AH: ORCiD 0000-0002-0335-984X
YW: ORCiD 0000-0001-5903-9370

Abstract

We present here a work in progress, summarizing research from 2018 relevant to Tourette syndrome. This working draft aims towards a preprint that we plan to submit for publication around the end of 2018. The authors briefly summarize a few reports they consider most important or interesting. We welcome article suggestions and thoughtful feedback from readers, who can comment using the balloon icons that appear if you hover the mouse pointer over the upper right edge of the text on this page.

Introduction

This article is meant to disseminate recent scientific progress on Gilles de la Tourette Syndrome (TS). Through the end of the year, it will be a work in progress, maintained as a web page on the Authorea online authoring platform. Around the end of the year, we plan to submit it for publication as the annual update for the Tics collection on F1000Research.

Methods

We searched PubMed from time to time during 2018 using the search strategy “("Tic Disorders"[MeSH] OR Tourette NOT Tourette[AU]) AND 2018[PDAT] NOT 1950:2017[PDAT]”. On 06 July 2018 this search returned 91 citations. Colleagues also recommended articles, and we attended selected medical conferences. We selected material for this review subjectively, guided by our judgment of possible future impact on the field.

Results

Phenomenology and natural history

The EMTICS ONSET and COURSE studies: a plan for important research on development and course of tic disorders \citep{29982875}.

Epidemiology

Tics are 4-6 times more common in children with ADHD than in those without, and tics add to clinical problems and reduced quality of life \citep{29317441}.

 

Transient environmental effects on tic severity

Tic suppression

Sensory phenomena and premonitory urges

Other

Weingarden et al.  report that self-esteem is decreased in adults with TS and CTD (n=122) \cite{Weingarden_2018}. This, however, is less related to tics / tic severity but rather related to psychiatric comorbidities. When treating these patients, self-esteem was improved more by comprehensive Behavioral Intervention for Tics (CBIT) than by Psychoeducation and Supportive Therapy (PST), which seems plausible. It would be interesting to replicate the same study in children and adolescents.  A review also examines the concept of self-esteem in TS and CTD, drawing a similar conclusion, i.e. that poor self-esteem appears more strongly related to psychiatric comorbidities than to tic severity and, unsurprisingly, affects quality of life \cite{Silvestri2018}.
TS phenotypes were investigated in 174 children and adolescents in French University Clinic \cite{Cravedi2018}. Three clusters were identified. One of them corresponded to a tic-only phenotype ('pure' TS) whereas another cluster charged learning and intellectual disabilities, ASD, and ADHD. The third cluster corresponded to an ADHD profile with rather high intelligence and handwriting problems due to tics. Therapeutic  implications are discussed.
A case report that adds another variant of malignant TS in the form of closed head trauma due to head banging in a 15 year old, with important sequelae, underlining the need for rapid and agressive tic management in some patients \cite{Fasano2018}

Etiology

Genetics

\cite{Hirschtritt2018}

Epigenetics

Environmental risk factors

Pathophysiology

Animal models

"Aripiprazole selectively reduces motor tics in a young animal model for tourette's syndrome and comorbid attention deficit and hyperactivity disorder" \cite{29487562}.

Pathological studies

\ref{876427}

Electrophysiology

Neuroimaging studies

WM microstructure
\cite{Sigurdsson2018}
7T spectroscopy \cite{Mahone2018}

Pharmacological studies

"Dopaminergic Disturbances in Tourette Syndrome: An Integrative Account" \citep*{Maia_2018} 
D1 receptor antagonist ecopipam in children and adolescents (Gilbert D et al: Selective D1 receptor antagonism: clinical trial of a novel treatment for Tourette Syndrome. Mov Disord 2018 [in press]).

Clinical and neuropsychological studies

A research consortium in Germany has recently proposed that tics may correspond to altered perception-action binding \cite{Beste2018}. Here comes a first experimental demonstration in 35 adolescents with TS and 39 healthy controls using a Go/nogo task and subsequent EEG analysis, providing support for the idea that stimulus-action binding is stronger in patients with TS, and that "unbinding" may thus represent a useful therapeutic venue \cite{Petruo2018}.

Other

Inhibition in children with OCD and TS
\cite{Mancini2018}
Executive control in TS and tic reduction \cite{Yaniv2018}
 

Treatment

 

Psychological interventions

Group-based psychotherapeutic interventions for tics bear the promise of reduced costs and easier access to appropriate care. One recent paper has investigated the long term effects of this approach on tic severity, quality of life and school attendance in 28 children with TS 12 months after completing HRT training or education (a follow up to the 2016 study, \cite{Yates2016}), both showing positive effects in the long run but apparently without significant differences between both groups \cite{Dabrowski2018}
A scandinavian study investigated a combined ERP / HRT protocol comparing group with individual sessions (n=27 per group, n=54 total). The efficacy on decreasing tic severity was similar in both treatment arms \cite{Nissen2018}
Traditionally, ERP sessions (as compared to HRT / CBIT) were supposed to last for two hours, making them more difficult and expensive. In this study, session duration was shortened to one hour and shorter exposure was as effective, if not more, than the classic format \cite{van2018}.

Medication

A first direct comparison of pharmacotherapy with behavioral therapy in children and adolescents with TS / CTD  \cite{Rizzo2018}. Both approaches were effective in reducing tics and improve quality of life; however, only pharmacotherapy was effective in reducing OC symptoms. 

Neurosurgery

Efficacy and Safety of Deep Brain Stimulation in Tourette Syndrome: The International Tourette Syndrome Deep Brain Stimulation Public Database and Registry \citep{Martinez_Ramirez_2018}. This report summarizes information on 185 Tourette patients from 10 countries. Mean improvement in total YGTSS score was 40% at 6 months after vs. before surgery, and 45% at 12 months. The difference between stimulation sites (CM-Pf, anterior GPi, posterior GPi) was not statistically significant. About a third of patients had side effects, mostly related to stimulation not surgery.
\citet{Smeets2018} discuss ethical considerations regarding DBS in TS patients under the age of 18. \citet{Canaz2018} also offer their experience in two pediatric TS patients who underwent DBS.