The effect of transcranial direct current stimulation and nutritional counseling therapy on attentional bias to food cues: A randomized clinical trial.

Effect of home-based transcranial direct current stimulation combined with nutritional counseling therapy on binge eating disorder symptoms: a randomized pilot trial

Background: Binge Eating Disorder (BED) is a psychiatric disorder that has several medical and social consequences. Cognitive Behavioral Therapy (CBT) is the reference treatment, but presents significant dropout rates and elevated failure of therapeutic response. Therefore, new therapies targeting Central Nervous System (CNS) modulation, such as transcranial direct current stimulation (tDCS), might improve therapeutical responses, by modulating cognitive control over eating behavior and/or by enhancing inhibitory control due to synergistic action when combined with the current treatments available. Methods: Women with moderated BED, aged between 18 and 65 years and BMI ? 25 Kg/m² will be included. The participants will be divided into one of four groups: (1) Active tDCS; (2) Nutritional Counseling Therapy (NCT); (3) Active tDCS + NCT; (4) Sham tDCS + NCT. The electrodes of the tDCS will be positioned over the right Dorsolateral Pre-Frontal Cortex (DLPFC) - anode and left DLPFC - cathode. The participants will have a weekly appointment for 8 weeks where they will undergo the stimulation and/or the NCT. The groups that have the tDCS therapy will also receive the stimulation at home 4x/week in the first 5 weeks. The follow up is 8 weeks. The primary outcomes are the severity of symptoms, measured by the Binge Eating Scale (BES), and the inhibitory parameters of cortical excitability, measured by Transcranial Magnetic Stimulation (TMS) - Short Intracortical Inhibition (SICI). The secondary outcomes are weight loss, eating behavior, inhibitory control (Go/No-go), parameters of cortical excitability (Intracortical Facilitation (ICF) and cortical silent period (CSP)), and serum levels of leptin. Discussion: Cumulative research has provided evidence that tDCS improves disordered eating behaviors. Nevertheless, studies investigating the efficacy of long-term tDCS combined to standard treatment to BED are scarce. Based on exciting findings in trials that have associated tDCS and cognitive-behavioral approaches in Major Depressive Disorder (MDD), we hypothesize that the proposed protocol will be able to amplify therapeutical responses by reducing the severity of BED symptoms and enhancing inhibitory pathways assessed by cortical excitability parameters.

Objective: Food-related attentional bias has been defined as the tendency to give preferential attention to food-related stimuli. Attentional bias is of interest as studies have found that increased attentional bias is associated with obesity; others, however, have not. A possible reason for mixed results may be that there is no agreed upon measure of attentional bias: studies differ in both measurement and scoring of attentional bias. Additionally, little is known about the stability of attentional bias over time. The present study aims to compare attentional bias measures generated from commonly used attentional bias tasks and scoring protocols, and to test re-test reliability.Methods: As part of a larger study, 69 participants (67% female) completed two food-related visual probe tasks at baseline: lexical (words as stimuli), and pictorial (pictures as stimuli). Reaction time bias scores (attentional bias scores) for each task were calculated in three different ways: by subtracting the reaction times for the trials where probes replaced (1) neutral stimuli from the trials where the probes replaced all food stimuli, (2) neutral stimuli from the trials where probes replaced high caloric food stimuli, and (3) neutral stimuli from low caloric food stimuli. This resulted in three separate attentional bias scores for each task. These reaction time results were then correlated. The pictorial visual probe task was administered a second time 14-days later to assess test-retest reliability.Results: Regardless of the scoring use, lexical attentional bias scores were minimal, suggesting minimal attentional bias. Pictorial task attentional bias scores were larger, suggesting greater attentional bias. The correlation between the various scores was relatively small (r = 0.13–0.20). Similarly, test-retest reliability for the pictorial task was poor regardless of how the test was scored (r = 0.20–0.41).Conclusion: These results suggest that at least some of the variation in findings across attentional bias studies could be due to differences in the way that attentional bias is measured. Future research may benefit from either combining eye-tracking measurements in addition to reaction times.

ABSTRACTNew methods of calculating indices from the dot-probe task measure temporal dynamics in attention bias or fluctuations in attention bias towards and away from emotional stimuli over time. However, it is unclear how task-specific parameters such as stimulus valence and stimulus onset asynchrony (SOA) as well as participant sex affect temporal dynamics in attention bias. To address this, male and female participants (N = 106) completed either a fearful or happy face dot-probe task with four levels of SOA (84 ms, 168 ms, 336 ms, and 672 ms). Results suggest that temporal dynamics in attention bias are (1) greatest at the longest SOA, (2) greater in females, and (3) insensitive to stimulus valence. These findings indicate that participant sex and task timing, but not stimulus valence, are related to temporal dynamics in attention bias and should be considered in future studies utilizing this approach.

