Korsakoff's Syndrome Patients Research Articles

Social norms in Korsakoff's syndrome and alcohol-related dementia.

Social cognition is essential for individuals to perceive, process, and interpret social information that enables them to function effectively in society. Korsakoff's syndrome (KS) and alcohol-related dementia (ARD) are alcohol-related cognitive disorders that are likely to impair social cognition. This study aimed to investigate the ability to judge social norms in KS and ARD in comparison to healthy subjects. The study included 30 patients with KS, 10 patients with ARD, and 74 age-, sex-, and education-matched control participants. The Social Norms Questionnaire - Dutch version (SNQ-NL) was used to measure social cognition, and standardized tests were used to examine the association between social cognition and executive functioning. Both KS and ARD patients performed worse in judging social norms when compared to healthy controls, but there was no significant difference between KS and ARD. Both KS and ARD patients performed worse on the SNQ-NL, judging appropriate behavior as inappropriate (Overadhere errors), than controls. When compared to control participants, patients with KS demonstrated significantly more Break Errors, while the differences between the ARD group and the control group did not reach statistical significance. There were no significant correlations between the SNQ-NL variables and performances on standardized tests for executive functioning in both the KS and control group. This study aimed to investigate the ability to judge social norms in KS and ARD in comparison to healthy subjects. The results show that compared to a control group, both KS and ARD patients performed worse in judging social norms. KS and ARD patients scored equally low on social norms identification. Overall, these findings can further help us understand the difficulties in social behavior as experienced by patients and care staff, since problems in accurately judging social norms could possibly contribute to the severe behavioral issues as observed in alcohol-related disorders.

Personality traits and personality problems in Korsakoff syndrome patients

ABSTRACT Personality research is of relevance because it provides insights into the psychological strengths and vulnerabilities of a person. Korsakoff’s syndrome (KS) is a severe neuropsychiatric disorder following acute thiamine deficiency, usually as a consequence of alcohol-use disorders. Research on personality traits of KS patients is currently limited. The aim of the current exploratory study was therefore to examine the personality traits and problems of KS patients. We assessed self-reported and informant-reported personality traits and problems in institutionalized KS patients (n = 30). Results indicate that the psychotic personality organization was more frequently present in KS patients compared to a psychiatric reference population, leading to increased vulnerability for the development of severe psychiatric issues. Informants observed more premorbid and current cluster B (“emotional”) and C (“anxious”) personality behavior in comparison to the general population. Also, rigid- and socially avoidant behavior in KS patients was observed to increase over the years. They also observed personality problems such as emotional-, unpredictable-, dramatic-, anxious and fearful behavior in the present and in the past. KS patients reported themselves as healthy individuals, indicating a lack of self-awareness. We recommend training programs for the medical team focussed on psycho-education and supportive interventions for patients with complex personality problems concomitant to KS.

