Efficacy and safety of combined deep brain stimulation with capsulotomy for comorbid motor and psychiatric symptoms in Tourette's syndrome: Experience and evidence

OBJECTIVES

To evaluate the efficacy and safety of combined deep brain stimulation (DBS) with capsulotomy for comorbid motor and psychiatric symptoms in patients with Tourette's syndrome (TS).

METHODS

This retrospective cohort study consecutively enrolled TS patients with comorbid motor and psychiatric symptoms who were treated with combined DBS and anterior capsulotomy at our center. Longitudinal motor, psychiatric, and cognitive outcomes and quality of life were assessed. In addition, a systematic review and meta-analysis were performed to summarize the current experience with the available evidence.

RESULTS

In total, 5 eligible patients in our cohort and 26 summarized patients in 6 cohorts were included. After a mean 18-month follow-up, our cohort reported that motor symptoms significantly improved by 62.4 % (P = 0.005); psychiatric symptoms of obsessive-compulsive disorder (OCD) and anxiety significantly improved by 87.7 % (P < 0.001) and 78.4 % (P = 0.009); quality of life significantly improved by 61.9 % (P = 0.011); and no significant difference was found in cognitive function (all P > 0.05). Combined surgery resulted in greater improvements in psychiatric outcomes and quality of life than DBS alone. The synthesized findings suggested significant improvements in tics (MD: 57.92, 95 % CI: 41.28-74.56, P < 0.001), OCD (MD: 21.91, 95 % CI: 18.67-25.15, P < 0.001), depression (MD: 18.32, 95 % CI: 13.26-23.38, P < 0.001), anxiety (MD: 13.83, 95 % CI: 11.90-15.76, P < 0.001), and quality of life (MD: 48.22, 95 % CI: 43.68-52.77, P < 0.001). Individual analysis revealed that the pooled treatment effects on motor symptoms, psychiatric symptoms, and quality of life were 78.6 %, 84.5-87.9 %, and 83.0 %, respectively. The overall pooled rate of adverse events was 50.0 %, and all of these adverse events were resolved or alleviated with favorable outcomes.

CONCLUSIONS

Combined DBS with capsulotomy is effective for relieving motor and psychiatric symptoms in TS patients, and its safety is acceptable. However, the optimal candidate should be considered, and additional experience is still necessary.

Pharmacological treatment of Tourette's syndrome: from the past to the future

Tourette's syndrome (TS) is a neuropsychiatric disease featuring tics and vocal tics, with a prevalence of approximately 1%, including 75% of the total number of male patients. TS seriously disturbs the patients' career, education, and life and brings a serious and unbearable psychological burden to the patients themselves and their families. At present, there are no specific clinical medications recommended for treating TS. Therefore, it is necessary to select the appropriate medication for symptomatic treatment based on the doctor's personal experience and the patient's symptoms, with the main goal of relieving symptoms, thus improving the patient's social skills and psychological problems. Here we conducted a comprehensive search on PubMed to review and organize the history and current status of the development of drug therapy for TS through a timeline format. We also systematically evaluated the effects of each drug for TS treatment to summarize the current problems and new research directions and to provide some ideas for clinical treatment.

Causal associations between COVID-19 and childhood mental disorders

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can invade both the peripheral and central nervous systems and impact the function of the brain. Therefore, it is necessary to evaluate the mutual influences between COVID-19 outcomes and childhood mental disorders.

METHODS

We examined genetic correlations and potential causalities between three childhood mental disorders and three COVID-19 phenotypes by genetically proxied analyses. The three mental disorders included attention-deficit/hyperactivity disorder (ADHD, N = 292,548), Tourette's syndrome (TS, N = 14,307), and autism spectrum disorder (ASD, N = 46,350). The three COVID-19 traits included SARS-CoV-2 infection (N = 2,597,856), hospitalized COVID-19 (N = 2,095,324), and critical COVID-19 (N = 1,086,211). Literature-based analysis was used to build gene-based pathways connecting ADHD and COVID-19.

