Chronic alcoholism and the frontal lobe: which executive functions are imparied?

A Study of the association of neurocognition with relapse and quality of life in patients of alcohol dependence

Background

Alcohol is a widely consumed substance associated with around 5.6% of all causes of death. Alcohol use disorder (AUD) is a chronic relapsing and remitting illness and has been known to be associated with impaired executive functions, processing speed, memory, attention, and fluency. It is also associated with impaired quality of life (QoL), which in turn can affect overall prognosis.

Aim

To assess neurocognition in patients with alcohol dependence and correlate it with QoL and relapse.

Materials and Methods

This study was a prospective, longitudinal study of sixty alcohol dependence patients from January 2020 to June 2021 after appropriate ethical approval. Participants were assessed for baseline alcohol dependence, neurocognition (focused, sustained and divided attention; processing speed; verbal and category fluency; working memory; response inhibition; verbal comprehension; verbal learning and memory; visuospatial construction; visual learning and memory) and QoL using Alcohol Use Disorders Identification Test (AUDIT), National Institute of Mental Health and Neurosciences (NIMHANS) battery for neurocognition and WHO-BREF (WHO-Quality of Life-short-form scale) World Health Organization-scale, respectively. A follow-up was conducted in three months to assess relapse in the patients. Statistical analysis was conducted by International Business Machines Statistical Package for the Social Sciences (IBM SPSS) v16.

Results

Mean age of the study participants was 41.3 ± 5.03 years, mean age of onset of alcohol use was 20.88 ± 4.27 years, mean duration of alcohol use of 16.6 ± 7.92 years, and average 14.55 ± 4.86 drinks per day. The mean AUDIT score of the study population was 25.21 ± 7.18. There was significant positive correlation between duration of use and CTT-2; 37 out of 57 participants relapsed to alcohol (three participants had died in follow-up) with mean 37.48 ± 23.27 days of relapse, mean 3.32 ± 1.2 drinking days per week, and mean 6 ± 1.2 drinks per drinking day. There was negative and positive correlation between neurocognition and relapse and between neurocognition and QoL.

Conclusion

Alcohol use also resulted in impaired cognitive function of the study participants. There was also significant difference in score for neurocognition test between relapse and abstinent group. The significant correlation between neurocognition and QoL as well as neurocognition and relapse proves the deleterious effect of alcohol in every aspect of life.

The effects of acamprosate on prefrontal cortical function are mimicked by CaCl2 and they are influenced by the history of alcohol exposure

Alcohol use disorder is associated with functional changes in the medial prefrontal cortex (mPFC), which include altered glutamatergic transmission and deficits in executive functions that contribute to relapse. Acamprosate (calcium-bis N-acetylhomotaurinate) reduces alcohol craving and relapse, effects that are thought to be mediated by acamprosate's ability to ameliorate alcohol-induced dysregulation of glutamatergic signaling. Treatment with acamprosate and its active moiety calcium (CaCl2) both improve deficits in cognitive flexibility in postdependent mice following chronic intermittent ethanol (CIE) exposure. Here, we show that mice that self-administered alcohol under goal-directed conditions (i.e., operant responding on a fixed-ratio schedule) also display similar deficits in cognitive flexibility and altered glutamatergic signaling in the mPFC, both of which were improved with acamprosate or CaCl2. However, under conditions shown to bias behavior towards habitual responding (operant self-administration after CIE exposure, or on a variable interval schedule), alcohol-induced changes to glutamatergic transmission were unaffected by either acamprosate or CaCl2 treatment. Together, these findings suggest that the variable effects of acamprosate on synaptic signaling may reflect a shift in mPFC networks related to the loss of behavioral control in habitual alcohol-seeking.

Intrinsic brain functional connectivity patterns in alcohol use disorder

Alcohol use disorder is associated with damaging effects to the brain. This study aimed to examine differences in static and dynamic intrinsic functional connectivity patterns in individuals with a history of alcohol use disorder in comparison to those with no history of alcohol abuse. A total of 55 participants consisting of 23 patients and 32 control individuals underwent neuropsychological assessments and resting-state functional magnetic resonance imaging on a 3 Tesla MRI scanner. Differences in functional connectivity between the two groups were determined using static and dynamic independent component analysis. Differences in static functional connectivity between the two groups were identified in the default mode network, attention network, frontoparietal network, frontal cortical network and cerebellar network. Furthermore, the analyses revealed specific differences in the dynamic temporal characteristics of functional connectivity between the two groups of participants, in a cluster involving key regions in reward, sensorimotor and frontal cortical functional networks, with some connections correlating with the length of sobriety and some others with the severity of drinking. The findings altogether suggest dysregulation in the intrinsic connectivity of cortico-basal ganglia-thalamo-cortical loops that may reflect persistent alcohol use disorder-related network abnormalities, compensatory recovery-related processes whereby additional neural resources are recruited to achieve normal levels of performance, or a predisposition toward developing alcohol use disorder.

Chronic alcohol exposure during critical developmental periods differentially impacts persistence of deficits in cognitive flexibility and related circuitry

Cognitive flexibility in decision making depends on prefrontal cortical function and is used by individuals to adapt to environmental changes in circumstances. Cognitive flexibility can be measured in the laboratory using a variety of discrete, translational tasks, including those that involve reversal learning and/or set-shifting ability. Distinct components of flexible behavior rely upon overlapping brain circuits, including different prefrontal substructures that have separable impacts on decision making. Cognitive flexibility is impaired after chronic alcohol exposure, particularly during development when the brain undergoes rapid maturation. This review examines how cognitive flexibility, as indexed by reversal and set-shifting tasks, is impacted by chronic alcohol exposure in adulthood, adolescent, and prenatal periods in humans and animal models. We also discuss areas for future study, including mechanisms that may contribute to the persistence of cognitive deficits after developmental alcohol exposure and the compacting consequences from exposure across multiple critical periods.

Externalizing psychopathology and cognitive functions in patients with early- and late-onset alcohol dependence

BACKGROUND

Alcohol use disorder is attributing to a significant health-care burden worldwide. Early-onset alcohol dependence is associated with more adverse outcomes than those with late-onset alcohol dependence. Comorbid externalizing disorders and cognitive deficits may be associated with the negative outcomes in early-onset alcohol dependence. This study aims at exploring the externalizing psychopathology and cognitive performance in early-onset alcohol dependence versus late-onset alcohol dependence.

MATERIALS AND METHODS

This is a cross-sectional study carried out on patients attending the psychiatry unit of a tertiary care center of north India after obtaining approval from the institutional ethics committee. A total of 57 patients with alcohol dependence enrolled in the study, after screening a total of 112 patients. Patients were evaluated for the externalizing psychopathology (using SSAGA intravenous [IV]) and cognitive performance (using Wisconsin Card Sorting Test [WCST] and continuous performance test [CPT]). Comparison of sociodemographic, clinical variables as well as externalizing psychopathology and cognitive performance was done between early-onset and late-onset alcohol dependence.

RESULTS

Comparison between early-onset and late-onset alcohol dependence revealed that the score of individual externalizing psychopathologies and the total externalizing psychopathology score on SSAGA IV in the early-onset group are significantly higher than late-onset alcohol dependence. Similarly, there is a significant difference in the executive functions (on WCST) between the two groups (early onset < late onset). On CPT, there are significantly more errors of omission in the early-onset group in comparison to their late-onset counterparts.

CONCLUSION

Early-onset alcohol dependence is associated with more externalizing psychopathology and more cognitive dysfunction than late-onset alcohol dependence.

Meta-analysis of grey matter changes and their behavioral characterization in patients with alcohol use disorder

Alcohol Use Disorder (AUD) is associated with reductions in grey matter (GM) volume which can lead to changes in numerous brain functions. The results of previous studies on altered GM in AUD differ considerably in the regions identified. Three meta-analyses carried out between 2014 and 2017 yielded different results. The present study includes the considerable amount of newer research and delivers a state-of-the art meta-analysis in line with recently published guidelines. Additionally, we behaviorally characterized affected regions using fMRI metadata and identified related brain networks by determining their meta-analytic connectivity patterns. Twenty-seven studies with 1,045 AUD patients and 1,054 healthy controls were included in the analysis and analyzed by means of Anatomical Likelihood Estimation (ALE). GM alterations were identified in eight clusters covering different parts of the cingulate and medial frontal gyri, paracentral lobes, left post- and precentral gyri, left anterior and right posterior insulae and left superior frontal gyrus. The behavioral characterization associated these regions with specific cognitive, emotional, somatosensory and motor functions. Moreover, the clusters represent nodes within behaviorally relevant brain networks. Our results suggest that GM reduction in AUD could disrupt network communication responsible for the neurocognitive impairments associated with high chronic alcohol consumption.

