Therapeutic use of transcranial Alternating Current Stimulation for Obsessive Compulsive Disorder

Transcranial Alternating Current (tACS) is a form of non-invasive brain stimulation that delivers a weak electrical current that alternates at a specified frequency back and forth between electrodes. The tACS device in this trial (BrightStim) consists of a purpose-built handheld battery driven unit that delivers a current controlled voltage across an active and reference electrode. The active and reference electrodes are placed within commercially supplied saline soaked sponges. We have developed this device within our research team to produce the same effects as existing commercial devices but to be programmable in a manner that the research team can preset the conditions of use with no capacity for the patients to alter this or use the device in a manner outside of our research protocol. The device has been certified for use by the Alfred Hospital Bioengineering department. To date, there have been hundreds of studies of tACS, including in people with depression, conducted internationally. There have been no issues or problems reported in these studies over and above the known side effects. The BrightStim stimulator is currently being used in a clinical trial in the prevention of dementia in people with mild cognitive impairment (Alfred Health Ethics Approval 274/18, CTN number CT-2018- CTN-03008-1), and has been approved for a clinical trial in depression for young people by Monash Health Human Research Ethics Committee (RES-18-0000-521A). It has also been used in other experimental studies with healthy controls by our research group, and has also been demonstrated to produce effects equivalent to those produced with a widely commercially available device in a structured assessment. No safety or other issues/problems arose in any of these studies. Mode of action: polarisation of neurons via mild electrical current Dosage Regime: tACS will be applied targeting the medial prefrontal cortex with a placement of electrodes at the AFz and Iz positions. Individualised alpha frequency will be determined for participants that attend a pre-treatment EEG session and stimulation will occur at this frequency. For remote participants, stimulation frequency will be set at 10Hz. Stimulation intensity is set at 1.5mA. Treatment will occur over a six-week period in both the initial and cross over study phases. During the first three weeks, participants will receive treatment twice daily (intensive treatment phase), 5 days per week. In the subsequent three weeks, they will receive treatment once daily, three days per week (consolidation phase). After this, they will be followed up for three months to evaluate whether they have achieved treatment persistent benefits. After this time, in the open label crossover phase, participants who initially received sham will receive active tACS for 6 weeks with intensive (3 weeks) and consolidation phases (3 weeks) as before.