Function and dysfunction of prefrontal brain circuitry in alcoholic Korsakoff's syndrome

"Do not take that medication": negative prospective memory in Korsakoff's syndrome

BACKGROUND

While prospective memory (i.e., the ability to execute a future plan) has been extensively researched, little is known about negative prospective memory (i.e., the ability to remember not to execute a future plan) in Korsakoff's syndrome (KS). We thus evaluated both prospective memory and negative prospective memory in KS, as well as the relationship between both types of prospective memory and inhibition.

METHODS

Patients with KS and control participants were invited to press a button on the keyboard (i.e., prospective memory) or not to press a button when a cue word (e.g., negative prospective memory) was encountered.

RESULTS

The analysis demonstrated that patients with KS had more prospective memory errors (i.e., forgetting to click the keyboard when the instruction was to do so) than control participants. The analysis also demonstrated that patients with KS had more negative prospective memory errors (i.e., clicking the keyboard when the instruction was not to do so) than control participants. Similar levels of commissions and omissions were observed in patients with KS than in control participants. Interestingly, prospective and negative prospective performances were significantly correlated with performance on an inhibition assessment task.

DISCUSSION

Our study demonstrates that KS is characterized by not only difficulty in remembering to execute a future intention but also by difficulty in remembering not to execute a future intention. A decline in negative prospective memory in KS can be associated with difficulty in inhibiting no longer appropriate previously learned intentions.

Destination memory disorders: At the junction between memory and socioaffective processing

The junction between memory dysfunction and socioaffective dysfunction is a complex area as research has typically been interested in one dysfunction rather than in the other. However, this junction can be studied under the lens of destination memory. Destination memory (i.e. the ability to remember to whom a piece of information was previously transmitted) is unique in that it draws on both memory and socioaffective processes. Research has demonstrated how destination memory is prone to distortions in neurological/psychiatric disorders. This paper aims to provide a focused review on the interplay between memory and socioaffective processes in the deterioration of destination memory within these disorders. It shows how both episodic memory and socioaffective dysfunction can jointly contribute to the decline in destination memory, although the contribution of each of the two factors may vary depending on the disorder.

Impaired Awareness in People with Severe Alcohol-Related Cognitive Deficits Including Korskoff's Syndrome: A Network Analysis

BACKGROUND

Impaired awareness of one's own functioning is highly common in people with Korsakoff's syndrome (KS). However, it is currently unclear how awareness relates to impairments in daily functioning and quality of life (QoL).

METHODS

We assessed how impaired awareness relates to cognitive, behavioral, physical, and social functioning and QoL by applying a network analysis. We used cross-sectional data from 215 patients with KS or other severe alcohol-related cognitive deficits living in Dutch long-term care facilities (LTCFs).

RESULTS

Apathy has the most central position in the network. Higher apathy scores relate positively to reduced cognition and to a greater decline in activities of daily living and negatively to social participation and the use of antipsychotic drugs. Impaired awareness is also a central node. It is positively related to a higher perceived QoL, reduced cognition and apathy, and negatively to social participation and length of stay in the LTCF. Mediated through apathy and social participation, impaired awareness is indirectly related to other neuropsychiatric symptoms.

CONCLUSIONS

Impaired awareness is closely related to other domains of daily functioning and QoL of people with KS or other severe alcohol-related cognitive deficits living in LTCFs. Apathy plays a central role. Network analysis offers interesting insights to evaluate the interconnection of different symptoms and impairments in brain disorders such as KS.

"Ten dollars today or 50 dollars after one month?" Temporal discounting in Korsakoff syndrome

OBJECTIVE

Little research has investigated decision making in patients with Korsakoff syndrome (KS). Specifically, to our knowledge, there is a lack of research investigating whether patients with KS may tend to prefer immediate over future rewards (i.e., temporal discounting). Further, we investigated the relationship between temporal discounting and inhibition.

METHODS

We, for the first time, invited patients with KS and control participants to perform a temporal discounting task, in which they answered questions probing preferences between an immediate, but smaller amount of money, and a delayed, but larger amount of money (e.g., "would you prefer 10 dollars today or 50 dollars after one month?"). Furthermore, inhibition was measured using the Stroop Colour Word Test.

RESULTS

Analysis demonstrated higher temporal discounting in patients with KS than in control participants. Temporal discounting in both populations was significantly correlated with inhibition.

CONCLUSIONS

Patients with KS may have difficulties to suppress the temptation of smaller, but immediate, rewards.

"What Did I Tell This Sad Person?": Memory for Emotional Destinations in Korsakoff's Syndrome

We investigated destination memory, defined as the ability to remember to whom a piece of information was previously transmitted, for emotional destinations (i.e., a happy or sad person) in Korsakoff's syndrome (KS). We asked patients with KS and control participants to tell facts to neutral, positive, or negative faces. On a subsequent recognition task, participants had to decide to whom they told each fact. Compared with control participants, patients with KS demonstrated lower recognition of neutral, emotionally positive, and emotionally negative destinations. Patients with KS demonstrated lower recognition of emotionally negative than for emotionally positive or neutral destinations, but there were no significant differences between recognition of neutral and emotionally positive destinations. Our study demonstrates a compromised ability to process negative destinations in KS. Our study highlights the relationship between memory decline and impaired emotional processing in KS.

