Extra Movements in Healthy People: Challenging the Definition and Diagnostic Practice of Tic Disorders.

The occurrence of motor/vocal tics, that is, "extra movements" and/or "extra vocalizations," is the leading diagnostic criterion for tic disorders. We show that extra movements are common also in healthy controls, so that a surplus of movements per se is not indicative of the presence of a tic disorder. This questions the usefulness of Diagnostic and Statistical Manual of Mental Disorders, 5th edition criteria for tic disorders in clinical practice. Apparently, it is not solely a surplus of movements that defines tic disorders. Instead, movement characteristics and patterns seem to play a crucial role. ANN NEUROL 2023;93:472-478.

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.

Testing the specificity of phenomenological criteria for functional tic-like behaviours in youth with Tourette syndrome.

BACKGROUND AND PURPOSE: The aim was to test the specificity of phenomenological criteria for functional tic-like behaviours (FTLBs). The European Society for the Study of Tourette Syndrome (ESSTS) criteria for the diagnosis of FTLBs include three major criteria: age at symptom onset ≥12 years, rapid evolution of symptoms and specific phenomenology. METHODS: Children and adolescents with primary tic disorders have been included in a Registry in Calgary, Canada, since 2017. Using the Yale Global Tic Severity Scale, the proportion of youth with primary tic disorders who met specific phenomenological criteria for FTLBs at first visit was assessed: (1) having ≥1 specific complex motor tic commonly seen in FTLBs, including complex arm/hand movements, self-injurious behaviour, blocking, copropraxia; (2) having ≥1 specific complex phonic tic commonly seen in FTLBs, including saying words, phrases, disinhibited speech, coprolalia; (3) having a greater number of complex tics than simple tics. Children seen for the first time between 2017 and 2019 and between 2021 and 2023 were analysed separately. RESULTS: Of 156 participants included between 2017 and 2019, high specificity (94.2%) of the age at onset criterion (≥12 years) and of having at least two complex motor behaviours and one complex phonic behaviour at first visit (96.2%) was observed. Some of the complex motor tics had lower specificity. The specificity of the FTLB diagnostic criterion of having more complex tics than simple tics was 89.7%. There was no significant difference in specificity of the criteria for children seen for the first time between 2017 and 2019 and between 2021 and 2023 (n = 149). CONCLUSION: This information supports the use of the ESSTS criteria for FTLBs in clinical practice.

Co-morbid tics and stereotypies: a systematic literature review.

BACKGROUND: Tics and stereotypies are childhood-onset repetitive behaviours that can pose significant diagnostic challenges in clinical practice. Both tics and stereotypies are characterised by a complex co-morbidity profile, however little is known about the co-occurrence of these hyperkinetic disorders in the same patient population. OBJECTIVE: This review aimed to assess the relationship between tics and stereotypies when these conditions present in co-morbidity. METHODS: We conducted a systematic literature review of original studies on co-morbid tics and stereotypies, according to the standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: Our literature search identified six studies of suitable sample size (n ≥ 40) presenting data on the association between tics and stereotypies in otherwise typically developing patients. A considerable proportion (23%) of patients diagnosed with stereotypic movement disorder present with co-morbid tics (range 18-43%). Likewise, the prevalence of primary stereotypies is increased in patients with tic disorders such as Tourette syndrome (8%, range 6-12%). DISCUSSION: Tics and stereotypies can often develop in co-morbidity. The association of tics and stereotypies in the same patient has practical implications, in consideration of the different treatment approaches. Future research should focus on the assessment and management of both conditions, particularly in special populations (e.g. patients with pervasive developmental disorders).

Association between body mass index and tic disorders in school-age children.

OBJECTIVE: To explore the relationship between body mass index (BMI ) and the severity of tic disorders (TDs) in children 6-14 years old. METHODS: A total of 86 children diagnosed with TDs in a hospital between Jan. 2023 and Sept. 2023 were collected by convenient sampling method, and the general data and TD-specific data were collected and analyzed. RESULTS: Univariate analysis showed that patients with different Yale Global Tic Severity Scale (YGTSS) grades had statistically significant differences in age, BMI, residence, snacking pattern, weekly physical exercise frequency, weekly physical exercise time, and proportion of cesarean birth. Multiple linear regression analysis showed that the YGTSS score grades were related to BMI, snacking pattern, and cesarean birth of the patients. Correlation analysis revealed a positive correlation between BMI grades and the YGTSS score grades, with a higher BMI indicating more severe TDs. Predictive value evaluation showed that BMI, snacking pattern, and cesarean birth had predictive values for TD severity, and the highest value was found in the combined prediction. CONCLUSION: BMI, snacking pattern, and cesarean birth are of predictive values for the severity of TDs. In addition, BMI is positively correlated with the severity of TDs, and a higher BMI suggests more severe TDs.

