Amnesic Disorders Research Articles

Nicotinic receptor activation in perirhinal cortex and hippocampus enhances object memory in rats

The perirhinal cortex (PRh) and its cholinergic inputs are implicated in object recognition memory. Conversely, the hippocampus (HPC) may be involved in spatial recognition processes that are not essential to the recognition of objects per se. Systemic nicotine has been shown to facilitate both object and spatial memory. The current study compared the roles of perirhinal and hippocampal nicotinic acetylcholine receptors (nAChRs) in object and spatial recognition memory using spontaneous object recognition (SOR) and object-location (OL) tasks for rats. Systemic pre-sample (acquisition) nicotine administration dose-dependently facilitated SOR and OL performance compared to vehicle conditions in which performance was at chance with a 72-h retention delay between the sample and choice phases. Subsequently, pre-sample intra-PRh infusions of nicotine significantly facilitated SOR; somewhat surprisingly, pre-sample intra-HPC nicotine also enhanced object recognition memory. Further experiments indicated facilitative effects on OL performance caused by pre-sample intra-PRh or intra-HPC nicotine administration. These results not only demonstrate that nAChR activation facilitates performance on object recognition and object-location memory tasks, but suggest that these effects can be produced by nAChR action in either PRh or HPC. Thus, although PRh and HPC are not required for OL or SOR task performance, respectively, nAChR-mediated enhancement of neural function in either of these temporal lobe regions appears capable of promoting stronger memory encoding and/or consolidation in either task. These findings further support the supposed interactive relationship between the HPC and PRh in object information processing and highlight the potential therapeutic value of nicotinic receptor activation in amnesic disorders.

Functional Neuroimaging in Dementia and other Amnesic Disorders: A Radiological Review

Problem statement: The structural and functional neuroimaging have much to contribute to the cognitive neuroscience. Approach: We describe a radiological review of the major dementia syndromes and Mild Cognitive Impairment (MCI), included Alzheimer's disease, Lewy body dementia, Vascular dementia, Front temporal Lobar degeneration, Dementia associated with parkinsonism and other amnesic syndromes. Results: The different syndromes and diseases presenting with dementia have different patterns of brain perfusion abnormalities, it is possible to distinguish them with good specificity with neuroimaging. Conclusion: New imaging techniques carry the hope of revolutionizing the diagnosis of dementia so as to obtain a complete molecular, structural and metabolic characterization, which could be used to improve diagnosis and to stage each patient and follow disease progression and response to treatment. Structural and functional imaging modalities contribute to the diagnosis and understanding of the different dementias.

002 Clinical varieties of memory disorders

: This talk will give an overview regarding clinical memory disorders. These encompass far more than just the dementias. Amnesic disorders can be transient or persisting. They can have a...

On a Peculiar Environmental Dependency Syndrome in a Case with Frontal-Temporal Damage: Zelig-like Syndrome

We report on the case of a patient with frontal-temporal damage from cerebral hypoxia, affected by amnesic disturbances and behaviour disorder, who presented a peculiar phenomenon of environmental dependency. He assumed a different social role in keeping with different environmental circumstances by interpreting a character corresponding to the particular context. Three experiments were carried out in which the environmental variables were manipulated to verify the phenomenon in controlled conditions, and an investigation was conducted during the patient's spontaneous manifestations. The phenomenon was interpreted as a loss of frontal inhibition whose function was the control of his own identity and consequent “attraction” towards a social role proposed by the environment.

Textbook of Geriatric Psychiatry, Third Edition

Textbook of Geriatric Psychiatry, Third Edition

A Theory of Autobiographical Memory: Necessary Components and Disorders Resulting from their Loss

In this paper we argue that autobiographical memory can be conceptualized as a mental state resulting from the interplay of a set of psychological capacities—self-reflection, self-agency, self-ownership and personal temporality—that transform a memorial representation into an autobiographical personal experience. We first review evidence from a variety of clinical domains—for example, amnesia, autism, frontal lobe pathology, schizophrenia—showing that breakdowns in any of the proposed components can produce impairments in autobiographical recollection, and conclude that the self-reflection, agency, ownership, and personal temporality are individually necessary and jointly sufficient for autobiographical memorial experience. We then suggest a taxonomy of amnesic disorders derived from consideration of the consequences of breakdown in each of the individual component processes that contribute to the experience of autobiographical recollection.

