Effects of Multiple-Session Transcranial Direct Current Stimulation (tDCS) on Behavioral, Physiological, and Electrophysiological Measures With Adults With Autism Spectrum Disorder (ASD)

DEVICE

Anodal tDCS + Social Learning

Anodal tDCS lowers neuronal membrane potentials, leading to increased probability of depolarization from incoming stimuli.

BEHAVIORAL

Placebo Anodal tDCS + Social Learning

Social learning tasks are completed on a computer and consist of viewing video modeling of social interactions, facial emotion detection practice, and videos for emotion and empathy learning.

Measure of Emotional Distress - Anxiety

Time frame: Before and after each 5-day block of tDCS stimulation

Patient-Reported Outcomes Measurement Information System (PROMIS) Item Bank v. 1.0 - Emotional Distress - Anxiety (PEDA) A change in PEDA scores corresponds to a change in emotional distress and anxiety. Each question on the PEDA provides a 5-point scale where lower scores mean a better outcome.

Measure of Social Anxiety

Time frame: Before and after each 5-day block of tDCS stimulation

Liebowitz Social Anxiety Scale (LSAS) The LSAS assesses the range of social interaction and performance situations that individuals with social anxiety may fear and/or avoid. Each two-part question of the LSAS provides a 4-point scale where lower scores mean a better outcome.

Measure of Social Anxiety/Anxiety

Time frame: Before and after each 5-day block of tDCS stimulation

Vocal acoustic analysis measures changes in fundamental frequency (F0), which is an indicator of change in social anxiety/anxiety, where lower F0 means a better outcome.

Measure of Social Anxiety

Time frame: Before and after each 5-day block of tDCS stimulation

Heart-Rate Variability (HRV) A change in HRV is an indicator of change in the level of social anxiety, where higher HRV means a better outcome.

Measure of Social Impairment

Time frame: Before and after each 5-day block of tDCS stimulation

Social Responsiveness Scale - 2nd Edition (SRS-2) A self-report tool that quantifies social impairment and its severity associated with ASD. Lower SRS-2 scores mean a better outcome.

Measure of Empathy

Time frame: Before and after each 5-day block of tDCS stimulation

Empathy Quotient (EQ) A self-report measure that quantifies empathy. Higher EQ scores mean a better outcome.

Measure of Prosodic Alignment

Time frame: Before and after each 5-day block of tDCS stimulation

Vocal acoustic analysis measures the rate of prosodic alignment between speakers sharing in a conversation. Higher rates of prosodic alignment between speakers mean a better outcome.

Measure of Emotion Expression Entrainment

Time frame: Before and after each 5-day block of tDCS stimulation

Facial expression and gesture analysis measures the rate of emotion entrainment to others during conversation tasks. Increased rate of emotion entrainment means a better outcome.

Measure of Social Learning

Time frame: Before and after each 5-day block of tDCS stimulation

Electroencephalography (EEG) spectral power for alpha (8-12Hz) and theta (4-8Hz) oscillations measures changes in social learning. Reductions in power for alpha and theta mean a better outcome.

Measure of Quality of Life

Time frame: Before and after each 5-day block of tDCS stimulation

World Health Organization Quality of Life Questionnaire (WHOQOL) The WHOQOL measures quality of life in areas of social relationships, psychological and physical health, environment, and independence. Higher WHOQOL mean a better outcome.

What is a clinical trial?

A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.

Is it safe to participate?

Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.

Will I be compensated?

Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.

Will I receive a placebo instead of treatment?

When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.

Can I leave a trial if I change my mind?

Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.

How long does a clinical trial last?

Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.