Heterogeneity of Executive Function Abilities in Recently Detoxified Patients with Alcohol Use Disorder: Evidence from a Cluster Analysis

BACKGROUND

Impairments of executive functions (EF) have been consistently reported in patients with alcohol use disorder (AUD), mostly in studies which were based on comparisons of means between groups. However, given the high heterogeneity in AUD patients, this approach could actually cover a wide range of EF patterns. In the present study, we addressed the paucity of the literature about cognitive heterogeneity in AUD by applying a cluster analytical approach on EF measures.

METHODS

Seventy-eight withdrawn AUD patients and 77 healthy Control participants completed measures targeting a variety of EF components. We then used cluster analysis to identify subgroups of AUD patients. Furthermore, the AUD subgroups were compared to the Control group to establish their specific EF patterns.

RESULTS

Findings showed that AUD patients could be divided into 3 clusters based on their EF performances. A first cluster accounting for half of the AUD sample was characterized by unimpaired EF (Cluster 1). The 2 other clusters displayed major EF deficits but differed regarding the deficient EF component. While Cluster 2 was mainly impaired on measures of rule deduction and mental flexibility, Cluster 3 was mainly characterized by a lower processing speed and impaired inhibition of an ongoing motor response. Differences in EF performances of AUD patients could be related to differences in premorbid cognitive reserve, impulsiveness patterns, and withdrawal complications.

CONCLUSIONS

This study highlights the importance of the cognitive heterogeneity in AUD by showing that AUD patients display substantially different EF patterns. Future studies should try to go beyond mere group comparisons to further deepen our understanding about cognitive differences between AUD patients. In the long run, this could lead to more personalized prevention and treatment programs specifically tailored to the patient's impairments.

Unveiling causal interactions in complex systems

Throughout time, operational laws and concepts from complex systems have been employed to quantitatively model important aspects and interactions in nature and society. Nevertheless, it remains enigmatic and challenging, yet inspiring, to predict the actual interdependencies that comprise the structure of such systems, particularly when the causal interactions observed in real-world phenomena might be persistently hidden. In this article, we propose a robust methodology for detecting the latent and elusive structure of dynamic complex systems. Our treatment utilizes short-term predictions from information embedded in reconstructed state space. In this regard, using a broad class of real-world applications from ecology, neurology, and finance, we explore and are able to demonstrate our method's power and accuracy to reconstruct the fundamental structure of these complex systems, and simultaneously highlight their most fundamental operations.

Random Forest Classification of Alcohol Use Disorder Using EEG Source Functional Connectivity, Neuropsychological Functioning, and Impulsivity Measures

: Individuals with alcohol use disorder (AUD) manifest a variety of impairments that can be attributed to alterations in specific brain networks. The current study aims to identify features of EEG-based functional connectivity, neuropsychological performance, and impulsivity that can classify individuals with AUD (N = 30) from unaffected controls (CTL, N = 30) using random forest classification. The features included were: (i) EEG source functional connectivity (FC) of the default mode network (DMN) derived using eLORETA algorithm, (ii) neuropsychological scores from the Tower of London test (TOLT) and the visual span test (VST), and (iii) impulsivity factors from the Barratt impulsiveness scale (BIS). The random forest model achieved a classification accuracy of 80% and identified 29 FC connections (among 66 connections per frequency band), 3 neuropsychological variables from VST (total number of correctly performed trials in forward and backward sequences and average time for correct trials in forward sequence) and all four impulsivity scores (motor, non-planning, attentional, and total) as significantly contributing to classifying individuals as either AUD or CTL. Although there was a significant age difference between the groups, most of the top variables that contributed to the classification were not significantly correlated with age. The AUD group showed a predominant pattern of hyperconnectivity among 25 of 29 significant connections, indicating aberrant network functioning during resting state suggestive of neural hyperexcitability and impulsivity. Further, parahippocampal hyperconnectivity with other DMN regions was identified as a major hub region dysregulated in AUD (13 connections overall), possibly due to neural damage from chronic drinking, which may give rise to cognitive impairments, including memory deficits and blackouts. Furthermore, hypoconnectivity observed in four connections (prefrontal nodes connecting posterior right-hemispheric regions) may indicate a weaker or fractured prefrontal connectivity with other regions, which may be related to impaired higher cognitive functions. The AUD group also showed poorer memory performance on the VST task and increased impulsivity in all factors compared to controls. Features from all three domains had significant associations with one another. These results indicate that dysregulated neural connectivity across the DMN regions, especially relating to hyperconnected parahippocampal hub as well as hypoconnected prefrontal hub, may potentially represent neurophysiological biomarkers of AUD, while poor visual memory performance and heightened impulsivity may serve as cognitive-behavioral indices of AUD.

Random Forest Classification of Alcohol Use Disorder Using fMRI Functional Connectivity, Neuropsychological Functioning, and Impulsivity Measures

Individuals with alcohol use disorder (AUD) are known to manifest a variety of neurocognitive impairments that can be attributed to alterations in specific brain networks. The current study aims to identify specific features of brain connectivity, neuropsychological performance, and impulsivity traits that can classify adult males with AUD (n = 30) from healthy controls (CTL, n = 30) using the Random Forest (RF) classification method. The predictor variables were: (i) fMRI-based within-network functional connectivity (FC) of the Default Mode Network (DMN), (ii) neuropsychological scores from the Tower of London Test (TOLT), and the Visual Span Test (VST), and (iii) impulsivity factors from the Barratt Impulsiveness Scale (BIS). The RF model, with a classification accuracy of 76.67%, identified fourteen DMN connections, two neuropsychological variables (memory span and total correct scores of the forward condition of the VST), and all impulsivity factors as significantly important for classifying participants into either the AUD or CTL group. Specifically, the AUD group manifested hyperconnectivity across the bilateral anterior cingulate cortex and the prefrontal cortex as well as between the bilateral posterior cingulate cortex and the left inferior parietal lobule, while showing hypoconnectivity in long-range anterior-posterior and interhemispheric long-range connections. Individuals with AUD also showed poorer memory performance and increased impulsivity compared to CTL individuals. Furthermore, there were significant associations among FC, impulsivity, neuropsychological performance, and AUD status. These results confirm the previous findings that alterations in specific brain networks coupled with poor neuropsychological functioning and heightened impulsivity may characterize individuals with AUD, who can be efficiently identified using classification algorithms such as Random Forest.

Mild Effect of Nalmefene on Alcoholic Cue-Induced Response Invigoration in Alcohol Use Disorder Without Accompanying Changes in Electrophysiological Signatures of Early Visual Processing and Executive Control

Nalmefene is approved for as-needed pharmacological treatment in alcohol use disorder (AUD) by the European Medicines Agency. While the cellular effects of nalmefene have been thoroughly investigated, data are very limited on how this agent influences neural signals associated with inhibitory control and the visual analysis of environmental cues. This double-blind crossover study assessed the behavioral and neural effects of acute nalmefene administration in patients diagnosed with AUD. In experiment 1, we validated our experimental paradigm (electroencephalography combined with a modified Go/NoGo task using images of alcoholic and nonalcoholic drinks as prime stimuli) in 20 healthy adults to ensure that our protocol is suitable for assessing the behavioral and neural aspects of executive control. In experiment 2, we recruited 19 patients with AUD, and in a double-blind crossover design, we investigated the effects of nalmefene versus placebo on task performance (response accuracy, the sensitivity index, and reaction times), visual responses to appetitive cues (occipital P1, N1, and P2 components), and electrophysiological markers of conflict detection and response inhibition (frontal N2 and P3 waveforms). Under placebo, patients produced faster reaction times to alcohol-primed Go stimuli, an effect that was weak despite being statistically significant. However, the effect of alcoholic cues on the speed of response initiation disappeared after receiving nalmefene. We found no placebo versus nalmefene difference regarding our patients’ ability to accurately inhibit responses to NoGo stimuli or for occipital and frontal event-related potentials. Our results suggest that nalmefene might be potent in reducing the vigor to act upon alcoholic cues in AUD patients, but this effect is most probably mediated via subcortical (rather than cortical) neural circuits.

