poor retrograde temporal memory could hardly be explained by only a thalamic lesion. It is concluded that the patient's impairment of temporal order memory for the retrograde material is probably due to the direct disconnection between the frontal lobe and the hippocampus by disruption of the fornix.- - - - - - - - - - ranking = 4keywords = memory (Clic here for more details about this article) |
5/305. Basal forebrain amnesia: does the nucleus accumbens contribute to human memory?OBJECTIVE: To analyse amnesia caused by basal forebrain lesions. methods: A single case study of a patient with amnesia after bleeding into the anterior portion of the left basal ganglia. Neuropsychological examination included tests of attention, executive function, working memory, recall, and recognition of verbal and non-verbal material, and recall from remote semantic and autobiographical memory. The patient's MRI and those of other published cases of basal forebrain amnesia were reviewed to specify which structures within the basal forebrain are crucial for amnesia. RESULTS: attention and executive function were largely intact. There was anterograde amnesia for verbal material which affected free recall and recognition. With both modes of testing the patient produced many false positive responses and intrusions when lists of unrelated words had been memorised. However, he confabulated neither on story recall nor in day to day memory, nor in recall from remote memory. The lesion affected mainly the nucleus accumbens, but encroached on the inferior limb of the capsula interna and the most ventral portion of the nucleus caudatus and globus pallidus, and there was evidence of some atrophy of the head of the caudate nucleus. The lesion spared the nucleus basalis Meynert, the diagnonal band, and the septum, which are the sites of cholinergic cell concentrations. CONCLUSIONS: It seems unlikely that false positive responses were caused by insufficient strategic control of memory retrieval. This speaks against a major role of the capsular lesion which might disconnect the prefrontal cortex from the thalamus. It is proposed that the lesion of the nucleus accumbens caused amnesia.- - - - - - - - - - ranking = 4.5keywords = memory (Clic here for more details about this article) |
6/305. Confabulation and delusional misidentification: a four year follow-up study.We describe a patient, AZ, who showed, in addition to an amnesic syndrome which eventually improved, longstanding confabulation and delusional misidentification following bilateral frontal and right temporal post-traumatic lesions. Confabulation appeared in personal recollections and on long-term verbal memory testing. Misidentification concerned mainly his wife and house. During the four year follow-up AZ's confabulation progressively shrinked so as to become restricted to verbal memory tasks. By contrast, misidentification persisted. General semantic memory was unimpaired throughout, while performance on frontal tests was initially poor and partly improved in time. We argue that confabulation and misidentification, though often intermingled and occurring after similar lesion pattern, should be considered as different neuropsychological entities.- - - - - - - - - - ranking = 1.5keywords = memory (Clic here for more details about this article) |
7/305. Sensorimotor skill learning in amnesia: additional evidence for the neural basis of nondeclarative memory.We investigated sensorimotor skill learning, a form of nondeclarative (implicit) memory, in 28 subjects with declarative (explicit) memory defects caused by either mesial temporal (n = 15) or basal forebrain (n = 13) damage and in 66 normal control subjects. All 28 amnesics had normal learning of a rotor pursuit task. We also studied in detail the sensorimotor skill learning of patient Boswell. As a result of bilateral damage to both mesial and lateral aspects of the temporal lobes and to the basal forebrain, Boswell has one of the most severe impairments ever reported for learning of all types of declarative knowledge. Compared to matched controls, Boswell acquired and retained normally the skills associated with performing motor tasks. We conducted a long-term (2-year) followup study of Boswell's retention of the rotor pursuit task, and we found that he retained the skill as well as normal controls. Our study builds on previous work in the following respects: (1) It provides evidence, for the first time, that skill learning is normal in basal forebrain amnesics; (2) it shows that patient Boswell has normal learning and long-term retention of sensorimotor skills, in spite of his extensive damage; and (3) it offers additional evidence that mesial temporal lobe damage spares skill learning. These findings demonstrate unequivocally that sensorimotor skill learning does not require structures in mesial and lateral temporal regions nor in basal forebrain.- - - - - - - - - - ranking = 3keywords = memory (Clic here for more details about this article) |
8/305. memory lost and regained following bilateral hippocampal damage.We present a longitudinal neuropsychological study (31 examinations over a period of 18 months) of patient DE DF demonstrated bilateral atrophy of the hippocampal formation and globus pallidus resulting from carbon monoxide poisoning. Eighteen months after the event, the volume of the hippocampal formation was reduced by 42% on the left side and 28% on the right. The patient initially presented with a severe global amnesia. Then, he showed a gradual, yet selective recovery of episodic memory function. Verbal free recall and spatial memory performance remained reduced, whereas immediate word recall and recognition memory, as well as picture learning and memory, improved to levels at the lower range of normal performance. Interestingly, nonspatial associative learning was never much impaired and recovered completely by the end of testing. These data are taken as evidence that the human hippocampal formation does not equally support different forms of episodic memory.- - - - - - - - - - ranking = 2.5keywords = memory (Clic here for more details about this article) |
9/305. Unreliable admissions to homicide. A case of misdiagnosis of amnesia and misuse of abreaction technique.BACKGROUND: The past decade has witnessed a recognition that unsafe criminal convictions may be occasioned by unreliable confessions. AIMS: To present a case which illustrates the dangers of using abreaction interview techniques in a legal context and demonstrate the relevance of the memory distrust syndrome to an unsafe confession to murder. METHOD: We under took a detailed assessment of a person appealing against his original murder conviction, 'the appellant', and a careful scrutiny of all the relevant papers in the case. RESULTS: The appellant served 25 years in prison before his conviction was quashed as 'unsafe' on the basis of fresh psychological and psychiatric evidence. CONCLUSIONS: amnesia for an offence had been misdiagnosed, and the use of repeated abreaction interviews had further confused both the appellant and the original court. At the Appeal Court, the advice was that the man had experienced a form of source amnesia which resulted in an unreliable confession.- - - - - - - - - - ranking = 0.5keywords = memory (Clic here for more details about this article) |
10/305. neuroimaging and behavioral correlates of recovery from mnestic block syndrome and other cognitive deteriorations.OBJECTIVE: We conducted a follow-up study on a patient with enduring psychic shock-induced cognitive impairment to study by neuropsychological and functional imaging methods the degree of his recovery process on the brain and cognitive levels. BACKGROUND: Based on the assumption that trauma and stress conditions can alter the functions of the nervous systems, we report on a patient whom we studied 2 and 12 months after he suffered "mnestic block syndrome" and additional cognitive deterioration symptoms. methods: We report on a patient studied 2 and 12 months after he suffered "mnestic block syndrome" and additional cognitive deterioration symptoms. magnetic resonance imaging and fluorodeoxyglucose positron emission tomography were used for neural and detailed neuropsychological testing for cognitive deficits. RESULTS: The patient initially manifested severe intellectual decline, including severe anterograde and retrograde amnesia. His symptoms were correlated with major, although selective, reductions in his brain metabolism (2-3 SD below those of controls). Presently, he shows a normal brain metabolism and has regained parts of his memory and many of his other intellectual capabilities. Nevertheless, he still has long-term memory impairments. CONCLUSIONS: This case demonstrates a close relation between brain metabolism and cognitive performance, with major deficits of both at 2 months and major recovery of both at 12 months after a shocking event. It can serve as an example for possible stress-related deteriorations in certain brain regions, which can be partly corrected by psychotherapeutic interventions, passing time, and favorable environmental conditions.- - - - - - - - - - ranking = 1keywords = memory (Clic here for more details about this article) |
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