ClinicalTrials.gg
RecruitingNCT06495684Updated Sep 11, 2026

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

An interventional study of Anodal tDCS + Social Learning and Placebo Anodal tDCS + Social Learning in Autism Spectrum Disorder and Autism or Autistic Traits, sponsored by University of New Mexico. Recruiting at 1 site in United States. Open to participants aged 18 Years to 35 Years. Per ClinicalTrials.gov, last updated 2026-09-11.

Primary conditionAutistic DisorderRegistry: Autism Spectrum DisorderReclassifiedWhy we changed it
Registry
Autism Spectrum Disorder — the first condition term the registry derived for this study.
ClinicalTrials.gg
Autistic Disorder
Why
  1. The study's listed conditions name Autistic Disorder, a narrower term within Autism Spectrum Disorder.
Confidence
High: the new condition is named in the study's own listed conditions. Of 351 hand-checked studies reclassified this way, 68% were exactly right and 84% in the right disease family; the registry's first term was right for 5% (measured 2026-10-21). How we classify →
Wrong?
Tell us the study's main condition →

Sponsored by University of New Mexico · Not applicable, Interventional, and Treatment

From the registry’s dates

  • Registered 3 months after the study started (first participant enrolled Mar 2024, registered Jun 2024).
  • Started Mar 2024; still recruiting 2 years 8 months later.
Phase
Not applicable
Study type
Interventional
Enrollment
20
Allocation
Randomized
Ages
18 Years to 35 Years
Sex
All
01

Study summary

The purpose of this clinical trial is to investigate the effects of multiple sessions of transcranial direct current stimulation (tDCS) delivered while participants complete tasks that target social learning with high functioning adults with ASD and/or high traits of ASD.

The main question it aims to answer is:

What are the effects of multiple sessions of active compared to sham tDCS, with tDCS simultaneously paired with social learning tasks, from employing a within-subject, cross-over randomized controlled trial design?

Participants will:

  • Complete a randomly assigned block of 5 sessions of active and a block of 5 sessions of sham tDCS, with a four-week break occurring between the two blocks.
  • Complete social learning tasks simultaneously during receipt of tDCS at each session (whether receiving active or sham tDCS).
  • Complete behavioral, physiological, and electrophysiological testing before and after each block of active or sham tDCS.
  • Complete a social validity questionnaire after completion of the study.
Read the detailed description

Our long-term goal is to develop safe and effective treatments to reduce negative symptoms of social communication impairments to improve overall quality of life. Our central hypotheses are (1) active, anodal tDCS over the right temporoparietal junction (rTPJ) paired with social learning activities will result in improved performance on behavioral and physiological measures, when compared to sham stimulation, (2) these improvements in performance will be correlated with changes in electrophysiological measures that contribute to successful participant social alignment after receipt of anodal tDCS, such as reductions in spectral alpha power (8-12Hz), which has been robustly associated with accurate internal modeling of sensorimotor activity during action comprehension and speech perception, and (3) improvements in performance on social measures will be accompanied by power reductions in theta oscillations (4-8Hz), which arise from prefrontal cortices and support context-specific cognitive control.

Specific Aim 1: Determine the effects of multiple sessions of active compared to sham tDCS. This aim will employ a within-subject, cross-over randomized controlled trial (RCT) design to explore the effects of 5 sessions of active vs. 5 sessions of sham tDCS on behavioral, physiological, and electrophysiological measures with autistic adults or adults with high traits of autism.

Objective 1: The development of improved stimulation protocols

While even a single session of tDCS has been shown to improve performance on social measures with adults diagnosed with autism spectrum disorder (ASD), recent work with children with ASD has shown that increasing the number of sessions from one to even five produces positive effects that are retained for up to one year, even when tDCS was not paired with a task. Importantly, it has been shown that pairing a task with the receipt of tDCS improves results when compared to delivering tDCS without a task. However, the majority of literature on the use of tDCS with adults with ASD has been restricted to studies examining a low number of sessions and/or tDCS paired with no task or tasks that are unrelated to treating the core diagnostic social impairments of ASD. This reinforces the need for research examining multiple sessions of tDCS paired with social interventions that are relevant to core diagnostic social impairments in autistic adults or adults with high traits of autism.

Objective 2: The improvement of social communication and social alignment in autistic adults or adults with high traits of autism

Successful social communication is a complex social process that not only requires the expression and reception of verbal speech, but also the modification and coordination of many behaviors to achieve social alignment. Social alignment is a mostly unconscious phenomenon in which people become more similar to a conversation partner by adjusting communication features such as vocal speech prosody (patterns of voice stress or intonation), facial expressions, and gestures.It is also suggested that social alignment reduces the burden placed on the cognitive system, thus making social interactions easier, and possibly less anxiety filled. Autistic individuals have significantly lower social alignment when compared to their neurotypical peers.