Avaliação neurocognitiva no abuso e dependência do álcool: implicações para o tratamento

The aim of the Neuropsychology applied to the Alcohol Dependence field is the comprehension of the effects of brain dysfunction on cognition and human behavior. It investigates neurocognitive impairments and associates them to structural and functional neuroimaging findings (CT, MRI, PET and SPECT). Acute use of alcohol impairs attention, memory, executive functions and visuospatial skills, while chronic abuse causes neurocognitive deficits in memory, learning, visuospatial functions, psychomotor speed processing, executive functions and decision-making, and may lead to persistent amnesic disorder and alcoholic dementia. Executive Dysfunction related to frontal lobe has direct implications on treatment, by the choosing of strategies and for prognostic evaluation. It is presented an easy tool to screen cognitive impairments, the Frontal Assessment Battery--FAB.15. Neuropsychological Assessment is useful for early detection of impairments and evaluation of their evolution and Cognitive Rehabilitation has a significant role on deficits recovery and psychosocial adjustment of these patients.

Nelly's Version

Nelly's Version

Serial Position Learning Effects in Patients With Aneurysms of the Anterior Communicating Artery

Ruptured and repaired Anterior Communicating Artery (ACoA) aneurysm can result in devastating impairments involving memory, executive function, confabulation, and personality changes. This study tested serial position learning effects (SPEs) in patients following repaired and ruptured ACoA aneurysm, using results on the Rey Auditory Verbal Learning Test (RAVLT). Thirty patients with ruptured aneurysms of the ACoA and 31 matched controls were included in the study. The primacy-recency effects were maintained during five learning trials in ACoA group, albeit at an overall lower level than in the controls. There was no difference in primacy-recency relation across five learning trials in ACoA group. On the delayed recall trial the patient group demonstrated neither a primacy, nor a recency phenomenon, reflecting a lack of recall of any parts of the word list. This kind of primacy-recency profile across learning trials in ACoA group has no similarity with SPE results in frontal lesion groups, or with SPE distributions in other amnesic disorders, despite the fact that memory and executive deficits were evident in our ACoA group.

Diagnóstico diferencial del síndrome posconmocional

Posconcussional syndrome is characterized by a heterogeneous group of somatic, cognitive and psychosocial symptoms, which occur in patients with head trauma, generally of mild severity. It is the neuropsychiatric postraumatic disorder more prevalent in the field of forensic medicine. Classical authors (Lishamn and Barraquer, for example) focused on controversial aspects of this syndrome, such as conceptual problems and etiology (organic versus functional). The objective of this report is to review the posconcussional literature in search of relevant aspects in forensic neuropsychology: conceptual aspects, epidemiology, etiology, clinical features, methodology for assessment, and its differential diagnosis with other postraumatic disorders, such as postraumatic stress disorder, adjustment disorder, anxiety disorder, mood disorders (major depressive disorder), substancerelated disorders, dementia due to head trauma, amnesic disorder, somatoform disorders, factitious disorder, malingering, chronic pain and chronic whiplash syndrome.

Executive Amnesia in a Patient with Pre-frontal Damage due to a Gunshot Wound

This paper reports the case of a young patient with extensive pre-frontal damage in whom we tested the hypothesis that intensive training improves executive performance as assessed by the Wisconsin Card Sorting Test (WCST). As long as her declarative memory, complex perceptual abilities and global cognitive status were spared, we surmised that any deficit in executive learning would have occurred in relative isolation. We showed that her abnormal performance on the WCST, both on the standard as well as on the post-instruction condition, was due to an impairment of shifting attention across perceptual dimensions (extra-dimensional). In contrast, her ability to shift attention within perceptual categories (intra-dimensional) was spared, as were her declarative memory, object and visuospatial perception, oral language comprehension and praxis (ideomotor, tool use and constructional). This case supports the hypothesis that executive amnesia is a type of amnesic disorder distinct from the classic amnesic syndrome due to mamillo-temporomedial damage. As such, it is probably closely related to procedural learning and may depend on the same fronto-subcortical loops that mediate the actual execution of behaviour.

