Perceptual Learning in Detoxified Alcoholic Men: Contributions From Explicit Memory, Executive Function, and Age

Predicting alcohol relapse post-detoxification: The role of cognitive impairments in alcohol use disorder patients

BACKGROUND

Studies on early abstinence suggest that cognitive function is significantly reduced in the first year of abstinence, which raises the question of whether it is relevant to early relapse in patients with substance use disorders. This study investigates the extent to which impairments in executive function and memory predict alcohol relapse in patients with alcohol use disorder (AUD). Understanding these relationships is crucial for improving therapeutic approaches to prevent relapse in patients with AUD.

METHODS

We selected 116 adult patients (79 male and 37 female) diagnosed with AUD based on DSM-5 criteria, all of whom were undergoing alcohol detoxification treatment. A comprehensive array of neuropsychological tests was administered to assess global cognition, memory, and executive functions. Patients' alcohol use was monitored monthly during a 6-month follow-up period. Logistic regression and Cox regression were used to explore the relationship between cognitive function and the likelihood of alcohol relapse.

RESULTS

Impairments in global cognition, semantic and phonemic fluency, cognitive flexibility, and learning ability during detoxification were significant predictors of relapse in AUD patients, showing similar predictive values at both 3 and 6 months post-treatment. An abnormal Montreal Cognitive Assessment (MoCA) score increased the risk of relapse by 123% (HR: 2.227), and impairments in both semantic and phonemic fluency each increased the risk by 142% (HR: 2.423). Additionally, abnormal performance on the MoCA, Trail Making Test Part B (TMT-B), and California Verbal Learning Test (CVLT) was associated with a higher number of drinking days at 3 months (IRR: 3.764; IRR: 2.237; IRR: 2.738, respectively) and abnormal MoCA and TMT-B scores at 6 months (IRR: 2.451; IRR: 1.859, respectively).

CONCLUSIONS

The MoCA test is a valuable tool for predicting relapse risk in AUD patients undergoing detoxification treatment, with similar predictive value for relapse at 3 or 6 months. Learning ability needs to be assessed and their impairments considered in the treatment of AUD patients. Future research should explore strategies for managing patients with impairments in memory and learning ability to enhance treatment effectiveness and prevent relapse.

Memory impairment in alcohol use disorder is associated with regional frontal brain volumes

BACKGROUND

Episodic memory deficits occur in alcohol use disorder (AUD), but their anatomical substrates remain in question. Although persistent memory impairment is classically associated with limbic circuitry disruption, learning and retrieval of new information also relies on frontal systems. Despite AUD vulnerability of frontal lobe integrity, relations between frontal regions and memory processes have been under-appreciated.

METHODS

Participants included 91 AUD (49 with a drug diagnosis history) and 36 controls. Verbal and visual episodic memory scores were age- and education-corrected. Structural magnetic resonance imaging (MRI) data yielded regional frontal lobe (precentral, superior, orbital, middle, inferior, supplemental motor, and medial) and total hippocampal volumes.

RESULTS

AUD were impaired on all memory scores and had smaller precentral frontal and hippocampal volumes than controls. Orbital, superior, and inferior frontal volumes and lifetime alcohol consumption were independent predictors of episodic memory in AUD. Selectivity was established with a double dissociation, where orbital frontal volume predicted verbal but not visual memory, whereas inferior frontal volumes predicted visual but not verbal memory. Further, superior frontal volumes predicted verbal memory in AUD alone, whereas orbital frontal volumes predicted verbal memory in AUD+drug abuse history.

CONCLUSIONS

Selective relations among frontal subregions and episodic memory processes highlight the relevance of extra-limbic regions in mnemonic processes in AUD. Memory deficits resulting from frontal dysfunction, unlike the episodic memory impairment associated with limbic dysfunction, may be more amenable to recovery with cessation or reduction of alcohol misuse and may partially explain the heterogeneity in episodic memory abilities in AUD.

Visuoperceptive Impairments in Severe Alcohol Use Disorder: A Critical Review of Behavioral Studies

The present literature review is aimed at offering a comprehensive and critical view of behavioral data collected during the past seventy years concerning visuoperception in severe alcohol use disorders (AUD). To pave the way for a renewal of research and clinical approaches in this very little understood field, this paper (1) provides a critical review of previous behavioral studies exploring visuoperceptive processing in severe AUD, (2) identifies the alcohol-related parameters and demographic factors that influence the deficits, and (3) addresses the limitations of this literature and their implications for current clinical strategies. By doing so, this review highlights the presence of visuoperceptive deficits but also shows how the lack of in-depth studies exploring the visual system in this clinical population results in the current absence of integration of these deficits in the dominant models of vision. Given the predominance of vision in everyday life, we stress the need to better delineate the extent, the specificity, and the actual implications of the deficits for severe AUD.

Neural correlates of visuoperceptive changes in severe alcohol use disorder: A critical review of neuroimaging and electrophysiological findings

Visuoperceptive deficits are frequently reported in severe alcohol use disorder (SAUD) and are considered as pervasive and persistent in time. While this topic of investigation has previously driven researchers' interest, far fewer studies have focused on visuoperception in SAUD since the '90s, leaving open central questions regarding the origin and implications of these deficits. To renew research in the field and provide a solid background to work upon, this paper reviews the neural correlates of visuoperception in SAUD, based on data from neuroimaging and electrophysiological studies. Results reveal structural and functional changes within the visual system but also in the connections between occipital and frontal areas. We highlight the lack of integration of these findings in the dominant models of vision which stress the dynamic nature of the visual system and consider the presence of both bottom-up and top-down cerebral mechanisms. Visuoperceptive changes are also discussed in the framework of long-lasting debates regarding the influence of demographic and alcohol-related factors, together stressing the presence of inter-individual differences. Capitalizing on this review, we provide guidelines to inform future research, and ultimately improve clinical care.

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

BACKGROUND

The aim of the present study was to determine whether the Brief Evaluation of Alcohol-Related Neuropsychological Impairments (BEARNI), a screening tool developed to identify neuropsychological deficits in alcohol use disorder (AUD) patients, can also be used for the early identification of AUD patients at risk of developing Korsakoff's syndrome (KS).

METHODS

Eighteen KS patients, 47 AUD patients and 27 healthy controls underwent BEARNI testing (including 5 subtests targeting episodic memory, working memory, executive function, visuospatial abilities, and ataxia) and a comprehensive neuropsychological examination.

RESULTS

Performance of AUD and KS patients on BEARNI subtests was consistent with the results on the standardized neuropsychological assessment. On BEARNI, ataxia and working memory deficits observed in AUD were as severe as those exhibited by KS patients, whereas for visuospatial abilities, a graded effect of performance was found. In contrast, the subtests involving long-term memory abilities (episodic memory and fluency) were impaired in KS patients only. AUD patients with a score lower than 1.5 points (out of 6) on the episodic memory subtest of BEARNI exhibited the lowest episodic memory performance on the neuropsychological battery and could be considered at risk of developing KS.