Exploring the psychometric properties of the premonitory urge for tics scale (PUTS) and its association with psychiatric symptoms in Chinese children with tic disorders.

BACKGROUND: The Premonitory Urge for Tics Scale (PUTS) is a common self-report measure of premonitory urges for patients with tic disorders. This study aims to evaluate the Chinese version of the PUTS (PUTS-C) and to explore its association with psychiatric symptoms in Chinese children diagnosed with tic disorders. METHODS: The psychometric evaluation involved 204 outpatients with tic disorders, aged 7-16 years, who were divided into two age groups: (7-10 years, n = 103; 11-16 years, n = 95). RESULTS: The PUTS-C demonstrated good internal consistency (McDonald'sω = 0.84) and two-week test-retest reliability (0.76). We observed a statistically significant correlation between the total PUTS-C score and various Yale Global Tic Severity Scale (YGTSS) subscales and total tic severity scores. The PUTS-C score also showed significant correlations with the Children Yale-Brown Obsessive Compulsive Scale (CY-BOCS), Screening Child Anxiety-Related Emotional Disorders (SCARED), and Children's Depression Inventory (CDI). Notably, premonitory urges independently predicted tic severity, beyond the influence of comorbid symptoms. A two-factor structure of the PUTS-C was identified in the total sample through factor analysis. CONCLUSIONS: The PUTS-C possesses acceptable validity and good reliability. It appears that premonitory urges in Chinese patients with tic disorders are associated with obsessive-compulsive symptoms, anxiety, and depression, but can independently predict tic severity. Specific PUTS-C factors possibly related to motor and vocal tics. Future research should continue to investigate age-related differences and the association with tics and other sensory symptoms.

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.

Cytokine levels reflect tic symptoms more prominently during mild phases.

Tic disorder is a neuropsychiatric condition that affects 3% of all children and can have a significant impact on their quality of life. Cytokines, interferons, interleukins, lymphokines, and tumor necrosis factors are involved in the neuroinflammatory circuitry of tic disorders. This study aimed to identify the cytokines involved in the pathogenesis of tic disorders. We enrolled 44 patients with tic disorder and 38 healthy controls. Patients were free of psychotropic medications for at least 3 weeks. Whole blood samples were analyzed using a Luminex® human cytokine multiplex assay kit. Patients were divided into groups with "mild tics" and "above moderate tics" based on Yale Global Tic Severity Scale (YGTSS) scores for comparison. The final analysis included 35 patients (28 male and 7 female) and 31 controls (20 male and 11 female). In the mild tic group, interleukin (IL)-12 p70 negatively correlated with motor tic scores. Granulocyte-macrophage colony-stimulating factor, IL-4, IL-8, and tumor necrosis factor (TNF)-α were positively correlated to phonic tic scores. IL-12 p40 and TNF-α were positively correlated to total tic scores. IL-12 p70 and IL-17a negatively correlated to impairment scores and total YGTSS scores. Tic disorder patients and healthy controls exhibit different cytokine profiles. Only patients with mild symptoms exhibit significant correlations, suggesting that the correlations between cytokine levels and tic symptoms are more relevant during the mild or remission phases. Our results present the importance of IL-1ß and TNF-α, among others, but the identification of key cytokines are still necessary.

Distinguishing functional from primary tics: a study of expert video assessments.

