The effect of transcranial ultrasound pulse repetition frequency on sustained inhibition in the human primary motor cortex: A double-blind, sham-controlled study.

BACKGROUND: Non-invasive brain stimulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation hold promise for inducing brain plasticity. However, their limited precision may hamper certain applications. In contrast, Transcranial Ultrasound Stimulation (TUS), known for its precision and deep brain targeting capabilities, requires further investigation to establish its efficacy in producing enduring effects for treating neurological and psychiatric disorders. OBJECTIVE: To investigate the enduring effects of different pulse repetition frequencies (PRF) of TUS on motor corticospinal excitability. METHODS: T1-, T2-weighted, and zero echo time magnetic resonance imaging scans were acquired from 21 neurologically healthy participants for neuronavigation, skull reconstruction, and the performance of transcranial ultrasound and thermal modelling. The effects of three different TUS PRFs (10, 100, and 1000 Hz) with a constant duty cycle of 10 % on corticospinal excitability in the primary motor cortex were assessed using TMS-induced motor evoked potentials (MEPs). Each PRF and sham condition was evaluated on separate days, with measurements taken 5-, 30-, and 60-min post-TUS. RESULTS: A significant decrease in MEP amplitude was observed with a PRF of 10 Hz (p = 0.007), which persisted for at least 30 min, and with a PRF of 100 Hz (p = 0.001), lasting over 60 min. However, no significant changes were found for the PRF of 1000 Hz and the sham conditions. CONCLUSION: This study highlights the significance of PRF selection in TUS and underscores its potential as a non-invasive approach to reduce corticospinal excitability, offering valuable insights for future clinical applications.

Symptom Severity and Health Impacts of Functional Tic-Like Behaviors in Youth.

BACKGROUND: We performed this study to improve understanding of the relationship between functional tic-like behaviors (FTLBs) and quality of life, loneliness, family functioning, anxiety, depression, and suicidality. METHOD: This cross-sectional study assessed self-reported quality of life, disability, loneliness, depression, anxiety, family functioning, tic severity, and suicide risk in age- and birth-sex matched youth with FTLBs, Tourette syndrome (TS), and neurotypical controls. We performed specific subanalyses comparing individuals with FTLBs who identified as transgender/gender diverse (TGD) with cisgender individuals. RESULTS: Eighty-two youth participated (age range 11 to 25, 90% female at birth), including 35 with FTLBs, 22 with TS, and 25 neurotypical controls. A significantly higher proportion of participants with FTLB identified as TGD (15 of 35) than TS (two of 22) and neurotypical control (three of 25) participants. Compared with neurotypical controls, individuals with FTLBs had significantly lower quality of life, greater disability, loneliness, social phobia, anxiety symptoms, depressive symptoms, and suicidality. Compared with individuals with TS, individuals with FTLBs had more school/work absences due to tics, had more depressive symptoms, were more likely to be at high risk for suicidality, and had disability in self-care and life activity domains. There were no significant differences between cisgender and TGD participants with FTLB in any of the domains assessed. CONCLUSIONS: Youth with FTLB have unique health care needs and associations with anxiety, depression, sex, and gender.

Premonitory Urge in Patients with Tics and Functional Tic-like Behaviors.

BACKGROUND: Premonitory urges (PU) are well described in primary tics, but their frequency and intensity in functional tic-like behaviors (FTLB) are unclear. OBJECTIVE: To study the experience of PU in patients with FTLB. METHODS: We compared the results of the premonitory urge for tics scale (PUTS) in adults with tics and FTLB in the University of Calgary Adult Tic Registry. RESULTS: We included 83 patients with tics and 40 with FTLB. When comparing patients with tics, FTLB with tics and FTLB only, we did not detect significant differences either in the total PUTS score (P = 0.39), or in any of the individual PUTS item sub-scores (P values ranging between 0.11 and 0.99). CONCLUSIONS: Patients with FTLB report PU at similar frequency and intensity to patients with tics. This finding confirms that PU are not a useful feature to discriminate FTLB from tics.

Psychological Factors Associated with Functional Tic-like Behaviours during the COVID-19 Pandemic.

