Amnestic disorders and their role in cognitive theory

Amnesia refers to a disorder of memory, and classical amnesia with continuous problems in aquiring new information is the most studied type of amnesia. The integration into a memory systems model of clinical studies of classical amnesia, cognitive theory, and studies with neuroimaging methods is one of the prime success stories in modern cognitive neuroscience. The clinical spectrum of amnesia encompasses a wide range of disorders ranging from specific encoding deficits for language or visuospatial information to psychogenic amnesia with confusion and loss of memory for personal identity. Two cases are reviewed, one with selective verbal amnesia and the other with focal retrograde amnesia, presenting some puzzles and challenges to current modular thinking about memory that may lead to theoretical advances. An interactive model emphasizing the communication between brain codes and regions in memory may have promise.     

The effects of context and subjects' perceived control in breaching posthypnotic amnesia

Subjects selected on the basis of being amnesic and experiencing their amnesia as “voluntary” or “involuntary” were subjected to two conditions designed to breach their amnesia: (1) lie detector, and (2) honesty instructions. A third group receiving relaxation instructions served as a control. Posthypnotic amnesia was breached under lie detection and honesty conditions. However, there appeared to be an interaction between how subjects reported their experience of amnesia (voluntary and involuntary) and the degree to which amnesia was breached. Voluntary subjects accounted for the majority of breaching. Implications for (1) studies on breaching, (2) theories and processes of breaching, Implications for (1) studies on breaching, (2) theories and processes of posthypnotic amnesia, and (3) studies in posthypnotic amnesia are discussed.     

Crime and amnesia: A review

The present article reviews amnesia for criminal offenses. It discusses the organic disorders most likely to be implicated, and the nature and differentiation of psychogenic amnesia. With the exception of alcohol and drug intoxication, organic dysfunction is a rare (though important) cause of amnesia for crime. Likewise, fugue states may occasionally be triggered by an offence, but are a very rare cause of the amnesia claimed by offenders. Amnesia is most commonly seen in homicide cases, in which it is claimed by 25% to 45% of offenders, but it occurs also in other types of violent crime, and occasionally in nonviolent crime. It arises in states of extreme emotional arousal, in alcoholic intoxication, and in states of florid psychosis; and it is also associated with depressed mood. Various methods have been advocated for the differentiation of genuine amnesia from deliberate simulation: this distinction can be difficult, but it is noticeable that many amnesic subjects either have reported the crime themselves or have made no attempt to conceal it. The nature of the deficit in this type of amnesia, and its implications for assessment, are also discussed.     

On the relation between genuine and simulated amnesia

When claims of amnesia are made in legal cases, it is necessary to determine whether they are genuine or simulated. This article assesses current knowledge of the relation between genuine and simulated amnesia and discusses issues that are critical to understanding of the problem. It is argued that there are few well established facts regarding the nature of simulated amnesia, and no evidence that experts can distinguish accurately between genuine and simulated amnesia. Suggestions are made for future research that draw upon recent advances in cognitive psychology, social psychology, and neuropsychology.     

Managing Racial Anger: A Critical Skill in Cultural Competence

Anger management has been overlooked as a vital component of cultural competency training. Clinical and teaching examples demonstrate the effective use of anger in facilitating therapy and training.     

Growth points in research on memory and hippocampus.

We present an overview of two of our on-going projects relating processes in the hippocampus to memory. We are trying to understand why retrograde amnesia occurs after damage to the hippocampus. Our experiments establish the generality of several new retrograde amnesia phenomena that are at odds with the consensus view of the role of the hippocampus in memory. We show in many memory tasks that complete damage to the hippocampus produces retrograde amnesia that is equivalent for recent and remote memories. Retrograde amnesia affects a much wider range of memory tasks than anterograde amnesia. Normal hippocampal processes can interfere with retention of a long-term memory stored outside the hippocampus. We conclude that the hippocampus competes with nonhippocampal systems during memory encoding and retrieval. Finally, we outline a project to understand and manipulate adult hippocampal neurogenesis in order to repair damaged hippocampal circuitry to recover lost cognitive functions.     

