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NCT Number: NCT06272669

Cumulative and Booster Effects of Multisession Prefrontal tDCS in ASD Adolescents

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by disturbances in communication, poor social skills, and aberrant behavior. To date, ASD has no known cure, and the disorder remains a highly disabling condition. Recently, transcranial direct-current stimulation (tDCS), a non-invasive brain stimulation technique, has shown great promise as a potentially effective and cost-effective tool for reducing the core symptoms in patients with autism, such as anxiety, aggression, impulsivity, and inattention. Although the preliminary findings in patients with ASD are encouraging, it remains to be determined whether this experimental data can translate into benefits in real life. Further studies are needed to determine the factors that can lengthen the therapeutic effects or cognitive benefits of tDCS, and to determine possible risk factors associated with relapse in patients with ASD. Booster sessions of tDCS is an important component of treatment planning and prognosis and may promote better outcomes to control for resurgence of symptoms. This study has three aims. First, the investigators aim to evaluate the therapeutic effects of tDCS on improving cognitive function in patients with ASD. Second, the investigators aim to better understand the neural mechanisms underlying the neuro-enhancing effects of tDCS in patients with ASD. Third, the investigators aim to assess the effectiveness of booster treatment cycles of tDCS for enhancing cognitive and social functions in individuals with ASD.

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Key information

Conditions

Transcranial Direct Current Stimulation Autism Spectrum Disorder Autistic Spectrum Disorder Child Development Disorders, Pervasive Electroencephalography Mental Disorders Neurodevelopmental Disorders

Age range

12 year–21 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The Hong Kong Polytechnic University

Hung Hom, Kowloon, Hong Kong

Location status: Recruiting

Location contact

Yvonne Han, PhD

CONTACT

[email protected]

+852 27667578

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Individuals who are confirmed by a clinical psychologist based on the Diagnostic and Statistical Manual of Mental Disorders-5th Ed (DSM-V) criteria of Autism spectrum disorder and structured interview with their parents or primary caregivers on their developmental history using the Autism Diagnostic Interview-Revised (ADI-R).

Exclusion criteria

  • Individuals without a confirmed diagnosis from the clinical psychologist, with a history of other neurological and psychiatric disorders and head trauma, or on psychiatric medication will be excluded from the study.

Treatment and study plan

Active-tDCS

Device

For active-tDCS condition, participants will receive stimulation on the dorsolateral prefrontal cortex with ramp up and ramp down mode for 10 seconds, eliciting a tingling sensation on the scalp that fades over seconds. Following that, a twenty-minute executive functional training task will be initiated five minutes subsequent to the stimulation mode, and the stimulation will be terminated when the training task ends.

sham-tDCS

Device

For sham-tDCS condition, participants will receive initial stimulation with ramp up and ramp down mode for 30 seconds, eliciting a tingling sensation on the scalp then it will be discontinued. Participants will also receive the twenty-minute executive functional training task five minutes subsequent to the stimulation mode.

Primary outcomes

  1. Change in social responsiveness - Social Responsiveness Scale-2nd edition (SRS-2)

    Time frame: Phase 1 (RCT): Week 0, week 2, week 4, and week 6 of the study (4 time points); Phase 2 (crossover): Week 0 and week 2 (2 time points); Phase 3 (follow-up): Week 6, 10, 14, 18, 22, 26 (6 time points)

    SRS-2 is a sensitive measure of social functioning in children that detects even subtle symptoms that are highly related to ASD. It uses a four-point scale and focuses on different aspects of socialization. The total score reflects the clinical effectiveness of tDCS, and higher scores indicate greater symptom severity. It has been shown that SRS-2 is sensitive to detect changes in social communication improvement related to improved cognitive functioning after treatment. SRS-2 assessments will be conducted 1 day before and 1 day after tDCS treatment.

Secondary outcomes

  1. Clinical response in tDCS outcome

    Time frame: Phase 1 (RCT): Week 0, week 2, week 4, and week 6 of the study (4 time points); Phase 2 (crossover): Week 0 and week 2 (2 time points)

    Based on the tDCS outcome recorded 1 day after tDCS treatment, participants will be categorized into responders and non-responders based on the percentage of change in the total SRS score. Participants who show reductions of at least 10% in total SRS scores as compared to baseline scores will be considered responders. This percentage reduction benchmark was set with reference to the minimal clinically important difference (MCID) and calculated using the standard error measurement method from an ASD sample in a previous randomized controlled trial.

  2. Change in neuropsychological measures - CANTAB® cognitive tests

    Time frame: Phase 1 (RCT): Week 0, week 2, week 4, and week 6 of the study (4 time points); Phase 2 (crossover): Week 0 and week 2 (2 time points); Phase 3 (follow-up): Week 6, 10, 14, 18, 22, 26 (6 time points)

    Cambridge Neuropsychological Test Automated Battery (CANTAB®) includes computerized tests that are correlated to neural networks and have demonstrated high sensitivity in detecting changes in neuropsychological performance. The tests in this battery-the Reaction Time (RTI), Spatial Working Memory (SWM), and Multitasking Tests (MTT)-are well validated and are highly sensitive to the core domains impaired in patients with ASD, including to response/reaction time, working memory, attention, inhibition, and cognitive flexibility.

Study contacts

Contact information is provided by the study sponsor or research team.

Yvonne Han, PhD

CONTACT

[email protected]

+852 2766 7578

Sponsors and collaborators

Lead sponsor

The Hong Kong Polytechnic University

Other

Registry information

Official study title

Cumulative and Booster Effects of Multisession Prefrontal tDCS on Cognitive and Social Impairments in Adolescents With Autism Spectrum Disorder

Important dates

Study start
2022
Primary completion
2026
Study completion
2026
First posted
Feb 22, 2024
Registry last updated
Nov 21, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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