Effectiveness of an Integrated Intervention Program for Alcoholism (IIPA) for enhancing self-regulation: Preliminary evidence

OBJECTIVE

Alcoholism could be a core problem of self-regulatory failure. Several neurocognitive theories have hypothesized hypo-functioning or dysfunction of reflective (executive) system and heightened functioning of reactive (impulsive) system in self-regulatory failure implicated in drug addiction. Similarly, stress and affect dysregulation may breakdown self-regulation. The present study aimed to develop an Integrated Intervention Program for Alcoholism (IIPA) to enhance self-regulation and to test its effectiveness in the treatment of alcoholism.

METHOD

Individuals with early onset alcoholism (n = 50) were recruited after getting written informed consent. The study used randomized case control design. The participants were matched on age (+/-1 year) and education (+/-1 year). The TAU group received usual treatment for alcoholism which included pharmacotherapy, 6 sessions/week yoga and 3 sessions/week group therapy on relapse prevention. The intervention group received IIPA for 18 days along with usual treatment (except yoga sessions). The IIPA included several cognitive remediation tasks and mind-body exercise (Qigong and Tai Chi Chuan). Both groups were assessed on executive function tests and affect regulation scale at pre and post-intervention. The subjects were also followed up for 6 months to compare the abstinence between groups.

RESULTS

Both groups were comparable at baseline. At post-intervention, the IIPA group showed a significant improvement compared to the TAU group on executive functioning and affect regulation. Follow-up results showed lower relapses in six months in the IIPA group.

CONCLUSION

Preliminary evidence showed that IIPA is effective in facilitating self-regulation. Further study may examine its utility and feasibility in other clinical conditions.

An Event-related Potential Study of Error-monitoring Deficits in Female College Students Who Participate in Binge Drinking

Objective

This study investigated error-monitoring deficits in female college students with binge drinking (BD) using event-related potentials (ERPs) and the modified Flanker task.

Methods

Participants were categorized into BD (n=25) and non-BD (n=25) groups based on the scores of the Korean-version of the Alcohol Use Disorder Identification Test (AUDIT-K) and the Alcohol Use Questionnaire (AUQ). The modified Flanker task, consisting of congruent (target and flanker stimuli are the same) and incongruent (target and flanker stimuli are different) conditions, was used to evaluate error-monitoring abilities.

Results

The BD group exhibited significantly shorter response times and more error rates on the Flanker task, as well as reduced error-related negativity (ERN) amplitudes compared with the non-BD group. Additionally, ERN amplitudes measured at FCz and Cz were significantly correlated with scores on the AUDIT-K and AUQ in the whole participants. The BD and non-BD groups did not show any significant differences in error positivity amplitudes.

Conclusion

The present results indicate that college students with BD have deficits in error-monitoring, and that reduced ERN amplitudes may serve as a biological marker or risk factor of alcohol use disorder.

Neural correlates of visual attention in alcohol use disorder

Numerous studies have documented cognitive impairments in multiple domains in patients with an alcohol use disorder (AUD), including perceptuomotor, executive, and visuospatial functions. Although the neural underpinnings of cognitive deficits in AUD have been studied extensively, the neural basis of attention deficits in AUD remains relatively unexplored. Here, we investigated neural responses to a visual attention task (VAT) in 19 recently abstinent patients with AUD and 23 healthy control participants (HC) using functional MRI (fMRI). AUD had a mean number of 62 ± 34SD drinks per week and 29 ± 13 years' history of alcohol use. Results show that there were no behavioral differences (accuracy or reaction time) between groups during the VAT. For both groups, the VAT activated brain areas associated with visual attention load (i.e., parietal and prefrontal cortices) and visual processing (i.e., occipital cortex), which is in line with previous reports on the same task in healthy volunteers. Despite similar behavioral performances, AUD participants showed decreased VAT activation in regions of the dorsal and ventral attention networks, including parietal and prefrontal cortices, and in the insula as compared to controls. These findings corroborate differences in attention networks in AUD compared to HC that might underlie attention deficits in AUD, whereas impairments in the insula could reflect a disruption of interoception processing as found in other addictions.

Light social drinkers are more distracted by irrelevant information from an induced attentional bias than heavy social drinkers

It is well established that alcoholics and heavy social drinkers show a bias of attention towards alcohol-related items. Previous research suggests that there is a shared foundation of attentional bias, which is linked to attentional control settings. Specifically, attentional bias relates to a persistent selection of a Feature Search Mode which prioritises attentional bias-related information for selection and processing. However, no research has yet examined the effect of pre-existing biases on the development of an additional attentional bias. This paper seeks to discover how pre-existing biases affect the formation of a new, additional attentional bias. Twenty-five heavy and 25 light social drinkers, with and without a pre-existing bias to alcohol-related items, respectively, had an attentional bias towards the colour green induced via an information sheet. They then completed a series of one-shot change detection tasks. In the critical task, green items were present but task-irrelevant. Irrelevant green items caused significantly more interference for light than heavy social drinkers. This somewhat counter intuitive result is likely due to heavy drinkers having more experience in exerting cognitive control over attentional biases, something not previously observed in investigations of the effects of holding an attentional bias. Our findings demonstrate for the first time that an established attentional bias significantly modulates future behaviour.

Neuropsychological Performance in Alcohol Dependent Patients: A One-Year Longitudinal Study

OBJECTIVE

Despite several studies that have highlighted the harmful effects of alcohol consumption on cognitive functions it remains unclear whether certain brain areas are more sensitive than others are or whether alcohol causes widespread cognitive deficit. Moreover, the role of continued abstinence has yet to be clarified regarding the quality of recovery on the different cognitive domains. The aim of this 1-year longitudinal study was to evaluate the recovery of cognitive deficits in the medium (6 months) and long term (12 months) after the interruption of drinking.

METHODS

Forty-one alcohol-dependent patients were recruited from two outpatient treatment facilities and cognitive functions were compared on a control group of forty healthy controls. The patients were then re-assessed at 6 and 12 months. Changes in neuropsychological measures were evaluated with repeated measures analysis of variance (ANOVA). We also compared 1-year follow-up scores with control data (unpaired t tests) to identify tests on which significant differences persisted.

RESULTS

Patients performed significantly worse than controls in all cognitive domains investigated and this cognitive impairment was evident in recently abstinent patients. A year of abstinence resulted in a significant improvement in all cognitive domains assessed after detoxification from alcohol. After year 1, alcoholic subjects had returned to normal levels compared to healthy controls on all domains except for general non-verbal intelligence, verbal memory and some visuospatial skills.

CONCLUSION

Our results support the hypothesis of widespread impairment resulting from alcohol consumption. The recovery of cognitive functions is not homogeneous during prolonged abstinence.

Cognitive deficits in problematic drinkers with and without mild to borderline intellectual disability

We examined cognitive deficits in problematic drinkers with and without mild to borderline intellectual disability (MBID). Problematic drinkers were expected to show a significantly lower estimated performance IQ (PIQ), but not a lower estimated verbal IQ (VIQ), compared to light drinkers. Participants ( N = 474) were divided into four groups based on IQ and severity of alcohol use-related problems. IQ was estimated using (a short form of) the Wechsler Adult Intelligence Scale third edition. Severity of alcohol use-related problems was assessed using the Alcohol Use Disorder Identification Test. Overall, there were no significant differences between light and problematic drinkers on estimated VIQ. Within the group without MBID, estimated PIQ was significantly lower. Estimated PIQ was not lower in problematic drinkers with MBID compared to light drinkers with MBID. The results are indicative of cognitive deficits in problematic drinkers without MBID. Screening for cognitive deficits with additional instruments is advised.

