The Use of Transcranial Direct Current Stimulation (tDCS) in Adults With Developmental Disabilities

Study Overview
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Brief Summary
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Aggressive behaviours are highly prevalent among people with developmental disabilities, both in community and inpatient or residential settings, with adverse consequences for the individuals involved and others. Some predictive factors, particularly impulsivity, are dynamic with neurobiological underpinnings, and as such amenable to change or neuromodulation using non-invasive brain stimulation techniques. With this in mind, we designed an experimental protocol to determine the efficacy of transcranial Direct Current Stimulation (tDCS) as a non-invasive brain stimulation technique to reduce impulsivity and aggression associated with developmental disability.

Detailed Description
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This study aims to assess the efficacy of anodal tDCS in modulating Rapid Response Impulsivity (RRI) and reducing incidents of aggression in people with developmental disabilities is residential or hospital settings. Using a single blind, parallel arms, randomized controlled trial design, adults (n=60) aged 18 to 65 with developmental disabilities, who have a history of impulsivity leading to aggression, will be randomised to receive either repetitive anodal or sham tDCS. Enrolled participants will receive either three treatment sessions of tDCS or sham tDCS. Behavioural and impulsivity will be measured before and immediately after treatment, one week, and one month after treatment end. Data will be analysed in SPSS using repeated measures ANOVA.

Official Title
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The Use of Transcranial Direct Current Stimulation (tDCS) to Reduce Impulsivity and Aggression in Adults With Developmental Disabilities: The tDCS-RIADD Randomized Controlled Trial Protocol

Conditions
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Aggression

Intervention / Treatment
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* Device: Transcranial Direct Current Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults aged 18-64 years Diagnosis of a developmental disability History of one or more incidents of aggression in the last month Consent to participate in the trial by the individual or their Substitute Decision Maker Exclusion Criteria: History of epilepsy or seizures History of acquired brain injury Having metal in the brain/skull, e.g. splinters, fragments or clips Having a cochlear implant Having an implanted neuro-stimulator (e.g. direct brain stimulation, epidural/subdural stimulation, vagal nerve stimulation) History of brain surgery of procedure History of severe adverse reaction to tDCS Having a cardiac pacemaker or intracardiac lines Current alcohol or drug misuse Having a sensitive scalp

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Active tDCS<br>Transcranial Direct Current Stimulation: Soterix tDCS kit will be used to deliver the stimulation using two sponge electrodes soaked in a saline solution. The stimulation montage will comprise of left anodal Dorsal Lateral Prefrontal cortex (DLPFC) stimulation. The anodal electrode will be placed over the area corresponding to the left DLPFC (F5 of the EEG10-20 international system) and the reference (cathodal) electrode over the right supraorbital ridge. The active stimulation condition will use a constant current of 2mA, delivered via gradual increase and decrease over 10 seconds at the onset and offset of stimulation (current ramps), respectively. The duration a single tDCS session will be 20 minutes. | Device: Transcranial Direct Current Stimulation<br>* non-invasive brain stimulator<br>|
| Sham Comparator: Sham tDCS<br>Sham Transcranial Direct Current Stimulation: Soterix tDCS kit will be used to deliver the sham stimulation using two sponge electrodes soaked in a saline solution. The sham stimulation montage will comprise of left anodal Dorsal Lateral Prefrontal cortex (DLPFC) stimulation for 10s only. The anodal electrode will be placed over the area corresponding to the left DLPFC (F5 of the EEG10-20 international system) and the reference (cathodal) electrode over the right supraorbital ridge. The sham tDCS is identical to the active tDCS except that the current will be delivered only in the first 10 seconds, after which the stimulation will cease but with the electrodes still in place throughout the session. The duration of each sham tDCS session will be 20 minutes. | Device: Transcranial Direct Current Stimulation<br>* non-invasive brain stimulator<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Aggression | To determine the effect of tDCS treatment on aggressive symptoms measured by The Modified Overt Aggression Scale (MOAS); Total weighted scores range from 0-40, with a higher score indicating more aggressive behavior. | change from baseline one week and one month after the third tDCS session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Maladaptive behaviors | Behavior Problems Inventory (BPI); The total frequency scores range from 0-120 and severity of self-injurious behaviour and aggression subscales from 18-54, with higher scores indicating higher frequency and severity | change from baseline one week and one month after the third tDCS session | 
| Intervention side effects | Tracking potential side effects of tDCS/sham treatments using tDCS adverse effects questionnaire. | Up to 72hrs after the first, second, and third active or sham tDCS treatments. | 
| Trait Impulsivity | Barratt Impulsiveness Scale-11 (BIS-11); The total scores range from 30 - 120, with higher scores indicating higher impulsivity. | Baseline | 
| Impulsivity | To determine the effects of tDCS treatment on symptoms of impulsivity measured by the Stop Signals Task (SST) | change from baseline and the same day after the third tDCS sessions | 
| Treatment Acceptability | Total scores on the tDCS Treatment Acceptability Questionnaire | Up to 72hrs after the third active or sham tDCS treatments. |