Epidemiology of Huntington's Disease in Latin America: A Systematic Review and Meta-Analysis.

BACKGROUND: Latin America has played a crucial role in advancing our understanding of Huntington's disease (HD). However, previous global reviews include limited data from Latin America. It is possible that English-based medical search engines may not capture all the relevant studies. METHODS: We searched databases in Spanish, Portuguese, and English. The names of every country in Latin America in English-based search engines were used to ensure we found any study that had molecular ascertainment and provided general epidemiological information or subpopulation data. Additionally, we contacted experts across the region. RESULTS: The search strategy yielded 791 citations; 24 studies met inclusion criteria, representing 12 of 36 countries. The overall pooled prevalence was 0.64 per 100,000 (prediction interval, 0.06-7.22); for cluster regions, it was 54 per 100,000 (95% CI, 34.79-84.92); for juvenile HD, it was 8.7% (prediction interval, 5.12-14.35), and 5.9% (prediction interval, 2.72-13.42) for late-onset HD. The prevalence was higher for Mexico, Peru, and Brazil. However, there were no significant differences between Central America and the Caribbean versus South America. CONCLUSION: The prevalence of HD appears to be similar across Latin America. However, we infer that our findings are underestimates, in part because of limited research and underdiagnosis of HD because of limited access to molecular testing and the availability of neurologists and movement disorders specialists. Future research should focus on identifying pathways to improve access to molecular testing and education and understanding differences among different ancestral groups in Latin America. © 2024 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.

Prospective follow-up study of youth and adults with onset of functional tic-like behaviours during the COVID-19 pandemic.

BACKGROUND AND PURPOSE: Very little is known about the long-term prognosis of patients with functional tic-like behaviours (FTLBs). We sought to characterize the trajectory of symptom severity over a 12-month period. METHODS: Patients with FTLBs were included in our prospective longitudinal child and adult clinical tic disorder registries at the University of Calgary. Patients were prospectively evaluated 6 and 12 months after their first clinical visit. Tic inventories and severity were measured with the Yale Global Tic Severity Scale (YGTSS). RESULTS: Eighty-three youths and adults with FTLBs were evaluated prospectively until April 2023. Mean YGTSS total tic severity scores were high at baseline, with a mean score of 29.8 points (95% confidence interval [CI] = 27.6-32.1). Fifty-eight participants were reevaluated at 6 months, and 32 participants were reevaluated at 12 months. The YGTSS total tic severity score decreased significantly from the first clinical visit to 6 months (raw mean difference = 8.9 points, 95% CI = 5.1-12.7, p < 0.0001), and from 6 to 12 months (raw mean difference = 6.4 points, 95% CI = 0.8-12.0, p = 0.01). Multivariable linear regression demonstrated that tic severity at initial presentation and the presence of other functional neurological symptoms were associated with higher YGTSS total tic scores at 6 months, whereas younger age at baseline, receiving cognitive behavioural therapy for anxiety and/or depression, and prescription of selective serotonin reuptake inhibitors were associated with lower YGTSS total tic scores at 6 months. CONCLUSIONS: We observed a meaningful improvement in tic severity scores in youth and adults with FTLBs over a period of 6-12 months.

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.

Scales for Antipsychotic-Associated Movement Disorders: Systematic Review, Critique, and Recommendations.

BACKGROUND: Antipsychotic-associated movement disorders remain common and disabling. Their screening and assessment are challenging due to clinical heterogeneity and different use of nomenclature between psychiatrists and neurologists. OBJECTIVE: An International Parkinson and Movement Disorder Society subcommittee aimed to rate psychometric quality of severity and screening instruments for antipsychotic-associated movement disorders. METHODS: Following the methodology adopted by previous International Parkinson and Movement Disorders Society subcommittee papers, instruments for antipsychotic-associated movement disorders were reviewed, applying a classification as "recommended," "recommended with caveats," "suggested," or "listed." RESULTS: Our review identified 23 instruments. The highest grade of recommendation reached is "recommended with caveats," assigned to seven severity rating instruments (Extrapyramidal Symptoms Rating Scale, Barnes Akathisia Rating Scale, Abnormal Involuntary Movements Scale, Drug-Induced Extra-Pyramidal Symptoms Scale, Maryland Psychiatric Research Centre involuntary movements scale, Simpson Angus Scale, and Matson Evaluation of Drug Side effects). Only three of these seven (Drug-Induced Extra-Pyramidal Symptoms Scale, Maryland Psychiatric Research Centre, Matson Evaluation of Drug Side effects) were also screening instruments. Their main caveats are insufficient demonstration of psychometric properties (internal consistency, skewing, responsiveness to change) and long duration of administration. Eight "suggested" instruments did not meet requirements for the "recommended" grade also because of insufficient psychometric validation. Other limitations shared by several instruments are lack of comprehensiveness in assessing the spectrum of antipsychotic-associated movement disorders and ambiguous nomenclature. CONCLUSIONS: The high number of instruments "recommended with caveats" does not support the need for developing new instruments for antipsychotic-associated movement disorders. However, addressing the caveats with new psychometric studies and revising existing instruments to improve the clarity of their nomenclature are recommended next steps. © 2023 International Parkinson and Movement Disorder Society.

