Efficacy of Transcranial Electrical Stimulation (tES) on Emotion Processing

Study Overview
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Brief Summary
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The aim of this study is to assess the efficacy of transcranial Electrical Stimulation (tES) on emotion processing of healthy participants. Meanwhile, the investigators evaluate the effect of tES on electroencephalography (EEG) of both resting and task-related signal. The hypothesis of this study is that tES can improve the cognitive function of emotion by modulating brain activity.

Detailed Description
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This is a randomized, single-blind, sham-controlled study using transcranial Electrical Stimulation (tES) for 7-day treatment. Participants were randomly assigned to transcranial alternating current stimulation (tACS) group, transcranial direct current stimulation (tDCS) group or sham-control group. Active tES comprised 20 min sessions of 1.5 mA peak-to-peak current delivered over the dorsolateral prefrontal cortex, for 7 consecutive days. Sham group was administered similarly, but with current turned off after 30s. Apart from studying the effects of tES on physiology signals, subjective scale assessments and behavioral data are performed before and after the treatment.

Official Title
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Efficacy of Transcranial Electrical Stimulation (tES) of Dorsolateral- Prefrontal Cortex on Emotion Processing: A Randomized, Single-blind, Sham-controlled Trial

Conditions
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Healthy

Intervention / Treatment
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* Device: Transcranial alternating current stimulation (tACS) -active
* Device: Transcranial direct current stimulation (tDCS)-active
* Device: Transcranial electrical stimulation (TES)-sham


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age between 18 and 35 years with normal or corrected to normal vision participant or guardian need to sign informed consent Exclusion Criteria: reported neurological or psychiatric disorders history of any form of transcranial electrical stimulation experience use of mood stabilizer history of substance abuse or dependence severe somatic diseases that might interfere with regular antidepressant treatment including conditions such as kidney and liver failure, uncontrolled hypertension, cardiovascular, cerebrovascular and pulmonary disease, thyroid disease, diabetes, epilepsy and asthma use of anti-inflammatory medication for longer than 7 days in the last two months preceding the trial use of immunosuppressive medication such as oral steroid hormones women in pregnancy or lactation period

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: tACS group<br>Participants receive 20 min sessions of 1.5 mA alternating current delivered over the dorsolateral prefrontal cortex, for 7 consecutive days. | Device: Transcranial alternating current stimulation (tACS) -active<br>* Transcranial alternating current stimulation (tACS) is a non-invasive neuromodulation technique of the brain with an AC micro-electrical stimulator, two rubber electrodes in saline-soaked sponges, and a control software to set the output of the stimulation type. Participants receive 20 min sessions of 1.5 mA alternating current delivered over the dorsolateral prefrontal cortex, for 7 consecutive days.<br>* Other names: tACS active;|
| Experimental: tDCS group<br>Participants receive 20 min sessions of 1.5 mA direct current delivered over the dorsolateral prefrontal cortex, for 7 consecutive days. | Device: Transcranial direct current stimulation (tDCS)-active<br>* Transcranial direct current stimulation (tDCS) is a non- invasive neuromodulation technique of the brain with a DC micro-electrical stimulator, two rubber electrodes in saline-soaked sponges, and a control software to set the output of the stimulation type. Participants receive 20 min sessions of 1.5 mA direct current delivered over the dorsolateral prefrontal cortex, for 7 consecutive days.<br>* Other names: tDCS active;|
| Sham Comparator: Sham group<br>Participants receive sham stimulation that administered similarly, but with current continued less than 30s. | Device: Transcranial electrical stimulation (TES)-sham<br>* Transcranial electrical stimulation (TES) is a non-invasive neuromodulation technique of the brain with micro-electrical stimulator, two rubber electrodes in saline-soaked sponges, and a control software to set the output of the stimulation type. Participants receive sham stimulation over the dorsolateral prefrontal cortex, with current turned off after 30 second. The session last 20 min for 7 consecutive days.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The change of event-related potentials (ERPs) before and after stimulation. | The aim is to explore whether tES have a regulation effect on emotion processing of dynamic course. In the task, participants need to concentrate on the emotional picture with positive, negative and neutral faces. Then, different ERP components elicited by positive, negative and neutral faces using the signals recorded during facial emotion identification task. The investigators will analyze the ERP components change before and after stimulation to access tES effect on emotion processing. | Day1, Day7 | 
| The change of resting EEG power and lateralization index before and after stimulation. | The aim is to explore whether tES have a regulation effect at-risk of frequency domain. In the resting task, 8 mins resting EEG will be recorded. During recording, participants need to remain still and relaxed with their eyes open (O) and closed (C) in two alternating orders. In order to access tES effect on resting EEG, spectral analysis will be executed after the experiment. Analysis in frequency domain also contributed to expound the brain mechanism related cerebral cortex in emotion processing. In specific, EEG power of delta, theta, alpha, beta and gamma band would be calculated after recording. Besides, the EEG lateralization index also be analyzed between left and right brain. | Day1, Day7 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The change of scores in subjective scale measurement of State-Trait Anxiety Inventory from pre- to post-stimulation. | The main objective is to explore whether tES has an effect on subjective scale after stimulation. The scales include State-Trait Anxiety Inventory (STAI) and Difficulties in Emotion Regulation Scale (DERS). The STAI is a brief self-report assessment for trait anxiety and state measurement. The scales contain two 20-item pools of emotional state and personality trait, each item rated on a 4-point intensity scale ranging from not at all to very much so or from never to almost always respectively. DERS, on the other hand, is also a self-report measure function to assess the emotion regulation. | Day1, Day7 | 
| The change of scores in subjective scale measurement of Difficulties in Emotion Regulation Scale (DERS) from pre- to post-stimulation. | The main objective is to explore whether tES has an effect on subjective scale after stimulation. Difficulties in Emotion Regulation Scale (DERS), which is also a self-report measure function to assess the emotion regulation. | Day1, Day7 | 
| The change of behavioral data from pre- to post-stimulation. | The aim is to explore whether tES have a regulation effect on emotion identification task. During the task, participants need to respond as quickly as probable to emotional stimuli by pressing the space bar. Reaction time and accuracy from the facial emotion identification task pre- and post-stimulation would be recorded. After the experiment, the investigators will access the stimulation effect on their behavioral data change. | Day1, Day7 | 
| Adverse events from baseline to Day1. | The aim is to evaluate the adverse effects during the stimulation. | Day2, Day3, Day4, Day5, Day6, Day7 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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transcranial Electrical Stimulation (tES)