26 Apathy in Korsakoff Patients with and without Neurovascular Comorbidity

Objective:People with Korsakoff syndrome (KS) experience severe neuropsychological and neuropsychiatric complications following vitamin B1 deficiency predominantly due to alcoholism. KS often presents itself with neuropsychological symptoms such as problems in episodic memory, executive functioning, and social cognition. Common neuropsychiatric symptoms in KS are disorders of affect, confabulations, anosognosia, and apathy. Apathy can be defined by a pathological lack of goal-directed behaviors, goal-directed cognitions, and goal-directed emotions. Patients with KS have an increased risk of cerebrovascular comorbidity. Cerebrovascular accidents are known to increase the risk for developing apathy. Apathy in KS patients can negatively influence the ability to live an autonomous life, often making 24-hour care a necessity. Limited research on apathy in KS patients has been published to this day. Our aim was to assess apathy in Korsakoff patients with and without neurovascular comorbidity.Participants and Methods:General apathy and related subconstructs, such as judgment and decision-making skills, emotional blunting, and the intentions to perform pleasurable activities, were studied in fifteen KS patients, fifteen KS patients with additional cerebrovascular comorbidity, and fifteen healthy controls. The first responsible caregiver of each patient filled in the Apathy Evaluation Scale and Scale for Emotional Blunting. An examiner administered the interview-based Judgement scale of the Neuropsychology Assessment Battery with the KS patients and each KS patient filled in the self-report section of the Pleasurable Activities List. Both KS patient groups receive 24-hour care in a specialized facility for Korsakoff Syndrome.Results:Our study found higher levels of general apathy in both KS patient groups, when rated by their caregiver compared to healthy controls. No difference was found between the KS patient groups and the healthy control group on the self-reported section of the Pleasurable Activities List, which might suggest the presence of intrinsic motivation in KS patients. However, a discrepancy was found between the self-reported activity levels and proxy reported levels of apathy. KS patients with cerebrovascular comorbidity showed increased levels of emotional blunting compared to KS patients without cerebrovascular comorbidity and healthy controls. Decreased judgment and decision-making skills were found in both patient groups compared to healthy controls, with no difference found between KS patients with cerebrovascular comorbidity and KS patients without.Conclusions:Our findings suggest that people with Korsakoff syndrome experience more general apathy compared to healthy controls. Both patient groups showed decreased judgement and decision-making skills and increased emotional blunting. Intrinsic motivation was found to be intact in KS patients. Experiencing cerebrovascular comorbidity in KS carries a risk for developing emotional blunting. Our findings show that apathy greatly affects people with KS. Future scientific research is warranted to further benefit the care for this complex patient population.

47 Social Cognition and Moral Decision Making in Korsakoff's Syndrome

Objective:Korsakoff's syndrome (KS) is a neuropsychiatric disorder, caused by vitamin B1 insufficiency. KS is characterized by severe declarative amnesia. Often, also executive disorders are present. Emotion recognition and theory of mind are gold-standard measures of social cognition. Moral decision making is often assessed by means of moral dilemmas. Surprisingly social cognition and moral decision making has received hardly any attention in research on KS, although the severity of behavioural problems in KS suggest possible problems in both domains. The aim of this study was therefore to broadly assess social cognition and moral decision-making capacities in patients with KS.Participants and Methods:20 KS patients and 20 age-, education-, and gender-matched healthy controls were assessed on standardized tests for social cognition, namely the mini-Social Cognition and Emotional Assessment battery (mini-SEA), and a specialized version of the Sally-Anne Test. Moral decision making was assessed by means of the Moral Behaviour Inventory (MBI) for everyday moral dilemmas, and ten cartoons of abstract moral dilemmas. For moral decision making, “yes” and “no” responses were scored, together with a scoring for moral reasoning according to the Kohlberg stages of moral maturity.Results:KS patients have large impairments in both cognitive and affective aspects of social cognition. Their ability to recognize emotions, take the perspective of others, and understand socially awkward situations is vastly compromised. While KS patients were able to replicate the Sally Anne storyline, their task performance was on chance level. Regarding moral decision making, there was a tendency to more frequently carry out the moral dilemma. Moral maturity, as indexed by means of their reasoning behind the decision was of a lower level. Of interest, moral immaturity could find its origin already before the onset of the KS diagnosis, as suggested by elevated premorbid levels of delinquent behavior.Conclusions:Both social cognition and moral decision making are compromised in KS patients. Specifically social cognitive disorders are the direct result of KS, and are likely to strongly relate to social and neuropsychiatric issues in KS. Moral decision making was more likely to be already of a lower level of maturity, based on a strong relationship between premorbid delinquency and moral immaturity in KS patients. This study highlights the importance to properly index social cognition in neuropsychological assessments for individuals with a possible KS diagnosis

Impaired Executive Functioning Associated with Alcohol-Related Neurocognitive Disorder including Korsakoff's Syndrome.

