Patterns and Predictors of Tic Suppressibility in Youth With Tic Disorders

Description, Implementation, and Efficacy of the Comprehensive Behavioral Intervention for Tics as First-Line Treatment for Tourette and Other Tic Disorders

Objective: To provide an evidence-based review of the Comprehensive Behavioral Intervention for Tic (CBIT) disorders. Results: For close to a century, behavioral interventions for managing tics associated with Tourette and other tic disorders (TDs) were incorrectly considered ineffective and dangerous by the professional community, due, in large part, to unfounded fears that efforts to suppress tics would lead to a host of negative psychological, and even physical, outcomes (e.g., symptom substitution, tic rebound). Spurred by a growing body of research to the contrary, the Comprehensive Behavioral Treatment for Tics (CBIT) was developed to provide a tolerable and effective nonpharmacological treatment option, alone or in combination with medication, for youth and adults with tics associated with Tourette or other TDs. CBIT combines two evidence-based practices, habit reversal training (HRT) to address the urge-tic relationship and a functional intervention to identify and neutralize tic-related environmental factors. Based on positive findings from two large-scale randomized controlled trials that involved a total of 248 8-69-year olds with Tourette or chronic TD, CBIT has been designated as a first-line treatment, when available, for treating tics by the American Academy of Neurology and the European and Canadian medical academies. Conclusions: CBIT has demonstrated acute and durable efficacy when delivered alone or in combination with medication, in person, or via telehealth, and in the presence or absence of common comorbid conditions. Additional research is needed to develop and test treatment guidelines for the use of CBIT in combination with pharmacologic, neuromodulatory, and other intervention modalities.

Evidence-Based Behavior Therapy for Tourette Syndrome

This article provides an overview of evidence-based behavior therapy for Tourette syndrome (TS) in children, adolescents, and adults. First, this article describes evidence-based behavioral therapies for TS, examines their efficacy in randomized controlled trials, and identifies extant limitations. Second, based on the identified limitations, this article presents future directions for further research on behavioral therapies for TS. Finally, the article concludes with general recommendations for providing evidence-based behavior therapy for children, adolescents, and adults with TS.

Symptom Network Analysis in a Large Sample of Children and Adults with a Chronic Tic Disorder

BACKGROUND

Chronic tic disorders (CTD) are multifaceted disorders characterized by multiple motor and/or vocal tics. They are often associated with complex tics including echophenomena, paliphenomena, and coprophenomena as well as psychiatric comorbidities such as attention deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD).

OBJECTIVES

Our goal was to uncover the inter-relational structure of CTD and comorbid symptoms in children and adults and to understand changes in symptom structure across development.

METHODS

We used network and graph analyses to uncover the structure of association of symptoms in childhood/adolescence (n = 529) and adulthood (n = 503) and how this structure might change from childhood to adulthood, pinpointing core symptoms as a main target for interventions.

RESULTS

The analysis yielded core symptom networks in young and adult patients with CTD including complex tics and tic-related phenomena as well as touching people and objects. Core symptoms in childhood also included ADHD symptoms, whereas core symptoms in adults included symptoms of OCD instead. Interestingly, self-injurious behavior did not play a core role in the young CTD network, but became one of the central symptoms in adults with CDT. In addition, we found strong connections between complex motor and vocal tics as well as echolalia and echopraxia.

CONCLUSIONS

Next to other complex tics, echophenomena, paliphenomena, and coprophenomena can be regarded core symptoms of CTD. ADHD symptoms are closely related to CTD in childhood, whereas symptoms of OCD and self-injurious behavior are closely associated with CTD in adults. Our results suggest that a differentiation between motor and vocal tics is somewhat arbitrary.

Deep brain stimulation for Tourette's syndrome

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the efficacy and harm of deep brain stimulation for motor symptoms, with psychiatric and behavioural comorbidities, either individually or in combination, in adults and adolescents with Tourette's syndrome compared to placebo, sham intervention, or the best available behavioural and pharmacological treatment.