CONCLUSIONS

These findings suggest that BEARNI is a useful tool for detecting severe memory impairments, suggesting that it could be used for the early identification of AUD patients at high risk of developing KS.

A case-comparison study of executive functions in alcohol-dependent adults with maternal history of alcoholism

Introduction

As executive dysfunctions frequently accompany alcohol dependence, we suggest that reports of executive dysfunction in alcoholics are actually due, in some case to a maternal history of alcohol misuse (MHA+). A history of maternal alcohol dependence increases the risk for prenatal alcohol exposure to unborn children. These exposures likely contribute to executive dysfunction in adult alcoholics. To assess this problem, we propose a case-comparison study of alcohol-dependent subjects with and without a MHA.

Methods

Ten alcohol-dependent subjects, with a maternal history of alcoholism (MHA) and paternal history of alcoholism (PHA), were matched with 10 alcohol-dependent people with only a paternal history of alcoholism (PHA). Executive functions (cancellation, Stroop, and trail-making A and B tests) and the presence of a history of three mental disorders (attention deficit hyperactivity disorder, violent behavior while intoxicated, and suicidal behavior) were evaluated in both populations.

Results

Alcohol-dependent subjects with MHA showed a significant alteration in executive functions and significantly more disorders related to these functions than PHA subjects. The major measures of executive functioning deficit are duration on task accomplishment in all tests. Rates of ADHD and suicidality were found to be higher in MHA patients compared to the controls.

Conclusion

A history of MHA, because of the high risk of PAE (in spite of the potential confounding factors such as environment) must be scrupulously documented when evaluating mental and cognitive disorders in a general population of alcoholics to ensure a better identification of these disorders. It would be helpful to replicate the study with more subjects.

Altered neural dynamics in occipital cortices serving visual-spatial processing in heavy alcohol users

BACKGROUND

Visual-spatial processing deficits have been previously linked to heavy alcohol use, but the underlying neurological mechanisms are poorly understood. Neuroimaging studies have shown alcohol-related aberrations in occipital cortices that appear to be associated with these neuropsychological deficits in visual-spatial processing, however the neural dynamics underlying this altered processing remains unknown.

METHODS

Twenty-three adults with high scores on the Alcohol Use Disorders Identification Test - Consumption (male: ⩾5, female: ⩾4) were compared to 30 demographically-matched controls with low Alcohol Use Disorders Identification Test - Consumption scores (⩽2). All participants completed a visual-spatial processing task while undergoing high-density magnetoencephalography. Time-frequency windows of interest were determined using a data-driven method, and spectrally-specific neural activity was imaged using a beamforming approach. Permutation testing of peak voxel time series was then used to statistically compare across groups.

RESULTS

Participants with heavy alcohol use responded slower on the task and their performance was more variable. The magnetoencephalography data indicated strong theta (4-8 Hz), alpha (10-16 Hz), and gamma (62-72 Hz) responses in posterior brain regions across both groups. Following voxel time-series extraction, significant group differences were found in the left and right visual association cortices from about 375-550 ms post-stimulus, such that adults with heavy alcohol use had blunted alpha responses compared to controls.

CONCLUSION

Individuals with heavy alcohol use exhibited aberrant occipital alpha activity during visual-spatial processing. These data are the first to show spectrally-specific differences during visual-spatial processing related to heavy alcohol use, and highlight alcohol's effect on systems-level neural activity.

Cognitive Impairments in Early-Detoxified Alcohol-Dependent Inpatients and Their Associations with Socio-Demographic, Clinical and Psychological Factors: An Exploratory Study

PURPOSE

Cognitive impairment is common among patients with alcohol use disorder (AUD). However, neuropsychological assessment is not usually included as routine practice in alcohol rehabilitation programs. The aim of this study was to describe qualitatively the cognitive deficits in early-detoxified AUD patients undergoing rehabilitation and to explore relevant associations with socio-demographic, clinical and psychological factors.

PATIENTS AND METHODS

Forty-one patients with a diagnosis of AUD were consecutively recruited from a residential rehabilitation hospital in Northern Italy. Cognitive impairment was assessed using the Brief Neuropsychological Examination 2 (ENB-2). Anxiety, depression and severity of alcohol dependence were also evaluated using validated self-report questionnaires. Alcohol relapse was investigated 1 month after discharge.

RESULTS

Overall, 31.7% of AUD patients showed cognitive impairments according to the global score scale. However, 70.7% had an impaired performance on at least one test of the ENB-2, with particular regard to executive function, visuospatial and memory domains. Age, education and abstinence at admission were the most relevant factors associated with cognitive deficits in this clinical population.

CONCLUSION

The detection of cognitive impairments is essential in order to adapt alcohol rehabilitation treatment to patients with cognitive deficits and enhance clinical outcomes.

Trail Making Test: Normative Data for Patients with Severe Alcohol Use Disorder

Background: Patients with alcohol use disorders (AUD) often show cognitive impairment, particularly in executive functions that has been linked to poor treatment outcomes. The Trail Making Test (TMT) is the most widely used neuropsychological test to investigate executive functions with available normative data. However, no such norms exist for patients with AUD, although there is extensive evidence that TMT performance is altered in AUD patients. Purpose: To provide normative data for patients with AUD and compare the performance of AUD patients with already existing normative data from healthy subjects. Methods: Data of 494 recently detoxified patients with AUD who entered an abstinence-oriented residential treatment program were analyzed. Patients completed a standardized diagnostic procedure and the TMT Parts A and B at treatment admission. Results: AUD patients' performance on the TMT was impaired compared to the normative data of healthy individuals and decreased with increasing age and lower levels of education, with stronger effects in Part B assessing more complex executive functioning. Alcohol-related variables showed no direct associations with TMT performance. Conclusions: The results replicate the association of age and education with TMT performance, suggesting that AUD may be associated with impaired cognitive functioning earlier in life in abstinent patients shortly after withdrawal from alcohol compared to healthy individuals. The presented normative data for patients with AUD particularly improve the examination of executive deficits, and may enable clinicians to evaluate patients' cognitive functioning in treatment more precisely.

Widespread Cognitive Deficits in Alcoholism Persistent Following Prolonged Abstinence: An Updated Meta-analysis of Studies That Used Standardised Neuropsychological Assessment Tools

Objective

This study presents an updated meta-analysis replicating the study of (Stavro, K., Pelletier, J., & Potvin, S. (2013). Widespread and sustained cognitive deficits in alcoholism: A meta-analysis. Addiction Biology, 18, 203–213. doi:10.1111/j.1369-1600.2011.00418.x) regarding the cognitive functioning of alcoholics as a function of time abstinent.