(1) Background: chronic alcohol use is consistently associated with impaired executive functioning, but its profile across the spectrum from mild to major alcohol-related cognitive impairment is, to date, unclear. This study aims to compare executive performances of patients with alcohol-induced neurocognitive disorder, including Korsakoff's syndrome (KS), by using a computerized assessment battery allowing a fine-grained and precise neuropsychological assessment; (2) Methods: performances of 22 patients with alcohol-related cognitive impairment (ARCI) and 20 patients with KS were compared to those of 22 matched non-alcoholic controls. All participants were diagnosed in accordance with DSM-5-TR criteria and were at least six weeks abstinent from alcohol prior to assessment. Executive function was evaluated using four subtests of Cambridge Neuropsychological Test Automated Battery (CANTAB®); (3) Results: significant differences between groups were found on spatial working memory (updating), sustained attention and inhibitory control, set shifting, and planning. Healthy controls performed significantly better than both patient groups (Games-Howell post hoc; p < 0.05), but no differences in performance were found between the ARCI and KS group; (4) Conclusions: ARCI and KS patients showed significant executive impairments, most prominent in updating, set-shifting and general planning abilities. Findings suggest equivalent levels of executive function in ARCI and KS patients. Our results highlight executive function as a significant hallmark of alcohol-induced neurocognitive disorder and stipulate the importance of early assessment and evaluation of skills to guide treatment.

When Do Korsakoff Patients Justify Immoral Behaviors? The Influence of Premorbid Delinquency and Self-Other Perspectives in Moral Decision-Making and Moral Reasoning.

Korsakoff's syndrome (KS) is a chronic neuropsychiatric disorder caused by a vitamin B1 deficiency. KS is characterized by profound amnesia and often accompanied by poor executive functioning, decreased social-cognitive abilities, and difficulties in behavioral regulation. As moral behaviors and attitudes may provide insight in socio-behavioral interactions, the current study aimed to evaluate everyday moral maturity by administering self- versus other-oriented moral dilemmas in a group of KS patients (n = 20) and healthy controls (n = 20). Responses were scored according to the Kohlberg stages of moral reasoning. Furthermore, we assessed premorbid delinquency and current neurocognitive functioning as possible relevant factors. Our results show that KS patients were prone to lower levels of moral maturity when confronted with moral dilemmas relating to themselves, compared to dilemmas relating to (un)personal others in KS patients, while healthy subjects showed an opposite pattern. Moral immaturity could find its origin already before the onset of the KS diagnosis, as suggested by the elevated premorbid levels of delinquent behavior and correlation between premorbid delinquency and moral maturity in KS. Lower moral maturity could therefore be a possible predisposing factor to both delinquency and later development of Korsakoff's syndrome.

Korsakoff's Syndrome and Alzheimer's Disease-Commonalities and Specificities of Volumetric Brain Alterations within Papez Circuit.

Background: Alzheimer's disease (AD) and Korsakoff's syndrome (KS) are two major neurocognitive disorders characterized by amnesia but AD is degenerative while KS is not. The objective is to compare regional volume deficits within the Papez circuit in AD and KS, considering AD progression. Methods: 18 KS patients, 40 AD patients (20 with Moderate AD (MAD) matched on global cognitive deficits with KS patients and 20 with Severe AD (SAD)), and 70 healthy controls underwent structural MRI. Volumes of the hippocampi, thalami, cingulate gyri, mammillary bodies (MB) and mammillothalamic tracts (MTT) were extracted. Results: For the cingulate gyri, and anterior thalamic nuclei, all patient groups were affected compared to controls but did not differ between each other. Smaller volumes were observed in all patient groups compared to controls in the mediodorsal thalamic nuclei and MB, but these regions were more severely damaged in KS than AD. MTT volumes were damaged in KS only. Hippocampi were affected in all patient groups but more severely in the SAD than in the KS and MAD. Conclusions: There are commonalities in the pattern of volume deficits in KS and AD within the Papez circuit with the anterior thalamic nuclei, cingulate cortex and hippocampus (in MAD only) being damaged to the same extent. The specificity of KS relies on the alteration of the MTT and the severity of the MB shrinkage. Further comparative studies including other imaging modalities and a neuropsychological assessment are required.

The Use of an Errorless Learning Application to Support Re-Learning of (Instrumental) Activities for People Living with Korsakoff Syndrome.