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.

The spectrum of functional tic-like behaviours: Data from an international registry.

BACKGROUND AND PURPOSE: Between 2019 and 2022, there was a marked rise in adolescents/young adults seeking urgent help for functional tic-like behaviours (FTLBs). Given the global scale of this phenomenon, we aimed to pool cases from different institutions in an international registry to better characterize this spectrum and facilitate future longitudinal observation. METHODS: An international collaborative group from 10 tertiary referral centres for tic disorders collected retrospective data on FTLB patients who sought specialists' attention between the last quarter of 2019 and June 2022. An audit procedure was used for collection of data, which comprised demographics, course of presentation and duration, precipitating and predisposing factors, phenomenology, comorbidities, and pharmacological treatment outcome. RESULTS: During the study period, we collected data on 294 patients with FTLBs, 97% of whom were adolescents and young adults and 87% of whom were female. FTLBs were found to have a peak of severity within 1 month in 70% of patients, with spontaneous remissions in 20%, and a very high frequency of complex movements (85%) and vocalizations (81%). Less than one-fifth of patients had pre-existing primary tic disorder, 66% had comorbid anxiety disorders, 28% comorbid depressive disorders, 24% autism spectrum disorder and 23% attention deficit/hyperactivity disorder. Almost 60% explicitly reported exposure to tic-related social media content. The vast majority of pharmacologically treated patients did not report benefit with tic-suppressing medications. CONCLUSIONS: Our data from the largest multicentre registry of FTLBs to date confirm substantial clinical differences from primary tic disorders. Social modelling was the most relevant contributing factor during the pandemic. Future longitudinal analyses from this database may help understand treatment approaches and responsiveness.

"Unvoluntary" Movement Disorders: Distinguishing between Tics, Akathisia, Restless Legs, and Stereotypies.

Tics, stereotypies, akathisia, and restless legs fall at different places on the spectrum of discrete, unwanted and potentially disabling motor routines. Unlike tremor, chorea, myoclonus, or dystonia, this subgroup of abnormal movements is characterized by the subject's variable ability to inhibit or release undesired motor patterns on demand. Though it may be sometimes clinically challenging, it is crucial to distinguish these "unvoluntary" motor behaviors because secondary causes and management approaches differ substantially. To this end, physicians must consider the degree of repetitiveness of the movements, the existence of volitional control, and the association with sensory symptoms, or cognitive-ideational antecedent. This review aims to summarize the current existing knowledge on phenomenology, diagnosis, and treatment of tics, stereotypies, akathisia, and restless leg syndrome.

Social media as an incubator of personality and behavioral psychopathology: Symptom and disorder authenticity or psychosomatic social contagion?

There has been an increasing recognition among both medical and psychological professionals, as well as the public media, of a concerning trend for child and adolescent users of audiovisual-based, algorithmic social media platforms (e.g., TikTok) to present with or claim functional psychiatric impairment that is inconsistent with or distinct from classic psychiatric nosology. In this short communication, we provide a detailed historical overview of this transdiagnostic phenomenon and suggest a conceptual model to organize thinking and research examining it. We then discuss the implications of our suggested model for accurate assessment, diagnosis, and medical-psychiatric treatment. We believe there is an urgent need for focused empirical research investigation into this concerning phenomenon that is related to the broader research and discourse examining social media influences on mental health.

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 Tourette OCD Alberta Network: Development of a Continuing Professional Development Program for Community Based Mental Health Therapists.