BACKGROUND: Reliably applied criteria to differentiate functional from primary tics are lacking. In the absence of biological markers, the development of new diagnostic criteria to assist clinicians is predicated on expert judgement and consensus. This study examines the level of diagnostic agreement of experts in tic disorders using video footage and clinical descriptions. METHODS: Using a two-part survey, eight experts in the diagnosis and management of tics were first asked to study 24 case videos of adults with primary tics, functional tics or both and to select a corresponding diagnosis. In the second part of the survey, additional clinical information was provided, and the diagnosis was then reconsidered. Inter-rater agreement was measured using Fleiss' kappa. In both study parts, the factors which influenced diagnostic decision-making and overall diagnostic confidence were reviewed. RESULTS: Based on phenomenology alone, the diagnostic agreement among the expert raters was only fair for the pooled diagnoses (κ=0.21) as well as specifically for functional (κ=0.26) and primary tics (κ=0.24). Additional clinical information increased overall diagnostic agreement to moderate (κ=0.51) for both functional (κ=0.6) and primary tics (κ=0.57). The main factors informing diagnosis were tic semiology, age at tic onset, presence of premonitory urges, tic suppressibility, the temporal latency between tic onset and peak severity, precipitants and tic triggers and changes in the overall phenotypic presentation. CONCLUSIONS: This study confirmed that in the absence of clinical information, the diagnostic distinction between primary and functional tics is often difficult, even for expert clinicians.

Automated Motor Tic Detection: A Machine Learning Approach.

BACKGROUND: Video-based tic detection and scoring is useful to independently and objectively assess tic frequency and severity in patients with Tourette syndrome. In trained raters, interrater reliability is good. However, video ratings are time-consuming and cumbersome, particularly in large-scale studies. Therefore, we developed two machine learning (ML) algorithms for automatic tic detection. OBJECTIVE: The aim of this study was to evaluate the performances of state-of-the-art ML approaches for automatic video-based tic detection in patients with Tourette syndrome. METHODS: We used 64 videos of n = 35 patients with Tourette syndrome. The data of six subjects (15 videos with ratings) were used as a validation set for hyperparameter optimization. For the binary classification task to distinguish between tic and no-tic segments, we established two different supervised learning approaches. First, we manually extracted features based on landmarks, which served as input for a Random Forest classifier (Random Forest). Second, a fully automated deep learning approach was used, where regions of interest in video snippets were input to a convolutional neural network (deep neural network). RESULTS: Tic detection F1 scores (and accuracy) were 82.0% (88.4%) in the Random Forest and 79.5% (88.5%) in the deep neural network approach. CONCLUSIONS: ML algorithms for automatic tic detection based on video recordings are feasible and reliable and could thus become a valuable assessment tool, for example, for objective tic measurements in clinical trials. ML algorithms might also be useful for the differential diagnosis of tics. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Contrasting features between Tourette syndrome and secondary tic disorders.

Tics are rapid, recurrent, non-rhythmic movements or emitted sounds. Tics are the hallmark of Tourette syndrome (TS); however, a number of other disorders may be associated with tics, so-called secondary tic disorders (STD). We assessed clinical history and performed blinded evaluations of video-recordings from patients with TS and STD in order to identify features that may differentiate tics associated with TS vs STD. There were 156 patients with TS and 38 with STD, 21 of whom had functional (psychogenic) tics. Patients with TS were more frequently male and had a younger age at onset. Tics in TS tend to involve muscles in the cranial-cervical area more often and have greater severity and complexity than those in patients with STD. Similar findings were observed when contrasting patients with TS with patients with functional tics only. Simple phonic tics showed the greatest diagnostic accuracy for TS, compared with STD, but marked overlap in the types of tics and comorbidities was observed between patients with TS and STD. Patients with TS were more likely males, had a younger age at onset, phonic tics and motor tics affecting predominantly the head and neck area, and had a greater complexity and severity of tics than those with STD. When these features are absent a consideration should be given to the possibility of a tic disorder other than TS.

European Society for the Study of Tourette Syndrome 2022 criteria for clinical diagnosis of functional tic-like behaviours: International consensus from experts in tic disorders.

