Tourette syndrome and other neurodevelopmental disorders: a comprehensive review

Sensory phenomena in children with Tourette syndrome or autism spectrum disorder

Background

Tourette syndrome (TS) and autism spectrum disorder (ASD) are two neurodevelopmental disorders with an onset before the age of 18 years. TS patients frequently reported atypical sensory phenomena (SP). Sensory processing abnormalities are also particularly frequent in ASD individuals.

Objectives

Considering the higher rate of atypical sensory behaviours in both neurodevelopmental disorders, in the present study we analysed sensory experiences in patients with ASD and in patients with TS.

Methods

We enrolled patients with a primary diagnosis of TS or ASD. All participants were assessed for primary diagnosis and associated comorbidities. The presence of sensory behaviours was investigated using the University of Sao Paulo's Sensory Phenomena Scale (USP-SPS).

Results

SP were significantly more represented in the ASD-group versus TS-group, except for sound just-right perceptions and energy to released. ASD participants presented higher mean scores in all fields of USP-SPS severity scale respect on TS patients and healthy controls. The USP-SPS total score had significant positive correlations with the CYBOCS and MASC total scores in the TS cohort. In the ASD group, the USP-SPS total score was significantly negative correlated with the total IQ and marginally positive correlated with ADOS total score.

Conclusion

SP are a frequently reported characteristic both of ASD and TS. Future studies are needed to better evaluate the differences on their phenomenology in patients with TS and ASD.

Altered dynamic functional and effective connectivity in drug-naive children with Tourette syndrome

Tourette syndrome (TS) is a developmental neuropsychiatric disorder characterized by repetitive, stereotyped, involuntary tics, the neurological basis of which remains unclear. Although traditional resting-state MRI (rfMRI) studies have identified abnormal static functional connectivity (FC) in patients with TS, dynamic FC (dFC) remains relatively unexplored. The rfMRI data of 54 children with TS and 46 typically developing children (TDC) were analyzed using group independent component analysis to obtain independent components (ICs), and a sliding-window approach to generate dFC matrices. All dFC matrices were clustered into two reoccurring states, the state transition metrics were obtained. We conducted Granger causality and nodal topological analyses to further investigate the brain regions that may play the most important roles in driving whole-brain switching between different states. We found that children with TS spent more time in state 2 (PFDR < 0.001), a state characterized by strong connectivity between ICs, and switched more quickly between states (PFDR = 0.025) than TDC. The default mode network (DMN) may play an important role in abnormal state transitions because the FC that changed the most between the two states was between the DMN and other networks. Additionally, the DMN had increased degree centrality, efficiency and altered causal influence on other networks. Certain alterations related to executive function (r = -0.309, P < 0.05) and tic symptom ratings (r = 0.282; 0.413, P < 0.05) may represent important aspects of the pathophysiology of TS. These findings facilitate our understanding of the neural basis for the clinical presentation of TS.

Morphological deficits of glial cells in a transgenic mouse model for developmental stuttering

Vocal production involves intricate neural coordination across various brain regions. Stuttering, a common speech disorder, has genetic underpinnings, including mutations in lysosomal-targeting pathway genes. Using a Gnptab-mutant mouse model linked to stuttering, we examined neuron and glial cell morphology in vocal production circuits. Our findings revealed altered astrocyte and microglia processes in these circuits in Gnptab-mutant mice, while control regions remained unaffected. Our results shed light on the potential role of glial cells in stuttering pathophysiology and highlight their relevance in modulating vocal production behaviors.

Clinical characteristics of comorbid tic disorders in autism spectrum disorder: exploratory analysis

BACKGROUND

The frequency, clinical characteristics, and associated symptoms of comorbid tic disorders in individuals with autism spectrum disorder (ASD) remain unclear.

METHODS

We included subsets of individuals from a larger genetic study who were diagnosed with ASD (n = 679; age: 4-18 years) and completed the Yale Global Tic Severity Scale (YGTSS) questionnaire. Based on the YGTSS score, the individuals were divided into two groups: ASD only (n = 554) and ASD with tics (n = 125). Individuals were assessed using the verbal and non-verbal intelligence quotient (IQ), Vineland Adaptive Behavior Scale (VABS-2), Social Responsiveness Scale-2 (SRS-2), Child Behavior Checklists (CBCL), and Yale-Brown Obsessive-Compulsive Scale (YBOCS), followed by between-group comparisons. All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) version 26.