Objective To study the attentional bias to threatening faces images of high and low social anxiety subjects in the threatening and non- threatening conditions.Methods 23 high social anxious subjects (HSAs) and 24 low social anxious subjects (LSAs) were chosen from 500 volunteers according to the score and divided randomly into two groups,one group was under the threatening condition (expecting to give a short speech) and the other under the non- threatening condition,and then a dot-probe task was performed and the attentional bias score (ABS) was recorded.Results Under the threatening condition,the ABS of HSAs and LSAs were (-2.63±1.83)ms and (0.42±1.36)ms,the different was significant (t=-4.641,P=0.000);under the non- threatening condition,the ABS of HSAs and LSAs were (-0.41±1.56)ms and (0.47±0.67)ms,the different was not significant (t=-1.732,P=0.106).The ABS of HSAs under the threatening and non- threatening condition were (-2.63±1.83)ms and (-0.41±1.56)ms,the different was significant (t=-3.122,P=0.005);the ABS of LSAs under the threatening and non- threatening condition were (0.42±1.36)ms and (0.47±0.67)ms,the different was not significant(t=-0.124,P=0.903).The effect of the interaction between social anxiety and the experiment condition on ABS was significant (F=6.881,P=0.012).The separately main effect of social anxiety and the experiment condition on ABS was significant (F=20.429,P=0.000) and (F=6.413,P=0.015) too.Conclusion Social anxious individuals attend to avoid the threatening faces images,especially under the threatening condition. Key words: Social anxiety; Attentional bias; Dot-probe task; Collage students

The aim of this study was to analyse initial orienting processes as well as maintenance of attention towards alcohol cues in recently detoxified alcoholics and light social drinkers. Furthermore, we investigated the influence of pre-treatment alcohol consumption and abstinence duration onto alcohol-related attentional bias. We used an alcohol-visual-dot-probe-task with two different stimulus onset asynchronies (SOA) to examine processes of initial orienting and maintenance of attention separately (50 and 500 ms SOA). With short SOA, we found a positive attentional bias towards alcohol cues in alcohol-dependent patients and light social drinkers that was positively associated with pre-treatment alcohol consumption in alcoholics. Using a longer SOA, a negative attentional bias was found in light social drinkers and in patients abstinent for more than 2 weeks indicating alcohol stimuli avoidance. In patients, we found a negative correlation between attentional bias and duration of abstinence. After initial visual orienting towards alcohol-related stimuli, light social drinkers as well as longer abstinent alcohol-dependent patients disengage their attention. In patients, this disengagement increased during the first 3 weeks after detoxification indicating assimilation to the attentional bias pattern of light social drinkers.

BackgroundAttentional processes toward high-calorie foods contribute to the maintenance of binge eating disorder (BED) and have been targeted by attentional modification trainings (AMTs). In this study, we quantified food-related attentional bias (AB) in individuals with BED versus control groups with normal-weight (NCG) and overweight (OCG), and evaluated whether AMT effects would persist after one week and generalize to novel stimuli.MethodsWe assessed eating pathology and AB in 135 participants (BED: n = 72; NCG: n = 32; OCG: n = 31). We used a dot-probe paradigm with concurrent eye-tracking and reaction-time measures. Sixty-one participants with BED were then randomized to four sessions of AMT or placebo training. All participants with BED underwent re-evaluations of AB and eating pathology one week after the final training session.ResultsAt baseline, the group with BED presented significantly greater AB toward high-calorie food cues than both the NCG and OCG did. One week post-training, no differential effects of AMT were observed: both the AMT and placebo groups showed modest, nonspecific reductions in initial fixation duration bias and reaction-time variability. Correlations between changes in AB toward food and eating pathology were small and not significant.ConclusionsThe presence of a food-related AB in individuals with BED was confirmed. However, AMT did not yield sustained or generalized modifications in attentional processing beyond those observed in the placebo condition. Nonspecific improvements may reflect enhanced overall attentional control or general exposure effects. Future research should isolate the active components of AMT and explore strategies to increase its ecological validity.Trial registration: Registered in the German Clinical Trials Register (DRKS00012984) on 2017-11-30.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40337-025-01450-4.

Background and AimsKnee osteoarthritis (KOA) is a prevalent degenerative disease characterized by pain and functional impairment. While traditional pain management provides limited relief, Transcranial Direct Current Stimulation (tDCS) has emerged...