BACKGROUND AND PURPOSE: In 2020, health professionals witnessed a dramatic increase in referrals of young people with rapid onset of severe tic-like behaviours. We assembled a working group to develop criteria for the clinical diagnosis of functional tic-like behaviours (FTLBs) to help neurologists, pediatricians, psychiatrists, and psychologists recognize and diagnose this condition. METHODS: We used a formal consensus development process, using a multiround, web-based Delphi survey. The survey was based on an in-person discussion at the European Society for the Study of Tourette Syndrome (ESSTS) meeting in Lausanne in June 2022. Members of an invited group with extensive clinical experience working with patients with Tourette syndrome and FTLBs discussed potential clinical criteria for diagnosis of FTLBs. An initial set of criteria were developed based on common clinical experiences and review of the literature on FTLBs and revised through iterative discussions, resulting in the survey items for voting. RESULTS: In total, 24 members of the working group were invited to participate in the Delphi process. We propose that there are three major criteria and two minor criteria to support the clinical diagnosis of FTLBs. A clinically definite diagnosis of FTLBs can be confirmed by the presence of all three major criteria. A clinically probable diagnosis of FTLBs can be confirmed by the presence of two major criteria and one minor criterion. CONCLUSIONS: Distinguishing FTLBs from primary tics is important due to the distinct treatment paths required for these two conditions. A limitation of the ESSTS 2022 criteria is that they lack prospective testing of their sensitivity and specificity.

New-onset functional tics during the COVID-19 pandemic: Clinical characteristics of 105 cases from a single centre.

BACKGROUND AND PURPOSE: The COVID-19 pandemic has been associated amongst other things with a sharp increase in adolescents and young adults presenting acutely with functional tics. Initial reports have suggested clinically relevant differences between functional tics and neurodevelopmental tics seen in primary tic disorders such as Tourette syndrome. We aimed to provide confirmatory findings from the largest single-centre cohort to date. METHODS: In the present study we present data from 105 consecutive patients who developed functional tics during a 3-year period overlapping with the COVID-19 pandemic (April 2020-March 2023). All patients underwent a comprehensive neuropsychiatric assessment at a single specialist centre for tic disorders. RESULTS: Female adolescents and young adults accounted for 69% of our sample. Functional tics had an acute/subacute onset in most cases (75% with a peak of severity within 1 month). We found a disproportionately high frequency of complex movements (81%) and vocalizations (75%). A subset of patients (23%) had a pre-existing primary tic disorder (Tourette syndrome with functional overlay). The most common psychiatric co-morbidities were anxiety (70%) and affective disorders (40%). Moreover, 41% of patients had at least one functional neurological disorder in addition to functional tics. Exposure to tic-related social media content was reported by half of the patients. CONCLUSIONS: Our findings confirm substantial clinical differences between functional tics developed during the pandemic and neurodevelopmental tics. Both patient- and tic-related red flags support the differential diagnostic process and inform ongoing monitoring in the post-pandemic era.

Functional tics: Expanding the phenotypes of functional movement disorders?

BACKGROUND AND PURPOSE: Until the outbreak reported during the COVID-19 pandemic, functional tics were considered to be a relatively rare clinical phenotype, as opposed to other functional movement disorders such as functional tremor and dystonia. To better characterize this phenotype, we compared the demographic and clinical characteristics of patients who developed functional tics during the pandemic and those of patients with other functional movement disorders. METHODS: Data from 110 patients were collected at the same neuropsychiatry centre: 66 consecutive patients who developed functional tics without other functional motor symptoms or neurodevelopmental tics and 44 patients with a mix of functional dystonia, tremor, gait, and myoclonus. RESULTS: Both groups were characterized by female sex preponderance (70%-80%) and (sub)acute onset of functional symptoms (~80%). However, patients with functional tics had a significantly earlier age at onset of functional symptoms (21 vs. 39 years). Exposure to relevant social media content was reported by almost half of the patients with functional tics, but by none of the patients with other functional movement disorders. Comorbidity profiles were similar, with relatively high rates of anxiety/affective symptoms and other functional neurological symptoms (nonepileptic attacks). CONCLUSIONS: Patients who developed functional tics during the pandemic represent a phenotypic variant of the wider group of patients with functional movement disorders, associated with younger age at onset and influenced by pandemic-related factors, including increased exposure to specific social media content. Diagnostic protocols and treatment interventions should be tailored to address the specific features of this newly defined phenotype.

Dimensional Assessment of Depression and Anxiety in a Clinical Sample of Adults With Chronic Tic Disorder.