RESULTS

ADHD was positively correlated with the three COVID-19 outcomes (Rg: 0.22 ~ 0.30). Our Mendelian randomization (MR) analyses found that ADHD confers a causal effect on hospitalized COVID-19 (odds ratio (OR): 1.36, 95% confidence interval (CI): 1.10-1.69). TS confers a causal effect on critical COVID-19 (OR: 1.14, 95% CI: 1.04-1.25). Genetic liability to the COVID-19 outcomes may not increase the risk for the childhood mental disorders. Pathway analysis identified several immunity-related genes that may link ADHD to COVID-19, including CRP, OXT, IL6, PON1, AR, TNFSF12, and IL10.

CONCLUSIONS

Our study suggests that both ADHD and TS may augment the severity of COVID-19 through immunity-related pathways. However, our results did not support a causal role of COVID-19 in the risk for the childhood mental disorders.

Antioxidant Behavioural Phenotype in the Immp2l Gene Knock-Out Mouse

Mitochondrial dysfunction is strongly associated with autism spectrum disorder (ASD) and the Inner mitochondrial membrane protein 2-like (IMMP2L) gene is linked to autism inheritance. However, the biological basis of this linkage is unknown notwithstanding independent reports of oxidative stress in association with both IMMP2L and ASD. To better understand IMMP2L's association with behaviour, we developed the Immp2lKD knockout (KO) mouse model which is devoid of Immp2l peptidase activity. Immp2lKD -/- KO mice do not display any of the core behavioural symptoms of ASD, albeit homozygous Immp2lKD -/- KO mice do display increased auditory stimulus-driven instrumental behaviour and increased amphetamine-induced locomotion. Due to reports of increased ROS and oxidative stress phenotypes in an earlier truncated Immp2l mouse model resulting from an intragenic deletion within Immp2l, we tested whether high doses of the synthetic mitochondrial targeted antioxidant (MitoQ) could reverse or moderate the behavioural changes in Immp2lKD -/- KO mice. To our surprise, we observed that ROS levels were not increased but significantly lowered in our new Immp2lKD -/- KO mice and that these mice had no oxidative stress-associated phenotypes and were fully fertile with no age-related ataxia or neurodegeneration as ascertained using electron microscopy. Furthermore, the antioxidant MitoQ had no effect on the increased amphetamine-induced locomotion of these mice. Together, these findings indicate that the behavioural changes in Immp2lKD -/- KO mice are associated with an antioxidant-like phenotype with lowered and not increased levels of ROS and no oxidative stress-related phenotypes. This suggested that treatments with antioxidants are unlikely to be effective in treating behaviours directly resulting from the loss of Immp2l/IMMP2L activity, while any behavioural deficits that maybe associated with IMMP2L intragenic deletion-associated truncations have yet to be determined.

Immp2l knockdown in male mice increases stimulus-driven instrumental behaviour but does not alter goal-directed learning or neuron density in cortico-striatal circuits in a model of Tourette syndrome and autism spectrum disorder

Cortico-striatal neurocircuits mediate goal-directed and habitual actions which are necessary for adaptive behaviour. It has recently been proposed that some of the core symptoms of autism spectrum disorder (ASD) and Gilles de la Tourette syndrome (GTS), such as tics and other repetitive behaviours, may emerge because of imbalances in these neurocircuits. We have recently developed a model of ASD and GTS by knocking down Immp2l, a mitochondrial gene frequently associated with these disorders. The current study sought to determine whether Immp2l knockdown (KD) in male mice alters flexible, goal- or cue- driven behaviour using procedures specifically designed to examine response-outcome and stimulus-response associations, which underlie goal-directed and habitual behaviour, respectively. Whether Immp2l KD alters neuron density in cortico-striatal neurocircuits known to regulate these behaviours was also examined. Immp2l KD mice and wild type-like mice (WT) were trained on Pavlovian and instrumental learning procedures where auditory cues predicted food delivery and lever-press responses earned a food outcome. It was demonstrated that goal-directed learning was not changed for Immp2l KD mice compared to WT mice, as lever-press responses were sensitive to changes in the value of the food outcome, and to contingency reversal and degradation. There was also no difference in the capacity of KD mice to form habitual behaviours compared to WT mice following extending training of the instrumental action. However, Immp2l KD mice were more responsive to auditory stimuli paired with food as indicated by a non-specific increase in lever response rates during Pavlovian-to-instrumental transfer. Finally, there were no alterations to neuron density in striatum or any prefrontal cortex or limbic brain structures examined. Thus, the current study suggests that Immp2l is not necessary for learned maladaptive goal or stimulus driven behaviours in ASD or GTS, but that it may contribute to increased capacity for external stimuli to drive behaviour. Alterations to stimulus-driven behaviour could potentially influence the expression of tics and repetitive behaviours, suggesting that genetic alterations to Immp2l may contribute to these core symptoms in ASD and GTS. Given that this is the first application of this battery of instrumental learning procedures to a mouse model of ASD or GTS, it is an important initial step in determining the contribution of known risk-genes to goal-directed versus habitual behaviours, which should be more broadly applied to other rodent models of ASD and GTS in the future.