Addressing co-occurring conditions in behavioural therapy for tic disorders: a review and guideline

Co-occurring psychiatric conditions are very common in tic disorders and Tourette syndrome. These additional symptoms are often detrimental to quality of life and may impact upon the implementation and efficacy of evidence-based behavioural therapies (BT) for tics. Combining a review of the available literature, relevant theory, and expert clinical practice, we present a guideline for implementing behavioural and psychosocial interventions when common comorbidities are present. These include attention-deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), anxiety, disruptive behaviour, autism spectrum disorder (ASD) and depression. Practical recommendations are provided for assessment, formulation and management of specific and multiple comorbidities in BT for both children and adults. Despite comorbidities being common in tic disorders, few studies have comprehensively addressed how they may influence the efficacy or implementation of existing therapies or how such treatments may need to be modified or sequenced. We outline recommendations for future research, including randomised control trials of BT for those with specific or multiple comorbidities, as well as adequately powered sub-group analyses within larger scale trials or naturalistic study designs. Transdiagnostic models of psychiatric disorders and treatment, including modular cross-diagnostic therapies, which recognise the dimensionality of psychiatric disorders are also highlighted as an important focus in treatment development in tic disorders.

A Test of the Behavioral Model of Tic Disorders Using a Dynamical Systems Framework

Tic disorders are a class of neurodevelopmental disorders characterized by involuntary motor and/or vocal tics. It has been hypothesized that tics function to reduce aversive premonitory urges (i.e., negative reinforcement) and that suppression-based behavioral interventions such as habit reversal training (HRT) and exposure and response prevention (ERP) disrupt this process and facilitate urge reduction through habituation. However, previous findings regarding the negative reinforcement hypothesis and the effect of suppression on the urge-tic relationship have been inconsistent. The present study applied a dynamical systems framework and within-subject time-series autoregressive models to examine the temporal dynamics of urges and tics and assess whether their relationship changes over time. Eleven adults with tic disorders provided continuous urge ratings during separate conditions in which they were instructed to tic freely or to suppress tics. During the free-to-tic conditions, there was considerable heterogeneity across participants in whether and how the urge-tic relationship followed a pattern consistent with the automatic negative reinforcement hypothesis. Further, little evidence for within-session habituation was seen; tic suppression did not result in a reduction in premonitory urges for most participants. Analysis of broader urge change metrics did show significant disruption to the urge pattern during suppression, which has implications for the current biobehavioral model of tics.

Quantifying tics: Best practices and design considerations for video-based tic coding in research

Tic disorders (TD), including Tourette Syndrome, are characterized by involuntary, repetitive movements and/or vocalizations that can lead to persistent disability and impairment across the lifespan. Existing research demonstrates that video-based behavioral coding (VBBC) methods can be used to reliably quantify tics, enabling a more objective approach to tic measurement above and beyond standardly used TD questionnaires. VBBC is becoming more popular given the ease and ubiquity of obtaining patient videos. However, rigor and reproducibility of this work has been limited by undescribed and unstandardized approaches to using VBBC methods in TD research. The current paper describes "best practices" for VBBC in TD research, which have been tested and refined in our research over the past 15+ years, including considerations for data acquisition, coding implementation, interrater reliability demonstration, and methods reporting. We also address ethical considerations for researchers using this method.

Automated Quantification of Eye Tics Using Computer Vision and Deep Learning Techniques

BACKGROUND

Tourette syndrome (TS) tics are typically quantified using "paper and pencil" rating scales that are susceptible to factors that adversely impact validity. Video-based methods to more objectively quantify tics have been developed but are challenged by reliance on human raters and procedures that are resource intensive. Computer vision approaches that automate detection of atypical movements may be useful to apply to tic quantification.

OBJECTIVE

The current proof-of-concept study applied a computer vision approach to train a supervised deep learning algorithm to detect eye tics in video, the most common tic type in patients with TS.

METHODS

Videos (N = 54) of 11 adolescent patients with TS were rigorously coded by trained human raters to identify 1.5-second clips depicting "eye tic events" (N = 1775) and "non-tic events" (N = 3680). Clips were encoded into three-dimensional facial landmarks. Supervised deep learning was applied to processed data using random split and disjoint split regimens to simulate model validity under different conditions.

RESULTS

Area under receiver operating characteristic curve was 0.89 for the random split regimen, indicating high accuracy in the algorithm's ability to properly classify eye tic vs. non-eye tic movements. Area under receiver operating characteristic curve was 0.74 for the disjoint split regimen, suggesting that algorithm generalizability is more limited when trained on a small patient sample.

CONCLUSIONS

The algorithm was successful in detecting eye tics in unseen validation sets. Automated tic detection from video is a promising approach for tic quantification that may have future utility in TS screening, diagnostics, and treatment outcome measurement. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Functional connectivity during tic suppression predicts reductions in vocal tics following behavior therapy in children with Tourette syndrome

BACKGROUND

Comprehensive Behavioral Intervention for Tics (CBIT) is recommended as a first-line treatment for Tourette syndrome in children and adults. While there is strong evidence proving its efficacy, the mechanisms of reduction in tic severity during CBIT are still poorly understood. In a recent study, our group identified a functional brain network involved in tic suppression in children with TS. We reasoned that voluntary tic suppression and CBIT may share some mechanisms and thus we wanted to assess whether functional connectivity during tic suppression was associated with CBIT outcome.