OBJECTIVE: Among adults with Tourette syndrome, depression and anxiety symptoms are widely prevalent and consistently associated with poor quality of life. Important knowledge gaps remain regarding mood and anxiety dimensions of the adult Tourette syndrome phenotype. Taking a dimensional approach, this study sought to determine the prevalence, severity, and clinical correlates of depression and anxiety symptoms in a clinical sample of adults with Tourette syndrome and other chronic tic disorders. METHODS: A retrospective chart review was conducted of all adults with a chronic tic disorder presenting to a tertiary care Tourette syndrome clinic between December 2020 and July 2022. Information extracted during chart review included data from scales administered as part of routine care: Quality of Life in Neurological Disorders (Neuro-QoL) Depression Short Form, Neuro-QoL Anxiety Short Form, Adult Attention-Deficit/Hyperactivity Disorder Self-Report Screening Scale, Dimensional Obsessive-Compulsive Scale, and Yale Global Tic Severity Scale. Relationships between variables were examined by conducting between-group, correlation, and multivariable regression analyses. RESULTS: Data from 120 adult patients with a chronic tic disorder (77 men and 43 women) were analyzed. Neuro-QoL Anxiety scores were elevated in 66% of the cohort; Neuro-QoL Depression scores were elevated in 26%. Neuro-QoL Anxiety scores were significantly higher than general population norms, whereas Neuro-QoL Depression scores were not. After adjustment for covariates, depressive and anxiety symptom severity scores were significantly associated with each other and with obsessive-compulsive disorder symptom severity but not with tic severity. Sex-based differences emerged in the analyses. CONCLUSIONS: Among adults with chronic tic disorder, anxiety symptoms were more prevalent and severe than depressive symptoms, co-occurring psychiatric symptoms were more tightly linked with each other than with tic severity, and sex-based differences were evident.

Exposure and Response Prevention: Evaluation of Tic Severity Over Time for Children and Adolescents with Tourette Syndrome and Chronic Tic Disorders.

Tourette syndrome and chronic tic disorders are characterized by the presence of tics. Different behavioral therapies have shown to be efficacious for treating tics in children and adolescents, but Exposure and Response Prevention (ERP) is a less researched method. However, ERP is a method often used in the clinical setting. Therefore, the present study evaluated the severity of tics over time from beginning of ERP to follow-up approximately 1 year after last training session.In total, 116 patients treated with ERP face to face or ERP via web-based videoconferencing were included. The primary outcome measure was tic severity measured with the Danish version of the Yale Global Tic Severity Scale.The results showed that tic severity decreased during ERP and lasted in the follow-up period, with a statistically higher decrease in the group with patients who completed ERP as planned and the group that stopped earlier than planned because of reduction in tics, compared with those who dropped out due to lack of motivation (p < 0.001).The study concludes that ERP seems to have an immediate and a long-term effect on severity of tics, especially in those who complete the program or those who discontinue earlier due to good results.

Sociodemographic and clinical characteristics of children with tic disorders and behavioral problems: A real-world study and development of a prediction model.

BACKGROUND: Tic disorders (TD) are complex neuropsychiatric disorders frequently associated with a variety of comorbid problems, whose negative effects may exceed those of the tics themselves. In this study, we aimed to explore the sociodemographic and clinical characteristics of children with TD and behavioral problems, and develop a prediction model of behavioral problems based on the predictors under real-world conditions. METHODS: A hospital-based cross-sectional study was conducted on children with TD. Behavioral problems were surveyed using the Achenbach Child Behavior Checklist (CBCL). Sociodemographic information was collected from face-to-face interviews using an electronic questionnaire administered during the initial ambulatory visit. Clinical data were collected from medical records, and quality control was performed. The sociodemographic and clinical characteristics of patients with and without behavioral problems were statistically compared, and a nomogram prediction model was developed based on multivariate logistic regression analysis. The discriminatory ability and clinical utility of the nomogram were assessed by concordance index (C-index), receiver operating characteristic (ROC) curve, decision curve analysis (DCA) and clinical impact curve (CIC). RESULTS: A total of 343 TD cases were included in the final analysis, of which 30.32% had behavioral problems. The prediction model showed age 12-16 years, abnormal birth history, parenting pattern of indulgence, parent/close relatives with psychiatric disorders, chronic motor or vocal tic disorder (CTD)/Tourette syndrome (TS) and moderate/severe tic severity were associated with behavioral problems in children with TD. The C-index of the prediction model (nomogram) was 0.763 (95% confidence interval, 0.710 ~ 0.816). The nomogram was feasible for making beneficial clinical decisions, according to the satisfactory results of the DCA and CIC. CONCLUSIONS: A nomogram prediction model for comorbid behavioral problems in children with TD was established. The prediction model demonstrated a good discriminative ability and predictive performance for beneficial clinical decisions. This model further provides a comprehensive understanding of associated sociodemographic and clinical characteristics by visual graphs and allows clinicians to rapidly identify patients with a higher risk of behavioral problems and tailor necessary interventions to improve clinical outcomes.