Creative thinking in Tourette's syndrome: A comparative study of patients and healthy controls

INTRODUCTION

Tourette's syndrome is a neurological disorder characterized by tics, that may interfere with patients' everyday life. Research suggested that creative thinking (namely, divergent and convergent thinking) could help patients cope with their symptoms, and therefore it can be a resource in non-pharmacological interventions. The present study aimed at investigating (i) possible differences in creative thinking between Tourette's syndrome patients and healthy controls and (ii) whether creative thinking can support patients in coping with their symptomatology.

METHODS

A group of 25 Tourette's syndrome patients and 25 matched healthy controls underwent an assessment of creative thinking, fluid intelligence, and depressive symptoms. Creative thinking was compared between patients and healthy controls after controlling for fluid intelligence and depressive symptoms. Moreover, the moderating role of divergent and convergent thinking on the subjective impact of tics was tested in a group of 30 patients.

RESULTS

Tourette's syndrome patients outperformed healthy controls in convergent thinking. Moreover, divergent thinking was found as a significant moderator of the relationship between tics severity and the subjective impact in Tourette's syndrome patients.

CONCLUSIONS

Findings highlighted the specific impact of convergent and divergent thinking on Tourette's syndrome patients. Considering the supportive role of creative thinking in Tourette's syndrome, our results confirm that higher levels of divergent thinking may reduce the tic-related discomfort. These findings suggest the potential positive implications of creative thinking in non-pharmacological interventions for Tourette's syndrome.

Preliminary Experience with a Four-Lead Implantable Pulse Generator for Deep Brain Stimulation

BACKGROUND

Implantable pulse generators (IPGs) store energy and deliver electrical impulses for deep brain stimulation (DBS) to treat neurological and psychiatric disorders. IPGs have evolved over time to meet the demands of expanding clinical indications and more nuanced therapeutic approaches.

OBJECTIVES

The aim of this study was to examine the workflow of the first 4-lead IPG for DBS in patients with complex disease.

METHOD

The engineering capabilities, clinical use cases, and surgical technique are described in a cohort of 12 patients with epilepsy, essential tremor, Parkinson's disease, mixed tremor, and Tourette's syndrome with comorbid obsessive-compulsive disorder between July 2021 and July 2022.

RESULTS

This system is a rechargeable 32-channel, 4-port system with independent current control that can be connected to 8 contact linear or directionally segmented leads. The system is ideal for patients with mixed disease or those with multiple severe symptoms amenable to >2 lead implantations. A multidisciplinary team including neurologists, radiologists, and neurosurgeons is necessary to safely plan the procedure. There were no serious intraoperative or postoperative adverse events. One patient required revision surgery for bowstringing.

CONCLUSIONS

This new 4-lead IPG represents an important new tool for DBS surgery with the ability to expand lead implantation paradigms for patients with complex disease.

Me, My Tics and I: An Exploration of Self-Identity and its Implications for Psychological Wellbeing in Young Women with Tourette's Syndrome

Women with Tourette's syndrome (TS) continue to be under-researched, despite female sex being associated with increased tic-related impairment in adulthood. Existing literature indicates that individuals with TS are more likely than the general population to report self-stigma, but little is known about the subjective identities of women with TS and how this relates to psychological wellbeing. Semi-structured interviews were conducted via Zoom with a purposive sample of 11 females. All were diagnosed with TS and aged 18-28. Data was transcribed verbatim and thematic analysis applied. Five themes were established: "I'm not normal", "I just want to be me", I'm a "people pleaser", seeing oneself as an "outsider", and "it's just part of me…it's not going anywhere". Difficulties with self-acceptance and the autonomy to be one's true self were noted and appeared to be intensified by stereotypical gender roles and attempts to conceal tics. Findings also suggested that personal growth and feelings of mastery can be achieved through embracing TS as part of one's identity, or recognising it as just one aspect of the self. Psychological support focused on accepting and living with tics rather than reducing them may benefit this population and is currently difficult to access. Consideration should also be given to improving the availability of support groups where women with TS can meet others like themselves.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10882-023-09911-x.

