Cases reported "Amnesia, Retrograde"

Filter by keywords:



Filtering documents. Please wait...

1/14. Retrograde amnesia for world knowledge and preserved memory for autobiographic events. A case report.

    A patient (PC) with severe and chronic retrograde amnesia for world knowledge (tested with famous events and famous faces), but unimpaired autobiographical memory is described. The 64-year-old man had traumatic brain injury four years prior to the present evaluation. Current brain imaging showed principally damage involving the infero-lateral prefrontal and the lateral temporal regions of the left-hemisphere. PC was of average intelligence, had no depression and only minor language problems, but manifested some additional anterograde memory deficits and performed subaverage in various frontal lobe-sensitive tests. Patient PC represents one of the very few cases with a preserved retrograde episodic and an impaired retrograde knowledge system, showing a dissociation between preserved retrieval of autobiographical events and amnesia for nonpersonal famous events. It is hypothesized that the sparing of autobiographical memories can be linked to the integrity of the right frontal and temporo-polar cortices.
- - - - - - - - - -
ranking = 1
keywords = dissociation
(Clic here for more details about this article)

2/14. Selective impairment of reasoning about social exchange in a patient with bilateral limbic system damage.

    Social exchange is a pervasive feature of human social life. Models in evolutionary biology predict that for social exchange to evolve in a species, individuals must be able to detect cheaters (nonreciprocators). Previous research suggests that humans have a cognitive mechanism specialized for detecting cheaters. Here we provide neurological evidence indicating that social exchange reasoning can be selectively impaired while reasoning about other domains is left intact. The patient, R.M., had extensive bilateral limbic system damage, affecting orbitofrontal cortex, temporal pole, and amygdala. We compared his performance on two types of reasoning problem that were closely matched in form and equally difficult for control subjects: social contract rules (of the form, "If you take the benefit, then you must satisfy the requirement") and precaution rules (of the form, "If you engage in hazardous activity X, then you must take precaution Y"). R.M. performed significantly worse in social contract reasoning than in precaution reasoning, when compared both with normal controls and with other brain-damaged subjects. This dissociation in reasoning performance provides evidence that reasoning about social exchange is a specialized and separable component of human social intelligence, and is consistent with other research indicating that the brain processes information about the social world differently from other types of information.
- - - - - - - - - -
ranking = 1
keywords = dissociation
(Clic here for more details about this article)

3/14. Encoding and the frontal lobes: a dissociation between retrograde and anterograde memories.

    Recent functional neuroimaging studies have suggested that different neural substrates within the frontal lobes are associated with memory encoding, retrieval and monitoring. If this is the case, then it should be possible to find frontal patients with selective deficits to these processes. However, most laboratory based memory tests (e.g. Wechsler memory Scale) require a combination of all these processes making it hard to find clear dissociations between patients. Using tests of everyday memory, this study documents a clear dissociation between a frontal patient's (JB) impaired ability to retrieve events from the anterograde period relative to spared ability to retrieve events from the retrograde period. This is consistent with specific disruption to frontal mechanisms associated with encoding which disrupts the formation of new episodic memories. The defective mechanism may be related to more general aspects of cognitive processing (e.g. selection demands), but it is unlikely to reflect damage to working memory (as assessed by the n-back task) as there is a clear dissociation between spared performance on this task and impaired performance on a comparable episodic recognition memory task.
- - - - - - - - - -
ranking = 7
keywords = dissociation
(Clic here for more details about this article)

4/14. A case of psychogenic fugue: I understand, aber ich verstehe nichts.

    Psychogenic fugue is a disorder of memory that occurs following emotional or psychological trauma and results in a loss of one's personal past including personal identity. This paper reports a case of psychogenic fugue in which the individual lost access not only to his autobiographical memories but also to his native German language. A series of experiments compared his performance on a variety of memory and language tests to several groups of control participants including German-English bilinguals who performed the tasks normally or simulated amnesia for the German language. Neuropsychological, behavioral, electrophysiological and functional neuroimaging tests converged on the conclusion that this individual suffered an episode of psychogenic fugue, during which he lost explicit knowledge of his personal past and his native language. At the same time, he appeared to retain implicit knowledge of autobiographical facts and of the semantic or associative structure of the German language. The patient's poor performance on tests of executive control and reduced activation of frontal compared to parietal brain regions during lexical decision were suggestive of reduced frontal function, consistent with models of psychogenic fugue proposed by Kopelman and Markovitsch.
- - - - - - - - - -
ranking = 190.15924095356
keywords = fugue
(Clic here for more details about this article)

5/14. Actors but not scripts: the dissociation of people and events in retrograde amnesia.

    We describe our further investigations of the retrograde amnesia in a single case. R.F.R. became globally amnesic following an attack of herpes simplex encephalitis. He could generate and recognize superordinate level information about the vast majority of proper names including the names of people but he was very impaired at giving information about what had "happened" to these same individuals. He could also provide detailed information about family friends but he could not recall salient major personal episodes in which these same individuals had been involved. knowledge of people appears to be represented in a different way to that of events, even when a singular event has provided the main or only opportunity for learning about the individual.
- - - - - - - - - -
ranking = 4
keywords = dissociation
(Clic here for more details about this article)

6/14. The dissociation of anterograde and retrograde amnesia in a patient with herpes encephalitis.

