Transcranial Direct Current Stimulation in Children with Autism Spectrum Disorder

Not Applicable

Not yet recruiting

• Conditions: Autism Spectrum Disorder (ASD); Transcranial Direct Current Stimulation (tDCS); Electroencephalography

• Registration Number: NCT06880159
• Lead Sponsor: The Hong Kong Polytechnic University

Brief Summary

Background: Transcranial Direct Current Stimulation (tDCS) is a form of non-invasive brain stimulation that has aroused increased interests in the past decade. Not only that it is transient with little side-effects, and can be well-tolerated by children, it is also affordable and readily accessible, making it an appealing treatment option for autism spectrum disorder (ASD).

Objective: (1) To assess the therapeutic effects of tDCS when combined with cognitive training for 10 consecutive weekdays on improving cognitive processing in children with ASD, relative to control group receiving sham-stimulation, and (2) to evaluate the associated neural mechanisms underlying the treatment effect of tDCS on children with ASD.

Methods: To assess the therapeutic effects of tDCS, 100 adolescents with ASD (age 8-12 years) will be randomly assigned to active- (n=50), or sham- (n=50) tDCS groups. Twenty-minute sessions of 1.5 mA tDCS stimulation to the left dorsolateral prefrontal cortex (DLPRC) in conjunction with cognitive training exercise will be provided on 10 consecutive weekdays. EEGs and neuropsychological tests will be administered before and immediate after the series of tDCS sessions.

Hypothesis: We hypothesize that children with ASD who are randomly assigned to receive a montage of prefrontal tDCS, with cathode (inhibitory) placed over left DLPFC and anode (excitatory) over right supraorbital region) will evidence greater improvement in executive function (primary outcome) than children with ASD who are randomly assigned to receive sham-tDCS.

In addition to testing the primary clinical outcome, stated above, in planned exploratory analyses, we will also examine the effects of tDCS on secondary outcome measures of cognitive function, including information processing speed, working memory, inhibitory control, and cognitive flexibility; and conduct exploratory mediation analyses to better understand the potential neurophysiological factors underlying the therapeutic effects of tDCS. This will include E/I ratio as exploratory mediator variables. As these secondary analyses are exploratory, we will report them as such in presentations and published papers, and we will not draw definitive conclusions from them. Rather, they will be used to better understand the potential impact of tDCS and the mechanisms underlying impact, and to inform future research.

Detailed Description

Not available

Study Timeline

• Status Verified: 2025-03
• Study First Submitted: 2025-03-11
• Study First Submitted QC: 2025-03-11
• Last Update Submitted: 2025-03-11
• Study First Posted: 2025-03-17
• Last Update Posted: 2025-03-17
• Study Start: 2025-07
• Primary Completion: 2028-06
• Study Completion: 2028-06

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

• being 8-12 years old
• diagnosed with ASD given by registered psychiatrists or clinical psychologists according to the Diagnostic and Statistical Manual of Mental Disorders-5th Edition (DSM-5) criteria of ASD
• IQ score above 60
• able to communicate in Chinese

Exclusion Criteria

• with severe motor dysfunctions
• history of other neurological and psychiatric disorders or head trauma

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Average standardised score of executive function tests	First day of intervention, 1 day after the last day of intervention (2 time points, up to 2 weeks)	The executive function of the children with ASD will be assessed using the Executive Composite score, which will be derived by summing the scores from the test battery of executive functions.; Simple-task processing speed will be evaluated using the CANTAB® 5-choice Reaction Time (RTI) task. Complex-task processing speed will be assessed using the computerized version of the Wisconsin Card Sorting Test (WCST). The mean reaction time is calculated for the trials giving a correct answer during WCST.; The reaction time measured from both tasks will be converted to standard scores and averaged to yield an executive composite score. Lower scores indicate poorer executive functioning.

Secondary Outcome Measures

Name	Time	Method
Change in CANTAB® cognitive test - Reaction Time (RTI)	First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)	RTI assesses motor and mental response speeds, reaction time, response accuracy and impulsivity. It consists of 30 trials with five potential targets and requires participants to make flexible responses as fast as possible to the target stimulus (shown in yellow). Specifically, movement and reaction time will be measured, where shorter duration reflects faster processing speed.
Change in CANTAB® cognitive test - Stop Signal Task (SST)	First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)	SST assesses the ability of inhibition control. The participant must respond to an arrow stimulus, by selecting one of two options, depending on the direction in which the arrow points. If an audio tone is present, the subject must withhold making that response (inhibition). Accuracy will be measured, where higher accuracy indicates better inhibition control.
Change in CANTAB® cognitive test - Multitasking Test (MTT)	First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)	MTT assesses the ability to resolve the interference of task-irrelevant information (stroop-like effect). The test displays an arrow which can appear on either the left or right side of the screen and can point to either the left or right side. In each trial, participants are presented with a cue that indicates which button to press according to two different rules. And the rules that participants have to follow may change from trial to trial in a randomized order. Participant's response latencies and error scores will be measured.
Change in CANTAB® cognitive test - Emotion Recognition Task (ERT)	First day of intervention,1 day after the last day of intervention (2 time points, up to 2 weeks)	ERT assesses ability to identify six basic emotions in facial expressions along a continuum of expression magnitude. The participants must select which emotion the facial image displayed 0.2s ago. Accuracy and its percentage, as well as response latencies will be measured.

Trial Locations

Locations (1)

The Hong Kong Polytechnic University; 🇭🇰 Hung Hom, Kowloon, Hong Kong