Frontal Cortex Hyperactivation and Gamma Desynchrony in Fragile X Syndrome: Correlates of Auditory Hypersensitivity.

Fragile X syndrome (FXS) is an X-linked disorder that often leads to intellectual disability, anxiety, and sensory hypersensitivity. While sound sensitivity (hyperacusis) is a distressing symptom in FXS, its neural basis is not well understood. It is postulated that hyperacusis may stem from temporal lobe hyperexcitability or dysregulation in top-down modulation. Studying the neural mechanisms underlying sound sensitivity in FXS using scalp electroencephalography (EEG) is challenging because the temporal and frontal regions have overlapping neural projections that are difficult to differentiate. To overcome this challenge, we conducted EEG source analysis on a group of 36 individuals with FXS and 39 matched healthy controls. Our goal was to characterize the spatial and temporal properties of the response to an auditory chirp stimulus. Our results showed that males with FXS exhibit excessive activation in the frontal cortex in response to the stimulus onset, which may reflect changes in top-down modulation of auditory processing. Additionally, during the chirp stimulus, individuals with FXS demonstrated a reduction in typical gamma phase synchrony, along with an increase in asynchronous gamma power, across multiple regions, most strongly in temporal cortex. Consistent with these findings, we observed a decrease in the signal-to-noise ratio, estimated by the ratio of synchronous to asynchronous gamma activity, in individuals with FXS. Furthermore, this ratio was highly correlated with performance in an auditory attention task. Compared to controls, males with FXS demonstrated elevated bidirectional frontotemporal information flow at chirp onset. The evidence indicates that both temporal lobe hyperexcitability and disruptions in top-down regulation play a role in auditory sensitivity disturbances in FXS. These findings have the potential to guide the development of therapeutic targets and back-translation strategies.

Accelerated Theta Burst Transcranial Magnetic Stimulation for Refractory Depression in Autism Spectrum Disorder.

PURPOSE: Major depressive disorder (MDD) disproportionately affects those living with autism spectrum disorder (ASD) and is associated with significant impairment and treatment recidivism. METHODS: We studied the use of accelerated theta burst stimulation (ATBS) for the treatment of refractory MDD in ASD (3 treatments daily x 10 days). This prospective open-label 12-week trial included 10 subjects with a mean age of 21.5 years, randomized to receive unilateral or bilateral stimulation of the dorsolateral prefrontal cortex. RESULTS: One participant dropped out of the study due to intolerability. In both treatment arms, depressive symptoms, scored on the Hamilton Depression Rating Scale scores, diminished substantially. At 12 weeks post-treatment, full remission was sustained in 5 subjects and partial remission in 3 subjects. Treatment with ATBS, regardless of the site of stimulation, was associated with a significant, substantial, and sustained improvement in depressive symptomatology via the primary outcome measure, the Hamilton Depression Rating Scale. Additional secondary measures, including self-report depression scales, fluid cognition, and sleep quality, also showed significant improvement. No serious adverse events occurred during the study. Mild transient headaches were infrequently reported, which are expected side effects of ATBS. CONCLUSION: Overall, ATBS treatment was highly effective and well-tolerated in individuals with ASD and co-occurring MDD. The findings support the need for a larger, sham-controlled randomized controlled trial to further evaluate efficacy of ATBS in this population.

Differences in Tic Severity Among Adolescent Girls and Boys with Tourette Syndrome During the Pandemic.

Limited data are available regarding the impact of the coronavirus disease 2019 (COVID-19) pandemic on adolescents with Tourette syndrome (TS). We sought to compare sex differences in tic severity experienced by adolescents before and during the COVID-19 pandemic. We extracted from the electronic health record and retrospectively reviewed Yale Global Tic Severity Scores (YGTSS) from adolescents (ages 13 through 17) with TS presenting to our clinic before (36 months) and during (24 months) the pandemic. A total of 373 unique adolescent patient encounters (prepandemic: 199; pandemic: 173) were identified. Compared with prepandemic, girls accounted for a significantly greater proportion of visits during the pandemic (p < 0.001). Prepandemic, tic severity did not differ between girls and boys. During the pandemic, compared with girls, boys had less clinically severe tics (p = 0.003). During the pandemic, older girls, but not boys, had less clinically severe tics (ρ =- 0.32, p = 0.003). These findings provide evidence that, regarding tic severity assessed with YGTSS, the experiences of adolescent girls and boys with TS have differed during the pandemic.

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.

Access to Pediatric Neurology Training and Services Worldwide: A Survey by the International Child Neurology Association.

