A Clinical Trial with Combined Transcranial Direct Current Stimulation and Attentional Bias Modification in Alcohol-Dependent Patients.

BACKGROUND: Modifying attentional processes with attentional bias modification (ABM) might be a relevant add-on to treatment in addiction. This study investigated whether influencing cortical plasticity with transcranial direct current stimulation (tDCS) could increase training effects. tDCS could also help alcohol-dependent patients to overcome craving and reduce relapse, independent of training. These approaches were combined to investigate effects in the treatment of alcoholism. METHODS: Ninety-eight patients (analytical sample = 83) were randomly assigned to 4 groups in a 2-by-2 factorial design. Patients received 4 sessions of ABM (control or real training) combined with 2 mA tDCS (active: 20 minutes or sham: 30 seconds) over the left dorsolateral prefrontal cortex. Alcohol bias and craving were assessed, and treatment outcome was measured as relapse after 1 year. RESULTS: Attentional bias scores indicated that during the training only the group with active tDCS and real ABM displayed an overall avoidance bias (p < 0.05). From pre- to postassessment, there were no main or interaction effects of tDCS and ABM on the bias scores, craving, or relapse (p > 0.2). However, effects on relapse after active tDCS were in the expected direction. CONCLUSIONS: There was no evidence of a beneficial effect of tDCS or ABM or the combination. Whether the absence of effect was due to issues with the outcome measurements (e.g., lack of craving, high dropout, and unreliable measurements) or aspects of the intervention should be further investigated.

A clinical trial with combined transcranial direct current stimulation and alcohol approach bias retraining.

Two studies showed an improvement in clinical outcomes after alcohol approach bias retraining, a form of Cognitive Bias Modification (CBM). We investigated whether transcranial direct current stimulation (tDCS) could enhance effects of CBM. TDCS is a neuromodulation technique that can increase neuroplasticity and has previously been found to reduce craving. One hundred alcohol-dependent inpatients (91 used for analysis) were randomized into three experimental groups in a double-blind parallel design. The experimental group received four sessions of CBM while receiving 2 mA of anodal tDCS over the dorsolateral prefrontal cortex (DLPFC). There were two control groups: One received sham stimulation during training and one received active stimulation at a different moment. Treatment outcomes were abstinence duration (primary) and relapse after 3 and 12 months, craving and approach bias (secondary). Craving and approach bias scores decreased over time; there were no significant interactions with experimental condition. There was no effect on abstinence duration after three months (χ2(2) = 3.53, p = 0.77). However, a logistic regression on relapse rates after one year (standard outcome in the clinic, but not-preregistered) showed a trend when relevant predictors were included; relapse was lower in the condition receiving active stimulation during CBM only when comparing to sham stimulation (B = 1.52, S.E. = .836, p = .07, without predictors: p = .19). No strong evidence for a specific enhancement effect of tDCS on CBM was found. However, in a post-hoc analysis, tDCS combined with CBM showed a promising trend on treatment outcome. Important limitations are discussed, and replication is necessary to find more reliable effects.

Electrophysiological and Behavioral Effects of Combined Transcranial Direct Current Stimulation and Alcohol Approach Bias Retraining in Hazardous Drinkers.

BACKGROUND: Cognitive bias modification (CBM) can be used to retrain automatic approach tendencies for alcohol. We investigated whether changing cortical excitability with transcranial direct current stimulation (tDCS) could enhance CBM effects in hazardous drinkers. We also studied the underlying mechanisms by including behavioral (craving, implicit associations, approach tendencies) and electrophysiological (event-related potentials) measurements. METHODS: The analytical sample consisted of 78 hazardous drinkers (Alcohol Use Disorders Identification Test >8) randomly assigned to 4 conditions in a 2-by-2 factorial design (control/active CBM and sham/active tDCS). The intervention consisted of 3 sessions of CBM, specifically alcohol approach bias retraining, combined with 15 minutes 1 mA tDCS over the left dorsolateral prefrontal cortex. There was a pre- and postassessment before and after the intervention that included experimental tasks (Approach Avoidance Task, Implicit Association Task) and an electroencephalogram with an oddball and cue-reactivity task. RESULTS: tDCS decreased cue-induced craving (but not overall craving) on postassessment. CBM did not induce an avoidance bias during assessment. During the training, active and control-CBM only differed in bias score during the first session. We found no enhancement effects of tDCS on CBM. Electrophysiological data showed no clear effects of active tDCS or CBM on the P300. CONCLUSIONS: There were no electrophysiological or behavioral effects of repeated CBM and/or tDCS, except for an effect of tDCS on craving. Applied in these specific ways these techniques appear to have limited effects in a hazardous drinking population.

Promoting Healthy Aging Using a Robot Support System and Emotion Recognition.

The aging population poses challenges such as loneliness, decreased mobility, and medical conditions. To tackle these issues, a proposed robot platform offers personalized well-being behavior change suggestions. Developed through a user-centered process involving surveys and focus groups, and tested with a first prototype, the system is ideal for individuals with "special social needs". Technical results indicate that emotion recognition is valuable, with attention and valence being key metrics, but user acceptance and quality of facial/speech analysis for elderly users remain challenges.