Midazolam amnesia and retrieval from semantic memory: Developing methods to test theories of implicit memory

Studies of organic anterograde amnesia have been central to the development of theories of implicit memory. Pharmacological amnesia provides an additional method for exploring implicit memory, allowing for the experimental manipulation of amnesia and the testing of more participants. A significant concern with pharmacological amnesia is whether its cognitive effects are specific to explicit memory. The current research examines the effects of the benzodiazepine, midazolam, on retrieval from semantic memory and encoding in explicit memory. We focus on midazolam because it holds significant advantages over other benzodiazepines in inducing pharmacological amnesia and prior research suggests it may be useful for testing theories of implicit memory. Our results demonstrate that midazolam does not impair accuracy of retrieval from semantic categories, even when it produces anterograde amnesia for retrieved category items on a later recall test. These results suggest ways midazolam can be used to help test theories of implicit memory.     

Syndromes of retrograde amnesia: a conceptual and empirical synthesis

This article attempts a synthesis of the range of disorders that have been subsumed under the rubric of retrograde amnesia. At a functional level, it is possible to make distinctions between various forms of retrograde amnesia, including a distinction between episodic amnesia for personally experienced events and semantic retrograde amnesia for components of knowledge, such as those relating to people and events. At an anatomical level, discrete lesions to limbic-diencephalic structures usually result in a limited degree of retrograde amnesia. Marked episodic or marked semantic retrograde amnesia is usually associated with significant involvement of cortical and neocortical structures. Retrograde amnesia is a functionally heterogeneous rather than a unitary phenomenon. Discontinuities and dissociations found in published studies point to the potential fractionation of retrograde amnesia into component disorders, each with its own neural profile.     

Amnesia and criminal law: A clinical overview

The use of amnesia as a legal defense raises complex issues for both psychology and jurisprudence. Our review of the legal literature suggests that recent advances in the understanding of clinical disorders of memory have not yet found their way into the courtroom. In this paper, we address the assumptions that amnesia means simply having a very bad memory and that amnesia is a unitary syndrome. We then review recent neuropsychological research on amnesia and its implications for the judicial process. Emphasis is placed on describing the amnesic disorders that most often arise in criminal proceedings. It is concluded that both psychologists and legal professionals should ensure that research findings from the clinic and the laboratory are applied appropriately in cases of defendants claiming amnesia.     

Clinical pastoral education as professional training: some entrance, curriculum and assessment implications

Clinical Pastoral Education is professional training for pastoral care. This paper compares CPE against the professional training model. While limiting the discussion to Christian pastoral care, the professional education model suggests a clarification of the trainee's theological and other entry requirements for a basic unit, a more thoughtful provision of information during CPE training, a careful attention to group membership and an appropriate integration with the theological curriculum. It also suggests more specific competency standards and more reliable, valid and objective assessment methods.     

A neuropsychological study of fact memory and source amnesia

We investigated the ability of amnesic patients to learn new facts (e.g., Angel Falls is located in Venezuela) and also to remember where and when the facts were learned (i.e., source memory). To assess the susceptibility of fact and source memory to retrograde amnesia, patients prescribed electroconvulsive therapy were presented facts prior to the first treatment and were tested after their second treatment. All amnesic patients exhibited marked fact memory impairment. In addition, some amnesic patients exhibited source amnesia (i.e., they recalled a few facts but then could not remember where or when those facts had been learned). Source amnesia was unrelated to the severity of the memory deficit itself, because patients who exhibited source amnesia recalled as many facts as the patients who did not. These results show that the deficit in amnesia includes an impairment in acquiring and retaining new facts. Source amnesia can also occur, but it is dissociable from impaired recall and recognition and appears to reflect difficulty in remembering the specific context in which information is acquired. The findings are discussed in terms of their significance for how memory is organized.     

Functional amnesia: clinical description and neuropsychological profile of 10 cases

We carried out the first neuropsychological study of a series of patients with functional amnesia. We evaluated 10 patients, first with a neurological examination and then with three tests of anterograde amnesia and four tests of retrograde amnesia. Excluding one patient who later admitted to malingering, all patients had a significant premorbid psychiatric history and one or more possible precipitating factors for their amnesia. Eight of the 10 patients still had persistent retrograde amnesia at our last contact with them (median = 14 mo after the onset of amnesia). On tests of anterograde amnesia, the patients performed normally as a group, though some patients scored poorly on tests of verbal memory. On tests of retrograde amnesia, all patients had difficulty re-collecting well-formed autobiographical memories of specific events from their past. In contrast, patients performed as well as controls at distinguishing the names of cities from fictitious city names. On remote memory tests for past public events and famous faces, different patients exhibited different but internally consistent patterns of impaired and spared performance. The variability in the clinical and neuropsychological findings among our patients may be understood by supposing that memory performance is poor in proportion to how directly a test appears to assess a patient's common sense concept of memory. The presentation of patients with functional amnesia is as variable as humankind's concept of what memory is and how it works.     