Pediatric neurology is the medical subspecialty responsible for diagnosing and managing diseases and disorders of the nervous system in childhood and adolescence. In many, but not all, regions of the world, the discipline of pediatric neurology is recognized as a specialty or subspecialty of either neurology or pediatrics. Significant knowledge and competencies in this area are necessary to be effective in clinical practice. The need for this is driven by the high burden of disease from neurologic conditions in children and the effect on their families. As the first part of a multistaged project under the auspices of the International Child Neurology Association, in collaboration with key stakeholders, a survey was undertaken to establish which countries have practicing child neurologists. For those countries that have child neurologists, the survey established the number of practitioners and which countries have access to in-country child neurology training. Responses were obtained from 177 countries. Worldwide, there is a median of 0.07 and mean of 0.39 child neurologists per 100,000 population. The greatest deficits in child neurology specialists and access to training were evident in countries which fell under the World Bank rating of low-income country status (range of 0-0.008 child neurologists per 100,000 population). Seventy-three percent of low-income countries lack access to child neurologists: The majority are in the African and South-East Asia regions. For the population of 1.37 billion in the continent of Africa, there were 324 child neurologists, equating to a median of 0.01 per 100,000 population in comparison with a median of 0.59 child neurologists per 100,000 across high-income countries. Ninety-four countries had capacity to support in-country pediatric neurology training. Worldwide, there are inadequate numbers of child neurologists and a great need for increased training capacity.

Development of cancer surveillance guidelines in ataxia telangiectasia: A Delphi-based consensus survey of international experts.

BACKGROUND/OBJECTIVES: Ataxia telangiectasia (A-T) is a multiorgan disorder with increased vulnerability to cancer. Despite this increased cancer risk, there are no widely accepted guidelines for cancer surveillance in people affected by A-T. We aimed to understand the current international practice regarding cancer surveillance in A-T and agreed-upon approaches to develop cancer surveillance in A-T. DESIGN/METHODS: We used a consensus development method, the e-Delphi technique, comprising three rounds. Round 1 consisted of a Delphi questionnaire and a survey that collected the details of respondents' professional background, experience, and current practice of cancer surveillance in A-T. Rounds 2 and 3 were designed based on previous rounds and modified according to the comments made by the panellists. The pre-specified consensus threshold was ≥75% agreement. RESULTS: Thirty-five expert panellists from 13 countries completed the study. The survey indicated that the current practice of cancer surveillance varies widely between experts and centres'. Consensus was reached that evidence-based guidelines are needed for cancer surveillance in people with A-T, with separate recommendations for adults and children. Statements relating to the tests that should be included, the age for starting and stopping cancer surveillance and the optimal surveillance interval were also agreed upon, although in some areas, the consensus was that further research is needed. CONCLUSION: The international expert consensus statement confirms the need for evidence-based cancer surveillance guidelines in A-T, highlights key features that the guidelines should include, and identifies areas of uncertainty in the expert community. This elucidates current knowledge gaps and will inform the design of future clinical trials.

Empirical Frequency Bound Derivation Reveals Prominent Mid-Frontal Alpha Associated with Neurosensory Dysfunction in Fragile X Syndrome.

The FMR1 gene is inactive in Fragile X syndrome (FXS), resulting in low levels of FMRP and consequent neurochemical, synaptic, and local circuit neurophysiological alterations in the fmr1 KO mouse. In FXS patients, electrophysiological studies have demonstrated a marked reduction in global alpha activity and regional increases in gamma oscillations associated with intellectual disability and sensory hypersensitivity. Since alpha activity is associated with a thalamocortical function with widely distributed modulatory effects on neocortical excitability, insight into alpha physiology may provide insight into systems-level disease mechanisms. Herein, we took a data-driven approach to clarify the temporal and spatial properties of alpha and theta activity in participants with FXS. High-resolution resting-state EEG data were collected from participants affected by FXS (n = 65) and matched controls (n = 70). We used a multivariate technique to empirically classify neural oscillatory bands based on their coherent spatiotemporal patterns. Participants with FXS demonstrated: 1) redistribution of lower-frequency boundaries indicating a "slower" dominant alpha rhythm, 2) an anteriorization of alpha frequency activity, and 3) a correlation of increased individualized alpha power measurements with auditory neurosensory dysfunction. These findings suggest an important role for alterations in thalamocortical physiology for the well-established neocortical hyper-excitability in FXS and, thus, a role for neural systems level disruption to cortical hyperexcitability that has been studied primarily at the local circuit level in animal models.

Adolescent Gender Differences in Tic- and Non-Tic-Related Impairments in Tourette Syndrome.