Adult-specific Reelin expression alters striatal neuronal organization: implications for neuropsychiatric disorders

In addition to neuronal migration, brain development, and adult plasticity, the extracellular matrix protein Reelin has been extensively implicated in human psychiatric disorders such as schizophrenia, bipolar disorder, and autism spectrum disorder. Moreover, heterozygous reeler mice exhibit features reminiscent of these disorders, while overexpression of Reelin protects against its manifestation. However, how Reelin influences the structure and circuits of the striatal complex, a key region for the above-mentioned disorders, is far from being understood, especially when altered Reelin expression levels are found at adult stages. In the present study, we took advantage of complementary conditional gain- and loss-of-function mouse models to investigate how Reelin levels may modify adult brain striatal structure and neuronal composition. Using immunohistochemical techniques, we determined that Reelin does not seem to influence the striatal patch and matrix organization (studied by μ-opioid receptor immunohistochemistry) nor the density of medium spiny neurons (MSNs, studied with DARPP-32). We show that overexpression of Reelin leads to increased numbers of striatal parvalbumin- and cholinergic-interneurons, and to a slight increase in tyrosine hydroxylase-positive projections. We conclude that increased Reelin levels might modulate the numbers of striatal interneurons and the density of the nigrostriatal dopaminergic projections, suggesting that these changes may be involved in the protection of Reelin against neuropsychiatric disorders.

The Alternation of Gray Matter Morphological Topology in Drug-Naïve Tourette's Syndrome in Children

Tourette syndrome (TS) is a neurodevelopment disorder characterized by motor and phonic tics. We investigated the topological alterations in pediatric TS using morphological topological analysis of brain structures. We obtained three-dimensional T1-weighted magnetic resonance imaging (MRI) sequences from 59 drug-naïve pediatric patients with TS and 87 healthy controls. We identified morphological topographical alterations in the brains of patients with TS compared to those of the healthy controls via GRETNA software. At the global level, patients with TS exhibited increased global efficiency (E glob ) (p = 0.012) and decreased normalized characteristic path length (λ) (p = 0.027), and characteristic path length (Lp) (p = 0.025) compared to healthy controls. At the nodal level, we detected significant changes in the nodal betweenness, nodal degree, and nodal efficiency in the cerebral cortex-striatum-thalamus-cortex circuit. These changes mainly involved the bilateral caudate nucleus, left thalamus, and gyri related to tics. Nodal betweenness, nodal degree, and nodal efficiency in the right superior parietal gyrus were negatively correlated with the motor tic scores of the Yale Global Tic Severity Scale (YGTSS) (r = -0.328, p = 0.011; r = -0.310, p = 0.017; and r = -0.291, and p = 0.025, respectively). In contrast, nodal betweenness, nodal degree, and nodal efficiency in the right posterior cingulate gyrus were positively correlated with the YGTSS phonic tic scores (r = 0.353, p = 0.006; r = 0.300, p = 0.021; r = 0.290, and p = 0.026, respectively). Nodal betweenness in the right supplementary motor area was positively correlated with the YGTSS phonic tic scores (r = 0.348, p = 0.007). The nodal degree in the right supplementary motor area was positively correlated with the YGTSS phonic tic scores (r = 0.259, p = 0.048). Diagnosis by age interactions did not display a significant effect on brain network properties at either the global or nodal level. Overall, our findings showed alterations in the gray matter morphological networks in drug-naïve children with TS. These findings enhance our understanding of the structural topology of the brain in patients with TS and provide useful clues for exploring imaging biomarkers of TS.

Pediatric neuropsychiatric syndromes associated with infection and microbiome alterations: clinical findings, possible role of the mucosal epithelium, and strategies for the development of new animal models

INTRODUCTION

: Subsets of pediatric obsessive-compulsive disorder (OCD) and autism spectrum disorder (ASD) respectively have been associated with respiratory tract infections and alterations in the intestinal microbiome. Pediatric Acute-onset Neuropsychiatric Syndromes (PANS) refers to the sudden onset of neuropsychiatric symptoms that are triggered by several different infectious and non-infectious factors. Clinical studies and animal modeling are consistent with the proposal that inflammation plays an important etiological role in PANS, as well as in ASD associated with gut dysbiosis.