Functional tic-like behaviours (FTLB) are a female predominant functional neurological disorder that escalated in incidence during the SARS CoV2 pandemic. This study compared social and adaptive functioning, social media use, pandemic experiences, and psychiatric comorbidities between FTLB (n = 35), Tourette Syndrome (TS) (n = 22), and neurotypical (NT) (n = 25) participants ages 11 to 25 years. The psychiatric comorbidity burden for participants with FTLB was formidable, with frequencies ranging from 1.5 to 10 times higher for major depressive disorder and panic disorder compared to TS and NT participants. Borderline personality disorder (BPD), agoraphobia, social anxiety disorder, and generalized anxiety disorder were also significantly more common in FTLB compared to NT participants. Vulnerable attachment scores, social phobia and social interaction anxiety symptoms were higher in participants with FTLB than NT but not TS. Overall distress tolerance, resilient coping, suggestibility, hours on social media, and exposure to tic and TS content were not significantly different between groups. FTLB participants rated their mental health declined more severely during the pandemic than both TS and NT participants and were more likely to experience trouble sleeping, loneliness, and difficulty affording housing and food than NT participants. Participants with FTLB were significantly more likely to identify as gender minority people than TS and NT, though there were no significant differences based on gender identity in the study variables within the FTLB group. The association and potential pathways explaining how psychiatric disorders may be contributing to FTLB, and why certain groups appear at particular risk are discussed.

Are Cognitive Symptoms Part of the Phenotypic Spectrum of Idiopathic Adult-Onset Dystonia? Summary of Evidence from Controlled Studies.

BACKGROUND: Cognitive dysfunction has been reported in idiopathic adult-onset dystonia (IAOD), but whether this is a primary or secondary component of the disorder remains uncertain. OBJECTIVE: Here, we aimed to analyze the key domains of abnormal cognitive performance in IAOD and whether this is associated with motor or mood changes. METHODS: Article selection for our critical review was guided by PRISMA guidelines (mesh terms "dystonia" and "cognitive," publication period: 2000-2022). Only peer-reviewed, English-language original case-control studies involving patients with IAOD who were not exposed to dopamine- or acetylcholine-modulating agents and validated cognitive assessments were included. RESULTS: Abstract screening ultimately yielded 22 articles for full-text review and data extraction. A greater proportion of studies (17 of 22, 82%) reported abnormal cognitive performance in IAOD. Most of these studies focused on blepharospasm (BSP) and cervical dystonia (10 and 14, respectively). Most studies reporting cognitive impairment (11 of 17) identified multidomain impairment in cognition. Executive functions were the domain most frequently explored (14 of 22 studies), 79% of which detected worse performance in people with dystonia. Results related to other domains were inconclusive. Cognitive abnormalities were independent of motor symptoms in most studies (7 of 12) that explored this relationship and independent of mood status in all 8 that investigated this. CONCLUSIONS: Within IAOD, cognitive dysfunction (in particular, executive dysfunction) has been documented mainly in BSP and cervical dystonia. More comprehensive testing is warranted to assess abnormalities in other domains and in other forms of IAOD, as well as to evaluate longitudinal progression of cognitive disturbances in this condition.

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.

What are the Key Phenomenological Clues to Diagnose Functional Tic-Like Behaviors in the Pandemic Era?

BACKGROUND: Functional tic-like behaviors (FTLBs) can be difficult to distinguish from tics. OBJECTIVES: To describe the phenomenology of FTLBs in youth and assess the movements and vocalizations most suggestive of the diagnosis. METHODS: We compared the phenomenology of tics between youth (<20 yr) with FTLBs and with primary tics from our Registry in Calgary, Canada. RESULTS: Two hundred and thirty-six youths were included: 195 with primary tics (75% males; mean age: 10.8 yr) and 41 with FTLBs (98% females; 16.1 yr). In the bivariate models, FTLBs were most associated with copropraxia (OR = 15.5), saying words (OR = 14.5), coprolalia (OR = 13.1), popping (OR = 11.0), whistling (OR = 9.8), simple head movements (OR = 8.6), and self-injurious behaviors (OR = 6.9). In the multivariable model, FTLBs were still associated with saying words (OR = 13.5) and simple head movements (OR = 6.3). Only 12.2% of youth with FTLBs had throat clearing tics (OR = 0.2). CONCLUSIONS: This study shall help physicians diagnose youth with FTLBs according to the presence/association of specific movements and vocalizations.

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.

Evidence for a dissociation between moral reasoning and moral decision-making in Tourette syndrome.

Despite the growing interest on how Tourette syndrome (TS) affects social cognition skills, this field remains to date relatively under-explored. Here, we aim to advance knowledge on the topic by studying moral decision-making and moral reasoning in a group of adolescents with TS and a group of healthy controls. Overall, we found higher endorsement (i.e. a greater 'yes' response rate) for utilitarian solutions of incidental and instrumental moral dilemmas in TS compared to controls. By contrast, we reported an overall higher tendency of TS individuals to apply principles described in the moral foundation questionnaire to establish whether something is morally right or wrong. Our results document intact moral reasoning in TS and suggest that a deficit in suppressing inappropriate behaviours and/or altered sense of agency might be responsible for their higher utilitarian moral decision-making.