METHODS

Thirty-two children with TS, aged 8 to 13 years old, participated in a randomized controlled trial of CBIT v. a treatment-as-usual control condition. EEG was recorded during tic suppression in all participants at baseline and endpoint. We used a source-reconstructed EEG connectivity pipeline to assess functional connectivity during tic suppression.

RESULTS

Functional connectivity during tic suppression did not change from baseline to endpoint. However, baseline tic suppression-related functional connectivity specifically predicted the decrease in vocal tic severity from baseline to endpoint in the CBIT group. Supplementary analyses revealed that the functional connectivity between the right superior frontal gyrus and the right angular gyrus was mainly driving this effect.

CONCLUSIONS

This study revealed that functional connectivity during tic suppression at baseline predicted reduction in vocal tic severity. These results suggest probable overlap between the mechanisms of voluntary tic suppression and those of behavior therapy for tics.

The CBIT + TMS trial: study protocol for a two-phase randomized controlled trial testing neuromodulation to augment behavior therapy for youth with chronic tics

BACKGROUND

Comprehensive Behavioral Intervention for Tics (CBIT) is a first-line treatment for tic disorders that aims to improve controllability over tics that an individual finds distressing or impairing. However, it is only effective for approximately half of patients. Supplementary motor area (SMA)-directed neurocircuitry plays a strong role in motor inhibition, and activity in this region is thought to contribute to tic expression. Targeted modulation of SMA using transcranial magnetic stimulation (TMS) may increase CBIT efficacy by improving patients' ability to implement tic controllability behaviors.

METHODS

The CBIT + TMS trial is a two-phase, milestone-driven early-stage randomized controlled trial. The trial will test whether augmenting CBIT with inhibitory, non-invasive stimulation of SMA with TMS modifies activity in SMA-mediated circuits and enhances tic controllability in youth ages 12-21 years with chronic tics. Phase 1 will directly compare two rTMS augmentation strategies (1 Hz rTMS vs. cTBS) vs. sham in N = 60 participants. Quantifiable, a priori "Go/No Go Criteria" guide the decision to proceed to phase 2 and the selection of the optimal TMS regimen. Phase 2 will compare the optimal regimen vs. sham and test the link between neural target engagement and clinical outcomes in a new sample of N = 60 participants.

DISCUSSION

This clinical trial is one of few to date testing TMS augmentation of therapy in a pediatric sample. The results will provide insight into whether TMS is a potentially viable strategy for enhancing CBIT efficacy and reveal potential neural and behavioral mechanisms of change.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04578912 . Registered on October 8, 2020.

Failures of Urge Suppression in Obsessive-Compulsive Disorder: Behavioral Modeling Using a Blink Suppression Task

Many individuals with obsessive-compulsive disorder (OCD) report sensory-based urges (e.g. 'not-just-right experiences') in addition to, or instead of, concrete fear-based obsessions. These sensations may be comparable to normative "urges-for-action" (UFA), such as the urge to blink. While research has identified altered functioning of brain regions related to UFA in OCD, little is known about behavioral patterns of urge suppression in the disorder. Using an urge-to-blink task as a model for sensory-based urges, this study compared failures of urge suppression between OCD patients and controls by measuring eyeblinks during 60-second blocks of instructed blink suppression. Cox shared frailty models estimated the hazard of first blinks during each 60-second block and recurrent blinks following each initial erroneous blink. OCD patients demonstrated a higher hazard of first and recurrent blinks compared to controls, suggesting greater difficulty resisting repetitive sensory-based urges. Within OCD, relationships between task outcomes and symptom severity were inconsistent. Findings provide support for a deficit in delaying initial urge-induced actions and terminating subsequent actions in OCD, which is not clearly related to clinical heterogeneity. Elucidating the nature of behavioral resistance to urges is relevant for informing conceptualizations of obsessive-compulsive psychopathology and optimizing treatment outcomes.