BackgroundThe aim of this study was to improve our understanding of the underlying mechanisms in the maintenance of depression. We examined attentional bias (AB) for negative and positive adjectives and general threat words in strictly-defined clinical groups of participants with pure Major Depressive Disorder (MDD) without a history of anxiety disorders (AD), mixed MDD and AD, and remitted participants.MethodWe investigated both stimulus specificity and time course of AB in these groups, adopting a cross-sectional design. Data were drawn from the large scale Netherlands Study of Depression and Anxiety (NESDA), from which we selected all participants with pure current MDD without a history of AD (n = 29), all participants with current MDD and co-morbid AD(s) (n = 86), all remitted MDD participants (n = 294), and a comparison group without (a history of) MDD or ADs (n = 474). AB was measured with an Exogenous Cueing Task covering short and long presentation times (500 and 1250 ms) and 4 stimulus types (negative, positive, threat, neutral).ResultsBoth traditional and trial level (dynamic) AB scores failed to show an AB for negative adjectives in participants with MDD or mixed MDD/AD. Specifically for long duration trials (1250 ms), remitted participants showed a larger AB traditional score (albeit the actual score still being negative) than the comparison group. The mixed MDD/AD group showed a higher trial-level AB score away from positive adjectives (1250 ms) than the comparisons. In addition, the mixed MDD/AD group showed higher and more variable trial-level AB scores away from short and towards longer presented general threat words together with a non-significant tendency to show less negative traditional AB scores for threat trials (500 ms) than the comparison group.ConclusionsAll in all, the findings do not corroborate the view that an AB towards negative or away from positive adjectives is critically involved in currently depressed individuals. Yet, the relatively high (less negative) AB score for negative adjectives in remitted individuals points to the possibility that an AB for negative information may be involved as a risk factor in the recurrence of MDD.

Augmenting cognitive training with bifrontal tDCS decreases subclinical depressive symptoms in older adults: Preliminary findings

Left unilateral neglect is a neurological condition characterized by an impairment in orienting and responding to events occurring on the left side. To gain insight into the brain mechanisms of space processing and to provide theoretical foundations for patient rehabilitation, it is important to explore the attentional bias shown by neglect patients in the light of existing models of normal attentional orienting. Three experiments tested the hypothesis that attentional bias in neglect involves primarily exogenous, or stimulus-based, orienting of attention, with relatively preserved endogenous, or voluntary, orienting. Six patients with right hemisphere damage and left unilateral neglect and 18 age-matched participants without brain damage performed a cued reaction time (RT) task to targets which could appear in one of two lateral boxes. Cues consisted of a brief brightening of the contour of one of the boxes. The target followed the cue at 150, 550, or 1000 ms stimulus-onset asynchrony (SOA). In experiment 1, the cues were not informative about the future location of the target, and thus elicited a purely exogenous orienting of attention. Controls showed slowed RTs to the cued locations at SOAs > 150 ms, consistent with the notion of inhibition of return (IOR). Neglect patients had no evidence of IOR for right targets; they showed a disproportionate cost for left targets preceded by right (invalid) cues; this cost was maximal at the shortest SOA, consistent with the idea of a biased exogenous orienting in neglect. In experiment 2, 80% of the cues were valid (i.e., they correctly predicted the location of the impending target), thus inducing an initially exogenous, and later endogenous, attentional shift toward the cued box. Neglect patients showed again a cost for left invalidly cued targets, which this time persisted at SOAs > 150 ms, as if patients' attention had been cued to the right side not only exogenously, but also endogenously, thus rendering more difficult an endogenous reorienting toward the left. In experiment 3, only 20% of the cues were valid, so that the best response strategy was to endogenously orient attention toward the box opposite to the cued one. Controls were able to take advantage of invalid cues to rapidly respond to targets. In this condition, neglect patients were able to nullify their spatial bias; they achieved their fastest RTs to left targets, which were in the range of their RTs to right targets. However, for neglect patients fast responses to left targets occurred only at 1000 ms SOA, while controls were able to redirect their attention to the uncued box already at 550 ms SOA. Altogether, these results suggest that endogenous orienting is relatively spared, if slowed, in unilateral neglect.