RESULTS

Tic symptoms were observed in 125 (18.4%) participants; among them, most participants presented both motor and vocal tics (n = 40, 40.0%). The ASD with tics group had a significantly higher average age and full-scale IQ score than the ASD only group. After adjusting for age, the ASD with tics group had significantly higher scores in the SRS-2, CBCL, and YBOCS subdomains than the ASD only group. Furthermore, all variables except the non-verbal IQ and VABS-2 scores were positively correlated with the YGTSS total score. Finally, the proportion of tic symptoms was significantly higher among individuals with a higher IQ score (≥ 70).

CONCLUSIONS

The IQ score was positively correlated with the proportion of tic symptoms among individuals with ASD. Moreover, the severity of the core and comorbid symptoms of ASD was associated with the occurrence and severity of tic disorders. Our findings suggest the need for appropriate clinical interventions for individuals with ASD. Trial registration This study retrospectively registered participants.

Clarifying the Differences between Patients with Organic Tics and Functional Tic-Like Behaviors

Due to the global increase in the number of patients with Functional Tic-Like Behaviors (FTLB), it has become increasingly important to find reliable differences between this patient group and patients with organic tics (OTs), which can be used in differential diagnosis. The purpose of this retrospective study was to critically examine both established and suggested differences between the patient groups. A total of 53 FTLB patients and 200 OT patients were included. Several findings from the current literature were replicated in this study: Compared to patients with OTs, patients with FTLB had significantly more complex tics, were older at symptom onset, were more likely to be female, and were less likely to have family members with tics. Furthermore, the study also revealed new differences between the groups: Patients with FTLB had significantly more family members with a psychiatric disorder, were more likely to have experienced an adverse psychosocial event immediately before symptom onset, and had significantly fewer simple tics. Finally, this study was unable to replicate the previously found differences in comorbidities between patients with OTs and FTLB. These findings could contribute significantly to the understanding of FTLB's etiology and to improve diagnosis, as including the presence of simple tics and comorbidities in the diagnostic criteria might be discussed in future studies.

Former Training Relieves the Later Development of Behavioral Inflexibility in an Animal Model Overexpressing the Dopamine Transporter

A range of dopamine-dominating neuropsychiatric disorders present with cognitive deficits. In accordance, the dopamine transporter overexpressing rat model (DAT-tg rat) displays cognitive deficits by means of behavioral inflexibility and learning disabilities. It remains to be investigated when cognitive deficits emerge, due to the inherent DA irregularities, during the life course of the DAT-tg rat and what may relieve symptoms. The Morris water maze (MWM) was used to assess cognitive abilities in three cohorts of DAT-tg rats. In the first cohort, the development of cognitive deficits was assessed by repeatedly testing animals in the MWM at postnatal day (PND) 35, 60, and 90. In the second and third cohort, pharmacological interventions and transcranial direct current stimulation (tDCS) were tested in adult animals to understand what drives, and thus relieves, the deficits. Minor differences were observed between DAT-tg rats and control rats at PND 35 and 60, whereas cognitive deficits fully emerged at PND 90. A high dosage of methylphenidate diminished both behavioral inflexibility and improved learning abilities in adult rats. Interestingly, rats subjected early in life to the MWM also displayed improved behavioral flexibility as compared to rats naïve to the paradigm. Cognitive deficits gradually develop over time and fully emerge in adulthood. Pharmacological modulation of the ubiquitous DAT overexpression overall improves deficits in adult rats, whereas early training decreases later development of behavioral inflexibility. Thus, former training may constitute a preventive avenue that alters some aspects of cognitive deficits resulting from inherent DA abnormalities.

Increased Risk of Tourette Syndrome with Leukotriene Modifier Use in Children with Allergic Diseases and Asthma: A Nationwide Population-Based Study

(1) Background: Cysteinyl leukotriene receptor antagonists (LTRAs), including montelukast and zafirlukast, are FDA-approved for treating pediatric asthma and allergic diseases. Tourette syndrome (TS), a common neuropsychiatric disorder in children, is associated with allergic diseases and asthma. In this study, we investigated the risk of TS following an LTRA prescription for pediatric allergic diseases. (2) Methods: Children younger than 18 years of age who were newly diagnosed with asthma, allergic rhinitis, or atopic dermatitis between 1 January 2005 and 31 December 2018 and who were registered in the Taiwan National Health Insurance Research Database, which comprises the medical records of nearly 23 million Taiwanese population, were enrolled. LTRA users were matched with randomly selected LTRA non-users by sex, age, asthma-diagnosis year, and urbanization level. In total, 26,984 participants with allergic disease and TS were enrolled and included in the Cox proportional hazards model analysis. (3) Results: Children with allergic disease and asthma treated with LTRAs had a higher risk for TS than LTRA non-users (adjusted hazard ratio 1.376 [95% CI: 1.232−1.536], p < 0.001). LTRA users had a significantly higher risk for TS than LTRA non-users with allergic disease. The cumulative incidence of TS was significantly higher in LTRA users than in non-users with allergic diseases and asthma (log-rank test, p < 0.0001). (4) Conclusion: A prescription of LTRAs, mainly montelukast, increased the risk of TS among children with asthma, allergic rhinitis, or atopic dermatitis. The mechanism underlying the neuropsychiatric effect of LTRAs needs further investigation.