A Complex Interplay of Vitamin B1 and B6 Metabolism with Cognition, Brain Structure, and Functional Connectivity in Older Adults

Aging is associated with brain atrophy, functional brain network reorganization and decline of cognitive performance, albeit characterized by high interindividual variability. Among environmental influencing factors accounting for this variability, nutrition and particularly vitamin supply is thought to play an important role. While evidence exists that supplementation of vitamins B6 and B1 might be beneficial for cognition and brain structure, at least in deficient states and neurodegenerative diseases, little is known about this relation during healthy aging and in relation to reorganization of functional brain networks. We thus assessed the relation between blood levels of vitamins B1 and B6 and cognitive performance, cortical folding, and functional resting-state connectivity in a large sample of older adults (N > 600; age: 55-85 years), drawn from the population-based 1000BRAINS study. In addition to blood sampling, subjects underwent structural and functional resting-state neuroimaging as well as extensive neuropsychological testing in the domains of executive functions, (working) memory, attention, and language. Brain regions showing changes in the local gyrification index as calculated using FreeSurfer in relation to vitamin levels were used for subsequent seed-based resting-state functional connectivity analysis. For B6, a positive correlation with local cortical folding was found throughout the brain, while only slight changes in functional connectivity were observed. Contrarily, for B1, a negative correlation with cortical folding as well as problem solving and visuo-spatial working memory performance was found, which was accompanied by pronounced increases of interhemispheric and decreases of intrahemispheric functional connectivity. While the effects for B6 expand previous knowledge on beneficial effects of B6 supplementation on brain structure, they also showed that additional effects on cognition might not be recognizable in healthy older subjects with normal B6 blood levels. The cortical atrophy and pronounced functional reorganization associated with B1, contrarily, was more in line with the theory of a disturbed B1 metabolism in older adults, leading to B1 utilization deficits, and thus, an effective B1 deficiency in the brain, despite normal to high-normal blood levels.

The efficacy of a working memory training in substance use patients: A randomized double-blind placebo-controlled clinical trial

INTRODUCTION

Substance use disorder patients show impairments in working memory (WM) functioning. Previous findings indicate that a WM training results in improvements of working memory capacity (WMC) and in decreased clinical symptoms in a range of mental disorders, including alcohol use disorder.

METHOD

The aim of the current study is to investigate the efficacy of a 24-session WM training in addition to treatment as usual on craving, WMC, substance use, impulsivity, attention bias, and psychopathology using a randomized double-blind placebo-controlled trial. Inpatients (n = 180) diagnosed with an alcohol, cocaine, or cannabis use disorder were included.

RESULTS

Although the WM training resulted in better scores on the trained tasks in both groups, the placebo training resulted in a better or equal WMC compared to the experimental training, as measured with two nontrained transfer tasks. The WM training had no effect on craving, substance use, impulsivity, attention bias, and psychopathology.

CONCLUSION

Overall, we did not find evidence for the efficacy of WM training on WMC or clinical symptoms as compared to a placebo training in a population of substance use disorder patients. Future research needs to investigate further whether WMC is an important factor that is associated with substance-abuse-related behavior, and whether working memory training could be useful in substance use disorders.

Differential spontaneous recovery across cognitive abilities during detoxification period in alcohol-dependence

OBJECTIVE

There is a lack of consensus regarding the extent to which cognitive dysfunctions may recover upon cessation of alcohol intake by alcohol-dependents (AD), and the divergent findings are most likely due to methodological differences between the various studies. The present study was aimed at conducting a very strict longitudinal study of cognitive recovery in terms of assessment points, the duration of abstinence, control of age and duration of the addiction, and by use of individual analyses in addition to mean group comparisons. Our study further focused on the 2-3 week phase of alcohol detoxification that is already known to positively affect many biological, emotional, motivational, as well as neural variables, followed by longer-term therapies for which good cognitive functioning is needed.

METHODS

41 AD inpatients undergoing a detoxification program, and 41 matched controls, were evaluated twice in terms of five cognitive functions (i.e., short-term memory, working memory, inhibition, cognitive flexibility, and verbal fluency) within a three-week interval [on the first day (T1) and the 18th day (T2) of abstinence for AD patients]. Emotional (positive and negative affectivity and depression) and motivational (craving) variables were also measured at both evaluation times.

RESULTS

Although verbal fluency, short-term memory, and cognitive flexibility did not appear to be affected, the patients exhibited impaired inhibition and working memory at T1. While no recovery of inhibition was found to occur, the average working memory performance of the patients was comparable to that of the controls at T2. Improvements in emotional and motivational dimensions were also observed, although they did not correlate with the ones in working memory. Individual analysis showed that not all participants were impaired or recover the same functions.

CONCLUSIONS

While inhibition deficits appear to persist after 18 days of detoxification, deficits in working memory, which is a central component of cognition, are greatly reduced after alcohol detoxification. Individual differences in the trajectory of recovery do arise however, and it might be worth implementing individual assessments of impaired functions at the end of the detoxification phase in order to maximize the chances of success in longer-term treatments and abstinence.

Executive Functions, Memory, and Social Cognitive Deficits and Recovery in Chronic Alcoholism: A Critical Review to Inform Future Research

Alcoholism is a complex and dynamic disease, punctuated by periods of abstinence and relapse, and influenced by a multitude of vulnerability factors. Chronic excessive alcohol consumption is associated with cognitive deficits, ranging from mild to severe, in executive functions, memory, and metacognitive abilities, with associated impairment in emotional processes and social cognition. These deficits can compromise efforts in initiating and sustaining abstinence by hampering efficacy of clinical treatment and can obstruct efforts in enabling good decision making success in interpersonal/social interactions, and awareness of cognitive and behavioral dysfunctions. Despite evidence for differences in recovery levels of selective cognitive processes, certain deficits can persist even with prolonged sobriety. Herein is presented a review of alcohol-related cognitive impairments affecting component processes of executive functioning, memory, and the recently investigated cognitive domains of metamemory, social cognition, and emotional processing; also considered are trajectories of cognitive recovery with abstinence. Finally, in the spirit of critical review, limitations of current knowledge are noted and avenues for new research efforts are proposed that focus on (i) the interaction among emotion-cognition processes and identification of vulnerability factors contributing to the development of emotional and social processing deficits and (ii) the time line of cognitive recovery by tracking alcoholism's dynamic course of sobriety and relapse. Knowledge about the heterochronicity of cognitive recovery in alcoholism has the potential of indicating at which points during recovery intervention may be most beneficial.

Diversities of behavioral traits and neuropsychological function in different substance addiction

OBJECTIVE

There are various temperaments and personality characters that modulate the development of substance addiction. The pharmacological properties of substances would alter the homeostasis of brain function and influence the neuropsychological performance through different neurotransmissions which then facilitate diverse emotional and behavioral responses. Our goal is to assess the interaction between personality characteristics, neuropsychological performances and Stroop interference in alcoholics, heroin and amphetamine dependent persons.

METHODS

Subjects with alcohol (N=95), heroin (N=82) and amphetamine (N=57) dependence were recruited. Diagnostic interview and questionnaires evaluating the psychiatric symptoms were done, followed by neuropsychological assessments of Stroop and Wisconsin card sorting tests (WCST). Differences between the study groups were analyzed by one-way ANOVA with Scheffe's test.

RESULTS

The individuals with alcohol dependence had significantly higher scores of neurotic, dysphoric and impulsive traits (P<0.001) than heroin and amphetamine dependent groups. In Stroop tests, the alcohol dependent subjects also showed delayed response on incongruent naming interferences compared to both of heroin and amphetamine groups (P<0.001). Perseverative errors and responses of WCST were significantly higher in heroin than in alcoholic dependent persons (P<0.01).

CONCLUSIONS

Individuals with different substance dependence have distinct behavioral traits for developing addicted behaviors and had variant deficits of neuropsychological function.

Frontal lobe executive dysfunction and cerebral perfusion study in alcohol dependence syndrome

BACKGROUND

Long-term alcohol use leading to frontal lobe impairment has been a cause of concern for many decades. However, there are very few studies from India of evaluation of frontal lobe executive dysfunction among alcoholics. Hence, this study was undertaken to evaluate the frontal executive dysfunction using Wisconsin Card Sorting Test (WCST) and perfusion deficits by Single-Photon Emission Computerized Tomography (SPECT) among alcohol-dependent patients.

AIM

The aim of this study is to evaluate the frontal executive dysfunction using WCST and frontal lobe perfusion deficits by SPECT among alcohol-dependent patients.

MATERIALS AND METHODS

This was a cross-sectional study involving 20 alcohol dependence syndrome patients in a tertiary care center. After ethical clearance and informed consent, all were evaluated using WCST and SPECT.

RESULTS

About 45% patients had impairment on WCST, and it was related to the duration of drinking. About 55% showed reduced frontal lobe perfusion on SPECT scan and they had a long duration of drinking compared to controls. Among the patients showing impairment on WCST subscores, more than 50% had reduced frontal lobe perfusion on SPECT.