Treatment failure in persistent tic disorders: an expert clinicians' consensus-based definition.

A standardized definition of treatment failure in the management of tics is currently lacking. Such definition would prevent persistent use of unnecessary interventions and help clinicians to determine when to offer less established treatments (e.g., deep brain stimulation surgery). To achieve an expert consensus-based definition of failure of medical treatments for tics, we used a multi-step, multi-round, web-based Delphi approach involving international specialist clinicians with specific expertise in tic disorders. These experts were identified through professional networks or consortia related to chronic tic disorders. We created a survey and reviewed the questions with stakeholders prior to two rounds of Delphi surveys, followed by a final review and discussion among research team members. Both survey rounds were completed using a sample of 36 expert stakeholders from 14 countries, including neurologists, psychiatrists, and clinical psychologists. The Delphi process led to consensus on 10 statements which formed the final definition of treatment failure. The definition was structured and operationalized according to two separate sections, one for behavioral and one for pharmacological treatments. Core components of the definition and its operationalization included lack of efficacy, adherence, and tolerability, as well as a definition of failure of behavioral therapies as a whole, and of pharmacological therapies as a whole. The group concluded that the components of this specific definition reflect the range and complexity of characteristics to consider in establishing tic-related treatment failure. Future research should assess the feasibility of this operational definition and whether it will change clinical decision-making and improve management outcomes.

The Severity and Neural Correlates of Premonitory Urge in Tourette Syndrome: A Systematic Review and Meta-Analysis.

INTRODUCTION: Premonitory urge (PU) is an aversive bodily sensation that signals the onset of tic disorder.To our knowledge, PU typically precedes the appearance of tic symptoms, and both age and tic severity are correlated with PU. However, inconsistent findings have also been reported. Hence, we conducted a meta-analysis to examine the relationship among premonitory symptoms, patient age and the severity of tic symptoms, as well as to summarize the research on the neural underpinnings of PU in Tourette syndrome (TS). METHODS: We conducted a literature search of relevant studies published between December 2005 and April 2022 using databases such as PubMed, Elsevier, PsycINFO, and Web of Science. Our analysis was carried out using R software with the assistance of the "meta" and "metafor" packages. RESULTS: Our meta-analysis included 22 studies with a total of 1236 tic disorder patients. The mean Premonitory Urge for Tics Scale (PUTS) score was 20.17, with a 95% confidence interval of [18.14, 21.68]. Through meta-regression, we found that age and tic severity play important moderating roles in PU severity (p < 0.0001). Neuroimaging studies suggest that PU is related to the insula, prefrontal cortex (PFC), anterior cingulate cortex (ACC), and supplementary motor area (SMA), regardless of the structural or functional level. CONCLUSIONS: Our meta-analysis confirmed the positive relationship between the severity of tics and PU and identified age as a significant factor influencing PU. The neural mechanisms underlying PU remain largely unknown, but evidence suggests that the insula, PFC, ACC, and SMA are related regions.

The COVID-19 pandemic and its impact on tic symptoms in children and young people: a prospective cohort study.

To understand how children and young people with tic disorders were affected by COVID-19, we compared pre and during pandemic scores on the Yale Global Tic Severity Scale (YGTSS). Participants were young people (N = 112; male:78%; 9-17 years) randomised to the control arm of the "ORBIT-Trial" (ISRCTN70758207, ClinicalTrials.gov-NCT03483493). For this analysis, the control arm was split into two groups: one group was followed up to 12-months' post-randomisation before the pandemic started (pre-COVID group, n = 44); the other group was impacted by the pandemic at the 12-month follow-up (during-COVID group, n = 47). Mixed effects linear regression modelling was conducted to explore differences in YGTSS at 6- and 12-months post-randomisation. There were no significant differences in tic symptom or severity between participants who were assessed before and during COVID-19. This finding was not influenced by age, gender, symptoms of anxiety or autism spectrum disorder. Thus, the COVID-19 pandemic did not significantly impact existing tic symptoms.