Alterations of theta power and synchrony during encoding in young adult binge drinkers: Subsequent memory effects associated with retrieval after 48 h and 6 months

Introduction

Young emerging adults commonly engage in binge drinking which is associated with a range of neurocognitive deficits, including memory impairments. However, evidence on neural oscillations mediating episodic memory in this population is lacking. To address this gap, we recorded theta oscillatory activity in young binge (BDs) and light drinkers (LDs) during memory encoding and analyzed it prospectively as a function of subsequent retrieval. Theta underlies successful encoding of novel items in memory through corticolimbic integration. Subsequent memory effects (SMEs) are reflected in stronger theta activity during encoding of the items that are later remembered compared to those that are later forgotten.

Methods

In the present study, 23 BDs (age: 23.3 ± 3.3) and 24 LDs (age: 23.4 ± 3.3) rated emotionally evocative images with negative, positive, and neutral themes during implicit encoding. They performed a recognition memory task on two follow-up occasions after a short (48 h), and long retention delay (6 months). Electroencephalography (EEG) signal was recorded during the encoding session and analyzed in time-frequency domain with Morlet wavelets in theta band (4-7 Hz). To evaluate SMEs, the event-related theta oscillations acquired during encoding were analyzed based on recognition outcomes after the two retention intervals.

Results

The BD and LD groups did not differ on recognition memory. However, BDs showed attenuated event-related theta power during encoding of images that were successfully retained after 6 months compared to LDs. In addition, theta synchronous activity between frontal and left posterior regions during encoding successfully predicted recognition of the images after both retention delays in LDs but not in BDs. These SMEs on theta power and synchrony correlated negatively with high-intensity drinking in the previous 6 months. No differences between men and women were observed for any analysis.

Discussion

It has been well established that long-range neural synchrony between cortical and limbic nodes underlies successful memory encoding and retention which, in turn, depends on neural excitation/inhibition (E/I) balance. Given that binge drinking is associated with E/I dysregulation, the observed SME deficiencies are consistent with other evidence of neural hyperexcitability in BDs, and may be indicative of increased risk of developing alcohol use disorders.

The specificity of thalamic alterations in Korsakoff's syndrome: Implications for the study of amnesia

The pathophysiological mechanisms behind amnesia are still unknown. Recent literature, through the study of patients with Alcohol Use Disorder with and without Korsakoff's syndrome, increasingly shows that physiological alterations to the thalamus have an important role in the development of amnesia. This review gives an overview of neuropsychological, neuropathological and neuroimaging contributions to the understanding of Korsakoff's syndrome, highlighting the central role of the thalamus in this amnesia. The thalamus being a multi-nucleus structure, the limitations regarding the loci, nature and alterations to specific nuclei are discussed, along with potential solutions. Finally, future directions for clinical research are laid out to unravel the intricacies inherent to amnesia. They consider the need to evaluate the physiological role of the thalamus, not only as an entity but also as part of a brain circuit through a more integrative approach.

Impact of Alcohol Abuse on Susceptibility to Rare Neurodegenerative Diseases

Despite the prevalence and well-recognized adverse effects of prenatal alcohol exposure and alcohol use disorder in the causation of numerous diseases, their potential roles in the etiology of neurodegenerative diseases remain poorly characterized. This is especially true of the rare neurodegenerative diseases, for which small population sizes make it difficult to conduct broad studies of specific etiological factors. Nonetheless, alcohol has potent and long-lasting effects on neurodegenerative substrates, at both the cellular and systems levels. This review highlights the general effects of alcohol in the brain that contribute to neurodegeneration across diseases, and then focuses on specific diseases in which alcohol exposure is likely to play a major role. These specific diseases include dementias (alcohol-induced, frontotemporal, and Korsakoff syndrome), ataxias (cerebellar and frontal), and Niemann-Pick disease (primarily a Type B variant and Type C). We conclude that there is ample evidence to support a role of alcohol abuse in the etiology of these diseases, but more work is needed to identify the primary mechanisms of alcohol's effects.

Binge drinking is associated with altered resting state functional connectivity of reward-salience and top down control networks

Binge drinking is characterized by bouts of high-intensity alcohol intake and is associated with an array of health-related harms. Even though the transition from occasional impulsive to addictive alcohol use is not well understood, neurobiological models of addiction suggest that repeated cycles of intoxication and withdrawal contribute to the development of addiction in part through dysregulation of neurofunctional networks. Research on the neural sequelae associated with binge drinking is scant but resting state functional connectivity (RSFC) studies of alcohol use disorders (AUD) indicate that the development and maintenance of long-term excessive drinking may be mediated by network-level disruptions. The present study examined RSFC in young adult binge (BD) and light (LD) drinkers with seeds representing the networks subserving reward (the nucleus accumbens and caudate nucleus), salience (anterior cingulate cortex, ACC), and executive control (inferior frontal cortex, IFC). BDs exhibited enhanced connectivity between the striatal reward areas and the orbitofrontal cortex and the ACC, which is consistent with AUD studies and may be indicative of alcohol-motivated appetitive behaviors. Conversely, BDs demonstrated lower connectivity between the IFC and hippocampus which was associated with higher craving. This may indicate impaired ability to suppress unwanted thoughts and a failure to employ memory of the harmful consequences of heavy drinking in prospective plans and intentions. The observed greater connectivity of the reward/salience network and the lower prefrontal-hippocampal connectivity were associated with hazardous drinking levels indicating that dysregulation of neurofunctional networks may underlie binge drinking patterns.