Confabulation and multiple sclerosis: a rare association

Fantastic confabulation in the context of Multiple Sclerosis (MS) has not previously been reported in the literature. The association is of interest because clearly demonstrable brain pathology in MS together with other cognitive and behavioural correlates may further our understanding of the neural basis underlying confabulation. A single case report with magnetic resonance imaging of the brain and detailed neuropsychological evaluation. Confabulation occurred together with disinhibited and stimulus bound behaviour. While the patient's physical and emotional state limited the range of psychometric tests administered, the results revealed an inability to maintain focused, regulated information processing. Although memory difficulties were present, they were not in the nature of a severe amnesic disorder. The patient appeared to have a broad fund of knowledge, but the associations binding the information together and putting it into context were loose. All three features of a triad of responses previously described in confabulating patients were present, namely an inability to withhold answers, to monitor one's own responses and provide verbal self corrections. MRI of the brain showed bilateral periventricular lesions and discrete frontal lesions with 53% of the total lesion volume distributed in frontal areas. Cortical atrophy, most marked in frontal regions also was conspicuous. Confabulation linked to frontal lobe involvement may occur as part of the changes in mentation found in MS. It is, however, rare and although associated with impaired memory, may be found in the absence of a severe amnesic disorder. This conclusion is discussed in the light of observations from the literature suggesting that frontal involvement is a prerequisite before fantastic confabulation occurs.

Implicit and explicit memory in autism: is autism an amnesic disorder?

Medial temporal lobe amnesic disorder is characterized by an impairment in explicit memory (e.g., remembering a shopping list) and intact implicit memory (e.g., a woman seems familiar although you cannot remember having met her before). This study examined whether children with high-functioning autism have this same dissociation between explicit and implicit memory abilities. Children with autism and normal development participated in three memory tasks: one implicit task (perceptual identification) and two explicit tasks (recognition and recall). Children with autism showed intact implicit and explicit memory abilities. However, they did not show the typical pattern of recalling more items from both the beginning and end of a list and instead only recalled items from the end of the list. These results do not support the theory that high-functioning autism is a type of medial temporal lobe amnesia. However, these findings suggest that persons with autism use different organizational strategies during encoding or retrieval of items from memory.

ICD-10 Casebook: The Many Faces of Mental Disorders—Adult Case Histories According to ICD-10

