Other treatments
A fascinating report from the University of Nottingham described a potential novel treatment for tics that uses the peripheral nervous system to induce changes in primary sensorimotor cortex \citep{32502412}. The radical new idea arose from observations associating movement inhibition with 8-14 Hz activity in motor cortex. The authors first showed that rhythmic 12 Hz peripheral stimulation of the median nerve evoked synchronous contralateral EEG activity over primary sensorimotor cortex, whereas arrhythmic stimulation at the same mean rate did not. As hypothesized, median nerve stimulation (MNS) at 12 Hz created small but statistically significant effects on initiation of voluntary movements. Importantly, this stimulation did not meaningfully impair concentration, suggesting that the effect did not operate through simple distraction. Next they tested 10 Hz MNS in 19 TS patients, and demonstrated using blinded video ratings a significant reduction in tic number and severity during 1-minute stimulation epochs vs 1-minute no-stimulation epochs. Videos accompanying the publication showed dramatic benefit during MNS in some subjects.
\citet{31668476a} report intriguing results from a controlled, crossover design, pilot study of real-time fMRI neurofeedback. Tics improved more with real than sham feedback, the improvement was clinically meaningful (3.8-point decline in YGTSS total tic score), and the effect size was 0.59. Surprisingly, however, the two treatment conditions did not differ in the putative mechanism of benefit, namely control over SMA activity. An accompanying commentary is also useful \citep{32498788}.
The role of the microbiome in the etiology and pathogenesis of various CNS disorders has attracted widespread interest over the past decade, with fecal transplantation being hailed as a potential treatment. Zhao et al. \citep{Zhao2020} report in an exploratory trial in children with TS that this approach resulted in a significant tic decrease (>25% on the YGTSS-TTS) in four out of five subjects during the 8 week trial period. However, there was no placebo group and larger, randomized trials are warranted.
Physical exercise is advocated as positive for a plethora of somatic and mental disorders these days, and TS is no exception. Jackson et al. propose that aerobic exercise training (kick boxing) decreased tic frequency in young people with TS (n=18, age 10-20 years), likely though enhancement of cognitive control \citep{Jackson2020}. Interestingly, tic frequency reduction was less in a Tai Chi group, in which cognitive control enhancement was not significantly altered compared to controls. Thus, the type of physical exercise is important, "aerobic" being the key word here \citep{Jackson2020}. In the same vein, but on an observational basis, Pringsheim et al. report that in 110 children with TS, less vigorous physical activity indeed correlated with tic severity. This negative correlation could also be found for light exposure and subjective sleep quality \citep{Pringsheim2021}.
Spanish researchers conducted an open trial of a gluten-free diet in 34 TS patients (mostly children) without celiac disease \citep{29735930}. After a year, in the 29 patients who did not withdraw due to dietary noncompliance, tics, OCD symptoms and quality of life were all improved substantially compared to baseline. Prospective data on a dietary intervention, as in this study, are greatly needed. However, this study design cannot exclude improvement due to expectation effects or regression to the mean, so a randomized, controlled trial is essential before we can justify adding dietary restrictions to treatment recommendations.
A survey of 90 respondents from 13 countries showed that online support communities offer valuable informational and emotional support to those living with tic disorders / TS and their families, especially in the light of local face-to-face support that is often lacking. However, some disadvantages also became apparent, such as he suggestible nature of tics and being reminded of the challenging nature of tic disorders. Also, some conflict arising within online communities were noted \citep{Perkins2020}.
Complementary and alternative medicine (CAM) blossoms in all of medicine, and here too, TS is no exception. A survey of 110 patients with TS showed that more than two thirds used one or more CAM therapies. The most popular were: stress management, herbal medicine, homeopathy and meditation. 93% reported a decrease in tic frequency and 46% considered CAM more efficient than medication \citep{Patel2020}. Patients reported they often did not mention CAM treatments to their treating physicians, placing the onus on clinicians to ask patients specifically about them. These results also support the crucial need for randomized, controlled trials of any intervention.