Annual Research Review: The transdiagnostic revolution in neurodevelopmental disorders

Practitioners frequently use diagnostic criteria to identify children with neurodevelopmental disorders and to guide intervention decisions. These criteria also provide the organising framework for much of the research focussing on these disorders. Study design, recruitment, analysis and theory are largely built on the assumption that diagnostic criteria reflect an underlying reality. However, there is growing concern that this assumption may not be a valid and that an alternative transdiagnostic approach may better serve our understanding of this large heterogeneous population of young people. This review draws on important developments over the past decade that have set the stage for much-needed breakthroughs in understanding neurodevelopmental disorders. We evaluate contemporary approaches to study design and recruitment, review the use of data-driven methods to characterise cognition, behaviour and neurobiology, and consider what alternative transdiagnostic models could mean for children and families. This review concludes that an overreliance on ill-fitting diagnostic criteria is impeding progress towards identifying the barriers that children encounter, understanding underpinning mechanisms and finding the best route to supporting them.

Identify aberrant white matter microstructure in ASD, ADHD and other neurodevelopmental disorders: A meta-analysis of diffusion tensor imaging studies

BACKGROUND

Neurodevelopmental disorders (NDDs) usually present overlapping symptoms. Abnormal white matter (WM) microstructure has been found in these disorders. Identification of common and unique neural abnormalities across NDDs could provide further insight into the underlying pathophysiological mechanisms.

METHODS

We performed a voxel-based meta-analysis of whole-brain diffusion tensor imaging (DTI) studies in autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD) and other NDDs. A systematic literature search was conducted through March 2020 to identify studies that compared measures of WM microstructure between patients with NDDs and neurotypical controls. Peak voxel coordinates were meta-analyzed via anisotropic effect size-signed differential mapping (AES-SDM) as well as activation likelihood estimation (ALE).

RESULTS

Our final sample included a total of 4137 subjects from 66 studies across five NDDs. Fractional anisotropy (FA) reductions were found in the splenium of the CC in ADHD, and the genu and splenium of CC in ASD. And mean diffusivity (MD) increases were shown in posterior thalamic radiation in ASD. No consistent abnormalities were detected in specific learning disorder, motor disorder or communication disorder. Significant differences between child/adolescent and adult patients were found within the CC across NDDs, reflective of aberrant neurodevelopmental processes in NDDs.

CONCLUSIONS

The current study demonstrated atypical WM patterns in ASD, ADHD and other NDDs. Microstructural abnormalities in the splenium of the CC were possibly shared among ASD and ADHD.

Use of Nutritional Supplements Based on L-Theanine and Vitamin B6 in Children with Tourette Syndrome, with Anxiety Disorders: A Pilot Study

Background: Tourette syndrome (TS) is a neurodevelopmental disorder characterized by tics and co-occurring disorders. It has been suggested that anxiety occurs in 2–45% patients affected by Tourette syndrome. Despite dietary and nutritional factors have been found to affect a range of neurological conditions, no more studies have investigated the relationship between nutritional supplements and tics. Objective: To evaluate the effectiveness of supplementation of both L-Theanine and Vitamin B6 in reducing tics and co-occurring disorders in a sample of youth with chronic tic disorder (CTD) or Tourette syndrome with anxiety symptoms. Design: A open-label trial. Patients affected by Tourette syndrome were randomized to receive nutritional supplements based on L-Theanine and vitamin B6, or psychoeducation (PE). Participants: 34 children (30 boys and 4 girls) aged between 4 and 17 years affected by Tourette syndrome or chronic tic disorder, associated with anxiety symptoms. Results: Patients in both groups showed a reduction in the severity of tic and anxiety symptoms. Supplementation with L-Theanine and vitamin B6 was significantly more effective than psychoeducation in reducing tics and co-occurring disorders, as measured by neuropsychological findings. Conclusions: Supplementation of both L-Theanine and Vitamin B6 may help in the treatment of tic disorders associated with anxious symptoms. Between-group differences in clinician-rated severity did reach statistical significance only for tics. Despite this finding, further placebo-controlled trials are needed.