From urges to tics in children with Tourette syndrome: associations with supplementary motor area GABA and right motor cortex physiology

Tourette syndrome (TS) is a childhood-onset disorder in which tics are often preceded by premonitory sensory urges. More severe urges correlate with worse tics and can render behavioral therapies less effective. The supplementary motor area (SMA) is a prefrontal region believed to influence tic performance. To determine whether cortical physiological properties correlate with urges and tics, we evaluated, in 8-12-year-old right-handed TS children (n = 17), correlations of urge and tic severity scores and compared both to cortical excitability (CE) and short- and long-interval cortical inhibition (SICI and LICI) in both left and right M1. We also modeled these M1 transcranial magnetic stimulation measures with SMA gamma-amino butyric acid (GABA) levels in TS and typically developing control children (n = 16). Urge intensity correlated strongly with tic scores. More severe urges correlated with lower CE and less LICI in both right and left M1. Unexpectedly, in right M1, lower CE and less LICI correlated with less severe tics. We found that SMA GABA modulation of right, but not left, M1 CE and LICI differed in TS. We conclude that in young children with TS, lower right M1 CE and LICI, modulated by SMA GABA, may reflect compensatory mechanisms to diminish tics in response to premonitory urges.

Increased Alpha-Band Connectivity During Tic Suppression in Children With Tourette Syndrome Revealed by Source Electroencephalography Analyses

BACKGROUND

Tourette syndrome (TS) is a neurodevelopmental disorder involving chronic motor and phonic tics. Most individuals with TS can suppress their tics for at least a short period of time. Yet, the brain correlates of tic suppression are still poorly understood.

METHODS

In the current study, high-density electroencephalography was recorded during a resting-state and a tic suppression session in 72 children with TS. Functional connectivity between cortical regions was assessed in the alpha band (8-13 Hz) using an electroencephalography source connectivity method. Graph theory and network-based statistics were used to assess the global network topology and to identify brain regions showing increased connectivity during tic suppression.

RESULTS

Graph theoretical analyses revealed distinctive global network topology during tic suppression, relative to rest. Using network-based statistics, we found a subnetwork of increased connectivity during tic suppression (p < .001). That subnetwork encompassed many cortical areas, including the right superior frontal gyrus and the left precuneus, which are involved in the default mode network. We also found a condition-by-age interaction, suggesting age-mediated increases in connectivity during tic suppression.

CONCLUSIONS

These results suggest that children with TS suppress their tics through a brain circuit involving distributed cortical regions, many of which are part of the default mode network. Brain connectivity during tic suppression also increases as youths with TS mature. These results highlight a mechanism by which children with TS may control their tics, which could be relevant for future treatment studies.

Tourette syndrome: clinical features, pathophysiology, and treatment

Tourette syndrome is a chronic neurodevelopmental disorder characterised by motor and phonic tics that can substantially diminish the quality of life of affected individuals. Evaluating and treating Tourette syndrome is complex, in part due to the heterogeneity of symptoms and comorbidities between individuals. The underlying pathophysiology of Tourette syndrome is not fully understood, but recent research in the past 5 years has brought new insights into the genetic variations and the alterations in neurophysiology and brain networks contributing to its pathogenesis. Treatment options for Tourette syndrome are expanding with novel pharmacological therapies and increased use of deep brain stimulation for patients with symptoms that are refractory to pharmacological or behavioural treatments. Potential predictors of patient responses to therapies for Tourette syndrome, such as specific networks modulated during deep brain stimulation, can guide clinical decisions. Multicentre data sharing initiatives have enabled several advances in our understanding of the genetics and pathophysiology of Tourette syndrome and will be crucial for future large-scale research and in refining effective treatments.

Die Bedeutung des Vorgefühls bei Tic-Störungen

Zusammenfassung. Theoretischer Hintergrund: Die Funktion des Vorgefühls in der Pathogenese und Aufrechterhaltung von Tic-Störungen (TS) wird in den letzten Jahren verstärkt erforscht. Die mögliche funktionelle Bedeutung der Vorgefühle wird aber noch nicht ausreichend verstanden. Methode: Im vorliegenden Review wird der Kenntnisstand zu Vorgefühlen entlang eines integrativen funktionalen Störungsmodells zusammengefasst. Ergebnisse: Im Vergleich zum Jugendalter nehmen Tic-Symptome bei Tic-Störungen im Erwachsenenalter ab, während immer mehr Betroffene ein Vorgefühl berichten. Hierbei kann zwischen einem allgemeinen Vorgefühl (trait) und dem Drang, Tics auszuführen (state) unterschieden werden. Das Vorgefühl als trait ist abhängig von der Interozeptionsfähigkeit. An den Drang, Tics auszuführen, kann habituiert werden, moderiert von Aufmerksamkeits- und Attributionsprozessen. Durch das Auflösen des Vorgefühl-Tic-Reizreaktionsmusters reduzieren sich die Tic-Symptome. Schlussfolgerung: Für weitere Erkenntnisse in Bezug auf die Bedeutung von Vorgefühl und den Drang, Tics auszuführen, sollten zukünftige Forschungsansätze Drang und allgemeine Vorgefühle in therapeutischen Interventionsstudien berücksichtigen, weitere Interozeptionsparadigmen einbeziehen und die Entwicklung von allgemeinem Vorgefühl und Drang über die Lebensspanne hinweg untersuchen.