CONCLUSION

This study not only confirmed the executive function impairment and frontal lobe perfusion deficits in alcohol-dependent patients but also showed a concomitant presence of both in patients with chronic alcohol abuse.

Dorsolateral prefrontal cortex contributes to the impaired behavioral adaptation in alcohol dependence

Substance-dependent individuals often lack the ability to adjust decisions flexibly in response to the changes in reward contingencies. Prediction errors (PEs) are thought to mediate flexible decision-making by updating the reward values associated with available actions. In this study, we explored whether the neurobiological correlates of PEs are altered in alcohol dependence. Behavioral, and functional magnetic resonance imaging (fMRI) data were simultaneously acquired from 34 abstinent alcohol-dependent patients (ADP) and 26 healthy controls (HC) during a probabilistic reward-guided decision-making task with dynamically changing reinforcement contingencies. A hierarchical Bayesian inference method was used to fit and compare learning models with different assumptions about the amount of task-related information subjects may have inferred during the experiment. Here, we observed that the best-fitting model was a modified Rescorla-Wagner type model, the “double-update” model, which assumes that subjects infer the knowledge that reward contingencies are anti-correlated, and integrate both actual and hypothetical outcomes into their decisions. Moreover, comparison of the best-fitting model's parameters showed that ADP were less sensitive to punishments compared to HC. Hence, decisions of ADP after punishments were loosely coupled with the expected reward values assigned to them. A correlation analysis between the model-generated PEs and the fMRI data revealed a reduced association between these PEs and the BOLD activity in the dorsolateral prefrontal cortex (DLPFC) of ADP. A hemispheric asymmetry was observed in the DLPFC when positive and negative PE signals were analyzed separately. The right DLPFC activity in ADP showed a reduced correlation with positive PEs. On the other hand, ADP, particularly the patients with high dependence severity, recruited the left DLPFC to a lesser extent than HC for processing negative PE signals. These results suggest that the DLPFC, which has been linked to adaptive control of action selection, may play an important role in cognitive inflexibility observed in alcohol dependence when reinforcement contingencies change. Particularly, the left DLPFC may contribute to this impaired behavioral adaptation, possibly by impeding the extinction of the actions that no longer lead to a reward.

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Alcohol-dependent patients (ADP) had difficulty adapting to the reversals.

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The impaired adaptation was associated with a decrease in punishment sensitivity.

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The dorsolateral prefrontal cortex (DLPFC) of ADP failed to track prediction errors.

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A reduced tracking of the negative prediction error was present in the left DLPFC.

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The clinical severity of dependence was correlated with abnormal DLPFC activity.

A neuropsychological study of older adult first-time sex offenders

BACKGROUND/AIMS

The issue of whether sex offenders have cognitive deficits remains controversial. The objective of this study was to compare the neuropsychological function of older adult first time sex-offenders (FTSO), who had not previously been charged with a sexual offence prior to the age of 50, to historical long-term sex offenders (HSO) and non-sex offenders (NSO). The hypotheses were (a) that FTSO would demonstrate greater deficits in executive function, decision-making, and memory compared to non-sex offenders; and (b) the HSOs would present similar neuropsychological deficits to non-sex offenders.

METHOD

A battery of neuropsychological measures was administered to 100 participants comprising 32 FTSOs, 36 HSOs, and 32 NSOs.

RESULTS

Both FTSOs and HSOs showed significant impairment on tests of executive function (including verbal fluency, trail-making, and the Hayling test of response inhibition) as well as on tests of verbal and verbal memory compared to NSOs; however, there was no difference between the two sex offender groups.

CONCLUSIONS

Older adult sex offenders, overall, demonstrated poorer neuropsychological performance than older adult non-sex offenders did, although there was no difference between older first-time and historical offenders. Cognitive deficits may increase the risk of sexual offending due to impaired capacity in self-regulation, planning, judgment, and inhibition. A proportion of older adult sex offenders may be harboring acquired frontal lobe pathology.

Adolescence and Drug Use Vulnerability: Findings from Neuroimaging

Adolescence is a period of vulnerability for developing substance use disorder. Recent neuropsychological and neuroimaging studies have elucidated underlying neural vulnerabilities that contribute to initiation of substance use during adolescence. Findings suggest poorer performance on tasks of inhibition and working memory, smaller brain volumes in reward and cognitive control regions, less brain activation during executive functioning tasks, and heightened reward responsivity are predictive of youth initiating substance use during adolescence. In youth who are family history positive (FHP) for substance use disorder, poorer executive functioning, smaller volume of limbic brain regions (e.g., amygdala), sex-specific patterns of hippocampal volume, and a positive association between nucleus accumbens volume and family history density have been reported. Further, reduced white matter integrity, altered brain response during inhibitory control, including both greater and less frontal lobe response, blunted emotional processing, and weaker neural connectivity have also been found in FHP youth. Thus, there is significant overlap among the neural precursors shown to be predictive of alcohol and substance use initiation during adolescence and those that distinguish FHP from youth without a family history of substance use disorder, suggesting common targets for prevention and intervention. Understanding these predictive factors helps identify at-risk youth for prevention efforts, as well as create interventions targeting cognitive weaknesses or brain regions involved in substance use initiation.

Neuropsychological Impairment in Detoxified Alcohol-Dependent Subjects with Preserved Psychosocial Functioning

BACKGROUND

Chronic alcoholism and its related cognitive impairments are associated with increased social, relational, and professional deficits which have a variable overall impact on social integration. These impairments are known to have varying severities and have rarely been studied among healthy alcohol-dependent subjects with preserved psychosocial functioning. Thus, the objective of this study is to describe neuropsychological performance in this particular population.

METHOD

Twenty-nine socially adjusted alcohol-dependent men, hospitalized for a first or second withdrawal and abstinent for 3 weeks minimum, were compared to 29 healthy non-alcoholic controls. All subjects underwent clinical and psychiatric examination, neuropsychological tests of memory (M), working memory (WM), and executive functions (EF). Comparisons were performed using Student's t-tests or Mann-Whitney U tests.

RESULTS

No group differences were found on the Self-Reported Social Adjustment Scale (SAS-SR) or in the Mini-Mental State Examination. Compared to controls, patients had greater episodic, spatial, and WM deficits as well as slightly altered executive functions. In contrast, their executive functions (spontaneous flexibility, criteria generation, rule maintenance, and inhibitory control) were relatively preserved.

CONCLUSION

Our sample of socially and professionally integrated alcoholic patients shows fewer cognitive deficits than described in previous studies. Our results suggest that early on, alcohol-dependent subjects develop compensatory adaptation processes to preserve social function and adaptation. Minor cognitive impairments should be screened early in the disease to integrate cognitive interventions into the health-care plan to thus eventually prevent further socio-professional marginalization.

An Open-label, Self-control, Prospective Study on Cognitive Function, Academic Performance, and Tolerability of Osmotic-release Oral System Methylphenidate in Children with Attention-deficit Hyperactivity Disorder

BACKGROUND

Attention-deficit hyperactivity disorder (ADHD) is the most common mental and behavioral disorder in school-aged children. This study evaluated the effect of osmotic-release oral system (OROS) methylphenidate (MPH) on cognitive function and academic performance of Chinese school-aged children with ADHD.

METHODS

This 12-week, prospective, multicenter, open-label, self-controlled study enrolled 153 Chinese school-aged children with ADHD and 41 non-ADHD children. Children with ADHD were treated with once-daily OROS-MPH (18 mg, 36 mg, or 54 mg). The primary endpoints were Inattention/Overactivity (I/O) with Aggression Conners Behavior Rating Scale (IOWA) and Digit Span Test at week 12 compared with baseline. Secondary endpoints included opposition/defiant (O/D) subscale of IOWA, Clinical Global Impression (CGI), Coding Test, Stroop Color-word Test, Wisconsin Card Sorting Test (WCST), academic performance on teacher-rated school examinations, and safety at week 12 compared with baseline. Both non-ADHD and ADHD children received the same frequency of cognitive operational test to avoid the possible bias caused by training.

RESULTS

A total of 128 patients were evaluated with cognitive assessments. The OROS-MPH treatment significantly improved IOWA Conners I/O subscale scores at week 12 (3.8 ± 2.3) versus baseline (10.0 ± 2.4; P < 0.0001). Digit Span Test scores improved significantly (P < 0.0001) with a high remission rate (81.1%) at week 12 versus baseline. A significant (P < 0.0001) improvement was observed in O/D subscale of IOWA, CGI, Coding Test, Stroop Color-word Test, WCST, and academic performance at week 12 versus baseline. Very few practice-related improvements were noticed in the non-ADHD group at week 12 compared with baseline. No serious adverse events and deaths were reported during the study.

