Cumulative and Booster Effects of Multisession Prefrontal tDCS in Adolescents With ASD
Study Details
Study Description
Brief Summary
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, we aim to evaluate the therapeutic effects of tDCS on improving cognitive function in patients with ASD. Second, we aim to better understand the neural mechanisms underlying the neuro-enhancing effects of tDCS in patients with ASD. Third, we aim to assess the effectiveness of booster treatment cycles of tDCS for enhancing cognitive and social functions in individuals with ASD.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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N/A |
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Active-tDCS vs Sham-tDCS During the active- and sham-tDCS conditions, the participants will receive current with ramp up and ramp down mode for 10 seconds, eliciting a tingling sensation on the scalp that fades over seconds. Following that, the tasks will be initiated five minutes subsequent to the stimulation mode and terminated prior to its end for active-tDCS condition. Whereas, the sham condition with the same placement and intensity will only receive 30s initial stimulation and then discontinue. Throughout the active / sham-tDCS condition, participants are required to sit still and focus their attention on a "+" displayed on a computer monitor during the five-minute rest. After that, they will undergo active-tDCS (1mA, 20 min) to the left DLPFC or sham stimulation over 10 sessions in 2 weeks, while performing the executive function training tasks. |
Device: Active-tDCS
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.
Device: Sham-tDCS
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.
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| Other: Crossover trial Participants in the sham-tDCS group will receive 10-day active tDCS and assessments will be performed before and after the 10-tDCS session. |
Device: Active-tDCS
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.
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| Experimental: Booster effect All tDCS responders (>10% reduction in SRS scores) will enrol on a 6 months follow-up phase in which they will be randomized to receive either bimonthly 20-minute booster tDCS sessions, or bimonthly 20-minute booster sham tDCS sessions for 3 months, followed by monthly 20-minute booster tDCS, monthly 20-minute booster sham tDCS, for another 3 months, with a maximum of 9 (sham) tDCS booster sessions. |
Device: Active-tDCS
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.
Device: Sham-tDCS
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.
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Outcome Measures
Primary Outcome Measures
- Change in social responsiveness - Social Responsiveness Scale-2nd edition (SRS-2) [Phase 1 (RCT): First day of intervention, immediate, 2 weeks and 4 weeks after treatment (4 time points); Phase 2 (crossover): Before and after treatment (2 time points); Phase 3 (follow-up): Every 4 weeks during the 6-month follow-up (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 before and immediately after tDCS treatment.
Secondary Outcome Measures
- Clinical response in tDCS outcome [Phase 1 (RCT): First day of intervention, immediate, 2 weeks and 4 weeks after treatment (4 time points); Phase 2 (crossover): Before and after treatment (2 time points)]
Based on the tDCS outcome recorded immediately 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.
- Change in neuropsychological measures - CANTAB® cognitive tests [Phase 1 (RCT): First day of intervention, immediate, 2 weeks and 4 weeks after treatment (4 time points); Phase 2 (crossover): Before and after treatment (2 time points); Phase 3 (follow-up): Every 4 weeks during the 6-month follow-up (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.
Eligibility Criteria
Criteria
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.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | The Hong Kong Polytechnic University | Hung Hom | Kowloon | Hong Kong |
Sponsors and Collaborators
- The Hong Kong Polytechnic University
Investigators
- Principal Investigator: Yvonne Han, PhD, The Hong Kong Polytechnic University
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- HSEARS20220216004