Methods

A total of 34 studies (including a total of 2,786 participants) that met pre-determined inclusion and exclusion criteria were included in the analyses. The alcoholics were categorised into recently detoxified alcoholics (0–31 days sober), alcoholics 32–365 days sober and alcoholics >365 days sober consistent with the previous study. The current study employed more stringent control on the tests included in the analysis to include only those tasks described in contemporary neuropsychological test compendia. Forty-seven percent of the papers surveyed were not include in the previous meta-analysis.

Results

The results indicated that there was a diffuse and pervasive pattern of cognitive deficit among recently detoxified alcoholics and that these deficits, particularly with regard to memory functioning, persisted even in longer term abstinent alcoholics. This was inconsistent with the prior meta-analysis which contended that significant cognitive recovery was possible after as little as 1 year.

Conclusion

The persisting cognitive deficits were noted across a wide range of cognitive functions, supporting the notion of a diffuse rather than a specific compromise of cognition in alcoholism following discontinuation, as measured using standardised neuropsychological tests. Limitations on the finding included the fact that it was a cross-sectional rather than a longitudinal analysis, was subject to heterogeneity of method, had low representation of females in the samples, and had fewer studies of long-term sober samples.

Combining gray matter volume in the cuneus and the cuneus-prefrontal connectivity may predict early relapse in abstinent alcohol-dependent patients

Background

Developing more effective strategies to prevent relapse remains one of the major challenges of treating substance dependence. Previous studies have identified brain abnormalities in abstinent alcoholics. However, whether these persistent brain deficits in abstinence could predict early relapse to alcohol use has not been well established. This study aimed to identify biomarkers of relapse vulnerability by investigating persistent brain abnormalities in abstinent alcohol-dependent patients.

Methods

Brain imaging and impulsive behavior data were collected from 56 abstinent alcohol-dependent male inpatients and 33 age-matched male healthy controls. Voxel-based morphometry was used to investigate the differences of grey matter volume between the groups. The resting-state functional connectivity was examined using brain areas with gray matter deficits as seed regions. A preliminary prospective study design was used to classify patients into abstainers and relapsers after a 62-day average abstinence period.

Results

Compared with healthy controls, both relapsers and abstainers exhibited significantly reduced gray matter volume in the cuneus. Functional connectivity analysis revealed that relapsers relative to abstainers demonstrated increased cuneus-centered negative functional connectivity within a network of brain regions which are involved in executive control and salience. Abnormal gray matter volume in the left cuneus and the functional connectivity between the right cuneus and bilateral dorsolateral prefrontal cortex could successfully predict relapse during the 3-month follow-up period.

Conclusions

Findings suggest that the abnormal gray matter volume in the cuneus and resting-state cuneus-prefrontal functional connectivity may play an important role in poor treatment outcomes in alcoholics and serve as useful neural markers of relapse vulnerability.

Alcohol use disorder and cognitive impairment in old age patients: A 6 months follow-up study in an outpatient unit in Barcelona

There has been little research about deleterious effects, including cognitive impairment, related to hazardous long-term alcohol use in old adults. This study aims to assess cognitive decline in old patients with alcohol use disorder and changes in cognitive state at 6 months follow-up, achieving or not abstinence. A six-month follow-up study was conducted in an outpatient center in Barcelona on a sample of old adults (≥65 years old) who had hazardous alcohol use. The sample was compared with healthy volunteers adjusted for age, sex and years of education. A neuropsychological protocol was performed at baseline and after 6 months follow-up covering four cognitive domains: attention, visuospatial abilities, memory and executive functions. Several domains were significant impaired at baseline: visual immediate and delayed recall, working memory, immediate verbal learning, total words learned, set switching and sustained attention. At 6 months reassessment, alcohol abstinence was achieved in 93.5% of patients and it was detected a trend towards improvement in direct mean scores of all cognitive areas, although it was not significant. The current study points out a cognitive impairment in many areas secondary to alcohol long-term hazardous use in old adults. A trend towards cognitive improvement after recovery was detected in most patients.

Everyday memory problems in alcohol abuse and dependence: Frequency, patterns and patient-proxy agreement

Using self-report to assess everyday memory in alcoholics presents challenges given the presence of both memory and metamemory deficits. Accordingly, evaluation of the reliability and validity of proxy ratings as well as the frequency of these memory lapses are of clinical importance. In the present study, 180 patient-proxy dyads completed the Prospective and Retrospective Memory Questionnaire (PRMQ). 31.7% of proxy-rated versus 2.8% of patient-rated prospective memory scores fell in the impaired to below average range. 15% of proxy-rated retrospective memory scores were below average, whereas none of the patients reported problems in this regard. Longer delays between intention formation and action yielded better prospective memory performance, while the opposite was true for retrospective memory. Agreement between patients and proxies was generally poor to fair across severity levels and the magnitude of observed differences was large (standardized response mean > 0.8). For all PRMQ items, exact agreement occurred in 45.3% of the cases. Larger patient-proxy discrepancy was associated with older age, less education and greater disease severity. Proxy ratings were internally consistent, significantly correlated with objective memory performance, and were sensitive to differences in overall PRMQ performance between severity groups. Caution should be used in the interpretations of patients' reports.

ADX-47273, a mGlu5 receptor positive allosteric modulator, attenuates deficits in cognitive flexibility induced by withdrawal from 'binge-like' ethanol exposure in rats

Repeated exposure to and withdrawal from ethanol induces deficits in spatial reversal learning. Data indicate that metabotropic glutamate 5 (mGlu5) receptors are implicated in synaptic plasticity and learning and memory. These receptors functionally interact with N-methyl-d-aspartate (NMDA) receptors, and activation of one type results in the activation of the other. We examined whether (S)-(4-fluorophenyl)(3-(3-(4-fluorophenyl)-1,2,4-oxadiazol-5-yl)-piperidin-1-yl (ADX-47273), a positive allosteric modulator (PAM) of mGlu5 receptor, attenuates deficits in reversal learning induced by withdrawal (11-13days) from 'binge-like' ethanol input (5.0g/kg, i.g. for 5days) in the Barnes maze (a spatial learning) task in rats. We additionally examined the effects of ADX-47273 on the expression of the NMDA receptors subunit, GluN2B, in the hippocampus and prefrontal cortex, on the 13th day of ethanol withdrawal. Herein, withdrawal from repeated ethanol administration impaired reversal learning, but not the probe trial. Moreover, ADX-47273 (30mg/kg, i.p.) given prior to the first reversal learning trial for 3days in the Barnes maze, significantly enhanced performance in the ethanol-treated group. The 13th day of ethanol abstinence decreased the expression of the GluN2B subunit in the selected brain regions, but ADX-47273 administration increased it. In conclusion, positive allosteric modulation of mGlu5 receptors recovered spatial reversal learning impairment induced by withdrawal from 'binge-like' ethanol exposure. Such effect seems to be correlated with the mGlu5 receptors mediated potentiation of GluN2B-NMDA receptor mediated responses in the hippocampus and prefrontal cortex. Thus, our results emphasize the role of mGlu5 receptor PAM in the adaptive learning impaired by ethanol exposure.