We aimed to compare tic- and non-tic-related impairment experienced by adolescent girls and boys (ages 13 through 17) with Tourette syndrome and associations with age. We extracted from the electronic health record child and parental responses to the mini-Child Tourette Syndrome Impairment Scale (mini-CTIM) and other questionnaire data reflective of tic- and non-tic-related impairment of adolescents with Tourette syndrome presenting to our clinic over a 12-month period. We identified a total of 132 (49 female, 83 male) unique adolescent encounters. Mini-CTIM scores did not differ significantly between genders. Tic- and non-tic-related impairment were lower in older boys, but not older girls. Obsessive-compulsive symptoms correlated with parent-reported non-tic-related impairment experienced by adolescent girls but not boys. During adolescence, tic- and non-tic-related impairments may be less likely to improve with age in girls. Future longitudinal studies are needed to confirm this finding.

Biomarkers of tic severity in children with Tourette syndrome: Motor cortex inhibition measured with transcranial magnetic stimulation.

AIM: To compare transcranial magnetic stimulation (TMS)-derived measures of primary motor cortex (M1) physiology between children with and without Tourette syndrome, and to dimensionally analyze TMS measures with Tourette syndrome-related symptom severity. METHOD: We used a cross-sectional experimental design. Sixty 8- to 12-year-old children participated (30 with Tourette syndrome: three females, mean age 10 years 10 months, standard deviation [SD] 1 year 3 months; 30 typically developing children: seven females, mean age 10 years 7 months, SD 1 year 3 months). In the group with Tourette syndrome, 15 (one female, mean age 10 years 11 months, SD 1 year 3 months) had comorbid attention-deficit/hyperactivity disorder (ADHD), rated with the Conners, Third Edition and the parent-reported ADHD rating scales. Tic severity was rated with the Yale Global Tic Severity Scale and urge severity with the Individualized Premonitory Urge for Tics Scale. M1 short-interval cortical inhibition (SICI) and intracortical facilitation were compared between diagnostic groups and, within the group with Tourette syndrome, correlated with symptom severity using linear mixed-effects models for repeated measures. RESULTS: Accounting for ADHD, we found no difference in SICI or intracortical facilitation in those with Tourette syndrome versus typically developing children (p > 0.1). In the group with Tourette syndrome, reduced M1 SICI predicted greater total (p = 0.012) and global (p = 0.002) tic severity. There were no associations with urge severity (p > 0.5). INTERPRETATION: Reduced M1 SICI is robustly associated with increased tic, but not urge, severity. WHAT THIS PAPER ADDS: Increased tic severity is associated with reduced motor cortex short-interval cortical inhibition (SICI). Children with Tourette syndrome with increased urge severity also show increased tic severity. However, reduced motor cortex SICI is associated with tic, but not urge, severity.

Motor Function and Physiology in Youth With Neurofibromatosis Type 1.

BACKGROUND: Neurofibromatosis type 1 (NF1) is a genetic neurocutaneous disorder commonly associated with motor and cognitive symptoms that greatly impact quality of life. Transcranial magnetic stimulation (TMS) can quantify motor cortex physiology, reflecting the basis for impaired motor function as well as, possibly, clues for mechanisms of effective treatment. We hypothesized that children with NF1 have impaired motor function and altered motor cortex physiology compared to typically developing (TD) control children and children with attention-deficit/hyperactivity disorder (ADHD). METHODS: Children aged 8-17 years with NF1 (n = 21) were compared to children aged 8-12 years with ADHD (n = 59) and TD controls (n = 88). Motor development was assessed using the Physical and Neurological Examination for Subtle Signs (PANESS) scale. The balance of inhibition and excitation in motor cortex was assessed using the TMS measures short-interval cortical inhibition (SICI) and intracortical facilitation (ICF). Measures were compared by diagnosis and tested using bivariate correlations and regression for association with clinical characteristics. RESULTS: In NF1, ADHD severity scores were intermediate between the ADHD and TD cohorts, but total PANESS scores were markedly elevated (worse) compared to both (P < 0.001). Motor cortex ICF (excitatory) was significantly lower in NF1 than in TD and ADHD (P < 0.001), but SICI (inhibitory) did not differ. However, in NF1, better PANESS scores correlated with lower SICI ratios (more inhibition; ρ = 0.62, P = 0.003) and lower ICF ratios (less excitation; ρ = 0.38, P = 0.06). CONCLUSIONS: TMS-evoked SICI and ICF may reflect processes underlying abnormal motor function in children with NF1.

Spectrum of Pediatric to Early Adulthood POLR3A-Associated Movement Disorders.