Back to table of contents Previous article Next article Book Forum: ASSESSMENT AND DIAGNOSISFull AccessICD-10 Casebook: The Many Faces of Mental Disorders—Adult Case Histories According to ICD-10MARY V. SEEMAN, M.D., MARY V. SEEMANSearch for more papers by this author, M.D., Toronto, Ont., CanadaPublished Online:1 Oct 1999https://doi.org/10.1176/ajp.156.10.1656AboutSectionsView EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail “Names,” says an old maxim, “are things. They certainly are influences. Impressions are left and opinions are shaped by them.…The mean and selfish talk of their prudence and economy; the vain and proud prate about self-respect; obstinacy is called firmness, and dissipation the enjoyment of life; seriousness is ridiculed as cant, and strict morality and integrity, as needless scrupulosity; and so men deceive themselves.” Tryon Edwards (1809–1894) published this maxim in his first book of quotations in 1852 under the title Jewels for the Household. He certainly was not thinking about psychiatric diagnoses, but his words apply rather well to the self-deception that underlies the notion that to name something is to know it.Psychiatry is good at naming. The case histories in this little book were selected from those used in ICD-10 training courses around the world and in the clinical field trials that resulted in the current international classification system. The field trials apparently yielded some 400 case summaries. This book presents more than 100, each illustrating one of the categories of the adult diagnoses coded F0 to F6 in ICD-10. Because the psychiatric categories are very similar to those in DSM-IV, the cases may well be useful for training and discussion. And questioning.The personal stories are culled from around the world, and each contains the presenting problem, the history, the findings, and the course of illness. Each is followed by a discussion section that illustrates the application of ICD-10 guidelines in the making of a specific diagnosis. Each example is colorfully titled, so the story (and the salient diagnostic issues) remains firmly planted in the minds of students, e.g., “The Royal Visit,” “The Smell of Revenge,” “Pulling Up the Flax.”The editors direct interested students to two companion books, the “blue” book (ICD-10 chapter 5, “Clinical Descriptions and Diagnostic Guidelines”) for clinicians and the “green” book (ICD-10 chapter 5, “Diagnostic Criteria for Research”) for researchers. This one is the “red” book, meant as an easy introduction to the art of diagnosis based on predominantly cross-sectional information about presenting symptoms and physicians’ findings.Students may find it helpful to make the crosswalk between the international system and the American system. ICD-10 continues to use the term “organic mental disorders” (F0 and F1), F1 encompassing psychoactive substance abuse disorders. DSM-IV has stopped using the word “organic” (presumably all disease has biological correlates) and, instead, uses descriptive categories: deliriums, dementias, amnesic disorders, mental disorder due to a general medical condition, and substance-related disorders. ICD-10 F2 and F3 are grouped as psychotic mental disorders (schizophrenia and mood disorders), although many of the examples are without psychotic features. Why is something a psychotic disorder if only some of the cases, some of the time, exhibit psychosis? Incidentally, what is psychosis? The ICD-10 F4, F5, and F6 categories cover “neurotic, stress, and personality disorders.” DSM-IV calls these anxiety, somatoform, factitious, dissociative, sexual and gender identity, eating, impulse control, and personality disorders, having dispensed with the meaningless word “neurotic.” Perhaps, soon, the equally meaningless word “personality” will yield to more understandable descriptors.Despite the somewhat different names, the syndromes are clearly similar in the two systems, and, around the world, as in the United States, the available treatments continue to be limited in number and efficacy no matter what the disorder is called.There is certainly magic in names. “Some to the fascination of a name surrender judgement, hoodwinked” (William Cowper, 1731–1800).By T.B. Üstün, A. Bertelsen, J. van Drimmelen, C. Pull, A. Okasha, N. Sartorius, and other ICD-10 Reference and Training Center Directors. Washington, D.C., American Psychiatric Press, 1996, 237 pp., $35.00. FiguresReferencesCited byDetailsCited byNone Volume 156Issue 10 October 1999Pages 1656-1656 Metrics History Published online 1 October 1999 Published in print 1 October 1999

Thiamin Deficiency and Korsakoff's Syndrome: Failure to Find Memory Impairments Following Nonalcoholic Wernicke's Encephalopathy

Prolonged alcohol consumption is associated with a variety of neuropsychiatric conditions, including the dense amnesic disorder known as Korsakoff's syndrome. Korsakoff's syndrome is frequently diagnosed in alcoholics after an episode of acute thiamin deficiency. The accepted view within the medical literature is that the etiology of this disorder lies in thiamin deficiency or Wernicke's encephalopathy. However, examination of the published reports of pure thiamin deficiency unaccompanied by chronic and excessive consumption of alcohol shows that, in this group of patients, the rate of progression to Korsakoff's syndrome is low. This result suggests that the memory impairments associated with alcohol-related brain damage cannot be attributed to thiamin deficiency alone. The etiology of alcohol-related cognitive impairments such as Korsakoff's syndrome is still poorly understood but several lines of evidence suggest multiple causal factors interact to produce deficits in performance. Animal models that manipulate only a single putative etiological factor are unlikely to elucidate the multiple influences that lead to Korsakoff's syndrome. A study of the natural history of alcohol-related brain damage is needed that will allow an assessment of individual risk factors and their interactions.

Criterion-based validity of an intracarotid amobarbital recognition-memory protocol.