CONCLUSIONS

The OROS-MPH treatment effectively controlled symptoms of ADHD and significantly improved academic performance and cognitive function of Chinese school-aged children with ADHD. The treatment was found to be safe and generally well-tolerated over 12 weeks.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01933880; http://clinicaltrials.gov/ct2/show/NCT01933880?term=CONCERTAATT4099&rank=1.

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.

Differential fMRI BOLD responses in amygdala in intermittent explosive disorder as a function of past Alcohol Use Disorder

BACKGROUND

Individuals with intermittent explosive disorder (IED) were previously found to exhibit amygdala (AMYG) hyperactivation to anger faces during functional magnetic resonance imaging (fMRI). However, acute alcohol consumption, and/or life history of alcoholism, may blunt amygdala responses to negative emotional stimuli. Thus, we examined the influence of a past history of DSM-5 Alcohol Use Disorder (AUD) on the fMRI BOLD AMYG response to anger faces in IED.

METHOD

Forty-two IED participants, 18 with a past history of AUD (IED+AUD) and 24 without Past AUD (IED), and 32 healthy control (HC) participants, underwent fMRI scanning while viewing blocks of angry, fearful, and happy faces.

RESULTS

Compared to HC and IED+AUD participants, IED subjects exhibited greater AMYG responses to angry, but not to fear or happy, faces in the left AMYG. There were no group differences in responses to anger, fear, or happy, faces in the OFC.

CONCLUSION

These findings suggest the possibility of a longstanding effect of AUD on AMYG response in IED to anger-related stimuli and highlight the possibility that history of AUD should be considered as an important factor in the interpretation of fMRI studies involving the AMYG response to negative emotional stimuli.

Can brain games help smokers quit?: Results of a randomized clinical trial

BACKGROUND AND AIMS

Deficits in cognitive function are observed during nicotine withdrawal and present a challenge to successful smoking cessation. This clinical trial evaluated a cognitive exercise training (CT) program to improve smoking cessation rates.

METHODS

Adult treatment-seeking smokers (n=213) were randomized to receive nicotine patch therapy and 12 weeks of either computerized CT or computerized relaxation (control) training. Smoking status was biochemically verified at the end of treatment and 6-month follow-up.

RESULTS

Quit rates did not differ by treatment arm at either time-point, nor were there effects on withdrawal symptoms or smoking urges. Reaction time for emotion recognition and verbal interference tasks showed improvement in the CT group. When including only successful quitters, improvements in recognition memory, verbal interference accuracy, and attention switching error rate were also observed in the CT group, while commission errors on the continuous performance task decreased in the control group.

CONCLUSIONS

Despite modest changes in cognitive performance, these results do not support the efficacy of computerized cognitive training as an adjunctive therapy for smoking cessation.

Cognitive Function in Older Diabetic Subjects with a History of Alcohol Abuse

Either diabetes or alcohol abuse can impair cognitive function, especially at older ages. Whether a history of alcohol abuse increases the risk for cognitive impairment in diabetic patients has not been examined. Cognitive function of type 2 diabetic subjects with a history of alcohol abuse was expected to be more impaired than that of subjects with either diabetes or alcohol abuse alone. Men, >55 years of age, were categorized as 15 alcoholic-diabetic; 15 alcoholic-nondiabetic; 15 nonalcoholic-diabetic; 15 nonalcoholic-nondiabetic, and matched on age, sex, and education. Participants' verbal memory, visuospatial memory, and executive functions were assessed using a neurocognitive test battery. Significant interactions of diabetes and alcoholism for Visual Delayed Recall, Story Immediate Recall, and Story Delayed Recall implied that diabetes and alcohol abuse enhanced each other's effect in lowering cognitive test scores. Alcohol abuse history in older diabetic subjects presents an increased risk for cognitive impairment.

Glutamatergic plasticity and alcohol dependence-induced alterations in reward, affect and cognition

INTRODUCTION

Alcohol dependence is characterized by a reduction in reward threshold, development of a negative affective state, and significant cognitive impairments. Dependence-induced glutamatergic neuroadaptations in the neurocircuitry mediating reward, affect and cognitive function are thought to underlie the neural mechanism for these alterations. These changes serve to promote increased craving for alcohol and facilitate the development of maladaptive behaviors that promote relapse to alcohol drinking during periods of abstinence.

OBJECTIVE

To review the extant literature on the effects of chronic alcohol exposure on glutamatergic neurotransmission and its impact on reward, affect and cognition.

RESULTS

Evidence from a diverse set of studies demonstrates significant enhancement of glutamatergic activity following chronic alcohol exposure. In particular, up-regulation of GluN2B-containing NMDA receptor expression and function is a commonly observed phenomenon that likely reflects activity-dependent adaptive homeostatic plasticity. However, this observation as well as other glutamatergic neuroadaptations are often circuit and cell-type specific.

DISCUSSION

Dependence-induced alterations in glutamate signaling contribute to many of the symptoms experienced in addicted individuals and can persist well into abstinence. This suggests that they play an important role in the development of behaviors that increase the probability for relapse. As our understanding of the complexity of the neurocircuitry involved in the addictive process has advanced, it has become increasingly clear that investigations of cell-type and circuit-specific effects are required to gain a more comprehensive understanding of the glutamatergic adaptations and their functional consequences in alcohol addiction.

CONCLUSION

While pharmacological treatments for alcohol dependence and relapse targeting the glutamatergic system have shown great promise in preclinical models, more research is needed to uncover novel, possibly circuit-specific, therapeutic targets that exhibit improved efficacy and reduced side effects.

Confounders in the detection of minimal hepatic encephalopathy: a neuropsychological and quantified EEG study

BACKGROUND & AIMS

Chronic alcohol misuse, HCV infection and cirrhosis may cause cognitive alterations. The aim of the present study was to assess the influence of alcohol misuse, HCV infection and cirrhosis per se on the neuropsychological and electroencephalogram (EEG) profile and to evaluate the role of alcohol misuse and HCV infections as potential confounding factors in the detection of minimal hepatic encephalopathy.

METHODS

A comprehensive neuropsychological profile and EEG spectral parameters were obtained in six age-matched groups of 30 subjects each: (i) HCV-related hepatitis without cirrhosis, (ii) chronic alcohol abusers, (iii) patients with HCV-related cirrhosis, (iv) alcohol-related cirrhosis, (v) cirrhosis not related to alcohol or HCV and (vi) healthy subjects. Cirrhotic patients were matched for MELD score.

RESULTS

The factor 'cirrhosis' was associated with low Phonemic Verbal Fluency (PVF) and Difference between Trail Making Test B and A (TMT) (B-A) (P < 0.001). Chronic alcohol misuse was associated with low PVF, TMT (B-A), Memory with Interference Task at 10 (ITM 10) and 30 s (ITM 30) (all P < 0.05). An interaction was found between the factors 'cirrhosis', 'alcohol misuse' and tests (P < 0.01). HCV hepatitis reduced ITM 10 (P < 0.05), but no interaction was found between 'cirrhosis', 'HCV infection' and tests (P = 0.14). The EEG parameters were mainly influenced by 'cirrhosis' (P < 0.05), and EEG alterations were more pronounced in patients with alcoholic cirrhosis (P = 0.04).

CONCLUSIONS

Cirrhosis per se, chronic alcohol misuse and HCV infection were found to be associated with cognitive dysfunction. In patients with cirrhosis, the interaction with alcohol misuse further impinged on brain dysfunction.