Concordance and comorbidities among monozygotic twins with tic disorders

Gilles de la Tourette Syndrome (GTS) is a multifactorial neurodevelopmental disorder characterized by tics and multiple comorbidities. The pathophysiology is not yet fully understood, but both environmental and genetic risk factors seem to be involved. Twin studies provide important knowledge on genetic factors. We assessed the concordance of GTS and chronic tic disorders (CTD) in monozygotic (MZ) twins, and examined tic severity, symptoms of obsessive-compulsive disorder (OCD), attention deficit/hyperactivity disorder and autism spectrum disorder. Twin pairs, where at least one twin was diagnosed with any tic disorder, were identified through Danish Twin Registry, Psychiatric Central Registry, Danish National Patient Registry and National Tourette Clinic, Copenhagen University Hospital, Herlev. Zygosity was tested with single-nucleotide polymorphism (SNP) genotyping and clinical assessment was done with validated tools. 14 MZ twin pairs were included: five were discordant. Seven twin pairs were concordant for GTS, and for two pairs one twin had GTS and the other CTD. Among the twins with CTD or GTS, 50% had at least one comorbidity, which is higher than in background populations. The GTS + OCD-phenotype was significantly more frequent among GTS-concordant than among discordant twins. No statistically significant differences were found between the GTS-concordant and discordant twin pairs regarding tic severity or comorbidities. Thorough clinical assessment and SNP-based genotyping are important when conducting clinical twin studies. We found high concordance of GTS and CTD, which supports the notion that both disorders have common genetic risk factors. Further studies with larger cohorts including dizygotic twins are warranted for more conclusive results.

Psychosocial stress, self-esteem, and social adjustment: A moderated mediation analysis in Taiwanese adolescents with Tourette syndrome

PURPOSE

Recent studies have shown that tics and related comorbidities can cause poorer social adjustment, lower self-esteem, and higher psychosocial stress among adolescents with Tourette syndrome. This study explored the role of self-esteem in mediating the relationship between psychosocial stress and social adjustment among adolescents with Tourette syndrome, and the role of comorbidities in moderating the relationship between self-esteem and social adjustment.

DESIGN AND METHODS

In this descriptive cross-sectional study, 118 Taiwanese adolescents with Tourette syndrome aged between 12 and 20 years old were recruited via convenience sampling. Their demographic information, Yale Global Tic Severity Scale, stress index for children and adolescents with Tourette syndrome, social adjustment scale for adolescents with Tourette syndrome, and Self-Esteem Scale results were collected. Moderated mediation analysis of the study data was performed with the Hayes's PROCESS macro.

RESULTS

Our results revealed that the self-esteem of adolescents with Tourette syndrome fully mediates the relationship between their psychosocial stress and social adjustment (B = -0.0703, 95% CI, [-0.0176, -0.001]), while comorbidities moderates the relationship between their self-esteem and social adjustment (B = -0.8416, 95% CI, [-1.4529, -0.2302]). The relationship between self-esteem and social adjustment was more pronounced in adolescents without comorbidities than those with comorbidities.

CONCLUSIONS

Psychosocial stress correlates negatively with social adjustment and self-esteem, and indirectly influences social adjustment through self-esteem, while comorbidities (particularly their absence) moderates the relationship between self-esteem and social adjustment.

PRACTICE IMPLICATIONS

Different self-esteem strengthening programs to enhance social adjustment for adolescents with Tourette syndrome may be developed in future studies.

Investigating Shared Genetic Basis Across Tourette Syndrome and Comorbid Neurodevelopmental Disorders Along the Impulsivity-Compulsivity Spectrum

BACKGROUND

Tourette syndrome (TS) is often found comorbid with other neurodevelopmental disorders across the impulsivity-compulsivity spectrum, with attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD) as most prevalent. This points to the possibility of a common etiological thread along an impulsivity-compulsivity continuum.

METHODS

Investigating the shared genetic basis across TS, ADHD, ASD, and OCD, we undertook an evaluation of cross-disorder genetic architecture and systematic meta-analysis, integrating summary statistics from the latest genome-wide association studies (93,294 individuals, 6,788,510 markers).