Background: POLR3A pathogenic variants are associated with hypomyelination, hypodontia, hypogonadism, and movement disorders. Cases: We describe the range of movement disorders seen in six patients (four female, two male) with POLR3A variants [three novel (c.2214del, c.3775G>A, c.3905G>T) and six previously reported (c.760C>T, c.1771-7C>G, c.1909+22G>A, c.2005C>T, c.2422C>T, c.3337-11T>C)]. Patient 1 presented with a neonatal progeroid syndrome and developed parkinsonism, dystonia, ataxia, and spasticity. Patient 2 presented with infant-onset rapidly progressive chorea, and dystonia. Three patients (patients 3, 5, 6) presented predominantly with ataxia in combination with spasticity and dystonia. Patient 4 developed segmental dystonia during adolescence and ataxia in early adulthood. Four patients had vertical gaze impairment. The most common brain MRI abnormality was T2-weighted/FLAIR hyperintensity of the superior cerebellar peduncles and midbrain. Conclusion: POLR3A-related disorders exhibit significant phenotypic pleomorphism. Vertical gaze dysfunction and T2-weighted/FLAIR hyperintensity of the superior cerebellar peduncles and midbrain may be useful signs suggestive of this condition.

Ecopipam for Tourette Syndrome: A Randomized Trial.

BACKGROUND AND OBJECTIVES: All US Food and Drug Administration-approved medications for Tourette syndrome are antipsychotics, and their use is limited by the risk of weight gain, metabolic changes, and drug-induced movement disorders. Several small trials suggest that ecopipam, a first-in-class, selective dopamine 1 receptor antagonist, reduces tics with a low risk for these adverse events. This trial sought to further evaluate the efficacy, safety, and tolerability of ecopipam in children and adolescents with moderate to severe Tourette syndrome. METHODS: This was a multicenter, randomized, double-blind, placebo-controlled, phase 2b trial. Subjects aged ≥6 to <18 years with a baseline Yale Global Tic Severity Score Total Tic Score of ≥20 were randomly assigned 1:1 to ecopipam (n = 76) or placebo (n = 77). The primary endpoint was mean change over 12 weeks in the Yale Global Tic Severity Score Total Tic Score. The Clinical Global Impression of Tourette Syndrome Severity was the secondary endpoint. Safety and tolerability were evaluated at each study visit. RESULTS: Total tic scores were significantly reduced from baseline to 12 weeks in the ecopipam group compared with placebo (least squares mean differences -3.44, 95% confidence interval -6.09 to -0.79, P = .01). Improvement in Clinical Global Impression of Tourette Syndrome Severity was also greater in the ecopipam group (P = .03). More weight gain was seen in subjects assigned to placebo. No metabolic or electrocardiogram changes were identified. Headache (15.8%), insomnia (14.5%), fatigue (7.9%), and somnolence (7.9%) were the most common adverse events. CONCLUSIONS: Among children and adolescents with TS, ecopipam reduces tics to a greater extent than placebo, without observable evidence of common antipsychotic-associated side effects.

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.

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

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

ACR Appropriateness Criteria® Ataxia-Child.

Childhood ataxia may be due to multifactorial causes of impairment in the coordination of movement and balance. Acutely presenting ataxia in children may be due to infectious, inflammatory, toxic, ischemic, or traumatic etiology. Intermittent or episodic ataxia in children may be manifestations of migraine, benign positional vertigo, or intermittent metabolic disorders. Nonprogressive childhood ataxia suggests a congenital brain malformation or early prenatal or perinatal brain injury, and progressive childhood ataxia indicates inherited causes or acquired posterior fossa lesions that result in gradual cerebellar dysfunction. CT and MRI of the central nervous system are the usual modalities used in imaging children presenting with ataxia, based on the clinical presentation. This document provides initial imaging guidelines for a child presenting with acute ataxia with or without a history of recent trauma, recurrent ataxia with interval normal neurological examination, chronic progressive ataxia, and chronic nonprogressive ataxia. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Deep Brain Stimulation for Pediatric Dystonia: A Review of the Literature and Suggested Programming Algorithm.

Deep brain stimulation (DBS) is an established intervention for use in pediatric movement disorders, especially dystonia. Although multiple publications have provided guidelines for deep brain stimulation patient selection and programming in adults, there are no evidence-based or consensus statements published for pediatrics. The result is lack of standardized care and underutilization of this effective treatment. To this end, we assembled a focus group of 13 pediatric movement disorder specialists and 1 neurosurgeon experienced in pediatric deep brain stimulation to review recent literature and current practices and propose a standardized approach to candidate selection, implantation target site selection, and programming algorithms. For pediatric dystonia, we provide algorithms for (1) programming for initial session and follow-up sessions, and (2) troubleshooting side effects encountered during programming. We discuss common side effects, how they present, and recommendations for management. This topical review serves as a resource for movement disorders specialists interested in using deep brain stimulation for pediatric dystonia.