Does feigning amnesia impair subsequent recall?

Defendants who are accused of serious crimes sometimes feign amnesia to evade criminal responsibility. Previous research has suggested that feigning amnesia might impair subsequent recall. In two experiments, participants read and heard a story about a central character, described as “you,” who was responsible for the death of either a puppy (Experiment 1) or a friend (Experiment 2). On free and cued recall tests immediately after the story, participants who had feigned amnesia recalled less than did participants who had recalled accurately. One week later, when all participants recalled accurately, participants who had previously feigned amnesia still performed worse than did participants who had recalled accurately both times. However, the participants who had formerly feigned amnesia did not perform worse than did a control group who had received only the delayed recall tests. Our results suggest that a “feigned amnesia effect” may reflect nothing more than differential practice at recall. Feigning amnesia for a crime need not impair memory for that crime when a person later seeks to remember accurately.     

In defense of cultural competency in psychotherapy and treatment

Cultural competency guidelines and policies are being widely established. Yet some critics have challenged the evidence for cultural competency and the lack of efficacy studies that demonstrate its outcomes. Various positions are examined that discuss cultural competency research. They include the need for more resources for research, scientific practices that overlook ethnic research findings, fruitfulness of theory-driven rather than population-based research, problems in defining cultural competency as a technique, and development of policies in the absence of research. Implications of these positions are discussed.     

A developmental account of early childhood amnesia

This study was an attempt to demonstrate the utility of a developmental approach to the study of early childhood amnesia. Working from a model of early childhood memory development proposed by Nelson and Ross (1980), I hypothesized that children would show early childhood amnesia and that this could be tested by comparing obtained estimates of memory strength to values predicted by a standard retention function. The data confirm this hypothesis for 6- and 10-year-old children, and suggest that the early childhood amnesia period extends from birth to a point between the third and fourth birthdays. The data also support a prediction, derived from the aforementioned model, that children would report a disproportionate number of general memories from the amnesia period. Thus, the developmental model provides a useful vehicle for examining early childhood amnesia and helps to frame further questions such as why some specific memories from this period are retained even though most are lost.     

Neuropsychological profile following suicide attempt by hanging: two adolescent case reports.

Hippocampal damage and amnesia following hypoxia and ischemia are described in the few published adult cases of suicide attempt by hanging. However, a recent review (Caine & Watson, 2000) suggests a variable pattern of brain involvement and neuropsychological impairments following hypoxic-ischemic injury that may or may not involve amnesia. To help clarify the impact of hanging on the developing brain, we examined neuropsychological functioning in two adolescents who survived suicide attempt by hanging. Despite differences in Glasgow Coma Scale (GCS), coma duration, and structural imaging findings, both patients had similar IQ (VIQ>PIQ) and presented with various combinations of deficits in expressive/receptive language, visual-constructional and perceptual ability, processing speed, attention, working memory, and/or executive functioning shortly after injury. In spite of their similarities, only one of the patients presented with classic amnesia symptoms in his early recovery. This patient was evaluated 1 year postinjury, and persistent deficits in processing speed and memory encoding were noted. Several hanging-related variables, including longer estimated hanging duration, greater weight, and severe airway edema, were thought to place this patient at increased risk for cognitive deficits. Clinical MRI scans of this patient obtained 6 weeks postinjury revealed mild volume loss as well as abnormalities in bilateral superior cortex. However, CT and MRI scans obtained throughout early recovery did not reveal overt evidence of injury to specific memory-related structures. Comprehensive neuropsychological evaluation of all adolescent survivors of suicide attempt by hanging is recommended, as a variety of postacute cognitive deficits were observed in these patients despite relatively short (相似文献   

Effects of d-amphetamine and strychnine on cycloheximide- and diethyldithiocarbamate-induced amnesia in mice.