Recognition of younger and older faces in Korsakoff's syndrome

The own-age bias refers to the observation that face recognition is typically superior for own-age faces compared with other-age faces. We investigated this bias in Korsakoff patients, as well as its relationship with social contact and episodic memory. Korsakoff patients and age-matched controls were exposed to older faces (own-age faces) and younger faces (other-age faces). In the recognition phase, they were invited to decide whether faces had been exposed in the encoding phase or not. Results revealed an own-age bias in control participants (i.e., high recognition of older than for younger faces), but not in Korsakoff patients (i.e., similar recognition of older and younger faces). Furthermore, both Korsakoff's syndrome and controls reported more social contact with old than with young individuals. Recognition of younger and older faces in Korsakoff patients was significantly correlated with episodic performance but not with social contact with younger and older people. We conclude that the lack of own-age bias in Korsakoff's syndrome is related rather to compromise of episodic memory than to diminished social contact with younger adults.

Pharmacological enhancing agents targeting cognition in patients with alcohol-induced neurocognitive disorders: A systematic review

Debilitating neurocognitive deficits are seen in alcohol use disorders (AUD) and Wernicke-Korsakoff's syndrome (WKS). These shared characteristics suggest a spectrum of alcohol-induced neurocognitive disorders (AIND). Cognitive pharmacological enhancing agents (CPEA) have been examined in the treatment of other psychiatric disorders, but little is known about the effects of these agents on AINDs. Our aim was to synthesize the evidence for the effectiveness of CPEAs on AINDs. Databases were searched for controlled trials examining CPEAs on AUD, WKS, and alcohol-related dementia (ARD). Eligible studies were included in a qualitative synthesis and a quality assessment was conducted. The search identified 23 studies (4 ≤ ns ≤ 98). Evidence suggests that modafinil may improve executive functions in AUD and ARD, but this effect may only be present in patients with severe deficits. The studies were rated as having a moderate risk of bias. Despite the promising effects of modafinil, small samples and inconsistent evidence deem the results preliminary. More research is warranted examining the effects of transdiagnostic CPEAs on deficits across AINDs.

Effective Connectivity for Default Mode Network Analysis of Alcoholism

Introduction: With the recent technical advances in brain imaging modalities such as magnetic resonance imaging, positron emission tomography, and functional magnetic resonance imaging (fMRI), researchers' interests have inclined over the years to study brain functions through the analysis of the variations in the statistical dependence among various brain regions. Through its wide use in studying brain connectivity, the low temporal resolution of the fMRI represented by the limited number of samples per second, in addition to its dependence on brain slow hemodynamic changes, makes it of limited capability in studying the fast underlying neural processes during information exchange between brain regions. Materials and Methods: In this article, the high temporal resolution of the electroencephalography (EEG) is utilized to estimate the effective connectivity within the default mode network (DMN). The EEG data are collected from 20 subjects with alcoholism and 25 healthy subjects (controls), and used to obtain the effective connectivity diagram of the DMN using the Partial Directed Coherence algorithm. Results: The resulting effective connectivity diagram within the DMN shows the unidirectional causal effect of each region on the other. The variations in the causal effects within the DMN between controls and alcoholics show clear correlation with the symptoms that are usually associated with alcoholism, such as cognitive and memory impairments, executive control, and attention deficiency. The correlation between the exchanged causal effects within the DMN and symptoms related to alcoholism is discussed and properly analyzed. Conclusion: The establishment of the causal differences between control and alcoholic subjects within the DMN regions provides valuable insight into the mechanism by which alcohol modulates our cognitive and executive functions and creates better possibility for effective treatment of alcohol use disorder.

Moral reasoning, moral decision-making, and empathy in Korsakoff's syndrome

Korsakoff's syndrome (KS) is a neuropsychiatric disorder, caused by a vitamin B1 deficiency. Although it is known that patients with KS display diminished theory of mind functioning and frequently exhibit marked antisocial interactions little attention has so far focused on the integrity of moral decision-making abilities, moral reasoning, and empathy. In an experimental cross-sectional design, 20 patients diagnosed with KS, and twenty age-, education-, and gender-equivalent healthy participants performed tests assessing moral decision-making, moral reasoning maturity, empathy, and executive functioning. Participants were administered the Moral Behaviour Inventory (MBI) for everyday moral dilemmas, and ten cartoons of abstract moral dilemmas. Responses were scored according to the Kohlberg stages of moral reasoning. Empathy and executive functioning were assessed with the Interpersonal Reactivity Index (IRI) and the Frontal Assessment Battery (FAB). In contrast to frontal traumatic brain injury patients, KS patients did not display a utilitarian bias, suggesting preserved moral decision-making abilities. Of interest, KS patients had significantly lower levels of moral reasoning maturity on everyday moral dilemmas, and abstract moral dilemmas. In patients, empathy was moderately related to the level of moral maturity on both tasks, while executive functioning was not. In conclusion, KS patients have preserved moral decision-making abilities, but their moral reasoning abilities are poorer in everyday and abstract situations. Lower moral reasoning abilities and lower levels of empathy together may be responsible for adverse social functioning in KS.

Alcohol use disorders and the brain

A diagnosis of alcohol use disorder is associated with a higher risk of dementia, but a dose-response relationship between alcohol intake consumption and cognitive impairment remains unclear. Alcohol is associated with a range of effects on the central nervous system at different doses and acts on a number of receptors. Acute disorders include Wernicke's encephalopathy (WE), traumatic brain injury, blackouts, seizures, stroke and hepatic encephalopathy. The most common manifestations of chronic alcohol consumption are Korsakoff's syndrome (KS) and alcohol-related dementia (ARD). There is limited evidence for benefit from memantine in the treatment of ARD, but stronger evidence for the use of high-dose parenteral thiamine in the progression of neuropsychiatric symptoms for WE. Accumulating evidence exists for pharmacological treatment in the prevention of hepatic encephalopathy. Rehabilitation of people with ARD may take several years, and requires an approach that addresses physical and psychosocial factors.