RESULTS

As previously identified, a common unifying factor connects TS, ADHD, and ASD, while TS and OCD show the highest genetic correlation in pairwise testing among these disorders. Thanks to a more homogeneous set of disorders and a targeted approach that is guided by genetic correlations, we were able to identify multiple novel hits and regions that seem to play a pleiotropic role for the specific disorders analyzed here and could not be identified through previous studies. In the TS-ADHD-ASD genome-wide association study single nucleotide polymorphism-based and gene-based meta-analysis, we uncovered 13 genome-wide significant regions that host single nucleotide polymorphisms with a high posterior probability for association with all three studied disorders (m-value > 0.9), 11 of which were not identified in previous cross-disorder analysis. In contrast, we also identified two additional pleiotropic regions in the TS-OCD meta-analysis. Through conditional analysis, we highlighted genes and genetic regions that play a specific role in a TS-ADHD-ASD genetic factor versus TS-OCD. Cross-disorder tissue specificity analysis implicated the hypothalamus-pituitary-adrenal gland axis in TS-ADHD-ASD.

CONCLUSIONS

Our work underlines the value of redefining the framework for research across traditional diagnostic categories.

Comorbid chronic tic disorder and tourette syndrome in children requiring inpatient mental health treatment

OBJECTIVE

Children needing admission to an inpatient mental health unit often present with severe neuropsychiatric disorders characterised by complex psychopathology. We aimed to examine all admitted children with comorbid chronic tic disorder (CTD) and Tourette syndrome (TS) over a 10-year period and determine the clinical significance of these diagnoses.

METHOD

A retrospective, naturalistic study was conducted, comparing children with and without CTD/TS in terms of co-morbid diagnoses, medication use, access to education, aggression contributing to the admission, duration of admission, functional outcomes and satisfaction with treatment. Data were analysed using Chi-square/Fisher's exact test and t-test for categorical and continuous variables, respectively, and subsequently with unadjusted and adjusted linear and logistic regression analyses.

RESULTS

A relatively high proportion of children had co-morbid CTD/TS (19.7%). There was a significant association with co-morbid obsessive-compulsive disorder, intellectual disability and autism spectrum disorder but not attention deficit hyperactivity disorder. CTD/TS were associated with longer admissions even after adjustments for confounding but did not seem to be independently associated with other examined clinical characteristics.

CONCLUSIONS

The prevalence of CTD/TS in children needing inpatient treatment is significant. In our sample, comorbid CTD/TS seem to represent a marker of overall symptom severity as evidenced by longer admissions.

Role of Ash1l in Tourette syndrome and other neurodevelopmental disorders

Ash1l potentially contributes to neurodevelopmental diseases. Although specific Ash1l mutations are rare, they have led to informative studies in animal models that may bring therapeutic advances. Ash1l is highly expressed in the brain and correlates with the neuropathology of Tourette syndrome (TS), autism spectrum disorder, and intellectual disability during development, implicating shared epigenetic factors and overlapping neuropathological mechanisms. Functional convergence of Ash1l generated several significant signaling pathways: chromatin remodeling and transcriptional regulation, protein synthesis and cellular metabolism, and synapse development and function. Here, we systematically review the literature on Ash1l, including its discovery, expression, function, regulation, implication in the nervous system, signaling pathway, mutations, and putative involvement in TS and other neurodevelopmental traits. Such findings highlight Ash1l pleiotropy and the necessity of transcending a single gene to complicated mechanisms of network convergence underlying these diseases. With the progress in functional genomic analysis (highlighted in this review), and although the importance and necessity of Ash1l becomes increasingly apparent in the medical field, further research is required to discover the precise function and molecular regulatory mechanisms related to Ash1l. Thus, a new perspective is proposed for basic scientific research and clinical interventions for cross‐disorder diseases.

Using Online Support Communities for Tourette Syndrome and Tic Disorders: Online Survey of Users' Experiences

Background

People living with a tic disorder (TD)—such as Tourette syndrome (TS)—experience many negative psychological and social challenges arising from chronic tics, such as stigmatization from peers and poorer quality of life, and these can impact upon their families too. It can be difficult for this population to access face-to-face support for tics, and so online support communities offer one avenue for support from peers facing similar experiences. However, little is known about how online support communities may be used by people with TS and other TDs, and by others (eg, parents, caregivers) supporting a person with TS/TD.

Objective

This study aimed to explore users’ experiences of participation in online support communities for TS and TDs.

