Median Nerve Stimulation for Tourette Syndrome and Chronic Tic Disorder

Tourette syndrome (TS) and chronic tic disorder (CTD) are neurodevelopmental disorders that impact approximately 1% of 5-18 year olds worldwide. Both TS and CTD are characterised by the presence of tics, which are repetitive, purposeless, movements or vocalisations of short duration which can occur many times throughout a day. Tics can have a significant negative impact on daily functioning and quality of life, hence, many seek out approaches to manage and reduce their tics and the urges people with TS or CTD often feel preceding them. The two main evidence-based approaches to treating tics are behavioural therapies and medication; both of which can be effective, but accessibility and waitlists are often an issue for behavioural therapies and side effects are common with medication use. Consequently, there is an urgent need for the development of alternative, safe and accessible treatments. This study aims to examine the effects of rhythmic pulses of electrical stimulation delivered to the wrist in treating tics in people with TS and CTD. In recent work, the investigators have shown that this type of electrical stimulation known as median nerve stimulation (MNS), can substantially reduce tics and related urges during stimulation. The investigators now want to extend this work to examine the effects of the stimulation on a higher number of people, compared to placebo and treatment as usual. The investigators will do this through assessment of symptom change using questionnaires, interviews and videos collection during four weeks of stimulation and two time points afterwards. The investigators have developed a new MNS device for this trial which is portable and easy to use. The primary hypothesis is that active rhythmic MNS will lead to a reduction in tic severity compared to a placebo condition. The secondary hypothesis is that MNS will also have a positive beneficial effect on urges, impairment, well-being and co-occurring Obsessive-Compulsive Disorder (OCD) symptoms compared to both sham stimulation and no stimulation.