The Tourette OCD Alberta Network (TOAN) supports mental health therapists to improve the delivery of care to patients with Tourette syndrome (TS) and OCD in Alberta. We evaluated the professional development needs of health care workers to develop a continuing professional development (CPD) webinar series. Health care workers demonstrated an urgent need to access a CPD program grounded in evidenced based knowledge about TS and OCD. While 80% of health care workers treated children with TS and OCD, 50% had no formal training. A curriculum consisting of a series of twelve live, online webinars was developed and delivered between September 2020 and June 2021, covering a range of clinical topics. The webinars were attended on average by 63 attendees, with the outcome of a positive knowledge gain. In future, the educational program will need to reflect the ongoing developing clinical understanding of TS and OCD.

Engaging youth and parents in clinical pediatric research: A case-based example.

Background: Youth and parent engagement is a key component of clinical research. There are many ways to actively and meaningfully engage youth and parents as integral members of research teams, for example, through ad-hoc committees, advisory councils, or as co-leads on projects. When youth and parents are actively and meaningfully engaged in research projects, they share knowledge from their lived experiences to improve the quality and relevance of research. Methods: We describe a case-based example of engaging youth and parent research partners when co-designing a questionnaire to assess preferences for pediatric headache treatments, from both a researcher and youth/parent perspective. We also summarize best practices in patient and family engagement from the literature and pertinent guidelines to assist researchers with integrating patient and family engagement into their studies. Results: As researchers, we felt that the integration of a youth and parent engagement plan into our study significantly altered and strengthened questionnaire content validity. We encountered challenges throughout the process and detailed these experiences to help educate others about challenge mitigation and best practices in youth and parent engagement. As youth and parent partners, we felt that engaging in the process of questionnaire development was an exciting and empowering opportunity, and that our feedback was valued and integrated. Conclusions: By sharing our experience, we hope to catalyze thought and discussion around the importance of youth and parent engagement in pediatric research, with the goal of stimulating more appropriate, relevant, and high-quality pediatric research and clinical care in the future.

The recent surge of functional movement disorders: social distress or greater awareness?

PURPOSE OF REVIEW: To analyze the interrelated factors that have led to the striking increase in functional movement disorders in recent years, with a focus on functional tic-like behaviours (FTLB). RECENT FINDINGS: The sudden onset of FTLB has been widely observed in several countries since the beginning of the SARS-CoV-2 pandemic, whereas it was previously very rarely reported. Pandemic-related FTLB typically occur in young females, share complex, disabling and tic-lookalike patterns, and are usually triggered by the exposure to videos portraying tic-like behaviours on social media. Both pandemic-related FTLB and prepandemic FTLB are associated with high levels of depression and anxiety. FTLB related to the pandemic highlight the role of social media in the psychopathological behaviours of our time. SUMMARY: We suggest FTLB are due to a combination of predisposing factors (high genetic and epigenetic risk for anxiety and depression, negative past experiences) and precipitating factors (pandemic and its impact on mental health, exposure to certain social media content). These factors of vulnerability may increase the risk of developing behavioural and emotional problems in youth, such as FTLB. Early diagnosis and appropriate treatment of psychiatric comorbidities seem to be predictors of positive prognosis.

Prevalence and Incidence of Huntington's Disease: An Updated Systematic Review and Meta-Analysis.

The incidence and prevalence of Huntington's disease (HD) based on a systematic review and meta-analysis of 20 studies published from 1985 to 2010 was estimated at 0.38 per 100,000 person-years (95% confidence interval [CI], 0.16-0.94) and 2.71 per 100,000 persons (95% CI, 1.55-4.72), respectively. Since 2010, there have been many new epidemiological studies of HD. We sought to update the global estimates of HD incidence and prevalence using data published up to February 2022 and perform additional analyses based on study continent. Medline and Embase were searched for epidemiological studies of HD published between 2010 and 2022. Risk of bias was assessed using a quality assessment tool. Estimated pooled prevalence or incidence was calculated using a random-effects meta-analysis. A total of 33 studies published between 2010 and 2022 were included. Pooled incidence was 0.48 cases per 100,000 person-years (95% CI, 0.33-0.63). Subgroup analysis by continent demonstrated a significantly higher incidence of HD in Europe and North America than in Asia. Pooled prevalence was 4.88 per 100,000 (95% CI, 3.38-7.06). Subanalyses by continent demonstrated that the prevalence of HD was significantly higher in Europe and North America than in Africa. The minor increase in prevalence (more so than incidence) demonstrated in this updated review could relate to the enhanced availability of molecular testing, earlier diagnosis, increased life expectancy, and de novo mutations. Limitations include variable case ascertainment methods and lacking case validation data. © 2022 Her Majesty the Queen in Right of Canada. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. Reproduced with the permission of the Minister of Public Health Agency of Canada.