Korsakoff syndrome (KS) is a severe neuropsychiatric syndrome derived from acute thiamine deficiency and concomitant alcohol use disorders. KS patients need lifelong assistance because of the severity of their cognitive problems. In clinical practice and research, errorless learning has proven to be an effective cognitive rehabilitation method for patients with KS. Our study focused on optimizing errorless learning by introducing new software technology to support the training process of errorless learning. Although the benefits of errorless learning for patients with Korsakoff's syndrome have been thoroughly investigated, it is currently unclear whether new technology could contribute to better learning and maintenance of everyday tasks. Therefore, an errorless learning application was built. This device is a web application and can be used on a tablet, laptop, or smartphone. The application allows clinicians and researchers to insert pictures, videoclips, timers, and audio fragments in the different steps of an errorless learning training plan. This way, the different steps are visible and easy to follow for patients. Moreover, it ensures as a learning method that the training is executed exactly the same way for each and every training. The aim of this study was twofold: to examine whether the use of the errorless learning application is effective, and whether it leads to better results than a regular errorless learning of everyday activities. In total, 13 patients with KS were trained in instrumental activities of daily living by means of the application, and 10 patients were trained with traditional instructions. Results showed an equal improvement for both training methods. Importantly, the technology group could better remember the training when probed at a later moment than the traditional errorless learning group. These results are promising for further development of novel technology to support errorless learning applications in clinical practice.

Structural brain substrates of the deficits observed on the BEARNI test in alcohol use disorder and Korsakoff's syndrome.

Chronic and excessive alcohol consumption can result in alcohol use disorder (AUD) without neurological complications and in Korsakoff's syndrome (KS) when combined with thiamine deficiency. These two clinical forms are accompanied by widespread structural brain damage in both the fronto-cerebellar (FCC) and Papez circuits (PC) as well as in the parietal cortex, resulting in cognitive and motor deficits. BEARNI is a screening tool especially designed to detect neuropsychological impairments in AUD. However, the sensitivity of this tool to the structural brain damage of AUD and KS patients remains unknown. Eighteen KS patients, 47 AUD patients and 27 healthy controls (HC) underwent the BEARNI test and a 3T-MRI examination. Multiple regression analyses conducted between GM density and performance on each BEARNI subtest revealed correlations with regions included in the FCC, PC, thalamus and posterior cortex (precuneus and calcarine regions). All these brain regions were altered in KS compared to HC, in agreement with the cognitive deficits observed in the corresponding BEARNI subtests. The comparison between KS and AUD regarding the GM density in the several nodes of the FCC and calcarine regions revealed that they were atrophied to the same extent, suggesting that BEARNI is sensitive to the severity of alcohol-related GM abnormalities. Within the PC, the density of the cingulate cortex and thalamus, which correlated with the memory and fluency subscores, was smaller in KS than in AUD, suggesting that BEARNI is sensitive to specific brain abnormalities occurring in KS.

Identifying, Assessing, and Treating Korsakoff Syndrome Patients: Updated Perspectives.

Objectives consist of updating published reports on the recognition, assessment, and care of patients with Wernicke-Korsakoff syndrome (WKS). Methods included defining relevant terms, describing core clinical phenomena, conducting meaningful reviews for latter-day WKS publications, and selecting instructive case examples. Findings covered epidemiology, precipitants, neuroimaging studies, alternate learning strategies in WKS, adjunctive treatments, and promising research. In conclusion, patients, their family members, clinicians, and public health experts should benefit from this updated knowledge. Countries with substantial alcohol consumption should consider emulating Holland in designating WKS research centers, founding regional clinical facilities, and funding multidisciplinary expert teams.

Autobiographical memory in Korsakoff syndrome: A review

Autobiographical memory (AM) (i.e., memory for personal information) is a unique form of memory that goes beyond recalling information such as what, where and when of an event, to include what that event means and why it is important to our life story. This paper therefore reviews the available literature on AM in Korsakoff syndrome (KS). It summarizes the characteristics of AM disorders in KS patients. These disorders are mainly characterized by the difficulties that patients with KS have in retrieving and reliving specific AMs and in retrieving recent and remote memories. Another core characteristic of AM disorders in KS is confabulations. This paper hypothesizes that patients with KS may produce autobiographical confabulations to support their objectives and beliefs or even to answer a social demand or simply to share personal experiences with others. Although the current evidence demonstrates disorders of AM in KS, there is a need for more research about the characteristics of these disorders. This review thus proposes several perspectives for theoretical and clinical research.

Early Identification of Alcohol Use Disorder Patients at Risk of Developing Korsakoff's Syndrome.

