Tourette syndrome research highlights from 2016

Kevin J. Black, M.D. (1,3-5)* (ORCiD 0000-0002-6921-9567)
Cheryl A. Richards, Ph.D. (1,2)
Departments of (1) Psychiatry, (2) Medicine, (3) Neurology, (4) Radiology, and (5) Neuroscience, Washington University School of Medicine, St. Louis, Missouri, USA

* Address correspondence to Dr. Black at Campus Box 8134, 660 S. Euclid Ave., St. Louis, Missouri, USA or kevin@WUSTL.edu.

Copyright © 2016-2017, the authors.

Abstract

We present here a work in progress, summarizing research from 2016 relevant to Tourette syndrome. This working draft aims towards a preprint that we plan to submit for publication around 12/31/2016. The authors briefly summarize a few reports they consider most important or interesting, and provide links to others.

We welcome article suggestions and thoughtful feedback from readers, who can comment using the text balloon icons that appear if you hover the mouse pointer over the upper right edge of each section of the article.

Introduction

This article is meant to disseminate scientific progress on Gilles de la Tourette Syndrome (TS) during 2016. Draft versions originally appeared on the Authorea online authoring platform.

Methods

We searched PubMed from time to time during 2016 using the search strategy “("Tic Disorders"[MeSH] OR Tourette NOT Tourette[AU]) AND 2016[PDAT] NOT 1950:2015[PDAT]”. On 06 Jan 2017 this search returned 186 citations, none of which had first appeared in 2017. 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

Environmental effects on tics are typical in TS; they are included in the Diagnostic Confidence Index (Robertson 1999) and have been demonstrated under careful laboratory conditions (Woods 2009). However, typical patient and clinician understanding of TS depends largely on self-report and parental symptom report. Barnea and colleagues tested this assumption by recording video from 41 children age 6-18 with TS in each of 5 common, daily-life situations (Barnea 2016). Their findings were illuminating: First, tic frequency correlated only moderately with reports of children or parents. Tic frequency was much higher when children were watching TV and much lower when alone, compared to doing homework, receiving attention when ticcing, or talking to a stranger. Self-reported premonitory urges were stronger when patients were more aware of (video recorded) tics. These findings differ from typical reports to clinicians, and suggest that developing methods for tic monitoring outside the office may be important to improve reliability and validity in TS research.

Premonitory urges are usually reported later in life than tics are observed. However, a large case series (N > 1000) from one clinic suggests that “premonitory urges (PU) … were found to be highly associated with ‘not just right experiences’ and to emerge much earlier than previously thought alongside with the ability to suppress tics (PU in >60% and suppressibility in >75% at age 8–10 years)” (Sambrani 2016). These authors also felt that their data supported the idea that self-injurious behavior “belongs to the coprophenomena spectrum and hence should be conceptualized as a complex tic rather than a compulsion.”

Counterintuitively, in one experimental design, tics became less frequent during a short-term psychosocial stressor (Buse 2016).

Self-reported depressive symptoms were as common and severe in TS as in patients with major depression, though people with TS endorsed irritability more frequently (Piedad 2016).

Tic suppression

(Brandt 2016) performed a clever experiment to investigate the timing of urges in relation to tics, compulsions and blinks. Another group examined tics and urge to tic at 10- to 15-second intervals in 12 patients with moderate to severe TS; different patients had quite different relationships between urge and tic timing when examined at this temporal scale (Brabson 2016).

Title Comment
(Wylie 2016) Motor and vocal inhibition (action stopping) in young adults with TS.
(Drury 2016) "Self-reported emotion regulation in adults with Tourette's syndrome"

Sensory phenomena

Title Comment
(Beste 2016) "Altered perceptual binding in Gilles de la Tourette syndrome"

Other

Title Comment
(Brown 2016) Influence of Musical Engagement on Symptoms of Tourette’s Disorder
(Yang 2016) "The preva