Neuromodulation of Executive Function in the ADHD Brain

Study Overview
=================
Brief Summary
-----------------
This study aims to determine the transient, modulatory effects of transcranial direct current stimulation (tDCS) on executive function and inhibitory control in patients with ADHD compared to healthy controls.

Detailed Description
-----------------
This study aims to determine the transient, modulatory effects of transcranial direct current stimulation (tDCS) on executive function and inhibitory control in patients with ADHD. Deficits in these cognitive functions are core to ADHD, and cause significant impairment and morbidity. The study will also include a cohort of healthy controls for comparison.

Official Title
-----------------
Neuromodulation of Executive Function in the ADHD Brain

Conditions
-----------------
Attention Deficit Hyperactivity Disorder

Intervention / Treatment
-----------------
* Device: Transcranial Direct Current Stimulation


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria Male and female subjects 18-66 years of age Healthy volunteers or volunteers with a diagnosis of ADHD in adulthood, meeting the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) [American Psychiatric Association, 2013] criteria, including at least 5 moderate inattentive or impulsive-hyperactive symptoms, and onset of two symptoms of inattentive or of impulsive/hyperactive traits by the age of 12. Patient will be either off stimulant medications or, if undergoing treatment with stimulants, will be asked to discontinue two days prior to the experiment, under physician-guided protocol, and allowed to resume afterwards. Subjects may resume stimulant use between the two study visits so long as they discontinue use two days prior to the second study visit. If fatigue is problematic in subjects discontinuing medication, they will be allowed to continue with the study if they are able to follow the suggested taper plan (50% of the dose day one, 25% dose day 2, stop day of visit (day 3)). English-speaking Exclusion Criteria Current or past history of clinically unstable psychiatric conditions such as suicidal or homicidal behavior or psychotic disorders. Pregnant or nursing females. Inability to participate in testing procedures Contraindication to tDCS: history or epilepsy, metallic implants in the head and neck, brain stimulators, vagus nerve stimulators, VP shunt, pacemakers, pregnancy. Additional exclusion criteria for healthy controls: Diagnosis of psychiatric of neurological disorder Ongoing treatment with any psychotropic medications.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 66 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: ADHD<br>Patients with ADHD. | Device: Transcranial Direct Current Stimulation<br>* In tDCS, electrodes are applied on the scalp to transmit direct current at low current amplitudes.<br>|
| Other: Healthy Control<br>Volunteers without Neuropsychiatric Disorders. | Device: Transcranial Direct Current Stimulation<br>* In tDCS, electrodes are applied on the scalp to transmit direct current at low current amplitudes.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Accuracy and Reaction Time in Attention and Working Memory | N-Back Task | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 
| Change in Accuracy and Reaction Time in Attention and Working Memory | Flanker Task | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 
| Change in Accuracy and Reaction Time in Attention and Working Memory | Multi-Source Interference with International Affective Picture System Task | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 
| Change in Accuracy and Reaction Time in Inhibition/Decision Making | Delayed Discounting | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 
| Change in Accuracy and Reaction Time in Inhibition/Decision Making | Stop Signal Task | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 
| Change in Accuracy and Reaction Time in Inhibition/Decision Making | Cambridge Gambling Task | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amplitude of Encephalogram (EEG) Event Related Potentials | Measure of amplitude related to stimulus | Change Before and After Stimulation on Each of the Three Visits, Average 2-6 Weeks | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Executive Function