Methods

In total, 90 respondents (aged 13-62 years; 62% [56/90] female) from 13 countries completed an online survey exploring their experiences of using online support communities for TS and TDs. Respondents were people living with TS/TD themselves (n=68) or supportive others of someone with TS/TD (eg, parent, sibling, spouse; n=14), or both (n=8). The online survey contained open-ended questions eliciting their self-reported motivations for using online communities, their benefits and drawbacks of participation, and whether online support communities affected offline management of tics. Responses were analyzed using thematic analysis.

Results

Seven overarching themes captured experiences of using online support communities for TS/TDs. The overwhelming reason for their use was to find accessible support due to a lack of offline face-to-face support. Online support communities were valued sources of informational and emotional support, and also had a positive impact upon helping users’ psychological well-being. Online communities helped provide a space where people with TS/TDs could feel accepted and reduce the social isolation they felt offline. The suggestible nature of tics and being reminded of the challenging nature of TDs were main disadvantages arising from using online support communities, alongside conflict arising within online communities.

Conclusions

The findings suggest that online support communities appear to offer valuable informational and emotional support to those living with TS/TD and their families too, especially given the lack of locally available support. This facilitates a sense of community online, which can help users in overcoming long-standing social isolation and aid self-reported improvements in psychosocial well-being. Users reported some drawbacks in engaging with online support communities, such as conflict between different types of users and triggering content, which negatively affected experiences of community participation.

Incidence of Autism Spectrum Disorder in Youths Affected by Gilles de la Tourette Syndrome Based on Data from a Large Single Italian Clinical Cohort

Gilles de la Tourette syndrome (GTS) and autism spectrum disorder (ASD) are etiologically related neurodevelopmental disorders with an onset age before 18 years and a reported comorbidity of 2.9–20%. The aim of the present study was to identify the incidence of ASD in a large clinical sample of individuals affected by GTS and to compare our results with previously reported incidences. We retrospectively analyzed clinical data (n = 1200) from January 2010 to March 2019 obtained from the outpatient Catania Tourette Clinic, part of the Child and Adolescent Neurology and Psychiatry of the Medical and Experimental Department of Catania University. We used internationally validated evaluation tools. The neuropsychological evaluation was carried out by an expert and a certificated team of child and adolescent neurologists, supervised by two expert child neurologists (R.R. and M.G.). We investigated 975 GTS-affected individuals of various socioeconomic levels aged 5–18 years, and 8.9% (n = 87) were affected by ASD. The incidence of GTS with ASD was significantly lower (p < 0.001) in children than in adolescents. No statistically significant differences were found in the sex distribution and age of onset of tics between individuals with GTS alone and those with GTS and ASD. The incidence of GTS and ASD comorbidity in this study was high, and this has several implications in terms of treatment and prognosis.

Rage attacks in Tourette Syndrome and Chronic Tic Disorder: a systematic review

Tourette syndrome (TS) and chronic motor/vocal tic disorder (CTD) are neurodevelopmental conditions defined by the occurrence of multiple tics. Besides the well-known association with attention deficit/hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD), rage attacks (RA) represent common and detrimental symptoms for patients. Inorder to explore prevalence of RA in tic disorders, relation to tic severity/comorbidities and available treatments, we performed a systematic literature review based on PRISMA Guidelines. 32 studies published between January 2008 - December 2019 were deemed suitable for the analysis and provided a prevalence of 20-67 %. Most findings showed a direct correlation with tic severity and a significant impact on psychosocial functioning. Although apparently related to comorbid ADHD, RA also frequently occur as independent manifestations. Association with other comorbidities, such as OCD, impulse control and mood disorders has also been reported, not yet fully established. Behavioral interventions appear to be effective, whereas there is limited evidence concerning the efficacy of medication. In TS/CTD, RA may be regarded as a major comorbidity that requires clinical investigation in order to develop personalized treatments.

Inherited duplication of the pseudoautosomal region Xq28 in a subject with Gilles de la Tourette syndrome and intellectual disability: a case report

Background

Tourette syndrome (TS) is a complex neurodevelopmental disorder (NDD) characterized by multiple chronic involuntary motor and vocal tics with onset during childhood or adolescence. Most TS patients present with additional comorbidities, typically attention deficit hyperactivity disorder (ADHD), obsessive- compulsive disorder (OCD), autism spectrum disorder (ASD) and intellectual disability (ID). Both TS and ID are genetically complex disorders that likely occur as a result of the effects of multiple genes interacting with other environmental factors. In addition to single gene mutations and chromosomal disorders, copy number variations (CNVs) are implicated across many NDDs and ID and contribute to their shared genetic etiology. Screening of CNVs using microarray-based Comparative Genomic Hybridization (aCGH) is now routinely performed in all subjects with NDD and ID.