    Establishing the precise relationship between anterograde amnesia (AA) and retrograde amnesia (RA) has implications for psychological and neuroanatomical models of memory. Many patients have been described who demonstrate AA in conjunction with RA or who demonstrate AA with little, or no apparent, RA. Intact anterograde memory in conjunction with deficits on tasks of retrograde memory is rarely encountered. In this paper, we describe a young female patient (LD) whose RA is extremely severe when contrasted with her mild to moderate deficits on tasks of verbal anterograde memory. In addition, on tests of episodic and semantic autobiographical memory, LD appeared more impaired in her recall of specific episodes than of factual information about her past. The importance of this dissociation in RA for the episodic-semantic distinction and the possible role of visual imagery in recalling remote episodic events are discussed.
- - - - - - - - - -
ranking = 5
keywords = dissociation
(Clic here for more details about this article)

7/14. The case of K.C.: contributions of a memory-impaired person to memory theory.

    K.C. has been investigated extensively over some 20 years since a motorcycle accident left him with widespread brain damage that includes large bilateral hippocampal lesions, which caused a remarkable case of memory impairment. On standard testing, K.C.'s anterograde amnesia is as severe as that of any other case reported in the literature, including H.M. However, his ability to make use of knowledge and experiences from the time before his accident shows a sharp dissociation between semantic and episodic memory. A good deal of his general knowledge of the world, including knowledge about himself, is preserved, but he is incapable of recollecting any personally experienced events. In displaying such "episodic amnesia," which encompasses an entire lifetime of personal experiences, K.C. differs from many other amnesic cases. Here, we document for the first time the full extent of K.C.'s brain damage using MRI-based quantitative measurements. We then review the many investigations with K.C. that have contributed to our understanding not only of episodic and semantic memory but also to the development of other aspects of memory theory. These include the distinction between implicit and explicit memory, the prospect of new learning in amnesia, and the fate of recent and remote memory for autobiographical and public events, people, and spatial locations.
- - - - - - - - - -
ranking = 1
keywords = dissociation
(Clic here for more details about this article)

8/14. Functional focal retrograde amnesia: lost access to abstract autobiographical knowledge?

    We describe three patients exhibiting an acute reversible amnesia characterised by an impaired recollection of past events with preserved anterograde memory, thus consistent with a focal retrograde amnesia (FRA). This occurred after variable events: state of fugue, road accident, post-traumatic headache. Retrograde amnesia affected autobiographical memory so severely as to cover all of the patients' lives and to erase knowledge of their own identity. The retrieval of public events was variably affected, ranging from normality to severe impairment. No lesions were found on neuroimaging, and neurophysiological findings were unimpressive. FRA subsided in a few days, leaving a gap for the onset. The hypothesis of a psychogenic amnesia is considered, but overcoming the organic/psychogenic dichotomy the episodes appear as examples of "functional" memory inhibition, potentially triggered by different conditions, including events classifiable as psychic trauma. The clinical and neuropsychological traits of functional FRA are discussed. According to a current theory of autobiographical memory, the memory profile may be explained by a lost access to abstract autobiographical knowledge. Given some analogies with the more common transient global amnesia, a mechanism of spreading depression may also be hypothesised for functional FRA.
- - - - - - - - - -
ranking = 23.769905119195
keywords = fugue
(Clic here for more details about this article)

9/14. Anterograde amnesia with fornix damage following removal of IIIrd ventricle colloid cyst.

    Two patients developed anterograde amnesia following the apparently uncomplicated transcallosal-transventricular removal of a colloid cyst. Damage to the fornical columns was demonstrated on CT and MRI scans, whilst other memory related structures were entirely normal. Longitudinal neuropsychological evaluation, over 12-24 months, has revealed a very similar pattern of deficit in the two cases: verbal memory has remained persistently impaired whilst nonverbal anterograde memory has improved to some degree. Formal tests of remote public (famous faces and events) and personal autobiographical memory have supported the clinical impression that neither patient has a temporally extensive retrograde amnesia. These findings address the role of the fornix, and the dissociation of memory processes in humans.
- - - - - - - - - -
ranking = 1
keywords = dissociation
(Clic here for more details about this article)

10/14. Post-traumatic retrograde amnesia with selective impairment of autobiographical memory.

    A selective, temporally limited retrograde amnesia, confined to autobiographical memory, was the only sequela of a "minor" head trauma in two young men. The retrograde memory gap covered about one year of life before the trauma and persisted for several months, without any anterograde deficit or other cognitive disturbances. This unusual pattern of retrograde amnesia deserves close consideration and points to the dissociation of memory subsystems and mechanisms.
- - - - - - - - - -
ranking = 1
keywords = dissociation
(Clic here for more details about this article)
| Next ->


Leave a message about 'Amnesia, Retrograde'


We do not evaluate or guarantee the accuracy of any content in this site. Click here for the full disclaimer.