AREAS COVERED

The authors provide an overview of clinical studies of PANS and ASD associated with gastrointestinal symptoms, as well as the current strategies for studying these syndromes in rodent models. Finally, the authors highlight similarities between these syndromes that may provide clues to common etiological mechanisms.

EXPERT OPINION

Although data from existing animal models are consistent with an important role for anti-neuronal antibodies in PANS triggered by GAS infection, we lack models for identifying pathophysiological mechanisms of PANS associated with other infectious and non-infectious triggers. The authors propose a strategy for developing such models that incorporates known vulnerability and triggering factors for PANS into the modeling process. This novel strategy should expand our understanding of the pathophysiology of PANS, as well as facilitate the development of new pharmacological treatments for PANS and related syndromes.

A Process-Oriented View of Procedural Memory Can Help Better Understand Tourette's Syndrome

Tourette's syndrome (TS) is a neurodevelopmental disorder characterized by repetitive movements and vocalizations, also known as tics. The phenomenology of tics and the underlying neurobiology of the disorder have suggested that the altered functioning of the procedural memory system might contribute to its etiology. However, contrary to the robust findings of impaired procedural memory in neurodevelopmental disorders of language, results from TS have been somewhat mixed. We review the previous studies in the field and note that they have reported normal, impaired, and even enhanced procedural performance. These mixed findings may be at least partially be explained by the diversity of the samples in both age and tic severity, the vast array of tasks used, the low sample sizes, and the possible confounding effects of other cognitive functions, such as executive functions, working memory or attention. However, we propose that another often overlooked factor could also contribute to the mixed findings, namely the multiprocess nature of the procedural system itself. We propose that a process-oriented view of procedural memory functions could serve as a theoretical framework to help integrate these varied findings. We discuss evidence suggesting heterogeneity in the neural regions and their functional contributions to procedural memory. Our process-oriented framework can help to deepen our understanding of the complex profile of procedural functioning in TS and atypical development in general.

Association of Prenatal Maternal Anemia with Tics and Tourette's Syndrome in Offspring

Iron deficiency anemia (IDA) accounts for most of the anemia in pregnancy, and iron is essential for neurodevelopment. Tics and Tourette’s syndrome (TS) are neurodevelopmental disorders that manifest in childhood. A few studies reported an inconclusive association between iron deficiency and tics in children. No study has investigated the relationship between prenatal maternal anemia and tics in children. We aimed to assess the relationship between prenatal anemia exposure and the incidence of tics or TS in offspring. We linked the Taiwan National Health Insurance Research Database to the Maternal and Child Health Database for the analysis and identified 153,854 children with prenatal anemia exposure and 2,014,619 children without prenatal anemia exposure from 2004 to 2016 and followed them through 2017. Cox regression models were applied to compare the risk of tics or TS between the exposed and nonexposed groups. Among the exposed group, 37,832 were exposed at ≤12 weeks of gestational age (GA) and 116,022 at >12 weeks of GA. We observed an increased risk of tics and TS in those exposed at ≤12 weeks compared with the nonexposed group (adjusted hazard ratio (aHR) = 1.23, 95% confidence interval (CI): 1.12–1.34). The result remained consistent after adjusting for birth year, sex, birth order, maternal age, low-income levels, gestational age, birth weight, and alcohol use and smoking during pregnancy (aHR = 1.16, CI: 1.04–1.28). Fetuses exposed to maternal anemia at ≤12 weeks of GA are at high risk of tics or TS. However, this effect was attenuated to insignificance in the sibling comparison. Our study highlights the importance of detection of anemia during pregnancy and proper timing of iron supplementation.