Background: Special populations like people living with HIV/AIDS (PLWHA) and people with opioid use disorder (OUD) smoke tobacco cigarettes at rates three to four times greater than the general population. Patients with tobacco use disorder exhibit attentional bias (AB) for cigarette cues. Eye tracking can quantify this bias by measuring fixation time (FT) on cigarette and matched neutral cues, to calculate an AB score. Although previous studies have measured this bias in people who smoke without any other comorbid conditions, no study, to our knowledge, has measured or compared this bias in special populations. Methods: We performed exploratory analyses on eye tracking data collected in two separate randomized clinical trials (RCTs) (NCT05049460, NCT05295953). We compared FT and cigarette-cue AB score (measured by subtracting FT on neutral cues from FT on cigarette cues) between PLWHA and people with OUD who smoke, using a visual probe task and Tobii Pro Fusion eye tracker. We used two cigarette cue types, one encompassing people smoking cigarettes and the other consisting of cigarette paraphernalia. We used two cue presentation times, 1000 and 2000 milliseconds (ms). Results: Cues of people smoking cigarettes elicited greater AB than cues of cigarette paraphernalia across both subject groups when cues were presented for 2000 ms, but not 1000 ms. PLWHA who smoke exhibited greater AB for cues of people smoking cigarettes than cigarette paraphernalia when presented for 2000 ms compared to people with OUD who smoke. Conclusion: We use cigarette-cue AB to quantify craving and cigarette consumption in two populations smoking at elevated rates. The addition of social cues potentiates cigarette cue AB, based on cue type and stimulus presentation time. Understanding the neurobiology of this relationship can help design novel smoking cessation treatments that target AB and prevent relapse in these populations with suboptimal response to smoking cessation treatments. Trial registration: Clinical trials that provided the data for post hoc analyses are NCT05049460 and NCT05295953.

Transcranial direct current stimulation (tDCS) has been shown to improve pain symptoms in fibromyalgia (FM), a central pain syndrome whose underlying mechanisms are not well understood. This study was undertaken to explore the neurochemical action of tDCS in the brain of patients with FM, using proton magnetic resonance spectroscopy (1H-MRS). Twelve patients with FM underwent sham tDCS over the left motor cortex (anode placement) and contralateral supraorbital cortex (cathode placement) for 5 consecutive days, followed by a 7-day washout period and then active tDCS for 5 consecutive days. Clinical pain assessment and 1H-MRS testing were performed at baseline, the week following the sham tDCS trial, and the week following the active tDCS trial. Clinical pain scores decreased significantly between the baseline and active tDCS time points (P = 0.04). Levels of glutamate + glutamine (Glx) in the anterior cingulate were significantly lower at the post–active tDCS assessment compared with the post–sham tDCS assessment (P = 0.013), and the decrease in Glx levels in the thalami between these time points approached significance (P = 0.056). From baseline to the post–sham tDCS assessment, levels of N-acetylaspartate (NAA) in the posterior insula increased significantly (P = 0.015). There was a trend toward increased levels of γ-aminobutyric acid (GABA) in the anterior insula after active tDCS, compared with baseline (P = 0.064). Baseline anterior cingulate Glx levels correlated significantly with changes in pain score, both for the time period from baseline to sham tDCS (β1 = 1.31, P < 0.001) and for the time period from baseline to active tDCS (β1= 1.87, P < 0.001). The present findings suggest that GABA, Glx, and NAA play an important role in the pathophysiology of FM and its modulation by tDCS.

Research in the cognitive neuroscience field has shown that individuals with a stronger attention bias for negative information had higher depression risk, which may be the underlying pathogenesis of depression. This dysfunction of affect-biased attention also represents a decline in emotion regulation ability. Clinical studies have suggested that transcranial direct current stimulation (tDCS) treatment can improve the symptoms of depression, yet the neural mechanism behind this improvement is still veiled. This study aims to investigate the effects of tDCS on affect-biased attention. A sample of healthy participants received 20 min active (n = 22) or sham tDCS (n = 19) over the left dorsolateral prefrontal cortex (DLPFC) for 7 consecutive days. Electroencephalographic (EEG) signals were recorded while performing the rest task and emotional oddball task. The oddball task required response to pictures of the target (positive or negative) emotional facial stimuli and neglecting distracter (negative or positive) or standard (neutral) stimuli. Welch power spectrum estimation algorithm was applied to calculate frontal alpha asymmetry (FAA) in the rest task, and the overlapping averaging method was used to extract event-related potentials (ERP) components in the oddball task. Compared to sham tDCS, active tDCS caused an obvious increment in FAA in connection with emotion regulation (p < 0.05). Also, participants in the active tDCS group show greater P3 amplitudes following positive targets (p < 0.05) and greater N2 amplitudes following negative distracters (p < 0.05), reflecting emotion-related attention biases. These results offer valuable insights into the relationship between affect-biased attention and the effects of tDCS, which may be of assistance in exploring the neuropathological mechanism of depression and anxiety and new treatment strategies for tDCS.

Lateralized temporal order judgement in dyslexia