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Query: UMLS:C0002622 (amnesia)
 5,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Confabulation consequent to organic amnesia is a well-described clinical finding. A number of plausible theories of confabulation have been proposed, but the various claims and counterclaims have not been systematically tested. A standardized test battery that included four different kinds of questions plus measures of suggestibility and the tendency to utilize external cues was administered to ten amnesic patients who demonstrated varying degrees of confabulation. One additional patient, whose clinical condition changed dramatically during his hospital course, received the battery on a number of occasions. Differences among patients were found in overall performance, degree of confabulation, and ability to use cues. Hypothesized relationships between confabulation and suggestibility, degree of memory disorder, and degree of disorientation were not confirmed. However, confabulation proved to be strongly related to the inability to withhold answers, to monitor one's own responses and to provide verbal self-corrections. These results suggest a tentative model of the process of confabulation as well as a number of useful clinical signs indicationg recovery from amnesia.
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PMID:A study of confabulation. 88 68

Confabulation is a mysterious adjunct of amnesia. It remains unexplained why some patients invent untrue stories in response to questions (provoked confabulations) or even spontaneously with no apparent motivation (spontaneous confabulations). Hypothesized mechanisms range from a desire to fill gaps in memory to a loss of the temporal context in memory. We examined the mechanisms of confabulations in 16 amnesic patients. Patients were classified as spontaneous confabulators if they ever acted according to their confabulations. Provoked confabulations were measured as the number of intrusions in a verbal learning test. We found a double dissociation between the two types of confabulations, indicating that they represent different disorders rather than different degrees of the same disorder. Confabulating patients did not show an increased tendency to fill gaps in memory as measured by the number of fake questions concerning nonexistent items that they answered. Neither type of confabulation correlated with a failure to store new information as gauged with recognition tasks; pure information storage was even found to be normal in some patients. However, we found a positive correlation between several measures of verbal learning and verbal fluency with provoked, but not spontaneous, confabulations. In contrast, spontaneous, but not provoked, confabulations were associated with an inability to recognize the temporal order of stored information as measured by the comparison of two runs of a continuous recognition task. We suggest that provoked confabulations depend on an amnesic subject's search in his deficient memory and are the trade-off for increased item recollection. Spontaneous confabulations appear to be based on a failure to recognize the temporal order of stored information, resulting in erroneous recollection of elements of memory that do not belong together.
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PMID:The mechanisms of spontaneous and provoked confabulations. 881 98

Confabulation following brain injury is discussed in terms of (1) the conditions of brain dysfunction under which it occurs; (2) its association with amnesia, the denial syndromes, and reduplicative phenomena; (3) its positive, symbolic, adaptive aspects; and (4) the relationship of the content to current stresses and premorbid experience.
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PMID:Symbolic aspects of confabulation following brain injury: influence of premorbid personality. 888 73

Confabulation and amnesia are considered disorders of episodic but not of semantic memory. To test the limits of this view, retrieval from episodic and semantic memory was investigated in eight confabulating and nine non-confabulating amnesic subjects, and in 17 matched control subjects, by using a personal and an historical version of the Crovitz [Unconstrained search in long-term memory, Paper presented at the meeting of the Psychonomic Society, St Louis, MO, 1973] cue-word test. In response to cue words such as letter or battle subjects had to describe in detail, respectively, a related event from their personal lives or from history before their birth. We found that a subset of amnesic subjects, those with presumed damage or dysfunction in the region of the ventromedial frontal cortex, would confabulate in response to these cues. Their confabulations involved semantic, historical memories, as much as episodic, personal ones: and that distortions of content were at least as common as those of time. Even when not confabulating, they had much more difficulty than other amnesic subjects in recovering memories related to these cues. In confabulating, as compared to non-confabulating, amnesic subjects, prompting led to an increase in confabulations but also to greater recovery of veridical memories. By comparison, non-confabulating amnesic subjects whose memory loss was as severe as that of the confabulators, had a milder deficit on the personal as well as the historical cue-word test. They benefited from prompting somewhat more than matched control subjects. These results suggest that confabulation is associated with impaired strategic retrieval processes resulting from damage in the region of the ventromedial frontal cortex. These strategic retrieval processes help initiate and guide search in episodic and in semantic memory and they help monitor and organize the output from those systems.
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PMID:Strategic retrieval and the frontal lobes: evidence from confabulation and amnesia. 922 62

Multiple sclerosis (MS) is the most common inflammatory, demyelinating disease of the central nervous system. Besides neurological signs and symptoms, the disease may be associated with various psychiatric manifestations, and uncommonly, psychiatric manifestations may be the presenting symptom. On the other hand, confabulation is defined as falsification of memory occurring in clear consciousness in association with an organically derived amnesia or as spontaneous narrative reports of events that never happened. We report an unusual association of confabulation with MS. A 23-year-old man was admitted to a hospital, telling unusual stories. After evaluation and a detailed workup, the patient was given the diagnosis of MS with fantastic confabulations. Neuropsychological evaluation revealed mild frontal lobe dysfunction. Confabulation has been reported after frontal lobe lesions and is also hypothesized to be associated with a deficit primarily in the retrieval of more than one of the following: encoding, consolidation or storage. Clinicians' awareness of this kind of rare association may further enlighten the neural basis of confabulation.
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PMID:Multiple sclerosis presenting with fantastic confabulation. 1695 Mar 86