Diagnosis and Management of Functional Tic-Like Phenomena

Over the past 3 years, a global phenomenon has emerged characterized by the sudden onset and frequently rapid escalation of tics and tic-like movements and phonations. These symptoms have occurred not only in youth known to have tics or Tourette syndrome (TS), but also, and more notably, in youth with no prior history of tics. The Tourette Association of America (TAA) convened an international, multidisciplinary working group to better understand this apparent presentation of functional neurological disorder (FND) and its relationship to TS. Here, we review and summarize the literature relevant to distinguish the two, with recommendations to clinicians for diagnosis and management. Finally, we highlight areas for future emphasis and research.

Why Tic Severity Changes from Then to Now and from Here to There

Much of the research regarding Tourette's syndrome (TS) has focused on why certain individuals develop tics while others do not. However, a separate line of research focuses on the momentary influences that cause tics to increase or decrease in patients who are already known to have TS or another chronic tic disorder (CTD). Environmental and internal variables such as fatigue, anxiety, and certain types of thoughts all have been shown to worsen tic severity and may even overcome the positive effects of treatment. Other influences such as stress, distraction, and being observed have had mixed effects in the various studies that have examined them. Still, other variables such as social media exposure and dietary habits have received only minimal research attention and would benefit from additional study. Understanding the impact of these environmental and internal influences provides an opportunity to improve behavioral treatments for TS/CTD and to improve the lives of those living with these conditions. This review will examine the current literature on how these moment-to-moment influences impact tic expression in those with TS/CTD.

Cognitive control processes in behavior therapy for youth with Tourette's disorder

BACKGROUND

Cognitive control processes are implicated in the behavioral treatment of Tourette's disorder (TD). However, the influence of these processes on treatment outcomes has received minimal attention. This study examined whether cognitive control processes and/or tic suppression predicted reductions in tic severity and treatment response to behavior therapy.

METHOD

Fifty-three youth with TD or a pervasive tic disorder participated in a randomized wait list-controlled trial of behavior therapy. Following a baseline assessment to evaluate psychiatric diagnoses, tic severity, and cognitive control processes (e.g., response selection, inhibition, and suppression), youth were randomly assigned to receive eight sessions of behavior therapy (n = 23) or a wait list of equal duration (n = 28). Youth receiving immediate treatment completed a post-treatment assessment to determine improvement in tic severity. Meanwhile, youth in the wait list condition completed another assessment to re-evaluate tic severity and cognitive control processes, and subsequently received 8 sessions of behavior therapy followed by a post-treatment assessment to determine improvement.

RESULTS

A multiple linear regression model found that pretreatment inhibition/switching on the Delis-Kaplan Executive Function System Color-Word Interference Test predicted reductions in tic severity after behavior therapy (β = -.36, t = -2.35, p = .025, ƞ2  = .15). However, other cognitive control processes and tic suppression did not predict treatment response and/or reductions in tic severity. Small nonsignificant effects were observed in cognitive control processes after behavior therapy.

CONCLUSION

Cognitive control processes may influence tic severity reductions in behavior therapy. Notably, even when other cognitive control processes are impaired and youth are initially unable to voluntarily suppress their tics, youth with TD can still benefit from behavior therapy. Findings offer implications for clinical practice and research for TD.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part II: psychological interventions