The aim of the present study was to determine whether the Brief Evaluation of Alcohol-Related Neuropsychological Impairments (BEARNI), a screening tool developed to identify neuropsychological deficits in alcohol use disorder (AUD) patients, can also be used for the early identification of AUD patients at risk of developing Korsakoff's syndrome (KS). Eighteen KS patients, 47 AUD patients and 27 healthy controls underwent BEARNI testing (including 5 subtests targeting episodic memory, working memory, executive function, visuospatial abilities, and ataxia) and a comprehensive neuropsychological examination. Performance of AUD and KS patients on BEARNI subtests was consistent with the results on the standardized neuropsychological assessment. On BEARNI, ataxia and working memory deficits observed in AUD were as severe as those exhibited by KS patients, whereas for visuospatial abilities, a graded effect of performance was found. In contrast, the subtests involving long-term memory abilities (episodic memory and fluency) were impaired in KS patients only. AUD patients with a score lower than 1.5 points (out of 6) on the episodic memory subtest of BEARNI exhibited the lowest episodic memory performance on the neuropsychological battery and could be considered at risk of developing KS. These findings suggest that BEARNI is a useful tool for detecting severe memory impairments, suggesting that it could be used for the early identification of AUD patients at high risk of developing KS.

Unraveling Apathy in Korsakoff Syndrome Patients Receiving Long-Term Care With and Without Cerebrovascular Comorbidity.

BackgroundKorsakoff syndrome (KS) is a severe neuropsychiatric disorder caused by acute deficiency of vitamin B1 and concomitant alcoholism. Patients with KS are particularly vulnerable for cerebrovascular comorbidity. KS is characterized by cognitive and neuropsychiatric symptoms, one of which is apathy. Apathy is a pathological lack of goal‐directed behaviors, goal‐directed cognitions, and goal‐directed emotions. Cerebrovascular accidents are known to carry a risk for developing apathy. Apathy has a dramatic effect on the autonomy and daily lives of patients suffering from this condition.MethodsWe assessed general apathy and related subconstructs in fifteen patients with KS, fifteen patients with KS and cerebrovascular comorbidity who reside in a 24‐hour care facility, and fifteen healthy controls.ResultsCompared with healthy controls, both KS patient groups showed higher levels of apathy as rated by a close informant. We found no difference between both KS patient groups and the healthy control group on the self‐report section of the Pleasant Activities List, suggesting that motivation is still intact in KS patients. It is important to note a discrepancy was found between self‐reporting and proxy reporting on this list. KS patients with cerebrovascular comorbidity showed more severe emotional blunting compared to both KS patients without cerebrovascular comorbidity and healthy controls. The competency to consent was lower in patients compared with healthy controls, but no difference was found between KS patients with cerebrovascular comorbidity and those without.ConclusionsOur results suggest that KS patients show increased levels of general apathy compared with healthy controls. Patients show a diminished competency to consent and increased emotional blunting, while motivation is not compromised. Cerebrovascular comorbidity in KS forms a high risk for emotional blunting. The results of this study suggest that apathy is a severe problem in KS. More attention in both the literature and clinical practice would benefit this complex patient population.

Episodic future thinking together with observational learning benefits prospective memory in high‐functioning Korsakoff’s syndrome patients

ObjectivePatients with Korsakoff’s syndrome (KS) have difficulty carrying out tasks which rely on prospective memory (PM). Since remembering to carry out an action in the future is crucial for living independently, it is of primary interest to develop strategies that improve PM performance in KS patients.DesignThe study employed a computer categorization task as an ongoing activity into which a PM task was embedded. We included episodic future thinking (EFT) and observational learning (Experiment 2) to boost PM.MethodsExperiment 1 evaluated the efficacy of EFT following written PM task instructions in ten KS patients. Due to floor‐level PM performance in Experiment 1, Experiment 2 included an instructional video demonstrating the PM intention. In Experiment 2, twenty‐six KS patients performed both conditions (EFT and no‐EFT) at least 1 week apart, while twelve controls with alcohol use disorder without KS performed the no‐EFT condition. In Experiment 2, the PM instructions were also shown through video (observational learning component). Mild cognitive impairment was assessed in a short test battery.ResultsExperiment 1 showed overall floor performance in both conditions. Experiment 2 showed that KS patients performed PM tasks less accurately than the control group in the no‐EFT condition. In Experiment 2, where the observational learning component was included, EFT improved PM performance in KS patients. This effect was driven by a sub‐group of high‐functioning KS patients.ConclusionsThis study showed the value of an observational learning component together with EFT in improving PM performance, in relatively high‐functioning KS patients.Practitioner points KS patients performed the PM task less accurately than non‐KS controls with alcohol use disorder, confirming PM impairment in this patient population.Controls with alcohol use disorder performed the PM task at ceiling level.Showing an instructional video demonstrating the PM intention improved PM performance and later recall of PM task instructions in KS patients.Episodic future thinking strategy improved PM performance in KS patients with relatively intact cognitive functioning.