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.

Executive functions in alcohol-dependence: A theoretically grounded and integrative exploration

BACKGROUND

Alcohol-dependence is related to large-scale cognitive impairments, particularly for executive functions (EF). These deficits persist even after long-term abstinence and have a major impact on patients' everyday life and relapse risk. Earlier studies, based on multi-determined tasks, mostly focused on inhibition and did not offer a theoretically-grounded and exhaustive view of the differential deficit across EF. The present paper proposes a model-based exploration of EF in alcohol-dependent individuals (ALC), to precisely compare the specific deficit related to each executive subcomponent.

METHODS

Forty-seven recently detoxified ALC were compared to 47 matched healthy participants on a nine-tasks validated neuropsychological battery, simultaneously exploring and comparing the three main executive subcomponents (shifting, updating, and inhibition). Psychopathological comorbidities were also controlled for.

RESULTS

Reaction time indexes revealed a global slowing down among ALC, whatever the EF explored. Accuracy indexes revealed a moderate deficit for inhibition tasks but a massive impairment for shifting and updating ones. Complementary analyses indicated that the executive deficits observed were centrally related to alcohol-dependence, while comorbid depressive symptoms appeared to intensify the deficits observed.

CONCLUSIONS

By offering a direct comparison between the three major EF, these results showed that alcohol-related executive deficits extend beyond the classically described inhibition impairment. This impairment encompasses each EF subcomponent, as ALC actually presented stronger deficits for updating and shifting abilities. This first observation of a multifaceted EF deficit stresses the need for an individualized evaluation and rehabilitation of EF during and/or after the detoxification process.

Deviant functional activation and connectivity of the right insula are associated with lack of awareness of episodic memory impairment in nonamnesic alcoholism

A disorder of metamemory, expressed as unawareness of mnemonic ability, is typically associated with the profound amnesia of Korsakoff's Syndrome (KS). A similar but less severe type of limited awareness can also occur in non-KS alcoholism and is observed as an impairment in generating Feeling-of-Knowing (FOK) predictions about future recognition performance. We previously found that FOK accuracy was selectively related to volumes of the insula in alcoholics involved in the present study. Unknown, however, are the neural substrates of unawareness of memory impairment in alcoholism. A task-activated fMRI paradigm served to identify neural nodes and networks implicated in inaccurate self-estimation of mnemonic ability in sober alcoholics while they made prospective FOK judgments in an episodic memory paradigm. Lower activation in the right insula correlated with greater overestimations of future memory abilities in alcoholics. Weaker connectivity of the right insula with the left dorsal anterior cingulate cortex, a node of the salience network, and stronger connectivity of the right insula with the right ventromedial prefrontal cortex (vmPFC), a node of the default mode network (DMN), co-occurred in alcoholics relative to the controls. Specifically, alcoholics, who failed to desynchronize insula-vmPFC activity, had greater overestimation of their memory predictions and poorer recognition performance. This study provides novel support that deviant functional activation and connectivity involving the right insula, a hub of the salience network, appears to participate in disrupting metamemory functioning in alcoholics. Compromised FOK performance might result from disturbance of the switching mechanism between brain networks serving self-referential processes (i.e., DMN network) and networks serving externally-driven activities like memory monitoring (i.e., fronto-parietal network). Thus, compromise in insular network coupling could be a neural mechanism underlying anosognosia for subtle mnemonic impairment in nonamnesic alcoholism.

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.

Impairments in Component Processes of Executive Function and Episodic Memory in Alcoholism, HIV Infection, and HIV Infection with Alcoholism Comorbidity

BACKGROUND

Executive functioning and episodic memory impairment occur in HIV infection (HIV) and chronic alcoholism (ALC). Comorbidity of these conditions (HIV + ALC) is prevalent and heightens risk of vulnerability to separate and compounded deficits. Age and disease-related variables can also serve as mediators of cognitive impairment and should be considered, given the extended longevity of HIV-infected individuals in this era of improved pharmacological therapy.

METHODS

HIV, ALC, HIV + ALC, and normal controls (NC) were administered traditional and computerized tests of executive function and episodic memory. Test scores were expressed as age- and education-corrected Z-scores; selective tests were averaged to compute Executive Function and Episodic Memory Composite scores. Efficiency scores were calculated for tests with accuracy and response times.

RESULTS

HIV, ALC, and HIV + ALC had lower scores than NC on Executive Function and Episodic Memory Composites, with HIV + ALC even lower than ALC and HIV on the Episodic Memory Composite. Impairments in planning and free recall of visuospatial material were observed in ALC, whereas impairments in psychomotor speed, sequencing, narrative free recall, and pattern recognition were observed in HIV. Lower decision-making efficiency scores than NC occurred in all 3 clinical groups. In ALC, age and lifetime alcohol consumption were each unique predictors of Executive Function and Episodic Memory Composite scores. In HIV + ALC, age was a unique predictor of Episodic Memory Composite score.

CONCLUSIONS

Disease-specific and disease-overlapping patterns of impairment in HIV, ALC, and HIV + ALC have implications regarding brain systems disrupted by each disease and clinical ramifications regarding the complexities and compounded damping of cognitive functioning associated with dual diagnosis that may be exacerbated with aging.

Anosognosia for Memory Impairment in Addiction: Insights from Neuroimaging and Neuropsychological Assessment of Metamemory

In addiction, notably Alcohol Use Disorder (AUD), patients often have a tendency to fail to acknowledge the reality of the disease and to minimize the physical, psychological, and social difficulties attendant to chronic alcohol consumption. This lack of awareness can reduce the chances of initiating and maintaining sobriety. Presented here is a model focusing on compromised awareness in individuals with AUD of mild to moderate cognitive deficits, in particular, for episodic memory impairment-the ability to learn new information, such as recent personal experiences. Early in abstinence, alcoholics can be unaware of their memory deficits and overestimate their mnemonic capacities, which can be investigated with metamemory paradigms. Relevant neuropsychological and neuroimaging results considered suggest that the alcoholics' impairment of awareness of their attenuated memory function can be a clinical manifestation explained mechanistically by neurobiological factors, including compromise of brain systems that result in a mild form of mnemonic anosognosia. Specifically, unawareness of memory impairment in AUD may result from a lack of personal knowledge updating attributable to damage in brain regions or connections supporting conscious recollection in episodic memory. Likely candidates are posterior parietal and medial frontal regions known to be integral part of the Default Mode Network (DMN) and the insula leading to an impaired switching mechanism between the DMN and the Central-Executive Control (i.e., Lateral Prefronto-Parietal) Network. The cognitive concepts and neural substrates noted for addictive disorders may also be relevant for problems in self-identification of functional impairment resulting from injury following war-related blast, sport-related concussion, and insidiously occurring dementia.