Confabulation has been defined as the falsification of memory occurring in clear consciousness in association with an organically-derived amnesia. It was first described by Korsakoff in 1889 in alcoholic amnesic patients. Later studies showed that confabulation is also seen in a variety of other pathologies, such as anterior communicating artery rupture, traumatic brain injury, Alzheimer's disease, and brain tumors. Two forms of confabulation have been described: Momentary (provoked) confabulation which is produced in response to questions, for compensating the gaps in memory; and fantastic (spontaneous) confabulation consisting of grandiose and wish-fulfilling characteristics. There is no specific localization for provoked confabulations. However spontaneous confabulations appear as a result of basal forebrain and posterior orbitofrontal cortex lesions. There are numerous hypotheses for explaining the specific nature of confabulations with reference to impairment of general executive dysfunction, temporality, and memory-control processes. Commonly, these interpretations explain memory distortion in terms of frontal network dysfunction. There is a general consensus that confabulation is primarily the result of a deficit of memory retrieval, rather than one of encoding, consolidation, or storage. The normal process of memory recall consists of the evaluation of the cues for retrieval, matching the cues with episodic memory, and reality monitoring. One possible explanation for confabulation is that these patients have lost the checking procedure in memory retrieval, i.e. reality monitoring. This article aimed to describe confabulation and to review its clinical, neuroanatomical, and neuropsychological correlates in an effort to raise clinicians' awareness of the phenomenon and the problematic areas that need to be clarified.
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PMID:[Confabulation: a symptom which is intriguing but not adequately known]. 1756 83

Confabulation-fabricated or distorted memories about oneself-occurs in many disorders, but there is no reliable technique for investigating it in the laboratory. The authors used hypnosis to model clinical confabulation by giving subjects a suggestion for either (a) amnesia for everything that had happened since they started university, (b) amnesia for university plus an instruction to fill in memory gaps, or (c) confusion about the temporal order of university events. They then indexed different types of memory on a confabulation battery. The amnesia suggestion produced the most confabulation, especially for personal semantic information. Notably, subjects confabulated by making temporal confusions. The authors discuss the theoretical implications of this first attempt to model clinical confabulation and the potential utility of such analogues.
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PMID:A hypnotic analogue of clinical confabulation. 2597 80

Confabulation is often observed in amnesic patients after brain damage. However, evidence regarding the relationship between confabulation and other neuropsychological functions is scarce. In addition, previous studies have proposed two possibilities of the relationship between confabulation and false memory, in which patients with confabulation are likely to retrieve false memories, or confabulations are relatively independent of false memories. The present study investigated how confabulation is related to various cognitive functions, including orientation, attention, frontal lobe function, memory, and mental status, and to false memories, as assessed by the Deese-Roediger-Mcdermott (DRM) paradigm. Patients with organic amnesia participated, and confabulations were evaluated using the Confabulation Battery. Amnestic patients were classified into two groups: confabulating (CP) and nonconfabulating patients (NCP). The CP group was significantly impaired in time orientation, attention, and verbal memory, compared to the NCP group and age-matched healthy controls (HC). Results of the DRM paradigm revealed no significant difference in false memory retrieval induced by critical lures across CP, NCP, and HC groups. Confabulating responses in organic amnesia could be in part induced by disturbance of time consciousness and attention control in severe impairment of verbal memories, and confabulation and false memory could be modulated by different cognitive systems.
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PMID:Disturbance of time orientation, attention, and verbal memory in amnesic patients with confabulation. 2658 2

The Korsakoff syndrome is defined as "an abnormal mental state in which memory and learning are affected out of all proportion to other cognitive functions in an otherwise alert and responsive patient." Confabulation refers to false or erroneous memories arising, not deliberately, in the context of a neurological amnesia and is often thought of as pathognomonic of the Korsakoff syndrome. Although the exact pathophysiology is unknown, various studies have identified brain lesions in the thalami, mammillary bodies, and frontal cortex. We report a case of a 68-year-old male presenting with acute altered mental status on July 16, 2015. The neuropsychological dysfunctions included prominent Korsakoff's syndrome, which became apparent when the altered mental status resolved. Amnesia was accompanied by prominent confabulation, disorientation, and lack of insight into his own disability. Neuroradiological data indicated that the intralaminar and dorsomedial nuclei in bilateral thalami were infarcted by occlusion of the artery of Percheron. We believe that ours is one of few reported cases of Korsakoff syndrome in a patient with infarction involving the territory of the artery of Percheron. We conclude that bilateral thalamic lesions could cause Korsakoff's syndrome and the intralaminar and dorsomedial nuclei might be important structures in the pathogenesis of confabulation.
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PMID:Artery of Percheron Infarction as an Unusual Cause of Korsakoff's Syndrome. 2668 63

Confabulation, the production of statements and actions that are unintentionally incongruous to the subject's history, background, present and future situation, is observed in several conditions affecting the nervous system, but it has never been described in normotensive hydrocephalus. In this article we report on a patient with normotensive hydrocephalus who suffered from an amnesic-confabulatory syndrome. After hydrocephalus shunting, both amnesia and confabulation cleared up abruptly. We discuss this finding in terms of a possible disconnection of the hippocampus, due to transitory white matter damage, which may have recovered after hydrocephalus shunting.
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PMID:Recovery from confabulation after normotensive hydrocephalus shunting. 2672 92


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