We tested whether the behavioral components of an Intracarotid Amobarbital Protocol (IAP) had criterion validity. It was hypothesized that a recognition-memory test designed for intracarotid injections and used to predict the risk of global amnesia before an elective temporal lobectomy should also identify persons who are severely amnesic due to other neurologic causes. Divergent validity predicts that speech tasks would be unaffected by amnesia. Test-retest reliability also was measured. Fifteen persons with severe amnesia were administered four alternate forms of a yes/no recognition-memory protocol and a speech protocol. No drug injection occurred. Standardized neuropsychological tests were used to divide the amnesic group into those with Global Amnesia (i.e., retain no ongoing memories), Severe Amnesia (i.e., memory impaired), and Amnesia Plus (severe amnesia plus other neuropsychologic deficits). Two persons with Global Amnesia obtained scores at or below chance (i.e., failed) on the memory protocol. Unexpectedly, 12 of 13 severely amnesic persons obtained near-perfect memory scores. Amnesia had no impact on the speech protocol. Pass/Fail outcomes were highly correlated across all four sets. A four-item IAP memory protocol showed good reliability and criterion validity in identifying the rare condition of Global Amnesia, but it was insensitive to other disabling, severe amnesic disorders. This IAP memory protocol might have validity in predicting a postsurgical Global Amnesic disorder, but it did not identify and therefore could not predict other more common severe amnesic disorders.

The effects of single and repeated episodes of thiamin deficiency on memory in alcohol-consuming rats

The underlying pathogenesis of Korsakoff's syndrome, an amnesic disorder most commonly found in alcoholics, is not well understood. Chronic alcoholism is associated with thiamin deficiency and current thinking is that this may be the causal factor. In Experiment 1, rats were given a 20% (v/v) ethanol/water mix as their only source of fluid for 156 days. Three groups were made thiamin deficient through the combination of a thiamin-deficient diet and the centrally acting thiamin antagonist pyrithiamin hydrobromide, after 4, 15, and 26 weeks exposure to ethanol, respectively. The control group was given ad lib access to laboratory chow and water throughout this period. There were no differences between groups on either the working or reference versions of the Morris water tank paradigm. In Experiment 2, to test the hypothesis that a single bout of thiamin deficiency, with or without concurrent alcohol intake, is not sufficient to cause severe memory impairments, two groups of rats were subjected to three bouts of thiamin deficiency. One of these groups consumed an ethanol/water mix, the other tap water. A third group was made thiamin deficient on only one occasion. The control group was not made thiamin deficient and consumed lab chow and tap water throughout. Once again, there were no between-group differences in the data derived from testing in either the eight-arm radial maze or the Morris water tank task. These experiments indicate that the aetiology of Korsakoff's syndrome is more complex than previously thought.

Is autism an amnesic disorder? Evidence from the California Verbal Learning Test.

Is autism an amnesic disorder? Evidence from the California Verbal Learning Test.

Is autism an amnesic disorder? Evidence from the California Verbal Learning Test.

Is autism an amnesic disorder? Evidence from the California Verbal Learning Test.

Das Syndrom der partiellen cholinergen Deafferentierung des kortikalen Mantels - ein Konzept zur Beschreibung des brain-behaviour-relationships bei dementiellen Erkrankungen

The identification of morphological and biochemical changes in neurodegenerative disorders with both common and different patterns of neuropsychological dysfunction may help to define the neurobiological substrate of amnesic and dementing disorders, and, furthermore, will give some insight into the neuronal organisation of memory processes. The concept of "subcortical and cortical dementia" and the "cholinergic hypothesis of memory dysfunction" reflect two different theoretical approaches which relate psychopathological disturbances in Alzheimer's disease, Parkinson's disease, Korsakoff's psychosis and related conditions either to structurally or to chemically defined systems of the brain. In order to overcome limitations arising from this dichotomy of structural and chemical approaches to the brain-behaviour-relationship, the concept of a "syndrome of partial cholinergic deafferentation of the cortical mantle" is suggested in the present paper. This concept is supported by evidence derived from the biochemical, morphological and behavioural sequelae of acute and chronic experimental interference with the cholinergic afferentation of the cortical mantle by the application of neurotoxins, by pharmacological intervention and by neurotransplantation in rat. Regarding the cholinergic projection neurons of the basal forebrain and upper brainstem as components of the reticular activating system, the involvement of the cholinergic afferentation of the cortical mantle in the mediation of memory processes and their dysfunction under the conditions of neurodegenerative disorders can be explained on the basis of the "Hippocampal Memory Indexing Theory" of Teyler and DiScenna.