Differential compromise of prospective and retrospective metamemory monitoring and their dissociable structural brain correlates

Metamemory refers to personal knowledge about one's own memory ability that invokes cognitive processes relevant to monitoring and controlling memory. An impaired monitoring system can potentially result in unawareness of symptoms as can occur in addiction denial. Monitoring processes can be assessed with prospective measures such as Feeling-Of-Knowing (FOK) judgments on prediction of future recognition performance, or retrospective confidence judgments (RCJ) made on previous memory performance. Alcoholic patients with amnesia showed poor FOK but intact RCJ. The neuropsychological continuum from mild to moderate deficits in nonamnesic to amnesic alcoholism raised the possibility that alcoholics uncomplicated by clinically-detectable amnesia may suffer anosognosia for their mild memory deficits. Herein 24 abstinent alcoholics and 26 age-matched controls completed an episodic memory paradigm including prospective FOK and retrospective RCJ monitoring measures and underwent 3T structural magnetic resonance imaging. Alcoholics were less accurate than controls in recognition and in assessing their future recognition performance, which was marked by overestimation, but were as accurate as controls on confidence ratings of actual recognition performance. Examination of brain structure-function relations revealed a double dissociation where FOK accuracy was selectively related to insular volume, and retrospective confidence accuracy was selectively related to frontolimbic structural volumes. Impaired FOK with intact RCJ was consistent with mild anosognosia and suggested evidence for neuropsychological and neural mechanisms of unawareness in addiction.

T2 relaxation time alterations underlying neurocognitive deficits in alcohol-use disorders (AUD) in an Indian population: A combined conventional ROI and voxel-based relaxometry analysis

Long-term heavy alcohol consumption has traditionally been associated with impaired cognitive abilities, such as deficits in abstract reasoning, problem solving, verbal fluency, memory, attention, and visuospatial processing. The present study aimed at exploring these neuropsychological deficits in alcohol-use disorders (AUD) in an Indian population using the Postgraduate Institute Battery of Brain Dysfunction (PGIBBD) and their possible correlation with alterations in T2 relaxation times (T2-RT), using whole-brain voxel-based relaxometry (VBR) and conventional region of interest (ROI) approach. Multi-echo T2 mapping sequence was performed on 25 subjects with AUD and 25 healthy controls matched for age, education, and socioeconomic status. Whole-brain T2-RT measurements were conducted using VBR and conventional ROI approach. The study was carried out on a 3T whole-body MR scanner. Post processing for VBR and ROI analysis was performed using SPM 8 software and vendor-provided software, respectively. A PGIBBD test battery was conducted on all subjects to assess their cognitive abilities, and the results were reported as raw scores. VBR and ROI results revealed that AUD subjects showed prolonged T2-RTs in cerebellum bilaterally, parahippocampal gyrus bilaterally, right anterior cingulate cortex, left superior temporal gyrus, left middle frontal gyrus, and left calcarine gyrus. A significant correlation was also observed between the neuropsychological test raw scores and alterations in T2-RT in AUD subjects. Our results are consistent with previous studies suggesting tissue disruption or gliosis or demyelination as a possible reason for prolonged T2-RTs. This damage to brain tissue, which is evident as prolonged T2-RT, could possibly be associated with impaired cognitive abilities noticeable in AUD subjects.

Brain structural substrates of cognitive procedural learning in alcoholic patients early in abstinence

BACKGROUND

Procedural learning allows for the acquisition of new behavioral skills. Previous studies have shown that chronic alcoholism is characterized by impaired cognitive procedural learning and brain abnormalities affecting regions that are involved in the automation of new cognitive procedures in healthy individuals. The goal of the present study was to investigate the brain structural substrates of cognitive procedural learning in alcoholic patients (ALs) early in abstinence.

METHODS

Thirty-one ALs and 31 control participants (NCs) performed the Tower of Toronto task (4 daily learning sessions, each comprising 10 trials) to assess cognitive procedural learning. We also assessed episodic and working memory, executive functions, and visuospatial abilities. ALs underwent 1.5T structural magnetic resonance imaging.

RESULTS

The initial cognitive phase was longer in the AL group than in the NC group, whereas the autonomous phase was shorter. In ALs, the longer cognitive phase was predicted by poorer planning and visuospatial working memory abilities, and by smaller gray matter (GM) volumes in the angular gyrus and caudate nucleus. ALs' planning abilities correlated with smaller GM volume in the angular gyrus.

CONCLUSIONS

Cognitive procedural learning was impaired in ALs, with a delayed transition from the cognitive to the autonomous phase. This slowdown in the automation of the cognitive procedure was related to lower planning abilities, which may have hampered the initial generation of the procedure to be learned. In agreement with this neuropsychological finding, a persistent relationship was found between learning performance and the GM volumes of the angular gyrus and caudate nucleus, which are usually regarded as markers of planning and initial learning of the cognitive procedure.

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.

Are visual impairments responsible for emotion decoding deficits in alcohol-dependence?

Emotional visual perception deficits constitute a major problem in alcohol-dependence. Indeed, the ability to assess the affective content of external cues is a key adaptive function, as it allows on the one hand the processing of potentially threatening or advantageous stimuli, and on the other hand the establishment of appropriate social interactions (by enabling rapid decoding of the affective state of others from their facial expressions). While such deficits have been classically considered as reflecting a genuine emotion decoding impairment in alcohol-dependence, converging evidence suggests that underlying visual deficits might play a role in emotional alterations. This hypothesis appears to be relevant especially as data from healthy populations indicate that a coarse but fast analysis of visual inputs would allow emotional processing to arise from early stages of perception. After reviewing those findings and the associated models, the present paper underlines data showing that rapid interactions between emotion and vision could be impaired in alcohol-dependence and provides new research avenues that may ultimately offer a better understanding of the roots of emotional deficits in this pathological state.

