Transcranial Direct Current Stimulation (tDCS) Augments the Effects of Gamified, Mobile Attention Bias Modification

Study Overview
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Brief Summary
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The present study tested whether transcranial direct current stimulation (tDCS) across the prefrontal cortex (PFC), versus sham stimulation, effectively augments the beneficial effects of a gamified attention bias modification training (ABMT) mobile app.

Detailed Description
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Anxiety-related attentional bias (AB) is the preferential processing of threat observed in clinical and sub-clinical anxiety. Attention bias modification training (ABMT) is a computerized cognitive training technique designed to systematically direct attention away from threat and ameliorate AB, but mixed and null findings have highlighted gaps in our understanding of mechanisms underlying ABMT and how to design the most effective delivery systems. One neuromodulation technique, transcranial direct current stimulation (tDCS) across the prefrontal cortex (PFC) may augment the effects of ABMT by strengthening top-down cognitive control processes, but the evidence base is limited and has not been generalized to current approaches in digital therapeutics, such as mobile applications. The present study tested whether tDCS across the PFC, versus sham stimulation, effectively augments the beneficial effects of a gamified ABMT mobile app. Thirty-eight adults (Mage = 23.92, SD = 4.75; 18 females) evidencing low-to-moderate anxiety symptoms were randomly assigned to active or sham tDCS for 30-minutes while receiving ABMT via a mobile app. Participants reported on potential moderators of ABMT, including life stress and trait anxiety. ECG was recorded during a subsequent stressor to generate respiratory sinus arrhythmia (RSA) suppression as a metric of stress resilience.

Official Title
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Transcranial Direct Current Stimulation (tDCS) Augments the Effects of Gamified, Mobile Attention Bias Modification

Conditions
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Anxiety, Stress

Intervention / Treatment
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* Behavioral: ABMT
* Other: Transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: mild - moderate anxiety Exclusion Criteria: psychotic disorder substance use disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Factorial Assignment
Interventional Model Description: All participants received active behavioral intervention combined with either active brain stimulation or sham stimulation control
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: tDCS Active<br>Transcranial direct current stimulation with ABMT | Behavioral: ABMT<br>* mobile attention bias modification training for anxiety, using the app Personal Zen<br>* Other names: Personal Zen;Other: Transcranial direct current stimulation<br>* Soterix 1X1 tDCS Limited Total Energy (LTE) Stimulator<br>* Other names: tDCS;|
| Sham Comparator: tDCS sham<br>Transcranial direct current sham stimulation with ABMT | Behavioral: ABMT<br>* mobile attention bias modification training for anxiety, using the app Personal Zen<br>* Other names: Personal Zen;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Self-reported negative mood symptoms | Self report using the Depression, Anxiety, Stress Scale (DASS); Higher scores mean more severe negative mood/worse outcomes (scores ranging from 0-42) | Day 1 | 
| Self-reported subjective state anxiety | Self report of state anxiety using the State-Trait Anxiety Inventory (STAI); Higher scores mean greater anxiety severity/worse outcomes (scores ranging from 20-80). | Day 1 | 
| Threat bias, or dsyregulated attention towards threat, measured via computer assay | Using the computerized, reaction time-based cognitive assessment task, the dot probe, biased attention towards or away from threat-relevant information will be assessed based on reaction-time based scoring procedures. Higher scores mean greater bias/worse outcomes | Day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Magnitude of respiratory sinus arrhythmia, or variability in heart rate due to respiration rate | Respiratory sinus arrhythmia (RSA), calculated using mobile electrocardiogram, will be assessed during the Trier Social Stress Task, a standardized behavioral assessment of stress. Higher scores mean greater contribution of respiratory rate to heart rate. | Day 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anxiety, stress