The neural representation of actions in Tourette syndrome as a window to decipher tics and their suppression.

This scientific commentary refers to 'Elevated representational similarity of voluntary action and inhibition in Tourette syndrome', by Rae et al. (https://doi.org/10.1093/braincomms/fcad224).

Tourette syndrome and other tic disorders of childhood.

Tics are repetitive, patterned, and nonrhythmic movements or vocalizations/audible sounds that are misplaced in context. Phenomenology and characteristics of tics (e.g., premonitory urge, suppressibility) differentiate them from compulsions, stereotypies, functional tic-like behaviors, and other types of hyperkinetic movement disorders. With a prevalence of approximately 1% in school-aged boys, Tourette syndrome (TS) is considered a common childhood-onset neurodevelopmental disorder, defined by the combination of at least two motor tics and at least one phonic tic lasting more than 1 year. TS is a highly heritable disorder, with a wide spectrum of severity. In some individuals, tics can cause pain, distress, functional impairment, or stigmatization. About 90% of individuals with TS have at least one mental health comorbidity (attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, anxiety/depressive disorders). These comorbidities significantly impact patients' quality of life and must therefore be screened and managed accordingly in this population. Treatment of tics is based on behavioral therapies targeting tics (habit reversal training included in the comprehensive behavioral intervention for tics, and exposure and response prevention for tics), in association with medication if needed (e.g., alpha-2-agonists, second-generation antipsychotics). Deep brain stimulation is considered an experimental option in the most severe, treatment-resistant patients. In adulthood, less than 25% of individuals still have moderate or severe tics.

Social cognition in hyperkinetic movement disorders: a systematic review.

Numerous lines of research indicate that our social brain involves a network of cortical and subcortical brain regions that are responsible for sensing and controlling body movements. However, it remains unclear whether movement disorders have a systematic impact on social cognition. To address this question, we conducted a systematic review examining the influence of hyperkinetic movement disorders (including Huntington disease, Tourette syndrome, dystonia, and essential tremor) on social cognition. Following the PRISMA guidelines and registering the protocol in the PROSPERO database (CRD42022327459), we analyzed 50 published studies focusing on theory of mind (ToM), social perception, and empathy. The results from these studies provide evidence of impairments in ToM and social perception in all hyperkinetic movement disorders, particularly during the recognition of negative emotions. Additionally, individuals with Huntington's Disease and Tourette syndrome exhibit empathy disorders. These findings support the functional role of subcortical structures (such as the basal ganglia and cerebellum), which are primarily responsible for movement disorders, in deficits related to social cognition.

Immunology and microbiome: Implications for motor systems.

Immune-inflammatory mechanisms seem to play a relevant role in neurodegenerative disorders affecting motor systems, particularly Parkinson's disease, where activity changes in inflammatory cells and evidence of neuroinflammation in experimental models and patients is available. Amyotrophic lateral sclerosis is also characterized by neuroinflammatory changes that involve primarily glial cells, both microglia and astrocytes, as well as systemic immune dysregulation associated with more rapid progression. Similarly, the exploration of gut dysbiosis in these two prototypical neurodegenerative motor disorders is advancing rapidly. Altered composition of gut microbial constituents and related metabolic and putative functional pathways is supporting a pathophysiological link that is currently explored in preclinical, germ-free animal models. Less compelling, but still intriguing, evidence suggests that motor neurodevelopmental disorders, e.g., Tourette syndrome, are associated with abnormal trajectories of maturation that include also immune system development. Microglia has a key role also in these disorders, and new therapeutic avenues aiming at its modulation are exciting prospects. Preclinical and clinical research on the role of gut dysbiosis in Tourette syndrome and related behavioral disorders is still in its infancy, but early findings support the rationale to delve deeper into its contribution to neural and immune maturation abnormalities in its spectrum.

What can epidemiological studies teach on the pathophysiology of adult-onset isolated dystonia?