Tell about yourself to improve your autobiographical memory: A study of Korsakoff's syndrome

Korsakoff's syndrome (KS) has been associated with a difficulty to retrieve specific autobiographical memories. We investigated whether this difficulty can be alleviated after the retrieval of statements describing self-images. KS patients and control participants were recruited and asked to retrieve autobiographical memories after providing statements to the question “Who am I?” and after a control condition consisting of verbal fluency. Analysis showed higher autobiographical specificity in the “Who am I?” than in verbal fluency condition in both patients with KS and control participants. At a theoretical level, our findings demonstrate how retrieval of information related to conceptual self may influence autobiographical memory in KS. At a clinical level, our procedures are important as they demonstrate how a simple task (i.e., “Who am I?” statements) may serve as a tool to cue specific autobiographical memories in patients with KS.

Impaired affective prosody decoding in severe alcohol use disorder and Korsakoff syndrome

Recognizing others’ emotions is a fundamental social skill, widely impaired in psychiatric populations. These emotional dysfunctions are involved in the development and maintenance of alcohol-related disorders, but their differential intensity across emotions and their modifications during disease evolution remain underexplored. Affective prosody decoding was assessed through a vocalization task using six emotions, among 17 patients with severe alcohol use disorder, 16 Korsakoff syndrome patients (diagnosed following DSM-V criteria) and 19 controls. Significant disturbances in emotional decoding, particularly for negative emotions, were found in alcohol-related disorders. These impairments, identical for both experimental groups, constitute a core deficit in excessive alcohol use.

Preserved re-experience of discrete emotions: Amnesia and executive function.

Amnesic patients can re-experience emotions elicited by forgotten events, suggesting that brain systems for episodic and emotional memory are independent. However, the range of such emotional memories remains under-investigated (most studies employing just positive-negative emotion dyads), and executive function may also play a role in the re-experience of emotions. This is the first investigation of the intensity of the emotional re-experience of a range of discrete emotions (anger, fear, sadness, and happiness) for a group of amnesic patients. Twenty Korsakoff syndrome (KS) patients and 20 neurologically normal controls listened to four novel emotional vignettes selectively eliciting the four basic emotions. Emotional experience was measured using pen-and-paper Visual Analogue Mood Scales and episodic memory using verbal recollections. After 30min, the recollection of stories was severely impaired for the patient group, but the emotional re-experience was no different from that of controls. Notably, there was no relationship between episodic recall and the intensity of the four emotions, such that even profoundly amnesic patients reported moderate levels of the target emotion. Exploratory analyses revealed negative correlations between the intensity of basic emotions and executive functions (e.g., cognitive flexibility and response inhibition) for controls but not patients. The results suggest that discrete emotions can be re-experienced independently of episodic memory, and that the re-experience of certain discrete emotions appears to be dampened by executive control. KS patients with absent or mild cognitive symptoms should benefit from emotion-regulation interventions aimed at reducing the recognized affective burden associated with their episodic memory deficit.

Korsakoff's syndrome: a critical review.