Decreased white matter integrity in fronto-occipital fasciculus bundles: relation to visual information processing in alcohol-dependent subjects

Chronic alcohol abuse is characterized by impaired cognitive abilities with a more severe deficit in visual than in verbal functions. Neuropathologically, it is associated with widespread brain structural compromise marked by gray matter shrinkage, ventricular enlargement, and white matter degradation. The present study sought to increase current understanding of the impairment of visual processing abilities in alcohol-dependent subjects, and its correlation with white matter microstructural alterations, using diffusion tensor imaging (DTI). To that end, a DTI study was carried out on 35 alcohol-dependent subjects and 30 healthy male control subjects. Neuropsychological tests were assessed for visual processing skills and deficits were reported as raw dysfunction scores (rDyS). Reduced FA (fractional anisotropy) and increased MD (mean diffusivity) were observed bilaterally in inferior and superior fronto-occipital fasciculus (FOF) fiber bundles. A significant inverse correlation in rDyS and FA values was observed in these fiber tracts whereas a positive correlation of these scores was found with the MD values. Our results suggest that FOF fiber bundles linking the frontal lobe to occipital lobe might be related to visual processing skills. This is the first report of an alteration of the white matter microstructure of FOF fiber bundles that might have functional consequences for visual processing in alcohol-dependent subjects who exhibit no neurological complications.

Component processes of memory in alcoholism: pattern of compromise and neural substrates

Initially, alcohol-related memory deficits were considered only through the prism of Korsakoff's syndrome (KS). It is now clear, however, that chronic alcohol consumption results in memory disorders in alcoholics without ostensible neurologic complications, such as Wernicke's encephalopathy and KS. Most of the principal memory components are affected, including working memory, episodic memory, semantic memory, perceptual memory, and procedural memory. The extent of those cognitive impairments depends on several factors, such as age, gender, nutritional status, and psychiatric comorbidity. While memory disorders, especially episodic memory deficits, are largely definitive in patients with KS, recovery of memory abilities has been described with abstinence in uncomplicated alcoholics. Neuropsychologic impairments, and especially memory disorders, must be evaluated at alcohol treatment entry because they could impede patients from benefiting fully from cognitive and behavioral treatment approaches for alcohol dependence. Screening of memory deficits could also enable clinicians to detect, among alcoholics without ostensible neurologic complications, those at risk of developing permanent and debilitating amnesia that features KS.

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.

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.

Below and beyond the recognition of emotional facial expressions in alcohol dependence: from basic perception to social cognition

Studies that have carried out experimental evaluation of emotional skills in alcohol-dependence have, up to now, been mainly focused on the exploration of emotional facial expressions (EFE) decoding. In the present paper, we provide some complements to the recent systematic literature review published by Donadon and de Lima Osório on this crucial topic. We also suggest research avenues that must be, in our opinion, considered in the coming years. More precisely, we propose, first, that a battery integrating a set of emotional tasks relating to different processes should be developed to better systemize EFE decoding measures in alcohol-dependence. Second, we propose to go below EFE recognition deficits and to seek for the roots of those alterations, particularly by investigating the putative role played by early visual processing and vision-emotion interactions in the emotional impairment observed in alcohol-dependence. Third, we insist on the need to go beyond EFE recognition deficits by suggesting that they only constitute a part of wider emotional deficits in alcohol-dependence. Importantly, since the efficient decoding of emotions is a crucial ability for the development and maintenance of satisfactory interpersonal relationships, we suggest that disruption of this ability in alcohol-dependent individuals may have adverse consequences for their social integration. One way to achieve this research agenda would be to develop the field of affective and social neuroscience of alcohol-dependence, which could ultimately lead to major advances at both theoretical and therapeutic levels.

Prenatal cocaine exposure and gray matter volume in adolescent boys and girls: relationship to substance use initiation

BACKGROUND

Studies of prenatal cocaine exposure have primarily examined childhood populations. Studying adolescents is especially important because adolescence is a time of changing motivations and initiation of substance use.

METHODS

Using magnetic resonance imaging and whole-brain voxel-based morphometry, we assessed gray matter volume (GMV) differences in 42 prenatally cocaine exposed (PCE) and 21 noncocaine-exposed (NCE) adolescents, aged 14 to 17 years. Associations between GMV differences in significant clusters and the probability of substance use initiation were examined.

RESULTS

PCE relative to NCE adolescents demonstrated three clusters of lower GMV involving a limbic and paralimbic (p < .001, family-wise error [FWE] corrected), superior frontal gyrus (p = .001, FWE corrected), and precuneus (p = .019, FWE corrected) cluster. GMVs in the superior frontal and precuneus clusters were associated with initiation of substance use. Each 1-mL decrease in GMV increased the probability of initiating substance use by 69.6% (p = .01) in the superior frontal cluster and 83.6% (p = .02) in the precuneus cluster.

CONCLUSIONS

PCE is associated with structural differences in cortical and limbic regions. Lower GMVs in frontal cortical and posterior regions are associated with substance use initiation and may represent biological risk markers for substance use.

Prenatal substance exposure: neurobiologic organization at 1 month

OBJECTIVE

To examine the autonomic nervous system and neurobehavioral response to a sustained visual attention challenge in 1-month-old infants with prenatal substance exposure.

STUDY DESIGN

We measured heart rate, respiratory sinus arrhythmia, and neurobehavior during sustained visual orientation tasks included in the Neonatal Intensive Care Unit Network Neurobehavioral Scale in 1129 1-month-old infants with prenatal substance exposure. Four groups were compared: infants with prenatal cocaine and opiate exposure, infants with cocaine exposure, infants with opiate exposure, and infants with exposure to other substances (ie, alcohol, marijuana, and tobacco).

RESULTS

The infants with prenatal exposure to both cocaine and opiates had the highest heart rates and lowest levels of respiratory sinus arrhythmia during a sustained visual attention challenge compared with the other 3 groups. Infants with prenatal cocaine and opiate exposure had poorer quality of movement and more hypertonicity during the Neonatal Intensive Care Unit Network Neurobehavioral Scale examination. They also had more nonoptimal reflexes and stress/abstinence signs compared with infants with prenatal exposure to cocaine only and those with prenatal exposure to alcohol, tobacco, and marijuana.

CONCLUSION

Problems with arousal regulation were identified in infants with prenatal substance exposure. Autonomic dysregulation has been implicated as a mechanism by which these difficulties occur. Our results suggest that infants with prenatal exposure to both cocaine and opiates have the greatest autonomic response to the challenge of a sustained visual attention task, possibly putting these infants at risk for problems associated with physiologic and behavioral regulation, a necessary prerequisite for early learning.