Awareness and its relationships with neuropsychiatric symptoms in people with Korsakoff syndrome or other alcohol-related cognitive disorders living in specialized nursing homes

OBJECTIVES

Impaired awareness of functional deficits is often observed in people with Korsakoff syndrome (KS) and may result in refusal of care, although this area has been understudied. This study aimed to investigate levels of impaired awareness and their relationships with neuropsychiatric symptoms (NPS) in people with KS residing in specialized nursing homes.

METHODS

A cross-sectional, observational study was conducted among 215 residents with KS or other alcohol-related cognitive disorders. Awareness was measured with the Patient Competency Rating Scale (PCRS). NPS and subsyndromes were measured with the Neuropsychiatric Inventory-Questionnaire (NPI-Q). Adjusted multilevel regression analyses were performed to examine the relationships between the level of awareness and NPS.

RESULTS

The mean level of impaired awareness was 39.3 (SD = 19.9) indicating moderate impairment. Twenty-nine percent of the residents had no or mildly impaired awareness; 37% were moderately impaired, and 34% were severely impaired. Residents with moderately impaired awareness showed more severe apathy than residents with no or mildly impaired awareness (difference 1.23; 95% CI 1.02-1.48; p = 0.03). No associations were found between the level of awareness and other NPI outcomes. Cognitive functioning seems to have the strongest impact on the association between level of awareness and NPS in KS residents.

CONCLUSIONS

Impaired awareness of functional deficits is highly common in KS residents; however, apart from apathy, is not significantly related with NPS. Additional research should further examine, which interventions are effective in dealing with impaired awareness in these people, particularly when apathy is present.

Cognitive and affective theory of mind in Korsakoff's syndrome

OBJECTIVE

Korsakoff's syndrome (KS) is a chronic neuropsychiatric disorder characterised by severe anterograde amnesia and executive deficits. Theory of Mind (ToM) is the capacity to represent others' mental states such as their knowledge, thoughts, feelings, beliefs, and intentions in order to explain and predict their behaviour. Surprisingly this topic has received hardly any attention in research on KS, although the severity of behavioural problems in KS suggest possible ToM difficulties. The aim of the present study was therefore to assess whether cognitive and affective ToM are impaired in patients with KS.

METHODS

We examined 21 KS patients and 21 age- and gender-matched healthy controls on three standardised tests that assess cognitive and affective ToM, including the subtests of the mini-Social Cognition and Emotional Assessment battery and a specialised version of the Sally-Anne Test.

RESULTS

KS patients showed largely impaired cognitive and affective ToM compared to healthy controls, as reflected in large effect sizes on both cognitive and affective ToM tests. Executive deficits explained problems in emotion recognition, but not other ToM aspects.

CONCLUSION

KS patients have large impairments in both cognitive and affective aspects of social cognition. Their ability to recognise emotions, take the perspective of others, and understand socially awkward situations is vastly compromised. The impairments in ToM functioning are to a large degree functionally discrepant from executive disorders that are commonly present in KS. This study therefore highlights the importance to properly index ToM functioning in neuropsychological assessments for individuals with a possible KS diagnosis.

Executive Dysfunction in Patients With Korsakoff's Syndrome: A Theory-Driven Approach

Aims

In addition to amnesia, executive deficits are prominent in Korsakoff's syndrome (KS), yet poorly studied. This study investigates the degree of executive dysfunction in patients with KS for the three main executive subcomponents shifting, updating and inhibition using novel, theory-driven paradigms.

Short summary

Compared to healthy controls, patients with KS show impairments on the executive subcomponents shifting and updating, but not on inhibition.

Methods

Executive functions were measured with six carefully designed tasks in 36 abstinent patients with KS (mean age 62.3; 28% woman) and compared with 30 healthy non-alcoholic controls (mean age 61.8; 40% woman). ANOVAs were conducted to examine group differences and effect sizes were calculated.

Results

Compared to healthy controls, patients with KS were impaired on the executive subcomponents shifting and updating. No statistically significant group difference was found on the factor inhibition.

Conclusions

Executive dysfunction in long-abstinent patients with alcoholic KS shows a profile in which shifting and updating ability are affected most. It also highlights that executive dysfunction is an important feature of KS and requires more attention in scientific and clinical practice, as these deficits may also affect daily functioning.

A patient with Korsakoff syndrome of psychiatric and alcoholic etiology presenting as DSM-5 mild neurocognitive disorder

Background: Wernicke's encephalopathy (WE) and Korsakoff syndrome (KS) are underdiagnosed. The DSM-5 has raised the diagnostic threshold by including KS in the major neurocognitive disorders, which requires that the patient needs help in everyday activities. Methods: We report clinical, neuropsychological, and radiological findings from a patient who developed Wernicke-Korsakoff syndrome as a result of alcohol use and weight loss due to major depression. We assess the diagnosis in the context of the scientific literature on KS and according to the DSM-IV and the DSM-5. Results: The patient developed ataxia during a period of weight loss, thus fulfilling current diagnostic criteria of WE. WE was not diagnosed, but the patient partially improved after parenteral thiamine treatment. However, memory problems became evident, and KS was considered. In neuropsychological examination, the Logical Memory test and the Word List test were abnormal, but the Verbal Pair Associates test was normal (Wechsler Memory Scale-III). There were intrusions in the memory testing. The Wisconsin Card Sorting Test was broadly impaired, but the other test of executive functions (difference between Trail Making B and Trail Making A tests) was normal. There was atrophy of the mammillary bodies, the thalamus, the cerebellum, and in the basal ganglia but not in the frontal lobes. Diffusion tensor imaging showed damage in several tracts, including the uncinate fasciculi, the cinguli, the fornix, and the corona radiata. The patient remained independent in everyday activities. The patient can be diagnosed with KS according to the DSM-IV. According to the DSM-5, the patient has major neurocognitive disorders. Conclusions: Extensive memory testing is essential in the assessment of KS. Patients with a history of WE and typical clinical, neuropsychological, and radiological KS findings may be independent in everyday activities. Strict use of the DSM-5 may worsen the problem of Wernicke-Korsakoff syndrome underdiagnosis by excluding clear KS cases that do not have very severe functional impairment.