Groups of C57BL/6J mice were administred cycloheximide (CYC) 30 min before or immediately after training on a passive avoidance task and tested 72 hr later. Some CYC-pretreated groups were given strychnine or d-amphetamine (d-amp) immediately after training and others were given d-amp 1 hr after training. Other groups were given diethyldithiocarbamate (DDC) at various times before or after training. Some DDC-pretreated groups were gived-amp or strychnine as described above for CYC groups. Immediate posttraining administration of 5 mg/kg d-amp, but not strychnine, prevented amnesia in CYC-pretreated mice. The DDC induced an apparent amnesia when administered from 30 min before training to 3 hr after training. Posttraining administration of d-amp or strychnine did not prevent DDC-induced amnesia. These results are discussed in relation to previous suggestions that CYC- and DDC-induced amnesia may be the result of a functional impairment of catecholamine neurotransmitter systems by these drugs.     

Competency development and career success: The mediating role of employability

The present study aims to unravel the relationship between competency development, employability and career success. To do so, we tested a model wherein associations between employee participation in competency development initiatives, perceived support for competency development, self-perceived employability, and two indicators of subjective career success (i.e. career satisfaction and perceived marketability) have been specified. A survey was conducted among a sample of 561 employees of a large financial services organization. The results support the idea that employee participation in competency development initiatives as well as perceived support for competency development is positively associated with workers' perceptions of employability. Moreover, self-perceived employability appeared to be positively related with career satisfaction and perceived marketability. A full mediation effect was found for the relationship between participation in competency development initiatives and both career satisfaction and perceived marketability, while a partial mediation effect was found in case perceived support for competency development was the predictor variable. The implications of our findings for understanding the process through which individuals and organizations can affect subjective career success are discussed.     

Alcohol-Induced Amnesia and Personalized Drinking Feedback: Blackouts Predict Intervention Response

Alcohol-induced amnesia (“blackout”) is a reliable predictor of alcohol-related harm. Given its association with other negative consequences, experience of alcohol-induced amnesia may serve as a teachable moment, after which individuals are more likely to respond to intervention. To test this hypothesis, alcohol-induced amnesia was evaluated as a moderator of brief intervention effect on (a) alcohol-related consequences and (b) the proposed intervention mediators, protective behavioral strategies and peak blood alcohol concentration (BAC). Baseline alcohol risk measured using the Alcohol Use Disorders Identification Test (AUDIT) was also evaluated as a moderator to rule out the possibility that amnesia is simply an indicator of more general alcohol risk. College students (N = 198) reporting alcohol use in a typical week completed assessments at baseline and 1-month follow-up as part of a larger intervention trial. Participants were randomized to assessment only (AO; n = 58) or personalized feedback intervention (PFI; n = 140). Hierarchical regression was used to examine direct and indirect intervention effects. A significant group-by-amnesia interaction revealed that only PFI participants who had experienced alcohol-induced amnesia in the past month reported decreases in alcohol consequences at 1-month follow-up. The PFI reduced alcohol-related consequences indirectly through changes in peak BAC, but only among those who had experienced amnesia at baseline. In contrast, baseline alcohol risk (AUDIT) did not moderate intervention effects, and use of protective behavioral strategies did not statistically mediate intervention effects. Findings suggest that loss of memory for drinking events is a unique determinant of young adult response to brief alcohol intervention. Normative feedback interventions may be particularly effective for individuals who have experienced alcohol-induced amnesia in the past 30 days.     

The von Restorff effect and induced amnesia: production by manipulation of sound intensity.

When an outstanding item appears in an otherwise homogeneous list of items, the outstanding item is better remembered (the von Restorff effect), and items before and after it may be more poorly remembered (induced amnesia) than corresponding items in a control list. In the present experiments the outstanding item was a word presented as a loud shout among other words presented at normal conversational levels. In two experiments, large retrograde- and anterograde-induced amnesiae effects were demonstrated using a free-recall and a recognition task. In both experiments half of the subjects were told what to expect and were instructed to devise a strategy to eliminate induced amnesia. These instructions failed to eliminate the amnesiac effect. A third experiment was designed to demonstrate an empirical similarity between induced and clinical amnesia. In clinical retrograde (but not anterograde) amnesia, "lost" memories are sometimes recovered with time. Filled delays of 0, 30, or 120 sec interpolated between list presentation and recall demonstrated that induced retrograde amnesia disappeared at the longest delay but induced anterograde amnesia was unchanged. A fourth experiment eliminated some alternate interpretations of the effect.