In this review, we present a survey on Korsakoff’s syndrome (KS), a residual syndrome in patients who suffered from a Wernicke encephalopathy (WE) that is predominantly characterized by global amnesia, and in more severe cases also by cognitive and behavioral dysfunction. We describe the history of KS and its definition, its epidemiology, and the lack of consensus criteria for its diagnosis. The cognitive and behavioral symptoms of KS, which include anterograde and retrograde amnesia, executive dysfunction, confabulation, apathy, as well as affective and social-cognitive impairments, are discussed. Moreover, recent insights into the underlying neurocognitive mechanisms of these symptoms are presented. In addition, the evidence so far on the etiology of KS is examined, highlighting the role of thiamine and alcohol and discussing the continuity hypothesis. Furthermore, the neuropathology of KS is reviewed, focusing on abnormalities in the diencephalon, including the mammillary bodies and thalamic nuclei. Pharmacological treatment options and nonpharmacological interventions, such as those based on cognitive rehabilitation, are discussed. Our review shows that thiamine deficiency (TD) is a crucial factor in the etiology of KS. Although alcohol abuse is by far the most important context in which TD occurs, there is no convincing evidence for an essential contribution of ethanol neurotoxicity (EN) to the development of WE or to the progression of WE to KS. Future research on the postmortem histopathological analysis of brain tissues of KS patients is crucial for the advancement of our knowledge of KS, especially for associating its symptoms with lesions in various thalamic nuclei. A necessary requirement for the advancement of studies on KS is the broad acceptance of a comprehensive definition and definite diagnostic criteria. Therefore, in this review, we propose such a definition of KS and draft outlines for prospective diagnostic criteria.

The importance of mammillary body efferents for recency memory: towards a better understanding of diencephalic amnesia

Despite being historically one of the first brain regions linked to memory loss, there remains controversy over the core features of diencephalic amnesia as well as the critical site for amnesia to occur. The mammillary bodies and thalamus appear to be the primary locus of pathology in the cases of diencephalic amnesia, but the picture is complicated by the lack of patients with circumscribed damage. Impaired temporal memory is a consistent neuropsychological finding in Korsakoff syndrome patients, but again, it is unclear whether this deficit is attributable to pathology within the diencephalon or concomitant frontal lobe dysfunction. To address these issues, we used an animal model of diencephalic amnesia and examined the effect of mammillothalamic tract lesions on tests of recency memory. The mammillothalamic tract lesions severely disrupted recency judgements involving multiple items but left intact both recency and familiarity judgements for single items. Subsequently, we used disconnection procedures to assess whether this deficit reflects the indirect involvement of the prefrontal cortex. Crossed-lesion rats, with unilateral lesions of the mammillothalamic tract and medial prefrontal cortex in contralateral hemispheres, were unimpaired on the same recency tests. These results provide the first evidence for the selective importance of mammillary body efferents for recency memory. Moreover, this contribution to recency memory is independent of the prefrontal cortex. More broadly, these findings identify how specific diencephalic structures are vital for key elements of event memory.

Self-awareness of cognitive dysfunction: Self-reported complaints and cognitive performance in patients with alcohol-induced mild or major neurocognitive disorder.

Patients with Korsakoff's syndrome (KS) typically have difficulties in recognizing the impact of their alcohol-related cognitive deficits on daily-life functioning. In this study, mean scores on self-reported complaints (measured with Minnesota Multiphasic Personality Inventory-2-Restructured Form; MMPI-2-RF) and cognitive performance (measured with the Wechsler Adult Intelligence Scale-Third edition; WAIS-III; and the California Verbal Learning Test; CVLT) are compared between two matched patient groups with severe (KS) and mild alcohol-related cognitive disorders or non KS (NKS). KS patients demonstrate significantly lower scores on the WAIS-III indices and on the CVLT than the matched NKS group, and significantly higher scores on MMPI-2-RF validity scales that indicate denial of psychological complaints. Both groups are in the normal range on MMPI-2-RF Cognitive Complaints (COG) and Neurological Complaints (NUC) scales compared with the normative sample. Finally, self-reported complaints and cognitive performance are not correlated significantly in both groups. Despite their alcohol-related cognitive impairments, both groups report no cognitive complaints at all indicating self-awareness impairment. In addition to KS patients, also NKS patients are at risk that their apparently "without cognitive complaints" appearance on self-report questionnaires can be easily overlooked. These findings may have important clinical implications for diagnostic and treatment purposes.