Effects of single-session cathodal transcranial direct current stimulation on tic symptoms in Tourette’s syndrome

• Published in: Experimental brain research Vol. 237; no. 11; pp. 2853 - 2863
• Main Authors: Dyke, Katherine, Jackson, Georgina M., Nixon, Elena, Jackson, Stephen R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2019; Springer; Springer Nature B.V
• Subjects: Adolescent; Adult; Biomedical and Life Sciences; Biomedicine; Cortex (motor); Evoked Potentials, Motor - physiology; Excitability; Female; Gilles de la Tourette syndrome; Humans; Magnetic fields; Male; Motor Cortex - physiopathology; Neurodevelopmental disorders; Neurology; Neurosciences; Research Article; Statistical analysis; Supplementary motor area; Tourette syndrome; Tourette Syndrome - physiopathology; Tourette Syndrome - therapy; Transcranial Direct Current Stimulation; Transcranial Magnetic Stimulation; Young Adult; United Kingdom; Transcranial magnetic stimulation (TMS); Supplementary motor area (SMA); Tourette’s syndrome (TS); Transcranial direct current stimulation (tDCS)
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-019-05637-5

Tourette syndrome is a neurodevelopmental disorder characterised by motor and phonic tics. For some, tics can be managed using medication and/or forms of behavioural therapy; however, adverse side effects and access to specialist resources can be barriers to treatment. In this sham-controlled brain stimulation study, we investigated the effects of transcranial direct current stimulation (tDCS) on the occurrence of tics and motor cortical excitability in individuals aged 16–33 years with Tourette syndrome. Changes in tics were measured using video recordings scored using the RUSH method (Goetz et al. in Mov Disord 14:502–506, 1999) and changes in cortical excitability were measured using single-pulse transcranial magnetic stimulation (spTMS) over the primary motor cortex (M1). Video recordings and spTMS measures were taken before and after 20 min of sham or active tDCS: during which cathodal current was delivered to an electrode placed above the supplementary motor area (SMA). Tic impairment scores, calculated from the video data, were significantly lower post-cathodal stimulation in comparison with post-sham stimulation; however, the interaction between time (pre/post) and stimulation (cathodal/sham) was not significant. There was no indication of a statistically significant change in M1 cortical excitability following SMA stimulation. This study presents tentative evidence that tDCS may be helpful in reducing tics for some individuals, and provides a foundation for larger scale explorations of the use of tDCS as a treatment for reducing tics.