Part II of the European clinical guidelines for Tourette syndrome and other tic disorders (ECAP journal, 2011) provides updated information and recommendations for psychological interventions for individuals with tic disorders, created by a working group of the European Society for the Study of Tourette Syndrome (ESSTS). A systematic literature search was conducted to obtain original studies of psychological interventions for tic disorders, published since the initial European clinical guidelines were issued. Relevant studies were identified using computerized searches of the MEDLINE and PsycINFO databases for the years 2011-2019 and a manual search for the years 2019-2021. Based on clinical consensus, psychoeducation is recommended as an initial intervention regardless of symptom severity. According to a systematic literature search, most evidence was found for Habit Reversal Training (HRT), primarily the expanded package Comprehensive Behavioral Intervention for Tics (CBIT). Evidence was also found for Exposure and Response Prevention (ERP), but to a lesser degree of certainty than HRT/CBIT due to fewer studies. Currently, cognitive interventions and third-wave interventions are not recommended as stand-alone treatments for tic disorders. Several novel treatment delivery formats are currently being evaluated, of which videoconference delivery of HRT/CBIT has the most evidence to date. To summarize, when psychoeducation alone is insufficient, both HRT/CBIT and ERP are recommended as first-line interventions for tic disorders. As part of the development of the clinical guidelines, a survey is reported from ESSTS members and other tic disorder experts on preference, use and availability of psychological interventions for tic disorders.

Acute and Long-Term Effects of an Internet-Based, Self-Help Comprehensive Behavioral Intervention for Children and Teens with Tic Disorders with Comorbid Attention Deficit Hyperactivity Disorder, or Obsessive Compulsive Disorder: A Reanalysis of Data from a Randomized Controlled Trial

Attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD) and tic disorders (TD) commonly co-occur. In addition, specific inattention difficulties and poor impulse control are related to TD in the absence of comorbid ADHD. In this study we reanalyzed data from a recently completed study comparing internet-delivered, self-help comprehensive behavioral intervention for tics (ICBIT) with a waiting-list control group. The current study describes the effects of an (ICBIT) in children and adolescents with TD with and without comorbid diagnoses of ADHD or OCD at post intervention and over three- and six-month follow-up periods. Thirty-eight 7 to 18-year-olds completed the ICBIT. Of these, 16 were diagnosed with comorbid ADHD and 11 were diagnosed with OCD. A significant improvement in tic measures was found in all groups. Both the TD + ADHD and the TD − ADHD groups were similar in the magnitude of tic reduction from baseline to post-treatment, and at the three and six-month follow-up assessments. However, the TD + OCD group benefitted less from intervention than the TD—OCD group. There were meaningful reductions in parental reports of inattention, as well as hyperactive and impulsive symptoms at post intervention and over the 6-month follow-up period. Thus, ICBIT can be effectively delivered in the presence of comorbid ADHD or OCD symptomatology and may reduce symptoms of inattention and impulsivity. Larger studies of ICBIT in children and teens with TD and comorbid ADHD and OCD are needed to optimize responses to ICBIT.

Inhibitory control in youth with Tourette's Disorder, attention-deficit/hyperactivity disorder and their combination and predictors of objective tic suppressibility

The present study investigated inhibitory control deficits in Tourette's Disorder (TD)-only, Attention Deficit/Hyperactivity Disorder (ADHD)-only, and TD+ADHD and explored the degree to which measures of inhibitory control, and tic and ADHD severity predicted objective tic suppressibility. Participants were youth ages 9 to 14 (M = 11.15) with TD-only (n = 24), TD+ADHD (n = 19), ADHD-only (n = 139), and typically-developing controls (n = 59) drawn from a larger study. Groups were compared on computer-based and paper and pencil neurocognitive inhibitory control tasks. Among youth with TD, neurocognitive measures of inhibitory control, subjective tic-suppressibility (Premonitory Urge for Tics Scale, item 10), and ADHD symptom severity were evaluated as predictors of objective tic suppressibility (i.e., laboratory-based tic suppression task), controlling for total tic severity. There were significant group differences on Color-Word inhibition/switching performance, though post-hoc comparisons yielded no significant pairwise group contrasts. Subjective tic suppressibility was the only significant predictor of objective tic suppressibility. The evident intact neurocognitive inhibitory control among youth with TD suggests that individuals with TD may use compensatory neural mechanisms to support typical speed and accuracy of response. The role of cognitive flexibility in mechanisms of tic suppression should also be further explored.

Correlates and clinical implications of tic suppressibility

Purpose of review

Tic disorders are common in the pediatric population and are differentiated from other movement disorders by tic suppressibility. Understanding the mechanism of tic suppression may provide new insights to the pathophysiology of tic disorders. This article highlights clinical phenomenology and neuronal correlates of tic suppressibility.

Recent findings

Recent studies suggest that tic suppressibility exists in children shortly after onset of their tics. Moreover, those who are better able to suppress their tics have better tic outcomes. Interoceptive awareness and automatic action inhibition may be involved in tic suppression.