Transcranial electrical and magnetic stimulation (tES and TMS) for addiction medicine: A consensus paper on the present state of the science and the road ahead.

There is growing interest in non-invasive brain stimulation (NIBS) as a novel treatment option for substance-use disorders (SUDs). Recent momentum stems from a foundation of preclinical neuroscience demonstrating links between neural circuits and drug consuming behavior, as well as recent FDA-approval of NIBS treatments for mental health disorders that share overlapping pathology with SUDs. As with any emerging field, enthusiasm must be tempered by reason; lessons learned from the past should be prudently applied to future therapies. Here, an international ensemble of experts provides an overview of the state of transcranial-electrical (tES) and transcranial-magnetic (TMS) stimulation applied in SUDs. This consensus paper provides a systematic literature review on published data - emphasizing the heterogeneity of methods and outcome measures while suggesting strategies to help bridge knowledge gaps. The goal of this effort is to provide the community with guidelines for best practices in tES/TMS SUD research. We hope this will accelerate the speed at which the community translates basic neuroscience into advanced neuromodulation tools for clinical practice in addiction medicine.

Transcranial direct current stimulation, implicit alcohol associations and craving.

Previous research has shown that stimulation of the left dorsolateral prefrontal cortex (DLPFC) enhances working memory (e.g. in the n-back task), and reduces craving for cigarettes and alcohol. Stimulation of the right inferior frontal gyrus (IFG) improves response inhibition. The underlying mechanisms are not clearly understood, nor is it known whether IFG stimulation also reduces craving. Here, we compared effects of DLPFC, IFG, and sham stimulation on craving in heavy drinkers in a small sample (n=41). We also tested effects of tDCS on overcoming response biases due to associations between alcohol and valence and alcohol and approach, using implicit association tests (IATs). Mild craving was reduced after DLPFC stimulation. Categorization of valence attribute words in the IAT was faster after DLPFC stimulation. We conclude that DLPFC stimulation can reduce craving in heavy drinkers, but found no evidence for tDCS induced changes in alcohol biases, although low power necessitates caution.

Recovery of neurocognitive functions following sustained abstinence after substance dependence and implications for treatment.

BACKGROUND: Substance Use Disorders (SUDs) have been associated with impaired neurocognitive functioning, which may (partly) improve with sustained abstinence. New treatments are emerging, aimed at improving cognitive functions, and being tested. However, no integrated review is available regarding neurocognitive recovery following sustained abstinence. OBJECTIVES: In this review, results from prospective studies on neurocognitive recovery using neuropsychological assessments before and after sustained abstinence from SUDs are summarized and discussed. RESULTS: Thirty-five prospective studies were selected for this review, including twenty-two alcohol, three cannabis, four cocaine, three (meth)amphetamine, and three opioid studies. Results suggest that some cognitive functions (partially) recover after sustained abstinence, and that there are predictors of an unfavorable course such as poly-substance use and number of previous detoxifications. CONCLUSIONS: Prospective studies indicate that sustained abstinence after SUDs generally results in (partial) neurocognitive recovery. However, a final answer regarding full recovery awaits prospective studies with neurocognitive assessments before, during, and after sustained abstinence from SUDs. New interventions that might enhance neurocognitive recovery after abstinence are discussed, including neurocognitive training, medication and neuromodulation.

Anodal tDCS of dorsolateral prefontal cortex during an Implicit Association Test.

Anodal stimulation of dorsolateral prefrontal cortex by transcranial Direct Current Stimulation (tDCS) has been shown to enhance performance on working memory tasks. However, it is not yet known precisely which aspects of working memory - a broad theoretical concept including short-term memory and various executive functions - are involved in such effects. In the current study, we aimed to determine whether tDCS would reduce bias effects on an Implicit Association Test, in which subjects must respond either congruently or incongruently to pre-existing evaluative associations. Such biases reflect a conflict between automatic associations and executive function, and tDCS was hypothesized to cause a shift in this balance in favor of executive function. The results clearly contradicted this hypothesis: tDCS did improve reaction times, but in the congruent rather than incongruent mapping condition. We conclude that DLPFC tDCS does not directly improve the ability to overcome bias; previous findings concerning working memory enhancement appear to reflect effects on a different component of executive function.

Enhancement of selective attention by tDCS: interaction with interference in a Sternberg task.

Transcranial Direct Current Stimulation (tDCS) enhances performance on working memory tasks. However, such effects may be dependent on modulation of specific aspects of working memory. We therefore tested the hypothesis that tDCS improves selective attention in the context of a Sternberg task. Subjects had to maintain a memory set while responding to distracter stimuli. Probes consisted of one item from the memory set, and one item that could have been presented as a distracter. TDCS was found to improve reaction time significantly only when the incorrect choice had been a distracter stimulus. The results thus support the notion that tDCS effects on working memory might be mediated by a specific effect on selective attention.