Several demographic and environmental factors may play an important role in determining the risk of developing adult-onset isolated dystonia (AOID) and/or modifying its course. However, epidemiologic studies have provided to date only partial insight on the disease mechanisms that are actively influenced by these factors. The age-related increase in female predominance in both patients diagnosed with AOID and subjects carrying its putative mediational phenotype suggests sexual dimorphism that has been demonstrated for mechanisms related to blepharospasm and cervical dystonia. The opposite relationship that spread and spontaneous remission of AOID have with age suggests age-related decline of compensatory mechanisms that protect from the progression of AOID. Epidemiological studies focusing on environmental risk factors yielded associations only with specific forms of AOID, even for those factors that are not likely to predispose exclusively to specific focal forms (for example, only writing dystonia was found associated with head trauma, and only blepharospasm with coffee intake). Other factors show biological plausibility of their mechanistic role for specific forms, e.g., dry eye syndrome or sunlight exposure for blepharospasm, scoliosis for cervical dystonia, repetitive writing for writing dystonia. Overall, the relationship between environment and AOID remains complex and incompletely defined. Both hypothesis-driven preclinical studies and well-designed cross-sectional or prospective clinical studies are still necessary to decipher this intricate relationship.

Developmental stuttering, physical concomitants associated with stuttering, and Tourette syndrome: A scoping review.

BACKGROUND AND PURPOSE: Developmental stuttering and Tourette syndrome (TS) are common neurodevelopmental disorders. Although disfluencies may co-occur in TS, their type and frequency do not always represent pure stuttering. Conversely, core symptoms of stuttering may be accompanied by physical concomitants (PCs) that can be confused for tics. This scoping review aimed to explore the similarities and differences between stuttering and tics in terms of epidemiology, comorbidities, phenomenology, evolution, physiopathology, and treatment. We also described the nature of PCs in stuttering and disfluencies in TS. METHODS: A literature search on Medline, Embase and PsycInfo was executed in March 2022. From 426 studies screened, 122 were included in the review (a majority being narrative reviews and case reports). RESULTS: TS and stuttering have several epidemiological, phenomenological, comorbidity, and management similarities suggesting shared risk factors and physiopathology (involving the basal ganglia and their connections with speech and motor control cortical regions). PCs in stuttering commonly involve the face (eyelids, jaw/mouth/lip movements) and sometimes the head, trunk and limbs. PCs can be present from early stages of stuttering and vary over time and within individuals. The function of PCs is unknown. Some individuals with TS have a distinct disfluency pattern, composed of a majority of typical disfluencies (mostly between-word disfluencies), and a mix of cluttering-like behaviors, complex phonic tics (e.g. speech-blocking tics, echolalia, palilalia), and rarely, atypical disfluencies. CONCLUSION: Future investigations are warranted to better understand the complex relationships between tics and stuttering and address the management of disfluencies in TS and PCs in stuttering.

Study protocol: A cross-sectional survey of clinicians to identify barriers to clinical practice guideline implementation in the assessment and treatment of persistent tic disorders.

INTRODUCTION: Eight members of the International Parkinson's Disease and Movement Disorders Society Tic and Tourette Syndrome Study Group formed a subcommittee to discuss further barriers to practice guideline implementation. Based on expert opinion and literature review, the consensus was that practice variations continue to be quite broad and that many barriers in different clinical settings might negatively influence the adoption of the American Academy of Neurology and the European Society for the Study of Tourette Syndrome published guidelines. OBJECTIVES: 1) To identify how clinical practices diverge from the existing American Academy of Neurology and European Society for the Study of Tourette Syndrome guidelines, and 2) to identify categories of barriers leading to these clinical care gaps. METHODS AND ANALYSIS: This article presents the methodology of a planned cross-sectional survey amongst healthcare professionals routinely involved in the clinical care of patients with persistent tic disorders, aimed at 1) identifying how practices diverge from the published guidelines; and 2) identifying categories of barriers leading to these clinical care gaps. Purposeful sampling methods are used to identify and recruit critical persistent tic disorders stakeholders. The analysis will use descriptive statistics.

Patient experiences of virtual care across specialist neuroscience and psychiatry clinics related to the second wave of the COVID-19 pandemic in Calgary, Alberta.

Purpose: The emergence of the COVID-19 (SARS-CoV-2) pandemic has led to public health restrictions and a shift towards virtual care and telehealth. The aim of this study was to explore barriers and facilitators of virtual care from the perspective of neurological and psychiatric patients. Methods: One-on-one interviews were conducted remotely using telephone and online video teleconferencing. There was a total of 57 participants, and a thematic content analysis was conducted using NVivo software. Results: The two main themes were (1) virtual health service delivery and (2) virtual physician/patient interaction, with subthemes around how virtual care improved accessibility of care for patients and improved patient-centered care; how privacy and technical issues impact patients using virtual care; and the need for relationality and connection between health care providers and patients while using virtual care. Conclusions: This study showed that virtual care can increase accessibility and efficiency for patients and providers, indicating its potential for ongoing use in the delivery of clinical care. Virtual care was found to be an acceptable mode of healthcare delivery from the perspective of patients; however, there is a continued need for relationship-building between care providers and patients.