The role of the orbitofrontal cortex in alcohol use, abuse, and dependence

One of the major functions of the orbitofrontal cortex (OFC) is to promote flexible motivated behavior. It is no surprise, therefore, that recent work has demonstrated a prominent impact of chronic drug use on the OFC and a potential role for OFC disruption in drug abuse and addiction. Among drugs of abuse, the use of alcohol is particularly salient with respect to OFC function. Although a number of studies in humans have implicated OFC dysregulation in alcohol use disorders, animal models investigating the association between OFC and alcohol use are only beginning to be developed, and there is still a great deal to be revealed. The goal of this review is to consider what is currently known regarding the role of the OFC in alcohol use and dependence. I will first provide a brief, general overview of current views of OFC function and its contributions to drug seeking and addiction. I will then discuss research to date related to the OFC and alcohol use, both in human clinical populations and in non-human models. Finally I will consider issues and strategies to guide future study that may identify this brain region as a key player in the transition from moderated to problematic alcohol use and dependence.

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.

Hyperglycemia-related central pontine demyelinization after a binge-eating attack in a patient with type-2 diabetes: a case report

BACKGROUND

Here, we report a case of central pontine demyelinization in a type-2 diabetes patient with hyperglycemia after a binge-eating attack in the absence of a relevant hyponatremia.

CASE PRESENTATION

A 55-year-old, male type-2 diabetic patient with liver cirrhosis stage Child-Pugh B was admitted due to dysmetria of his right arm, gait disturbance, dizziness, vertigo, and polyuria, polydipsia after a binge-eating attack of sweets (a whole fruit cake and 2 Liters of soft drinks). A recently initiated insulin therapy had been discontinued for 8 months. A serum glucose measurement obtained 5 days prior to hospitalisation was 38.5 mmol/l (694 mg/dl). The patient graved for sweets since stopping alcohol consumption 8 months earlier. On admission, venous-blood glucose was 29.1 mmol/l (523.8 mg/dl), glycated hemoglobin was 168.0 mmol/mol or 17.6%. No supplementation of sodium chloride was reported. Laboratory exams revealed an elevated serum ammonia level (127.1 μmol/l), rendering a hepatic encephalopathy very likely. After initiation of insulin therapy, capillary glucose normalized, and serum sodium rose from 133 on admission to 144 mmol/l during the hospital stay. In retrospect, the mild hyponatremia on admission was classified as pseudohyponatremia due to hyperglycemia. The patient had an insulin resistance (HOMA-IR 7.8 (normal range < 2.5)). A T2-weighted magnetic resonance imaging (MRI) of the head and a cranial computed tomography scan were obtained demonstrating a symmetric central pontine demyelinization. After 26 days in hospital, the patient was discharged with an inkretin-mimetic therapy (dulaglutide SC, 1.5 mg/week) and an intensified conventional insulin therapy (insulin aspart: 14 units/d in euglycemia, insulin glargin 20 units/d).

CONCLUSIONS

Central pontine and/or cerebellar myelinolysis can be caused by sudden, severe, and sustained hyperglycemia, especially when another risk factor (in this case, liver cirrhosis) is present. Functional neurological deficits in the context of hyperglycemia should prompt for the consideration of this differential diagnosis in all diabetes patients.

Korsakoff Syndrome in Non-alcoholic Psychiatric Patients. Variable Cognitive Presentation and Impaired Frontotemporal Connectivity

Background: Non-alcoholic Wernicke's encephalopathy and Korsakoff syndrome are greatly underdiagnosed. There are very few reported cases of neuropsychologically documented non-alcoholic Korsakoff syndrome, and diffusion tensor imaging (DTI) data are scarce. Methods: We report clinical characteristics and neuropsychological as well as radiological findings from three psychiatric patients (one woman and two men) with a history of probable undiagnosed non-alcoholic Wernicke's encephalopathy and subsequent chronic memory problems. Results: All patients had abnormal neuropsychological test results, predominantly in memory. Thus, the neuropsychological findings were compatible with Korsakoff syndrome. However, the neuropsychological findings were not uniform. The impairment of delayed verbal memory of the first patient was evident only when the results of the memory tests were compared to her general cognitive level. In addition, the logical memory test and the verbal working memory test were abnormal, but the word list memory test was normal. The second patient had impaired attention and psychomotor speed in addition to impaired memory. In the third patient, the word list memory test was abnormal, but the logical memory test was normal. All patients had intrusions in the neuropsychological examination. Executive functions were preserved, except for planning and foresight, which were impaired in two patients. Conventional MRI examination was normal. DTI showed reduced fractional anisotropy values in the uncinate fasciculus in two patients, and in the corpus callosum and in the subgenual cingulum in one patient. Conclusions: Non-alcoholic Korsakoff syndrome can have diverse neuropsychological findings. This may partly explain its marked underdiagnosis. Therefore, a strong index of suspicion is needed. The presence of intrusions in the neuropsychological examination supports the diagnosis. Damage in frontotemporal white matter tracts, particularly in the uncinate fasciculus, may be a feature of non-alcoholic Korsakoff syndrome in psychiatric patients.