A role for cognitive rehabilitation in increasing the effectiveness of treatment for alcohol use disorders

Neurocognitive impairments are prevalent in persons seeking treatment for alcohol use disorders (AUDs). These impairments and their physical, social, psychological and occupational consequences vary in severity across persons, much like those resulting from traumatic brain injury; however, due to their slower course of onset, alcohol-related cognitive impairments are often overlooked both within and outside of the treatment setting. Evidence suggests that cognitive impairments can impede treatment goals through their effects on treatment processes. Although some recovery of alcohol-related cognitive impairments often occurs after cessation of drinking (time-dependent recovery), the rate and extent of recovery is variable across cognitive domains and individuals. Following a long hiatus in scientific interest, a new generation of research aims to facilitate treatment process and improve AUD treatment outcomes by directly promoting cognitive recovery (experience-dependent recovery). This review updates knowledge about the nature and course of cognitive and brain impairments associated with AUD, including cognitive effects of adolescent AUD. We summarize current evidence for indirect and moderating relationships of cognitive impairment to treatment outcome, and discuss how advances in conceptual frameworks of brain-behavior relationships are fueling the development of novel AUD interventions that include techniques for cognitive remediation. Emerging evidence suggests that such interventions can be effective in promoting cognitive recovery in persons with AUD and other substance use disorders, and potentially increasing the efficacy of AUD treatments. Finally, translational approaches based on cognitive science, neurophysiology, and neuroscience research are considered as promising future directions for effective treatment development that includes cognitive rehabilitation.

Brain volumes and neuropsychological performance are related to current smoking and alcoholism history

BACKGROUND

Dual dependence on alcohol and nicotine is common, with many reports suggesting that more than 80% of alcoholics also smoke cigarettes. Even after cessation of alcohol consumption, many recovering alcoholics continue to smoke. In this exploratory study, we examined how current smoking and a history of alcoholism interacted in relation to brain volumes and neuropsychological performance.

METHODS

Participants were 14 abstinent long-term alcoholics (seven current smokers and seven nonsmokers), and 13 nonalcoholics (six current smokers and seven nonsmokers). The groups were equivalent in age, gender, education, and intelligence quotient. Two multiecho magnetization-prepared rapid acquisition with gradient echo (MP-RAGE) scans were collected for all participants using a 3T magnetic resonance imaging scanner with a 32 channel head coil. Brain volumes for each gray and white matter region of interest were derived using FreeSurfer. Participants completed a battery of neuropsychological tests measuring intelligence quotient, memory, executive functions, personality variables, and affect.

RESULTS

COMPARED TO NONSMOKING NONALCOHOLICS, ALCOHOLICS WHO SMOKE (THE COMORBID GROUP) HAD VOLUMETRIC ABNORMALITIES IN: pre- and para-central frontal cortical areas and rostral middle frontal white matter; parahippocampal and temporal pole regions; the amygdala; the pallidum; the ventral diencephalic region; and the lateral ventricle. The comorbid group performed worse than nonsmoking nonalcoholics on tests of executive functioning and on visually-based memory tests. History of alcoholism was associated with higher neuroticism scores among smokers, and current smoking was associated with higher sensation seeking scores and lower extraversion scores among nonalcoholics.

CONCLUSION

Results from this exploratory study support and extend prior reports showing that alcoholism and smoking, alone and in combination, are associated with structural brain abnormalities and poorer performance on neuropsychological tests. Therefore, it is important to consider smoking status in alcoholism studies and vice versa.

Dynamics of the cognitive procedural learning in alcoholics with Korsakoff's syndrome

BACKGROUND

While procedures acquired before the development of amnesia are likely to be preserved in alcoholic patients with Korsakoff's syndrome, the ability of Korsakoff patients (KS) to learn new cognitive procedures is called in question. According to the Adaptive Control of Thoughts model, learning a new cognitive procedure requires highly controlled processes in the initial cognitive phase, which may be difficult for KS with episodic and working memory deficits. The goals of the present study were to examine the learning dynamics of KS compared with uncomplicated alcoholic patients (AL) and control subjects (CS) and to determine the contribution of episodic and working memory abilities in cognitive procedural learning performance.

METHODS

Fourteen KS, 15 AL, and 15 CS were submitted to 40 trials (4 daily learning sessions) of the Tower of Toronto task (disk-transfer task similar to the tower of Hanoi task) as well as episodic and working memory tasks.

RESULTS

The 10 KS who were able to perform the cognitive procedural learning task obtained lower results than both CS and AL. The cognitive phase was longer in the Korsakoff's syndrome group than in the other 2 groups but did not differ between the 3 groups any more when episodic memory abilities were controlled.

CONCLUSIONS

Our results indicate that KS have impaired cognitive procedural learning abilities compared with both AL and CS. Episodic memory deficits observed in KS result in a delayed transition from the cognitive learning phase to more advanced learning phases and, as a consequence, in an absence of automation of the procedure within 40 trials.

The contribution of executive functions deficits to impaired episodic memory in individuals with alcoholism

Individuals with alcoholism commonly exhibit impaired performance on episodic memory tasks. However, the contribution of their impaired executive functioning to poor episodic memory remains to be clarified. Thirty-six recently detoxified and sober asymptomatic alcoholic men and 36 matched non-alcoholic participants were tested for processing speed, prepotent response inhibition, mental flexibility, coordination of dual-task and a verbal episodic memory task. Compared with non-alcoholic individuals, the alcoholic patients showed impaired executive functions combined with below normal performance on both free and delayed recall. In contrast, processing speed, cued recall and recognition were preserved. Regression analyses revealed that 47% of alcoholics' episodic memory's free recall performance was predicted by mental flexibility and that 49% of their delayed recall performance was predicted by mental flexibility, manipulation of dual-task and prepotent response inhibition. Regarding participants' executive predictors of episodic memory performance, the slopes of β coefficients were significantly different between the two groups, with alcoholics requiring more their executive system than non-alcoholics. Once detoxified, alcoholic patients showed episodic memory deficits mainly characterized by impaired effortful (executive) processes. Compared with controls, patients used effortful learning strategies, which are nonetheless less efficient.

Face-name association learning and brain structural substrates in alcoholism

BACKGROUND

Associative learning is required for face-name association and is impaired in alcoholism, but the cognitive processes and brain structural components underlying this deficit remain unclear. It is also unknown whether prompting alcoholics to implement a deep level of processing during face-name encoding would enhance performance.

METHODS

Abstinent alcoholics and controls performed a levels-of-processing face-name learning task. Participants indicated whether the face was that of an honest person (deep encoding) or that of a man (shallow encoding). Retrieval was examined using an associative (face-name) recognition task and a single-item (face or name only) recognition task. Participants also underwent 3T structural MRI.

RESULTS

Compared with controls, alcoholics had poorer associative and single-item learning and performed at similar levels. Level of processing at encoding had little effect on recognition performance but affected reaction time (RT). Correlations with brain volumes were generally modest and based primarily on RT in alcoholics, where the deeper the processing at encoding, the more restricted the correlations with brain volumes. In alcoholics, longer control task RTs correlated modestly with smaller tissue volumes across several anterior to posterior brain regions; shallow encoding correlated with calcarine and striatal volumes; deep encoding correlated with precuneus and parietal volumes; and associative recognition RT correlated with cerebellar volumes. In controls, poorer associative recognition with deep encoding correlated significantly with smaller volumes of frontal and striatal structures.