Dendritic remodeling of hippocampal neurons is associated with altered NMDA receptor expression in alcohol dependent rats

Prolonged alcohol exposure has been previously shown to impair the structure and function of the hippocampus, although the underlying structural and biochemical alterations contributing to these deleterious effects are unclear. Also unclear is whether these changes persist into prolonged periods of abstinence. Previous work from our lab utilizing a clinically relevant rodent model of alcohol consumption demonstrated that alcohol dependence (induced by chronic intermittent ethanol vapor exposure or CIE) decreases proliferation and survival of neural stem cells in the hippocampal subgranular zone and hippocampal neurogenesis in the dentate gyrus, implicating this region of the cortex as particularly sensitive to the toxic effects of prolonged ethanol exposure. For this study, we investigated seven weeks of CIE-induced morphological changes (dendritic complexity and dendritic spine density) of dentate gyrus (DG) granule cell neurons, CA3, and CA1 pyramidal neurons and the associated alterations in biochemical markers of synaptic plasticity and toxicity (NMDA receptors and PSD-95) in the hippocampus in ethanol-experienced Wistar rats 3h (CIE) and 21days (protracted abstinence) after the last ethanol vapor exposure. CIE reduced dendritic arborization of DG neurons and this effect persisted into protracted abstinence. CIE enhanced dendritic arborization of pyramidal neurons and this effect did not persist into protracted abstinence. The architectural changes in dendrites did not correlate with alterations in dendritic spine density, however, they were associated with increases in the expression of pNR2B, total NR2B, and total NR2A immediately following CIE with expression levels returning to control levels in prolonged abstinence. Overall, these data provide the evidence that CIE produces profound changes in hippocampal structural plasticity and in molecular tools that maintain hippocampal structural plasticity, and these alterations may underlie cognitive dysfunction associated with alcohol dependence. In addition, the compensatory state concurrent with reduced plasticity during protracted abstinence could leave the hippocampus vulnerable to subsequent insult following chronic ethanol exposure.

Translational clinical neuroscience perspectives on the cognitive and neurobiological mechanisms underlying alcohol-related aggression

Alcohol-related violence, a longstanding, serious, and pervasive social problem, has provided researchers from diverse disciplines with a model to study individual differences in aggressive and violent behavior. Of course, not all alcohol consumers will become aggressive after drinking and similarly, not all individuals with alcohol use disorders will exhibit such untoward behavior. Rather, the relationship is best conceptualized as complex and indirect and is influenced by a constellation of social, cognitive, and biological factors that differ greatly from one person to the next. Animal experiments and human studies have elucidated how these mechanisms and processes explain (i.e., mediate) the relation between acute and chronic alcohol consumption and aggressive behavior. Further, the rich body of literature on alcohol-related aggression has allowed for identification of several potential high-yield targets for clinical intervention, e.g., cognitive training for executive dysfunction; psychopharmacology targeting affect and threat perception, which may also generalize to other psychiatric conditions characterized by aggressive behavior. Here we aim to integrate pertinent findings, derived from different methodological approaches and theoretical models, which explain heterogeneity in aggressive responses to alcohol. A translational platform is provided, highlighting common factors linking alcohol and aggression that warrant further, interdisciplinary study in order to reduce the devastating social impact of this phenomenon.

Cognitive control in alcohol use disorder: deficits and clinical relevance

Cognitive control refers to the internal representation, maintenance, and updating of context information in the service of exerting control over thoughts and behavior. Deficits in cognitive control likely contribute to difficulty in maintaining abstinence in individuals with alcohol use disorders (AUD). In this article, we define three cognitive control processes in detail (response inhibition, distractor interference control, and working memory), review the tasks measuring performance in these areas, and summarize the brain networks involved in carrying out these processes. Next, we review evidence of deficits in these processes in AUD, including both metrics of task performance and functional neuroimaging. Finally, we explore the clinical relevance of these deficits by identifying predictors of clinical outcome and markers that appear to change (improve) with treatment. We observe that individuals with AUD experience deficits in some, but not all, metrics of cognitive control. Deficits in cognitive control may predict clinical outcome in AUD, but more work is necessary to replicate findings. It is likely that performance on tasks requiring cognitive control improves with abstinence, and with some psychosocial and medication treatments. Future work should clarify which aspects of cognitive control are most important to target during treatment of AUD.

Evaluation of antidepressant and memory-improving efficacy of aripiprazole and fluoxetine in alcohol-preferring rats

INTRODUCTION AND AIMS

Dependence on ethanol increases the risk of depression in patients and leads to a damage and deficiencies of brain function, which manifest in cognitive functions impairment. Aripiprazole (ARI) is an atypical antipsychotic drug, which has also been shown to have a beneficial effect on cognitive function. Results of many studies show that, for ARI's antidepressant effect to manifest itself, it is necessary to use a combined therapy with a drug from the group of selective serotonin reuptake inhibitors (SSRIs). The aim of this paper was to assess the antidepressant and impact of ARI on spatial memory in alcohol-preferring rats (EtNPRs).

DESIGN AND METHODS

In our study, we used Porsolt's forced swimming test (antidepressant effect) and Morris water maze test. The tests have been conducted upon administration of ARI (6 mg/kg i.p.), fluoxetine (FLX; 5 mg/kg p.o.) and combined administration of both drugs in alcohol-dependent rats.

RESULTS

The results of behavioural tests carried out have shown a lack of antidepressant and procognitive effects of either ARI or FLX in EtPRs after acute and chronic treatment. Combined administration of both drugs would lead to spatial memory deterioration in the study animals.

DISCUSSION AND CONCLUSIONS

Our results suggest that ARI applied in the experiment had no antidepressant effect and failed to improve spatial memory in study rats. Potential antidepressant and procognitive properties of this drug resulting from its mechanism of action encourage attempts (design) of further research aimed at developing a dose, which will show such effects in alcohol-preferring animals.

Chronic alcohol consumption and its effect on nodes of frontocerebellar and limbic circuitry: comparison of effects in France and the United States

Alcohol use disorders present a significant public health problem in France and the United States (U.S.), but whether the untoward effect of alcohol on the brain results in similar damage in both countries remains unknown. Accordingly, we conducted a retrospective collaborative investigation between two French sites (Caen and Orsay) and a U.S. laboratory (SRI/Stanford University) with T1-weighted, structural MRI data collected on a common imaging platform (1.5T, General Electric) on 288 normal controls (NC), 165 uncomplicated alcoholics (ALC), and 26 patients with alcoholic Korsakoff's syndrome (KS) diagnosed at all sites with a common interview instrument. Data from the two countries were pooled, then preprocessed and analyzed together at the U.S. site using atlas-based parcellation. National differences indicated that thalamic volumes were smaller in ALC in France than the U.S. despite similar alcohol consumption levels in both countries. By contrast, volumes of the hippocampus, amygdala, and cerebellar vermis were smaller in KS in the U.S. than France. Estimated amount of alcohol consumed over a lifetime, duration of alcoholism, and length of sobriety were significant predictors of selective regional brain volumes in France and in the U.S. The common analysis of MRI data enabled identification of discrepancies in brain volume deficits in France and the U.S. that may reflect fundamental differences in the consequences of alcoholism on brain structure between the two countries, possibly related to genetic or environmental differences.

Profiles of impaired, spared, and recovered neuropsychologic processes in alcoholism

Long-term chronic alcoholism is associated with disparate and widespread residual consequences for brain functioning and behavior, and alcoholics suffer a variety of cognitive deficiencies and emotional abnormalities. Alcoholism has heterogeneous origins and outcomes, depending upon factors such as family history, age, gender, and mental or physical health. Consequently, the neuropsychologic profiles associated with alcoholism are not uniform among individuals. Moreover, within and across research studies, variability among subjects is substantial and contributes to characteristics associated with differential treatment outcomes after detoxification. In order to refine our understanding of alcoholism-related impaired, spared, and recovered abilities, we focus on five specific functional domains: (1) memory; (2) executive functions; (3) emotion and psychosocial skills; (4) visuospatial cognition; and (5) psychomotor abilities. Although the entire brain might be vulnerable in uncomplicated alcoholism, the brain systems that are considered to be most at risk are the frontocerebellar and mesocorticolimbic circuitries. Over time, with abstinence from alcohol, the brain appears to become reorganized to provide compensation for structural and behavioral deficits. By relying on a combination of clinical and scientific approaches, future research will help to refine the compensatory roles of healthy brain systems, the degree to which abstinence and treatment facilitate the reversal of brain atrophy and dysfunction, and the importance of individual differences to outcome.

Proteomic approaches and identification of novel therapeutic targets for alcoholism

Recent studies have shown that gene regulation is far more complex than previously believed and does not completely explain changes at the protein level. Therefore, the direct study of the proteome, considerably different in both complexity and dynamicity to the genome/transcriptome, has provided unique insights to an increasing number of researchers. During the past decade, extraordinary advances in proteomic techniques have changed the way we can analyze the composition, regulation, and function of protein complexes and pathways underlying altered neurobiological conditions. When combined with complementary approaches, these advances provide the contextual information for decoding large data sets into meaningful biologically adaptive processes. Neuroproteomics offers potential breakthroughs in the field of alcohol research by leading to a deeper understanding of how alcohol globally affects protein structure, function, interactions, and networks. The wealth of information gained from these advances can help pinpoint relevant biomarkers for early diagnosis and improved prognosis of alcoholism and identify future pharmacological targets for the treatment of this addiction.