Crossmodal processing of emotions in alcohol-dependence and Korsakoff syndrome

INTRODUCTION

Decoding emotional information from faces and voices is crucial for efficient interpersonal communication. Emotional decoding deficits have been found in alcohol-dependence (ALC), particularly in crossmodal situations (with simultaneous stimulations from different modalities), but are still underexplored in Korsakoff syndrome (KS). The aim of this study is to determine whether the continuity hypothesis, postulating a gradual worsening of cognitive and brain impairments from ALC to KS, is valid for emotional crossmodal processing.

METHODS

Sixteen KS, 17 ALC and 19 matched healthy controls (CP) had to detect the emotion (anger or happiness) displayed by auditory, visual or crossmodal auditory-visual stimuli. Crossmodal stimuli were either emotionally congruent (leading to a facilitation effect, i.e. enhanced performance for crossmodal condition compared to unimodal ones) or incongruent (leading to an interference effect, i.e. decreased performance for crossmodal condition due to discordant information across modalities). Reaction times and accuracy were recorded.

RESULTS

Crossmodal integration for congruent information was dampened only in ALC, while both ALC and KS demonstrated, compared to CP, decreased performance for decoding emotional facial expressions in the incongruent condition.

CONCLUSIONS

The crossmodal integration appears impaired in ALC but preserved in KS. Both alcohol-related disorders present an increased interference effect. These results show the interest of more ecological designs, using crossmodal stimuli, to explore emotional decoding in alcohol-related disorders. They also suggest that the continuum hypothesis cannot be generalised to emotional decoding abilities.

Barking up the Wrong Tree: Why and How We May Need to Revise Alcohol Addiction Therapy

One of the main characteristics of alcohol abuse and addiction is the loss of control over alcohol intake and the continuation of drinking in the face of negative consequences. Mounting evidence strongly suggests that an alcohol-induced imbalance between goal-directed and habitual behavior may be one of the main driving factors of this key feature of addiction and furthermore play a key role in staying abstinent. Current therapies often focus only on deficient inhibitory control (i.e., goal-directed behavior), but largely neglect the potential of the well-functioning habit formation found in patients. Yet, focusing on intact habitual/automatic mechanisms in addition to or maybe even instead of deficient cognitive control might equip us with a more effective tool to battle the current alcohol abuse and addiction epidemic, especially with respect to more severely impacted patients who likely suffer from permanent alcohol-induced brain damage. Against this background, I would like to advocate the application and scientific evaluation of habit reversal therapy (HRT) for alcohol abuse and addiction.

Visuospatial declarative learning despite profound verbal declarative amnesia in Korsakoff's syndrome

Korsakoff's syndrome (KS) is a neuropsychiatric disorder characterised by severe amnesia. Although the presence of impairments in memory has long been acknowledged, there is a lack of knowledge about the precise characteristics of declarative memory capacities in order to implement memory rehabilitation. In this study, we investigated the extent to which patients diagnosed with KS have preserved declarative memory capacities in working memory, long-term memory encoding or long-term memory recall operations, and whether these capacities are most preserved for verbal or visuospatial content. The results of this study demonstrate that patients with KS have compromised declarative memory functioning on all memory indices. Performance was lowest for the encoding operation compared to the working memory and delayed recall operation. With respect to the content, visuospatial memory was relatively better preserved than verbal memory. All memory operations functioned suboptimally, although the most pronounced disturbance was found in verbal memory encoding. Based on the preserved declarative memory capacities in patients, visuospatial memory can form a more promising target for compensatory memory rehabilitation than verbal memory. It is therefore relevant to increase the number of spatial cues in memory rehabilitation for KS patients.

Prevalence and severity of behavioural symptoms in patients with Korsakoff syndrome and other alcohol-related cognitive disorders: a systematic review

OBJECTIVE

Experiences from clinical practice suggest that behavioural symptoms in patients with Korsakoff syndrome (KS) are a frequent problem. Knowledge about behavioural symptoms is important in understanding and managing these symptoms. The aim of this study is to review the prevalence and severity of behavioural symptoms in KS.

METHODS

Relevant articles were identified by searching Medline (PubMed), PsycINFO, Embase and CINAHL up to 4 June 2014. Two reviewers independently selected the studies, extracted their baseline data and assessed methodological quality using a standardized checklist.

RESULTS

Fifteen studies fulfilled the inclusion criteria. A diversity of diagnoses was used indicating that KS and other alcohol-related cognitive disorders and terms were used interchangeably. None of the studies were primarily designed to estimate the prevalence or severity of behavioural symptoms in patients with KS. Most studies had serious methodological limitations. The reported prevalence estimates of behavioural symptoms in the included studies varied strongly. Most prevalent were depressive symptoms and disorders (2-50%, median 27%) and agitation and aggression (10-54%, median 27%). None of the reported, mean severity estimates met pathological thresholds. The highest severity estimates were found for apathy.

CONCLUSIONS

Good quality studies on behavioural symptoms in patients with KS are lacking. Observational research designed to provide reliable estimates of the prevalence and severity of behavioural symptoms in patients with KS is needed. This could improve understanding and managing these symptoms and help care staff to better support the needs of this specific patient group. Copyright © 2016 John Wiley & Sons, Ltd.

Alcohol-related cognitive impairment: current trends and future perspectives

Excessive alcohol use is associated with a wide range of physical, psychological and social consequences, and is responsible for a significant proportion of the burden of disease globally. An area which has received increasing interest is alcohol-related brain damage, not just because of the cost to the individual and society through resource utilization, but also because of the potential for prevention and reversibility. This paper aims to review the current literature on this subject and seeks to explore issues around diagnosis and treatment of alcohol-related brain damage.