Urge Intolerance and Impairment Among Youth with Tourette's and Chronic Tic Disorders

Individuals with Tourette's Disorder and Persistent Tic Disorders (TD) often experience premonitory urges-aversive sensations that precede tics and are relieved by tic expression. Given its role in the neurobehavioral model of TD, understanding factors that influence premonitory urges and associated relief can advance understanding of urge phenomenology and optimize treatments for individuals with TD. This study examined whether the novel construct of urge intolerance-difficulty tolerating premonitory urges-predicted tic severity and tic-related disability. Participants included 75 youth with TD and their caregivers. Assessments characterized tic severity, premonitory urge, distress tolerance, internalizing symptoms, and tic-related disability. Structural equation modeling revealed that higher levels of urge intolerance predicted greater levels of tic-related disability. Furthermore, the relationship between urge intolerance and tic-related disability was more robust for youth with clinically-elevated levels of internalizing symptoms. While further investigation is needed, urge intolerance represents a promising treatment target to improve tic-related disability in youth with TD.

The Histaminergic System in Neuropsychiatric Disorders

Histamine does not only modulate the immune response and inflammation, but also acts as a neurotransmitter in the mammalian brain. The histaminergic system plays a significant role in the maintenance of wakefulness, appetite regulation, cognition and arousal, which are severely affected in neuropsychiatric disorders. In this review, we first briefly describe the distribution of histaminergic neurons, histamine receptors and their intracellular pathways. Next, we comprehensively summarize recent experimental and clinical findings on the precise role of histaminergic system in neuropsychiatric disorders, including cell-type role and its circuit bases in narcolepsy, schizophrenia, Alzheimer's disease, Tourette's syndrome and Parkinson's disease. Finally, we provide some perspectives on future research to illustrate the curative role of the histaminergic system in neuropsychiatric disorders.

Amplified engagement of prefrontal cortex during control of voluntary action in Tourette syndrome

Tourette syndrome is characterized by ‘unvoluntary’ tics, which are compulsive, yet often temporarily suppressible. The inferior frontal gyrus is implicated in motor control, including inhibition of pre-potent actions through influences on downstream subcortical and motor regions. Although tic suppression in Tourette syndrome also engages the inferior frontal gyrus, it is unclear whether such prefrontal control of action is also dysfunctional: Tic suppression studies do not permit comparison with control groups, and neuroimaging studies of motor inhibition can be confounded by the concurrent expression or suppression of tics. Here, patients with Tourette syndrome were directly compared to control participants when performing an intentional inhibition task during functional MRI. Tic expression was recorded throughout for removal from statistical models. Participants were instructed to make a button press in response to Go cues, withhold responses to NoGo cues, and decide whether to press or withhold to ‘Choose’ cues. Overall performance was similar between groups, for both intentional inhibition rates (% Choose-Go) and reactive NoGo inhibition commission errors. A subliminal face prime elicited no additional effects on intentional or reactive inhibition. Across participants, the task activated prefrontal and motor cortices and subcortical nuclei, including pre-supplementary motor area, inferior frontal gyrus, insula, caudate nucleus, thalamus and primary motor cortex. In Tourette syndrome, activity was elevated in the inferior frontal gyrus, insula and basal ganglia, most notably within the right inferior frontal gyrus during voluntary action and inhibition (Choose-Go and Choose-NoGo), and reactive inhibition (NoGo-correct). Anatomically, the locus of this inferior frontal gyrus hyperactivation during control of voluntary action matched that previously reported for tic suppression. In Tourette syndrome, activity within the caudate nucleus was also enhanced during both intentional (Choose-NoGo) and reactive (NoGo-correct) inhibition. Strikingly, despite the absence of overt motor behaviour, primary motor cortex activity increased in patients with Tourette syndrome but decreased in controls during both reactive and intentional inhibition. Additionally, severity of premonitory sensations scaled with functional connectivity of the pre-supplementary motor area to the caudate nucleus, globus pallidus and thalamus when choosing to respond (Choose-Go). Together, these results suggest that patients with Tourette syndrome use equivalent prefrontal mechanisms to suppress tics and withhold non-tic actions, but require greater inferior frontal gyrus engagement than controls to overcome motor drive from hyperactive downstream regions, notably primary motor cortex. Moreover, premonitory sensations may cue midline motor regions to generate tics through interactions with the basal ganglia.