Efficacy of Caffeine in ADCY5-Related Dyskinesia: A Retrospective Study.

BACKGROUND: ADCY5-related dyskinesia is characterized by early-onset movement disorders. There is currently no validated treatment, but anecdotal clinical reports and biological hypotheses suggest efficacy of caffeine. OBJECTIVE: The aim is to obtain further insight into the efficacy and safety of caffeine in patients with ADCY5-related dyskinesia. METHODS: A retrospective study was conducted worldwide in 30 patients with a proven ADCY5 mutation who had tried or were taking caffeine for dyskinesia. Disease characteristics and treatment responses were assessed through a questionnaire. RESULTS: Caffeine was overall well tolerated, even in children, and 87% of patients reported a clear improvement. Caffeine reduced the frequency and duration of paroxysmal movement disorders but also improved baseline movement disorders and some other motor and nonmotor features, with consistent quality-of-life improvement. Three patients reported worsening. CONCLUSION: Our findings suggest that caffeine should be considered as a first-line therapeutic option in ADCY5-related dyskinesia. © 2022 International Parkinson and Movement Disorder Society.

Influence of sex on tic severity and psychiatric comorbidity profile in patients with pediatric tic disorder.

AIM: To investigate sex-related differences in tic severity, tic-related impairments, and psychiatric comorbidities in childhood. METHOD: In this cross-sectional study, tic severity/impairment and demographic factors were collected from 270 children and young people (aged 5-17y, mean 10y 6mo, SD 3y 4mo; 212 males and 58 females) with a tic disorder diagnosis at a specialty clinic. Psychiatric diagnoses and corresponding screening questionnaire scores were collected for attention-deficit/hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), major depressive disorder, and anxiety disorders. Logistic regression was used to compare the effect of sex and age on psychiatric comorbid diagnoses. The Mann-Whitney U test and t-tests were used to assess differences in questionnaire score distribution between sexes. RESULTS: Females had more severe motor tics (12.55 vs 10.81, p=0.01) and higher global severity scores (38.79 vs 32.66, p=0.03) on the Yale Global Tic Severity Scale. Females were less likely to be diagnosed with ADHD (odds ratio=0.48, 95% confidence interval=0.26-0.89). No significant sex difference was observed in diagnosis rates or symptom severity scores for anxiety or OCD. Females had significantly higher scores than males on the Children's Depression Inventory, Second Edition. INTERPRETATION: The higher level of motor tic severity and global severity in females further supports the differential natural history of tic disorders in females. Females with tic disorders may be underdiagnosed for ADHD.

Transitional Care for Young People with Neurological Disorders: A Scoping Review with A Focus on Patients with Movement Disorders.

Childhood-onset movement disorders represent a heterogenous group of conditions. Given the complexity of these disorders, the transition of care from pediatric to adult medicine is an important consideration. We performed a scoping review of the literature on transitional care in chronic neurological disease, exploring key transitional issues and proposed transitional care models. Our aim was to describe the current knowledge and gaps about the transition process of young adults with chronic neurological disorders, paying special attention to childhood onset movement disorders. A total of 64 articles were included in the qualitative synthesis; 56 articles reported on transitional care issues, and 8 articles reported on transitional care models. Only 2 articles included patients with movement disorders. The following 4 main transitional issues were identified following synthesis of the available literature: (1) inadequate preparation for the transition process, (2) inappropriate and inconsistent transition practices, (3) inadequate adult services, and (4) heightened emotional response surrounding transition. Of the reported transitional care models, multidisciplinary ambulatory care was the most common approach. In studies evaluating patient-related outcomes, positive health, educational, and vocational outcomes were found. The available literature provides insights on issues that can arise during transition that should be addressed to improve patient and caregiver comfort and satisfaction with care. Further research is needed to evaluate how transitional care programs affect outcomes and their cost effectiveness. More studies are required to determine the needs and outcomes specific to patients with childhood onset movement disorders. © 2020 International Parkinson and Movement Disorder Society.