Cognitive impairment in older people with alcohol use disorders in a UK community mental health service

Purpose

The assessment of cognitive impairment in community services for older people remains under-explored. The paper aims to discuss this issue.

Design/methodology/approach

Cognitive impairment was examined in 25 people aged 65 and over with alcohol use disorders, on the caseload of community mental health services over a six-month period. All subjects assessed using Addenbrooke’s Cognitive Assessment (ACE-III).

Findings

In total, 76 per cent of the group scored below the cut-off point for likely dementia but only 45 per cent of people scored below the cut-off point for tests of language, compared with 68-84 per cent people in other domains.

Research limitations/implications

This finding has implications for the detection of alcohol-related brain cognitive impairment in clinical settings.

Practical implications

Standardised cognitive testing is common within mental health services for older people, but may also have utility within addiction services.

Social implications

The early detection of alcohol-related cognitive impairment can improve social outcomes in both drinking behaviour and the social consequences of alcohol-related dementia.

Originality/value

This may be the first published study of cognitive impairment in patients under a mental team for older people with alcohol use disorders and offers some unique findings within this sampling frame.

Procedural Learning and Memory Rehabilitation in Korsakoff's Syndrome - a Review of the Literature

Korsakoff's syndrome (KS) is a chronic neuropsychiatric disorder caused by alcohol abuse and thiamine deficiency. Patients with KS show restricted autonomy due to their severe declarative amnesia and executive disorders. Recently, it has been suggested that procedural learning and memory are relatively preserved in KS and can effectively support autonomy in KS. In the present review we describe the available evidence on procedural learning and memory in KS and highlight advances in memory rehabilitation that have been demonstrated to support procedural memory. The specific purpose of this review was to increase insights in the available tools for successful memory rehabilitation and give suggestions how to apply these tools in clinical practice to increase procedural learning in KS. Current evidence suggests that when memory rehabilitation is adjusted to the specific needs of KS patients, this will increase their ability to learn procedures and their typically compromised autonomy gets enhanced.

Integrity of white matter microstructure in alcoholics with and without Korsakoff's syndrome

Alcohol dependence results in two different clinical forms: "uncomplicated" alcoholism (UA) and Korsakoff's syndrome (KS). Certain brain networks are especially affected in UA and KS: the frontocerebellar circuit (FCC) and the Papez circuit (PC). Our aims were (1) to describe the profile of white matter (WM) microstructure in FCC and PC in the two clinical forms, (2) to identify those UA patients at risk of developing KS using their WM microstructural integrity as a biomarker. Tract-based spatial statistics and nonparametric voxel-based permutation tests were used to compare diffusion tensor imaging (DTI) data in 7 KS, 20 UA, and 14 healthy controls. The two patient groups were also pooled together and compared to controls. k-means classifications were then performed on mean fractional anisotropy values of significant clusters across all subjects for two fiber tracts from the FCC (the middle cerebellar peduncle and superior cerebellar peduncle) and two tracts from the PC (fornix and cingulum). We found graded effects of WM microstructural abnormalities in the PC of UA and KS. UA patients classified at risk of developing KS using fiber tracts of the PC from DTI data also had the lowest scores of episodic memory. That finding suggests that WM microstructure could be used as a biomarker for early detection of UA patients at risk of developing KS.

Alcohol exposure after mild focal traumatic brain injury impairs neurological recovery and exacerbates localized neuroinflammation

Traumatic brain injury (TBI) represents a leading cause of morbidity and mortality among young individuals. Alcohol abuse is a risk factor associated with increased TBI incidence. In addition, up to 26% of TBI patients engage in alcohol consumption after TBI. Limited preclinical studies have examined the impact of post-injury alcohol exposure on TBI recovery. The aim of this study was to determine the isolated and combined effects of TBI and alcohol on cognitive, behavioral, and physical recovery, as well as on associated neuroinflammatory changes. Male Sprague-Dawley rats (∼300g) were subjected to a mild focal TBI by lateral fluid percussion (∼30PSI, ∼25ms) under isoflurane anesthesia. On day 4 after TBI, animals were exposed to either sub-chronic intermittent alcohol vapor (95% ethanol 14h on/10h off; BAL∼200mg/dL) or room air for 10days. TBI induced neurological dysfunction reflected by an increased neurological severity score (NSS) showed progressive improvement in injured animals exposed to room air (TBI/air). In contrast, TBI animals exposed to alcohol vapor (TBI/alcohol) showed impaired NSS recovery throughout the 10-day period of alcohol exposure. Open-field exploration test revealed an increased anxiety-like behavior in TBI/alcohol group compared to TBI/air group. Additionally, alcohol-exposed animals showed decreased locomotion and impaired novel object recognition. Immunofluorescence showed enhanced reactive astrocytes, microglial activation, and HMGB1 expression localized to the injured cortex of TBI/alcohol as compared to TBI/air animals. The expression of neuroinflammatory markers showed significant positive correlation with NSS. These findings indicated a close relationship between accentuated neuroinflammation and impaired neurological recovery from post-TBI alcohol exposure. The clinical implications of long-term consequences in TBI patients exposed to alcohol during recovery warrant further investigation.