CONCLUSIONS

Despite prompting, alcoholics did not take advantage of encoding memoranda at a deep level to enhance face-name recognition accuracy. Nonetheless, conditions of deeper encoding resulted in faster RTs and more specific relations with regional brain volumes than did shallow encoding. The normal relation between associative recognition and corticostriatal volumes was not present in alcoholics. Rather, their speeded RTs occurred at the expense of accuracy and were related most robustly to cerebellar volumes.

Learning from positive and negative monetary feedback in patients with alcohol dependence

BACKGROUND

Chronic and excessive consumption of alcohol is associated with structural, physiological, and functional changes in multiple regions of the human brain including the prefrontal cortex, the medial temporal lobe, and the structures of the reward system. The present study aimed to assess the ability of alcohol-dependent patients (ADP) to learn probabilistic stimulus-reward contingencies and to transfer the acquired knowledge to new contexts. During transfer, the relative preference to learn from positive or negative feedback was also assessed.

METHODS

Twenty-four recently detoxified ADP and 20 healthy controls engaged in a feedback learning task with monetary rewards. The learning performance per se and transfer performance including positive versus negative learning were examined, as well as the relationship between different learning variables and variables comprising alcohol and nicotine consumption patterns, depression, and personality traits (harm avoidance and impulsivity).

RESULTS

Patients did not show a significant general learning deficit in the acquisition of stimulus-response-outcome associations. Fifteen healthy subjects and 13 patients reached the transfer phase, in which ADP showed generally lower performance than healthy controls. There was no specific deficit with regard to learning from positive or negative feedback. The only near-significant (negative) correlation between learning variables and drug consumption patterns, depression, and personality traits emerged for harm avoidance and positive learning in controls.

CONCLUSIONS

Impaired transfer performance suggests that ADP had problems applying their acquired knowledge in a new context. Potential relations to dysfunctions of specific brain structures and implications of the finding for therapy are discussed.

Widespread and sustained cognitive deficits in alcoholism: a meta-analysis

The cognitive repercussions of alcohol dependence are well documented. However, the literature remains somewhat ambiguous with respect to which distinct cognitive functions are more susceptible to impairment in alcoholism and to how duration of abstinence affects cognitive recovery. Some theories claim alcohol negatively affects specific cognitive functions, while others assert that deficits are more diffuse in nature. This is the first meta-analysis to examine cognition in alcohol abuse/dependence and the duration of abstinence necessary to achieve cognitive recovery. A literature search yielded 62 studies that assessed cognitive dysfunction among alcoholics. Effect size estimates were calculated using the Comprehensive Meta-Analysis V2, for the following 12 cognitive domains: intelligence quotient, verbal fluency/language, speed of processing, working memory, attention, problem solving/executive functions, inhibition/impulsivity, verbal learning, verbal memory, visual learning, visual memory and visuospatial abilities. Within these 12 domains, three effect size estimates were calculated based on abstinence duration. The three groups were partitioned into short- (< 1 month), intermediate- (2 to 12 months) and long- (> 1 year) term abstinence. Findings revealed moderate impairment across 11 cognitive domains during short-term abstinence, with moderate impairment across 10 domains during intermediate term abstinence. Small effect size estimates were found for long-term abstinence. These results suggest significant impairment across multiple cognitive functions remains stable during the first year of abstinence from alcohol. Generally, dysfunction abates by 1 year of sobriety. These findings support the diffuse brain hypothesis and suggest that cognitive dysfunction may linger for up to an average of 1 year post-detoxification from alcohol.

Broad disruption of brain white matter microstructure and relationship with neuropsychological performance in male patients with severe alcohol dependence

AIMS

In the last years, refined magnetic resonance diffusion tensor imaging (DTI) methods have become available to study microstructural alterations in the human brain. We investigated to what extent white matter tissue abnormalities are present in male patients after chronic, excessive alcohol consumption and if these alterations are correlated with measures of alcohol consumption and neuropsychological performance.

METHODS

Twenty-four detoxified adult male patients with severe alcohol dependence and 23 healthy male control subjects were included in the study. Neuropsychological tests were assessed for executive function, attention, memory and visuospatial function. DTI was acquired and preprocessing of the data was performed using tract-based spatial statistics. Group differences of fractional anisotropy (FA) as well as correlation analyses with neuropsychological measures and drinking history were calculated.

RESULTS

Performance in alcoholic patients was significantly poorer in tests of non-verbal reasoning and attention. In detoxified alcoholic patients, lower FA was primarily found in the body of the corpus callosum, but these findings did not correlate directly with behavioral measures. However, executive and psychomotor performance (Trail-Making Test) correlated significantly with FA in right anterior cingulate and left motor areas.

CONCLUSION

These findings provide further evidence for reduced integrity of interhemispheric connections in male patients with severe alcohol dependence, and neurocognitive performance was in part correlated with FA.

Alcohol-related amnesia and dementia: animal models have revealed the contributions of different etiological factors on neuropathology, neurochemical dysfunction and cognitive impairment

Chronic alcoholism is associated with impaired cognitive functioning. Over 75% of autopsied chronic alcoholics have significant brain damage and over 50% of detoxified alcoholics display some degree of learning and memory impairment. However, the relative contributions of different etiological factors to the development of alcohol-related neuropathology and cognitive impairment are questioned. One reason for this quandary is that both alcohol toxicity and thiamine deficiency result in brain damage and cognitive problems. Two alcohol-related neurological disorders, alcohol-associated dementia and Wernicke-Korsakoff syndrome have been modeled in rodents. These pre-clinical models have elucidated the relative contributions of ethanol toxicity and thiamine deficiency to the development of dementia and amnesia. What is observed in these models--from repeated and chronic ethanol exposure to thiamine deficiency--is a progression of both neural and cognitive dysregulation. Repeated binge exposure to ethanol leads to changes in neural plasticity by reducing GABAergic inhibition and facilitating glutamatergic excitation, long-term chronic ethanol exposure results in hippocampal and cortical cell loss as well as reduced hippocampal neurotrophin protein content critical for neural survival, and thiamine deficiency results in gross pathological lesions in the diencephalon, reduced neurotrophic protein levels, and neurotransmitters levels in the hippocampus and cortex. Behaviorally, after recovery from repeated or chronic ethanol exposure there is impairment in working or episodic memory that can recover with prolonged abstinence. In contrast, after thiamine deficiency there is severe and persistent spatial memory impairments and increased perseverative behavior. The interaction between ethanol and thiamine deficiency does not produce more behavioral or neural pathology, with the exception of reduction of white matter, than long-term thiamine deficiency alone.