Case presentation

We report a case of a 12-year-old girl diagnosed with Gilles de la Tourette Syndrome associated to behavior disorders and intellectual disability in particular with regard to language. Array-CGH analysis showed a CNV of a subtelomeric region Xq28 (gain of 260 kb) inherited from the healthy father. The duplication contains two genes, VAMP7 and SPRY3 of the PAR2 pseudoautosomal region. FISH analysis revealed that the duplicated segment is located on the short arm of a chromosome 13, resulting in a trisomy of the region. In the proband the expression levels of the genes evaluated in the peripheral blood sample are comparable both those of the mother and to those of female control subjects.

Conclusions

Although the trisomy of the 260 kb region from Xq28 identified in proband is also shared by the healthy father, it is tantalizing to speculate that, together with genetic risk factors inherited from the mother, it may play a role in the development of a form of Tourette syndrome with intellectual disability. This hypothesis is also supported by the fact that both genes present in the duplicated region (VAMP7 and SPRY3) are expressed in the CNS and are implicated in neurotransmission and neurite growth and branching. In addition, similar CNVs have been identified in individuals whose phenotype is associated with autism spectrum disorders or intellectual disability.

A double-blind, randomized, sham-controlled study of cranial electrotherapy stimulation as an add-on treatment for tic disorders in children and adolescents

AIM

The aim of this study was to determine the efficacy and safety of cranial electrotherapy stimulation (CES) as an add-on treatment for TD.

METHODS

A randomized, double-blind, sham-controlled trial was conducted at an outpatient, single-center academic setting. A total of 62 patients aged 6-17 years with TD and lack of clinical response to 4 weeks' pharmacotherapy were enrolled. Patients were divided randomly into 2 groups and given 4 weeks' treatment, including 30 min sessions of active CES (500 μA-2 mA) or sham CES (lower than 100 μA) per day for 40 d on weekdays. Change in Yale Global Tic Severity Scale (YGTSS), Clinical Global Impression-severity of illness-severity (CGI-S) and Hamilton Anxiety Scale-14 items (HAMA-14) were performed at baseline, week 2, week 4. Adverse events (AEs) were also evaluated.

RESULTS

53 patients (34 males and 9 females) completed the trial, including 29 in the active CES group and 24 in the sham CES group. Both groups showed clinical improvement in tic severities compared to baseline respectively at week 4. Participants receiving active CES showed a reduction of 31.66 % in YGTSS score, compared with 23.96 % in participants in sham CES group, resulting in no significant difference between the two groups (t = 1.54, p = 0.13).

CONCLUSION

Four-week's treatment of CES for children and adolescents with TD is effective and safe, but the improvement for tic severity may be related to placebo effect.

Correlation between premonitory urges and tic symptoms in a Chinese population with tic disorders

IMPORTANCE

Tics usually start around 4-6 years old and affect about 1% of school-age children. Premonitory urges (PUs) are sensory phenomena that precede tics and are often described as unpleasant feelings. Recent evidence supports a relationship between PUs and tic severity, but reports are conflicting. In addition, there is no report of PUs in the Chinese population.

OBJECTIVE

To investigate the correlation between PUs and tic symptoms in the Chinese population with tic disorders.

METHODS

We recruited 252 Chinese individuals with chronic tic disorders (age 5-16 years). The Yale Global Tic Severity Scale (YGTSS) was used to assess tic symptoms, and the Premonitory Urge for Tics Scale (PUTS) was used to assess PUs. We calculated Spearman correlations between PUTS and YGTSS scores, and constructed a linear regression model to predict the tic symptom severity by PUs.

RESULTS

There was a significant positive correlation between PU severity (PUTS scores) and motor tic severity, total tic severity, tic-caused impairment (YGTSS scores) (P < 0.05). PU severity was a significant positive predictor of tic symptom severity (standardized beta coefficient = 0.174, t = 2.786, P = 0.006).

INTERPRETATION

We provide evidence for a correlation between PUs and tic symptoms. PU severity predicts tic symptom severity. Further research on PUs is needed to clarify the shared brain mechanism with tics, and their role in tic expression. A suitable tool to assess PUs in younger children is also needed.