The neurobiology of thalamic amnesia: Contributions of medial thalamus and prefrontal cortex to delayed conditional discrimination

Although medial thalamus is well established as a site of pathology associated with global amnesia, there is uncertainty about which structures are critical and how they affect memory function. Evidence from human and animal research suggests that damage to the mammillothalamic tract and the anterior, mediodorsal (MD), midline (M), and intralaminar (IL) nuclei contribute to different signs of thalamic amnesia. Here we focus on MD and the adjacent M and IL nuclei, structures identified in animal studies as critical nodes in prefrontal cortex (PFC)-related pathways that are necessary for delayed conditional discrimination. Recordings of PFC neurons in rats performing a dynamic delayed non-matching-to position (DNMTP) task revealed discrete populations encoding information related to planning, execution, and outcome of DNMTP-related actions and delay-related activity signaling previous reinforcement. Parallel studies recording the activity of MD and IL neurons and examining the effects of unilateral thalamic inactivation on the responses of PFC neurons demonstrated a close coupling of central thalamic and PFC neurons responding to diverse aspects of DNMTP and provide evidence that thalamus interacts with PFC neurons to give rise to complex goal-directed behavior exemplified by the DNMTP task.

The role of ventral midline thalamus in cholinergic-based recovery in the amnestic rat

The thalamus is a critical node for several pathways involved in learning and memory. Damage to the thalamus by trauma, disease or malnourishment can impact the effectiveness of the prefrontal cortex (PFC) and hippocampus (HPC) and lead to a profound amnesia state. Using the pyrithiamine-induced thiamine deficiency (PTD) rat model of human Wernicke-Korsakoff syndrome, we tested the hypothesis that co-infusion of the acetylcholinesterase inhibitor physostigmine across the PFC and HPC would recover spatial alternation performance in PTD rats. When cholinergic tone was increased by dual injections across the PFC-HPC, spontaneous alternation performance in PTD rats was recovered. In addition, we tested a second hypothesis that two ventral midline thalamic nuclei, the rhomboid nucleus and nucleus reuniens (Rh-Re), form a critical node needed for the recovery of function observed when cholinergic tone was increased across the PFC and HPC. By using the GABAA agonist muscimol to temporarily deactivate the Rh-Re the recovery of alternation behavior obtained in the PTD model by cholinergic stimulation across the PFC-HPC was blocked. In control pair-fed (PF) rats, inactivation of the Rh-Re impaired spontaneous alternation. However, when inactivation of the Rh-Re co-occurred with physostigmine infusions across the PFC-HPC, PF rats had normal performance. These results further demonstrate that the Rh-Re is critical in facilitating interactions between the HPC and PFC, but other redundant pathways also exist.

Thirty Days without a Bite: Wernicke's Encephalopathy in a Patient with Paranoid Schizophrenia

Wernicke’s Encephalopathy (WE) is a preventable neurologic condition characterized by altered mental status, ophthalmoplegia, and ataxia. Although historically associated with alcoholism, a few authors have described WE in patients with non-alcohol related psychiatric disorders. We report herein the case of a 36-year-old young man with paranoid schizophrenia who was brought to hospital for confusion and difficulties with his vision. His roommate said he had gone about thirty days without eating ‘…because he was on a slimming cure’. History and physical examination suggested WE as a result of isolation and poor diet leading to nutritional deficiency. This was confirmed by brain magnetic resonance imaging showing classic thalamic, mammillary bodies and brainstem lesions. Of note, his cognitive profile was far more heterogeneous than what had classically been described in the literature and involved both cortical and subcortical pathology, generating memory but also significant executive deficits. Intravenous treatment with thiamine was given and our patient showed mild improvements in visual acuity and nystagmus. However, persistent cognitive and physical disabilities consistent with Korsakoff syndrome remained, and he now lives in a supervised home. This case illustrates the tragic consequences of nutritional deficiencies in a patient with paranoid schizophrenia. The threshold to suspect WE in schizophrenic patients should be lowered and in doubt prophylactic parenteral thiamine should be administered.

Thalamic abnormalities are a cardinal feature of alcohol-related brain dysfunction

Two brain networks are particularly affected by the harmful effect of chronic and excessive alcohol consumption: the circuit of Papez and the frontocerebellar circuit, in both of which the thalamus plays a key role. Shrinkage of the thalamus is more severe in alcoholics with Korsakoff's syndrome (KS) than in those without neurological complication (AL). In accordance with the gradient effect of thalamic abnormalities between AL and KS, the pattern of brain dysfunction in the Papez's circuit results in anterograde amnesia in KS and only mild-to-moderate episodic memory disorders in AL. On the opposite, dysfunction of the frontocerebellar circuit results in a similar pattern of working memory and executive deficits in the AL and KS. Several hypotheses, mutually compatible, can be drawn to explain that the severe thalamic shrinkage observed in KS has different consequences in the neuropsychological profile associated with the two brain networks.

Revisiting the continuum hypothesis: toward an in-depth exploration of executive functions in korsakoff syndrome

Korsakoff syndrome (KS) is a neurological state mostly caused by alcohol-dependence and leading to disproportionate episodic memory deficits. KS patients present more severe anterograde amnesia than Alcohol-Dependent Subjects (ADS), which led to the continuum hypothesis postulating a progressive increase in brain and cognitive damages during the evolution from ADS to KS. This hypothesis has been extensively examined for memory but is still debated for other abilities, notably executive functions (EF). EF have up to now been explored by unspecific tasks in KS, and few studies explored their interactions with memory. Exploring EF in KS by specific tasks based on current EF models could thus renew the exploration of the continuum hypothesis. This paper will propose a research program aiming at: (1) clarifying the extent of executive dysfunctions in KS by tasks focusing on specific EF subcomponents; (2) determining the differential EF deficits in ADS and KS; (3) exploring EF-memory interactions in KS with innovative tasks. At the fundamental level, this exploration will test the continuum hypothesis beyond memory. At the clinical level, it will propose new rehabilitation tools focusing on the EF specifically impaired in KS.