Summary

We illustrate a possible underlying mechanism of tic suppressibility and its clinical correlations and implications. New concepts such as interoceptive awareness and action inhibition may help explain tic disorders. Further study will be useful to fill remaining knowledge gaps.

Tourette syndrome research highlights from 2019

This is the sixth yearly article in the Tourette Syndrome Research Highlights series, summarizing research from 2019 relevant to Tourette syndrome and other tic disorders. The highlights from 2020 is being drafted on the Authorea online authoring platform; readers are encouraged to add references or give feedback on our selections comments feature on this page. After the calendar year ends, this article is submitted as the annual update for the Tics collection F1000Research.

TicTimer Web: software for measuring tic suppression remotely

Woods and Himle developed a standardized tic suppression paradigm (TSP) for the experimental setting, to quantify the effects of intentional tic suppression in Tourette syndrome. We previously provided a computer program to facilitate recording tic occurrence and to automate reward delivery during the several experimental conditions of the TSP. The present article describes a web-based program that performs the same functions. Implementing this program on the web allows research sessions to be performed remotely, in tandem with a video calling program. Relevant data for each session, such as the timing of tics and dispensed rewards, are stored in plain text files for later analysis. Expected applications include research on Tourette syndrome and related disorders.

TicTimer Web: software for measuring tic suppression remotely

Woods and Himle developed a standardized tic suppression paradigm (TSP) for the experimental setting, to quantify the effects of intentional tic suppression in Tourette syndrome. We previously provided a computer program to facilitate recording tic occurrence and to automate reward delivery during the several experimental conditions of the TSP. The present article describes a web-based program that performs the same functions. Implementing this program on the web allows research sessions to be performed remotely, in tandem with a video calling program. Relevant data for each session, such as the timing of tics and dispensed rewards, are stored in plain text files for later analysis. Expected applications include research on Tourette syndrome and related disorders.

Development and Open Trial of a Psychosocial Intervention for Young Children With Chronic Tics: The CBIT-JR Study

The Comprehensive Behavioral Intervention for Tic Disorders (CBIT) has demonstrated efficacy in large randomized controlled trials for children (≥9 yrs), adolescents and adults with Tourette Syndrome and Chronic Tic Disorders. Given the early age of onset for tic disorders, a large portion of affected individuals with chronic tic disorders are less than 9 years of age and appropriate developmental adaptations of behavioral treatment have not yet been tested. The goal of this study was to adapt and evaluate the acceptability and utility of a family-based adaptation of CBIT for children under 9 years of age. Children 5-8 years of age (N = 15) with chronic tics were recruited from three study sites. CBIT was adapted for use with young children and included habit reversal strategies introduced in a developmentally appropriate game format and function-based interventions to reduce family accommodation of and attention to tic symptoms. Children and parents described high level of treatment satisfaction and study retention rate was 100%. Treatment response rate was 54% (CGI-I = 1 or 2) with a significant decrease in the YGTSS total score (Cohen's d = 0.73) that was largely maintained at 3-month and 1-year follow-up assessments. Treatment was associated with reduction of some symptoms of tic-related comorbid syndromes and with changes in parental accommodation and attention to tics. Future research should determine if parental attention to tics and symptom accommodation are important mediators of treatment outcome, or if participating in this intervention at a younger age may prevent the chronic course of tic symptoms.

The New Tics study: A Novel Approach to Pathophysiology and Cause of Tic Disorders

We report on the ongoing project "The New Tics Study: A Novel Approach to Pathophysiology and Cause of Tic Disorders," describing the work completed to date, ongoing studies and long-term goals. The overall goals of this research are to study the pathophysiology of Provisional Tic Disorder, and to study tic remission (or improvement) in a prospective fashion. Preliminary data collection for the project began almost 10 years ago. The current study is nearing completion of its third year, and has already reported several novel and important results. First, surprisingly, at least 90% of children who had experienced tics for only a mean of 3 months still had tics at the 12-month anniversary of their first tic, though in some cases tics were seen only with remote video observation of the child sitting alone. Thus almost all of them now had a DSM-5 diagnosis of Tourette's Disorder or Persistent (Chronic) Tic Disorder. Baseline clinical features that predicted 12-month outcome included tic severity, subsyndromal autism spectrum symptoms, an anxiety disorder, and a history of 3 or more phonic tics. Second, we found that poorer tic suppression ability when immediately rewarded for suppression predicted greater tic severity at follow-up. Third, striatal volumes did not predict outcome as hypothesized, but a larger hippocampus at baseline predicted worse severity at follow-up. Enrollment and data collection continue, including functional connectivity MRI (fcMRI) imaging, and additional analyses are planned once the full sample is enrolled.