Of great interest is also capitalizing on the rTPJ's role in social alignment because of the rTPJ's participation in using sensory information (including visual and auditory) to evaluate self against others and in mediating embodied processes relevant to perspective taking (such as facial expression and gesture). Consequently, the proposed project has significance in its approach for investigating tDCS applied over the rTPJ that is paired with social learning to target processes of social communication and social alignment in autistic adults or adults with high traits of autism.

02

Conditions studied

  • Autism Spectrum Disorder
  • Autism or Autistic Traits

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03

In context

Autistic Disorder Reclassified

1,030 studies on the registry are indexed under Autistic Disorder; 266 are open to participants now.

This study's planned enrollment of 20 is below the median of 49 across 811 interventional studies indexed under Autistic Disorder.

Browse Autistic Disorder studies →

Lead sponsor

University of New Mexico is the lead sponsor of 313 studies on the registry; 29 are open to participants now.

Of its 25 completed or terminated interventional studies of FDA-regulated products, 23 (92%) have results posted.

Compared within Autistic Disorder, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Autism Spectrum Disorder. The counts are of registry records indexed under each term, refreshed daily. How we classify →

04

Who can participate

Ages eligible
18 Years to 35 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Age 18-35 years
  2. Proficient in English
  3. Classification of autism or autism spectrum disorder on Autism Diagnostic Observation Scale, 2nd Edition (ADOS-2) or score of >= 17 on Autism Quotient (AQ)
  4. Good or corrected vision and hearing
  5. Right-handed based on the Edinburgh Handedness Inventory
  6. Score of >= 85 on Shipley-2

Exclusion criteria

Exclusion Criteria

  1. No known loss of consciousness for > 5 minutes
  2. No immediate biological family members with a history of epilepsy or seizure disorder
  3. No major medical needs (e.g., neurological disorders such as a seizure disorder; long-term illness)
  4. No surgically implanted metal above the neck (example: metal pins or plates, cochlear implants, aneurysm clips, brain electrodes)
  5. No hospitalization for depression, anxiety, or substance abuse in the past 12 months
  6. No individuals who are currently pregnant
  7. No pacemakers
  8. No history of neurological disorders such as stroke, multiple sclerosis, bipolar disorder, encephalitis, epilepsy, seizure disorder, or amyotrophic lateral sclerosis
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Double (Participant, Investigator)
Enrollment
20 participants (estimated)

Study arms

  • Experimental
    Anodal tDCS + Social Learning

    In this arm, participants will undergo 5 sessions of 30 minutes anodal tDCS combined with social learning tasks on consecutive weekdays.

    Device: Anodal tDCS + Social Learning

  • Sham comparator
    Placebo anodal tDCS + Social Learning

    In this arm, participants will undergo 5 sessions of 30 minutes placebo anodal tDCS combined with social learning tasks on consecutive weekdays.

    Behavioral: Placebo Anodal tDCS + Social Learning

Interventions

  • DeviceAnodal tDCS + Social Learning

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

  • BehavioralPlacebo 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.

06

What researchers measure

Primary outcomes

  1. Measure of Emotional Distress - Anxiety

    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.

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

  2. Measure of Social Anxiety

    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.

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

  3. Measure of Social Anxiety/Anxiety

    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.

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

  4. Measure of Social Anxiety

    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.

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

  5. Measure of Social Impairment

    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.

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

  6. Measure of Empathy

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

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

  7. Measure of Prosodic Alignment

    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.

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

  8. Measure of Emotion Expression Entrainment

    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.

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

  9. Measure of Social Learning

    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.

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

  10. Measure of Quality of Life

    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.

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

07

Study locations

1 of 1 sites recruiting
08

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Started Mar 2024 (actual). Primary completion is estimated for Oct 2026, 31 months after the start.

Of 354 non-industry interventional studies with no phase under Autistic Disorder, half reached primary completion within 26 months of starting (the median), counting those still running; a quarter within 14 and three quarters within 52. This study's planned 31 months is above that.

Counting every sponsor, half of 366 studies reached it within 26 months; a quarter within 13 and three quarters within 52.

How these figures are worked out, and which studies are left out of them.

Registered
Jun 25, 2024
First posted
Jul 11, 2024
StartActual
Mar 12, 2024
Primary completionEst.
Oct 30, 2026
CompletionEst.
Oct 30, 2027
Last update
Sep 11, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Sep 11, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
09

Registry details

Key details

Study ID
NCT06495684
Responsible party
Sponsor
First posted
Jul 11, 2024
Start date
Mar 12, 2024
Primary completion
Oct 30, 2026 (estimated)
Completion
Oct 30, 2027 (estimated)
Last update
Sep 11, 2026

Study contacts

Joan Esse Wilson, Ph.D.
Contact
joanwilson@unm.edu
575-646-4313
Bill Shuttleworth, Ph.D.
study director · University of New Mexico

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
Yes
View the source record on ClinicalTrials.gov ↗

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