Assessment and Management of Tic Disorders in Pediatric Primary Care Settings

Purpose of Review

Pediatricians and other primary care providers are often the first and sole healthcare clinicians of patients who present with tics. However, limited primary care pediatric training in neuropsychiatric concerns, as well as perceived lack of comfort and preparation, make it challenging for these clinicians to confidently identify and manage tic disorders.

Recent Findings

Current empirical findings of tic disorder management relevant to pediatric physicians, including assessment, psychoeducation, behavioral interventions, psychotropic medications, and alternative treatments are reviewed.

Summary

This article discusses neuropsychiatric and medical complexities of tic disorder assessment, with particular emphasis on differential and comorbid diagnoses. Tiered referral recommendations, based on symptom severity, impairment, and consideration of comorbid conditions, are provided. Future directions for tic management, including dissemination of evidence-based treatments of tic disorders and multidisciplinary teams within pediatric primary care settings, are included.

Clinical and genetic analysis of children with a dual diagnosis of Tourette syndrome and autism spectrum disorder

Gilles de la Tourette Syndrome (TS) is a neurodevelopmental disorder that causes children to make repeated, brief involuntary movements or sounds. TS can be co-morbid with other neurodevelopmental disorders, including autism spectrum disorder (ASD). Clusters of biologically related genes have been associated with neurodevelopmental disorders, suggesting shared pathologies. However, the genetic contribution to TS remains poorly defined. We asked whether children with both TS and ASD differed clinically from children with ASD alone, and identified potentially deleterious genetic events in children with TS and ASD. We compared clinical data from 119 children with ASD and TS to 2603 children with ASD, all from the Simons Simplex Collection. We performed gene set enrichment analysis on de novo genetic events in children with both TS and ASD to identify candidate genes and pathways, and compared these genes and pathways with those previously identified in TS. Children with TS and ASD were diagnosed at an older age, had higher IQ scores, and had more restricted and repetitive behavior than children with ASD but not TS. Gene Ontology analysis revealed that proteins important for specific biological pathways, including regulation of calcium ion-dependent exocytosis, basement membrane organization, and visual behavior and learning, and specific cellular pathways, including basal lamina and ciliary transition zone, are enriched among genes with de novo mutations in children with TS and ASD. Clinical and genetic analysis of cohorts of affected children can help to determine the underlying pathophysiology of TS and other neurodevelopmental disorders.

A Review on Functional Analyses of Tics

Tic disorders are characterized by a class of responses assumed to be neurobiological in origin. Still, several studies have shown that tic frequency can be influenced by antecedent environmental events and social consequences. Prior reviews have summarized the effects of environmental events but have not examined relations between tic diagnosis, behavioral deficits (e.g., intellectual disability), tic topography, and the consequences observed to maintain tics. These variables might be important when attempting to predict or identify relevant consequences. A more thorough understanding of the variables that maintain and give rise to tics might also be useful in predicting responsiveness to treatment and intervention refinement. We reviewed and summarized results from the 13 attempts to experimentally identify maintaining consequences for tics (i.e., functional analyses) that have been published to date. We examined patterns of functions across tic diagnoses (i.e., Tourette's syndrome or not), communication impairments (i.e., an intellectual disability or reported language difficulty), and tic topography. Results suggested that individuals with Tourette's syndrome and those without communication impairments are more likely to have functional analysis outcomes consistent with automatic reinforcement, but exceptions in both directions highlight the utility of functional analysis in treating tics.

Motor dysfunction as research domain across bipolar, obsessive-compulsive and neurodevelopmental disorders

Although genuine motor abnormalities (GMA) are frequently found in schizophrenia, they are also considered as an intrinsic feature of bipolar, obsessive-compulsive, and neurodevelopmental disorders with early onset such as autism, ADHD, and Tourette syndrome. Such transnosological observations strongly suggest a common neural pathophysiology. This systematic review highlights the evidence on GMA and their neuroanatomical substrates in bipolar, obsessive-compulsive, and neurodevelopmental disorders. The data lends support for a common pattern contributing to GMA expression in these diseases that seems to be related to cerebello-thalamo-cortical, fronto-parietal, and cortico-subcortical motor circuit dysfunction. The identified studies provide first evidence for a motor network dysfunction as a correlate of early neurodevelopmental deviance prior to clinical symptom expression. There are also first hints for a developmental risk factor model of these mental disorders. An in-depth analysis of motor networks and related patho-(physiological) mechanisms will not only help promoting Research Domain Criteria (RDoC) Motor System construct, but also facilitate the development of novel psychopharmacological models, as well as the identification of neurobiologically plausible target sites for non-invasive brain stimulation.