Premonitory Awareness Facilitates Tic Suppression: Subscales of the Premonitory Urge for Tics Scale and a New Self-Report Questionnaire for Tic-Associated Sensations

Awareness of premonitory urge in Tourette syndrome (TS) may facilitate tic suppression; however, previous studies have not supported this observation. We aimed to clarify the relationship between tic-associated sensation and tic suppression by identifying the subtypes of tic-associated sensations, including the Premonitory Urge for Tics Scale (PUTS). We developed a new questionnaire called "Rumination and Awareness Scale for tic-associated sensations" (RASTS) to assess the two additional aspects of tic-associated sensations: the intensity of somatosensory hyperawareness and the ability to identify signals of emerging tics. Sixty-two individuals with TS participated in the study (mean age = 19.2 ± 10.3 years). All participants completed the RASTS, PUTS, and Tic Suppression Scale. Of all participants, 41 were evaluated by the Yale Global Tic Severity Scale (YGTSS), while another group of 41 completed both the Leyton Obsessional Inventory-Child Version (LOI-CV) and the Tics Symptom Self-Report (TSSR). Factor analyses including nine items of the PUTS and the RASTS were conducted, and their relationships with patients' tic suppression ability were examined. The results support using RASTS for the two supposed dimensions (rumination about sensation and premonitory awareness) for assessing the two different tic-associated sensations, and PUTS for three dimensions for assessing the two types of quality of premonitory urges and intensity of premonitory urges. Premonitory awareness correlated with tic suppression ability. Conversely, rumination about sensation, PUTS total score, and the three subscales of PUTS correlated with obsessive-compulsive symptoms. In summary, being aware of signals for emerging tics facilitated self-initiated tic suppression, while ruminative tic-associated sensations did not. This study provides new insights into behavioral therapy for tics by identifying two distinct aspects of tic-associated sensations that include premonitory urges.

Tic Suppression in Children With Recent-Onset Tics Predicts 1-Year Tic Outcome

Successful voluntary tic suppression is a key component of the behavioral interventions that are used to treat tic disorders. This study aimed to examine tic suppression in children with recent-onset tics and determine whether the capacity to suppress tics predicts future tic severity. We tested 45 children (30 male, mean age 7.74 years) with recent-onset tics (mean 3.47 months prior to the first study visit; baseline) and re-examined each child at the 12-month anniversary of the first recognized tic (follow-up). At the baseline visit, children performed a tic suppression task with several conditions: tic freely, inhibit tics given a verbal request, and inhibit tics in the presence of a reward. At the baseline visit, children with tics for only a few months could suppress their tics, and tic suppression was especially successful when they received an immediate and contingent reward. Additionally, the ability to suppress tics in the presence of a reward predicted tic severity at follow-up. These findings suggest that better inhibitory control of tics within months of tic onset may be an important predictor of future tic symptom outcome.

Software for web-based tic suppression training

Exposure and response prevention (ERP) is a first-line behavior therapy for obsessive-compulsive disorder and Tourette syndrome (TS). However, ERP for tic disorders requires intentional tic suppression, which for some patients is difficult even for brief periods. Additionally, practical access to behavior therapy is difficult for many patients, especially those in rural areas. The authors present a simple, working web platform (TicTrainer) that implements a strategy called reward-enhanced exposure and response prevention (RE-ERP). This strategy sacrifices most expert therapist components of ERP, focusing only on increasing the duration of time for which the user can suppress tics through automated differential reinforcement of tic-free periods (DRO). RE-ERP requires an external tic monitor, such as a parent, during training sessions. The user sees increasing digital rewards for longer and longer periods of successful tic suppression, similar to a video game score. TicTrainer is designed with security in mind, storing no personally identifiable health information, and has features to facilitate research, including optional masked comparison of tics during DRO vs. noncontingent reward conditions. A working instance of TicTrainer is available from https://tictrainer.com/.

TicTimer software for measuring tic suppression

Woods and Himle developed a standardized tic suppression paradigm (TSP) for the experimental setting, to quantify the effects of intentional tic suppression in Tourette syndrome. The present article describes a Java program that automates record keeping and reward dispensing during the several experimental conditions of the TSP. The software can optionally be connected to a commercial reward token dispenser to further automate reward delivery to the participant. The timing of all tics, 10-second tic-free intervals, and dispensed rewards is recorded in plain text files for later analysis. Expected applications include research on Tourette syndrome and related disorders.