Cognitive impairments in alcohol-dependent subjects

Chronic excessive alcohol consumption induces cognitive impairments mainly affecting executive functions, episodic memory, and visuospatial capacities related to multiple brain lesions. These cognitive impairments not only determine everyday management of these patients, but also impact on the efficacy of management and may compromise the abstinence prognosis. Maintenance of lasting abstinence is associated with cognitive recovery in these patients, but some impairments may persist and interfere with the good conduct and the efficacy of management. It therefore appears essential to clearly define neuropsychological management designed to identify and evaluate the type and severity of alcohol-related cognitive impairments. It is also essential to develop cognitive remediation therapy so that the patient can fully benefit from the management proposed in addiction medicine units.

Neurocognitive deficits, craving, and abstinence among alcohol-dependent individuals following detoxification

Alcohol dependence, a chronic relapsing disorder, is characterized by an impaired ability to regulate compulsive urges to consume alcohol. Very few empirical studies have examined the presence of these executive deficits, how they relate to craving, and the enduring nature of these deficits during abstinence. As such, the current study aimed to characterize these cognitive deficits within a sample of 24 alcohol-dependent participants post-detoxification and 23 non-alcohol-dependent participants. Participants were administered the Sustained Attention to Response Task to measure response inhibition and sustained attention and the Random Number Generation Task to examine executive deficits. Correlations between cognitive performance and clinical measures of alcohol dependence were examined. As predicted, the alcohol-dependent group exhibited poorer performance across the domains of response inhibition, executive function, and attentional control. Cognitive performance was related to clinical measures of craving and years of alcohol consumption, whereas the duration of abstinence was not associated with improved cognitive performance. These findings highlight the need for therapeutic strategies to target these enduring neurocognitive deficits in improving the treatment of alcohol dependence.

Assessment of abstract reasoning abilities in alcohol-dependent subjects: an fMRI study

INTRODUCTION

Chronic alcohol abuse has been traditionally associated with impaired cognitive abilities. The deficits are most evident in higher order cognitive functions, such as abstract reasoning, problem solving and visuospatial processing. The present study sought to increase current understanding of the neuropsychological basis of poor abstract reasoning abilities in alcohol-dependent subjects using functional magnetic resonance imaging (fMRI).

METHODS

An abstract reasoning task-based fMRI study was carried out on alcohol-dependent subjects (n = 18) and healthy controls (n = 18) to examine neural activation pattern. The study was carried out using a 3-T whole-body magnetic resonance scanner. Preprocessing and post processing was performed using SPM 8 software.

RESULTS

Behavioral data indicated that alcohol-dependent subjects took more time than controls for performing the task but there was no significant difference in their response accuracy. Analysis of the fMRI data indicated that for solving abstract reasoning-based problems, alcohol-dependent subjects showed enhanced right frontoparietal neural activation involving inferior frontal gyrus, post central gyrus, superior parietal lobule, and occipito-temporal gyrus.

CONCLUSIONS

The extensive activation observed in alcohol dependents as compared to controls suggests that alcohol dependents recruit additional brain areas to meet the behavioral demands for equivalent task performance. The results are consistent with previous fMRI studies suggesting decreased neural efficiency of relevant brain networks or compensatory mechanisms for the execution of task for showing an equivalent performance.

Evaluation of the antidepressant, anxiolytic and memory-improving efficacy of aripiprazole and fluoxetine in ethanol-treated rats

Some study results indicate a positive effect of aripiprazole (ARI) on impaired cognitive functions caused by brain damage resulting from chronic EtOH abuse. However, other research shows that to manifest itself, an ARI antidepressant effect requires a combined therapy with another selective serotonin reuptake inhibitor antidepressant, namely, fluoxetine (FLX). The aim of this article was to assess antidepressant and anxiolytic effects of ARI as well as its effect on spatial memory in ethanol-treated (alcoholized) rats. On the basis of alcohol consumption pattern, groups of (1) ethanol-preferring rats, with mean ethanol intake above 50%, and (2) ethanol-nonpreferring rats (EtNPRs), with mean ethanol intake below 50% of total daily fluid intake, were formed. The group of EtNPRs was used for this study, subdivided further into three groups administered ARI, FLX and a combination of both, respectively. Behavioral tests such as Porsolt's forced swimming test, the Morris water maze test and the two-compartment exploratory test were employed. Behavioral test results demonstrated (1) no antidepressant effect of ARI in EtNPRs in subchronic treatment and (2) no procognitive effect of ARI and FLX in EtNPRs in combined single administration. Combined administration of both drugs led to an anxiogenic effect and spatial memory deterioration in study animals. ARI had no antidepressant effect and failed to improve spatial memory in rats. However, potential antidepressant, anxiolytic and procognitive properties of the drug resulting from its mechanism of action encourage further research aimed at developing a dose of both ARI and FLX that will prove such effects in alcoholized EtNPRs.

Thiamine deficiency induced neurochemical, neuroanatomical, and neuropsychological alterations: a reappraisal

Nutritional deficiency can cause, mainly in chronic alcoholic subjects, the Wernicke encephalopathy and its chronic neurological sequela, the Wernicke-Korsakoff syndrome (WKS). Long-term chronic ethanol abuse results in hippocampal and cortical cell loss. Thiamine deficiency also alters principally hippocampal- and frontal cortical-dependent neurochemistry; moreover in WKS patients, important pathological damage to the diencephalon can occur. In fact, the amnesic syndrome typical for WKS is mainly due to the damage in the diencephalic-hippocampal circuitry, including thalamic nuclei and mammillary bodies. The loss of cholinergic cells in the basal forebrain region results in decreased cholinergic input to the hippocampus and the cortex and reduced choline acetyltransferase and acetylcholinesterase activities and function, as well as in acetylcholine receptor downregulation within these brain regions. In this narrative review, we will focus on the neurochemical, neuroanatomical, and neuropsychological studies shedding light on the effects of thiamine deficiency in experimental models and in humans.

Response inhibition toward alcohol-related cues using an alcohol go/no-go task in problem and non-problem drinkers

BACKGROUND

Previous results suggested that alcohol abusers and alcohol dependent patients show cognitive biases in the treatment of alcohol-related cues, especially approach and inhibition deficit biases. Response inhibition was often tested using the go/no-go task in which the participants had to respond as quickly as possible to a class of stimuli (go stimuli) while refraining from responding to another class of stimuli (no-go stimuli). Previous studies assessing specific response inhibition deficits in the process of alcohol-related cues obtained conflicting results. The aims of the present study were to clarify response inhibition for alcohol cues in problem and non-problem drinkers, male and female and to test the effect of alcohol brand logos.

METHODS

Thirty-six non-problem drinker and thirty-five problem drinker undergraduate students completed a modified alcohol go/no-go task using alcohol and neutral object pictures, with or without brand logos, as stimuli. An additional control experiment was carried out to check whether participants' awareness that the study tested their response to alcohol might have biased the results.

RESULTS

All participants, whether problem or non-problem drinkers, showed significantly shorter mean reaction times when alcohol pictures are used as go stimuli and significantly higher percentages of commission errors (false alarms) when alcohol pictures are used as no-go stimuli. Identical effects were obtained in the control experiment when participants were unaware that the study focused on alcohol. Shorter reaction times to alcohol-related cues were observed in problem drinkers relative to non-problem drinkers but only in the experimental condition with no brand logos on alcohol pictures. The addition of alcohol brand logos further reduced reaction times in light drinkers, thereby masking group differences. There was a tendency for female problem drinkers to show higher rates of false alarms for alcohol no-go stimuli, although this effect was only very close to statistical significance.

CONCLUSIONS

All participants exhibited a cognitive bias in the treatment of alcohol cues that might be related to the positive emotional value of such alcohol-related cues. Stronger cognitive biases in the treatment of alcohol cues were observed in problem drinkers, although differences between problem and non-problem drinkers were relatively small-scale and required specific experimental parameters to be uncovered. In particular, the presence of alcohol brand logos on visual alcohol cues was an important experimental parameter that significantly affected behavioral responses to such stimuli.