Microstructural Abnormalities of the Dentatorubrothalamic Tract in Cervical Dystonia.

BACKGROUND: The dentatorubrothalamic tract (DRTT) remains understudied in idiopathic cervical dystonia (CD), despite evidence that the pathway is relevant in the pathophysiology of the disorder. OBJECTIVE: The aim of this study was to examine the DRTT in patients with CD using diffusion tensor imaging (DTI)-based tractography. METHODS: Magnetic resonance imaging scans from 67 participants were collected to calculate diffusion tractography metrics using a binary tractography-based DRTT template. Fractional anisotropy and diffusivity measures of left and right DRTT were computed and compared between 32 subjects with CD and 35 age-matched healthy volunteers. RESULTS: Fractional anisotropy of right DRTT and mean and axial diffusivity of left DRTT were significantly reduced in patients with CD. Similar abnormalities were observed in patients with focal CD and patients with CD without tremor. DTI metrics did not correlate with disease duration or severity. CONCLUSIONS: Significant reductions in DTI measures suggest microstructural abnormalities within the DRTT in CD, characterized by a tractography pattern consistent with decreased axonal integrity. © 2021 International Parkinson and Movement Disorder Society.

Rapid onset of functional tic-like behaviours in young adults during the COVID-19 pandemic.

BACKGROUND AND PURPOSE: Clinicians have reported an increase in functional tic-like behaviours in children and youth during the COVID-19 pandemic. We describe adults developing rapid onset of functional tic-like behaviours between May 2020 and June 2021. METHODS: Data were analysed from the Adult Tic Disorders Registry, a single-site,12-month prospective cohort study that began enrolment in January 2021. We compared clinical features of participants with Tourette syndrome or persistent motor/vocal tic disorder to participants with rapid onset tic-like behaviours. RESULTS: Thirty-three participants registered between January and June of 2021; nine had rapid onset tic-like behaviours, and 24 had Tourette syndrome or persistent motor tic disorder. Participants with rapid onset tic-like behaviours were younger (19.9 vs. 38.6 years, p = 0.003), had older age at onset (15.3 vs. 10.1, p = 0.0009), and were more likely female (p < 0.0001). They had higher motor and vocal tic severity and impairment scores (all p < 0.01) and were more likely to have complex arm/hand motor tics (p < 0.0001), complex vocal tics (p < 0.0001), and coprolalia (p = 0.004). They had significantly higher scores on all mental health symptom self-report measures (all p < 0.05) and were significantly more likely to be diagnosed with depression (p = 0.03). CONCLUSIONS: The clinical features that help differentiate rapid onset tic-like behaviours from Tourette syndrome or persistent motor tic disorder include their phenomenology, onset age, and clinical course. Rapid onset tic-like behaviours are a distinct subtype of functional neurological disorder that has emerged during the COVID-19 pandemic in young people and appears to be strongly socially influenced.

Bilateral transcranial magnetic stimulation of the supplementary motor area in children with Tourette syndrome.

AIM: To explore the feasibility and possible effects of low-frequency repetitive transcranial magnetic stimulation (rTMS) delivered to the supplementary motor area (SMA) on tic severity and motor system neurophysiology in children with Tourette syndrome. METHOD: Ten children with Tourette syndrome (eight males, two females; 9-15y) participated in this open-label, phase 1 clinical trial. Treatment consisted of 1800 low-frequency (1Hz) neuronavigated robotic rTMS (100% resting motor threshold) to the SMA, bilaterally for 15 sessions. The primary outcome was a change in Yale Global Tic Severity Scale (YGTSS) total score from baseline to posttreatment. Secondary outcome measures included changes in magnetic resonance spectroscopy metabolite concentrations, TMS neurophysiology measures, TMS motor maps, and clinical assessments (anxiety, depression) from baseline to the end of treatment. RESULTS: The YGTSS score decreased from baseline after treatment (p<0.001; Cohen's d=2.9). All procedures were well-tolerated. INTERPRETATION: Robot-driven, neuronavigated bilateral rTMS of the SMA is feasible in children with Tourette syndrome and appears to reduce tic severity. What this paper adds Repetitive transcranial magnetic stimulation (rTMS) is feasible to use in children with Tourette syndrome. rTMS is tolerated by children with Tourette syndrome. Precise targeting of the supplementary motor area using functional magnetic resonance imaging is also feasible in these children.