Altered sense of agency in Gilles de la Tourette syndrome: behavioural, clinical and functional magnetic resonance imaging findings

Current neurocognitive models of motor control postulate that accurate action monitoring is crucial for a normal experience of agency-the ability to attribute the authorship of our actions and their consequences to ourselves. Recent studies demonstrated that action monitoring is impaired in Gilles de la Tourette syndrome, a movement disorder characterized by motor and vocal tics. It follows that Tourette syndrome patients may suffer from a perturbed sense of agency, the hypothesis tested in this study. To this end, we recruited 25 Tourette syndrome patients and 25 matched healthy controls in a case-control behavioural and functional magnetic resonance imaging study. As an implicit index of the sense of agency, we measured the intentional binding phenomenon, i.e., the perceived temporal compression between voluntary movements and their external consequences. We found evidence of an impaired sense of agency in Tourette syndrome patients who, as a group, did not show a significant intentional binding. The more reduced was the individual intentional binding, the more severe were the motor symptoms. Specific differences between the two groups were also observed in terms of brain activation patterns. In the healthy controls group, the magnitude of the intentional binding was associated with the activity of a premotor-parietal-cerebellar network. This relationship was not present in the Tourette syndrome group, suggesting an altered activation of the agency brain network for self-generated acts. We conclude that the less accurate action monitoring described in Tourette syndrome also involves the assessment of the consequences of actions in the outside world. We discuss that this may lead to difficulties in distinguishing external consequences produced by their own actions from the ones caused by others in Tourette syndrome patients.

Sustained Relief after Pallidal Stimulation Interruption in Tourette's Syndrome Treated with Simultaneous Capsulotomy

INTRODUCTION

Globus pallidus internus (GPi) deep brain stimulation (DBS) combined with anterior capsulotomy offers a promising treatment option for severe medication-refractory cases of Tourette's syndrome (TS) with psychiatric comorbidities. Several patients treated with this combined surgery experienced sustained relief after discontinuation of stimulation over the course of treatment.

METHODS

Retrospectively, the medical records and clinical outcomes were reviewed of 8 patients (6 men; 2 women with mean age of 20.3 years) who had undergone bilateral GPi-DBS combined with anterior capsulotomy for medically intractable TS and psychiatric comorbidities. All patients had experienced an accidental interruption or intentional withdrawal of pallidal stimulation during treatment.

RESULTS

The widespread clinical benefits achieved during the combined treatment were fully maintained after intentional or accidental DBS discontinuation. The improvement in overall tic symptoms achieved was on average 78% at the follow-up or close to the DBS discontinuation, while it was 83% at last follow-up (LFU). At LFU, most patients had functionally recovered; exhibited only mild tics; displayed minor or no obsessive-compulsive disorder symptoms, anxiety, or depression; and experienced a much better quality of life.

CONCLUSION

Bilateral GPi-DBS combined with anterior capsulotomy appears to result in marked and sustained improvements in TS symptoms and psychiatric comorbidities, which are fully maintained over time, even without pallidal stimulation.

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.

Pallidal deep brain stimulation combined with capsulotomy for Tourette's syndrome with psychiatric comorbidity

OBJECTIVE

A current challenge is finding an effective and safe treatment for severely disabled patients with Tourette's syndrome (TS) and comorbid psychiatric disorders, in whom conventional treatments have failed. The authors aimed to evaluate the utility of globus pallidus internus deep brain stimulation (GPi-DBS) combined with bilateral anterior capsulotomy in treating these clinically challenging patients.

METHODS

The authors conducted a retrospective review of the clinical history and outcomes of 10 severely disabled patients with treatment-refractory TS and a psychiatric comorbidity, who had undergone GPi-DBS combined with bilateral anterior capsulotomy in their hospital. At the time of surgery, patients presented mainly with obsessive-compulsive disorder and affective disorders. Clinical outcome assessments of tic and psychiatric symptoms, as well as of general adaptive functioning and quality of life, were performed at the time of surgery and at 6, 12, and between 24 and 96 months postsurgery.

RESULTS

After surgery, all patients showed significant progressive improvements in tic and psychiatric symptoms, along with improvements in general adaptive functioning and quality of life. Tic alleviation reached 64% at 12 months and 77% at the last follow-up on the Yale Global Tic Severity Scale. At the final follow-up, patients had functionally recovered and displayed no or only mild tic and psychiatric symptoms. All patients tolerated treatment reasonably well, with no serious side effects.

