Imbalance between cognitive systems in alcohol-dependence and Korsakoff syndrome: An exploration using the Alcohol Flanker Task

The neutral condition in conflict tasks: On the violation of the midpoint assumption in reaction time trends

Although the relation between congruent and incongruent conditions in conflict tasks has been the primary focus of cognitive control studies, the neutral condition is often set as a baseline directly between the two conditions. However, empirical evidence suggests that the average neutral reaction time (RT) is not placed evenly between the two opposing conditions. This article set out to establish two things: First, to reinforce the informative nature of the neutral condition and second, to highlight how it can be useful for modelling. We explored how RT in the neutral condition of conflict tasks (Stroop, Flanker, and Simon Tasks) deviated from the predictions of current diffusion models. Current diffusion models of conflict tasks predict a neutral RT that is the average of the congruent and incongruent RT, called the midpoint assumption. To investigate this, we first conducted a cursory limited search that recorded the average RT's of conflict tasks with neutral conditions. Upon finding evidence of a midpoint assumption violation which showed a larger disparity between average neutral and incongruent RT, we tested the previously mentioned conflict tasks with two different sets of stimuli to establish the robustness of the effect. The midpoint assumption violation is sometimes inconsistent with the prediction of diffusion models of conflict processing (e.g., the Diffusion Model of Conflict), suggesting possible elaborations of such models.

Neurobiological mechanisms of control in alcohol use disorder - moving towards mechanism-based non-invasive brain stimulation treatments

Alcohol use disorder (AUD) is characterized by excessive habitual drinking and loss of control over alcohol intake despite negative consequences. Both of these aspects foster uncontrolled drinking and high relapse rates in AUD patients. Yet, common interventions mostly focus on the phenomenological level, and prioritize the reduction of craving and withdrawal symptoms. Our review provides a mechanistic understanding of AUD and suggests alternative therapeutic approaches targeting the mechanisms underlying dysfunctional alcohol-related behaviours. Specifically, we explain how repeated drinking fosters the development of rigid drinking habits and is associated with diminished cognitive control. These behavioural and cognitive effects are then functionally related to the neurobiochemical effects of alcohol abuse. We further explain how alterations in fronto-striatal network activity may constitute the neurobiological correlates of these alcohol-related dysfunctions. Finally, we discuss limitations in current pharmacological AUD therapies and suggest non-invasive brain stimulation (like TMS and tDCS interventions) as a potential addition/alternative for modulating the activation of both cortical and subcortical areas to help re-establish the functional balance between controlled and automatic behaviour.

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

ABSTRACT

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

Effectiveness of an Integrated Intervention Program for Alcoholism: Electrophysiological Findings

BACKGROUND

Neuroelectrophysiological measures such as electroencephalograms (EEGs) in resting state and event-related potentials (ERPs) provide valuable information about the vulnerability and treatment-related changes in persons with alcoholism. This study examined the effectiveness of an Integrated Intervention Program for Alcoholism (IIPA) using electrophysiological measures.

METHODS

Fifty individuals with early onset of alcohol dependence participated. They were grouped randomly into two: the treatment as usual (TAU) group and the treatment group, matched on age (±1 year) and education (±1 year). eyes closed and resting state EEGs and ERPs on cognitive tasks (flanker task, alcohol Go/No-Go task, and single outcome gambling task) were recorded before and after treatment. The TAU group received pharmacotherapy, six days/week yoga sessions, and three sessions/week group therapy on relapse prevention while the treatment group received IIPA along with usual treatment (except yoga) for 18 days.

RESULTS

There was no significant difference between the groups pre-treatment. RM-ANOVA for pre- and post-treatment stages showed a significant difference between the two groups in the absolute power of alpha, beta, theta, and delta, during eye closure, in the resting-state EEGs. The treatment group showed significantly larger N200/N2 amplitude in congruent and incongruent conditions (flanker task), N200/N2 amplitude for alcohol No-Go, P300/P3 amplitude for neutral No-Go on alcohol Go/No-Go task, and outcome-related positivity (ORP) amplitude on single outcome gambling task.

CONCLUSION

This exploratory study suggests that IIPA is effective for enhancing relaxation state and attentiveness, decreasing hyperarousal, and ameliorating neurocognitive dysfunctions of conflict-monitoring, response inhibition, and reward processing.

Neural correlates of error detection during complex response selection: Introduction of a novel eight-alternative response task

Error processing in complex decision tasks should be more difficult compared to a simple and commonly used two-choice task. We developed an eight-alternative response task (8ART), which allowed us to investigate different aspects of error detection. We analysed event-related potentials (ERP; N = 30). Interestingly, the response time moderated several findings. For example, only for fast responses, we observed the well-known effect of larger error negativity (N_e) in signalled and non-signalled errors compared to correct responses, but not for slow responses. We identified at least two different error sources due to post-experimental reports and certainty ratings: impulsive (fast) errors and (slow) memory errors. Interestingly, the participants were able to perform the task and to identify both, impulsive and memory errors successfully. Preliminary evidence indicated that early (N_e-related) error processing was not sensitive to memory errors but to impulsive errors, whereas the error positivity seemed to be sensitive to both error types.

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

Aims

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

Short summary

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

Methods

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

Results

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

Conclusions

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

Dehumanization of psychiatric patients: Experimental and clinical implications in severe alcohol-use disorders

Dehumanization, defined as the denial of one's membership to humanity, is a process repeatedly reported in extreme contexts (e.g., genocides) but also in everyday life interactions. Some antecedents of dehumanizing experiences (e.g., social exclusion, negative stereotypes) have been reported among patients presenting psychiatric disorders, but dehumanization's experience remains completely unexplored in addictive disorders. We propose a theoretical model and research agenda to overcome this limitation and to improve our understanding of dehumanization's experience in psychiatry, with a special focus on alcohol-related disorders. We also propose much-needed clinical avenues to reduce dehumanization in clinical contexts, centrally by (1) improving dehumanization awareness among medical workers; (2) reducing the need for healthcare workers to use dehumanization to alleviate professional exhaustion; and (3) optimizing medical training to increase empathy toward patients. Finally, some additional improvements are proposed to promote patient's choices, comfort, dignity, and ultimately humanity in hospitals.