CONCLUSIONS

GPi-DBS combined with bilateral anterior capsulotomy seems to offer major clinical benefits to severely disabled patients with otherwise treatment-refractory TS and psychiatric comorbidities.

Neurophysiological correlate of emotional regulation in cognitive and motor deficits in Tourette's syndrome

Objectives: The present study investigated the role of different emotions in the expression of cognitive and motor control abilities of children having Tourette's syndrome (TS) compared to healthy controls.Methods: The electroencephalography activity of 33 children (mean age in final sample: TS (n = 10) = 10.5 ± 2.3; control (n = 10) = 10.1 ± 2.9) was recorded during a visual task consisting of four emotional face cues (anger, happiness, neutral and sadness) followed by a target in congruent or incongruent position with emotional cue. The participants were asked to indicate the target location.Results: The TS patients showed a shorter latency of the P1 and N170 only for anger cues compared to controls. In addition, sLORETA results showed an increased activation in the left occipital area and a decreased activation in the left amygdala, temporal and cingulate for anger cues in TS patients. Coherently, TS patients showed a lower accuracy of response only with anger cue and severity of tics resulted correlated with the event-related potentials data and behavioural responses linked to anger cue.Conclusions: These results suggest that children with TS process emotions (in particular the anger) differently from the controls, and that its regulation seems to have an important role in the cognitive and motor deficits in TS.

Economic evaluation of deep-brain stimulation for Tourette's syndrome: an initial exploration

BACKGROUND

Deep-brain stimulation (DBS) can be effective in controlling medically intractable symptoms of Tourette's syndrome (TS). There is no evidence to date, though, of the potential cost-effectiveness of DBS for this indication.

OBJECTIVE

To provide the first estimates of the likely cost-effectiveness of DBS in the treatment of severe TS.

METHODS

We conducted a cost-utility analysis using clinical data from 17 Australian patients receiving DBS. Direct medical costs for DBS using non-rechargeable and rechargeable batteries and for the alternative best medical treatment (BMT), and health utilities for BMT were sourced from the literature. Incremental cost-effectiveness ratios (ICERs) were estimated using a Markov models with a 10-year time horizon and 5% discount rate.

RESULTS

DBS increased quality-adjusted life year (QALY) gained from 2.76 to 4.60 over a 10-year time horizon. The ICER for DBS with non-rechargeable (rechargeable) batteries, compared to BMT, was A$33,838 (A$15,859) per QALY. The ICER estimates are sensitive to DBS costs and selected time horizon.

CONCLUSIONS

Our study indicates that DBS may be a cost-effective treatment for severe TS, based on the very limited clinical data available and under particular assumptions. While the limited availability of data presents a challenge, we also conduct sensitivity analyses to test the robustness of the results to the assumptions used in the analysis. We nevertheless recommend the implementation of randomised controlled trials that collect a comprehensive range of costs and the use of a widely accepted health-related quality of life instrument to enable more definitive statements about the cost-effectiveness of DBS for TS.

Loss of Sight Caused by Ocular Self-Mutilative Behaviour: A Case of Malignant Tourette Syndrome

Tourette's Syndrome is developmental neuropsychiatric disorder characterized by stereotypic, non-rhythmic multiple motor and/or vocal tics. In rare cases, severe tics which can be life-threatening or self-mutilating may be observed in Tourette Syndrome. These types of cases that involve severe self-injurious behavior are called malignant Tourette's Syndrome. In this report, we present an adult case of Tourette Syndrome with vision loss as a result of recurrent and severe ocular self-mutilative tics.

Deep brain stimulation in Tourette's syndrome: evidence to date

Tourette's syndrome (TS) is a neurodevelopmental disorder that comprises vocal and motor tics associated with a high frequency of psychiatric comorbidities, which has an important impact on quality of life. The onset is mainly in childhood and the symptoms can either fade away or require pharmacological therapies associated with cognitive-behavior therapies. In rare cases, patients experience severe and disabling symptoms refractory to conventional treatments. In these cases, deep brain stimulation (DBS) can be considered as an interesting and effective option for symptomatic control. DBS has been studied in numerous trials as a therapy for movement disorders, and currently positive data supports that DBS is partially effective in reducing the motor and non-motor symptoms of TS. The average response, mostly from case series and prospective cohorts and only a few controlled studies, is around 40% improvement on tic severity scales. The ventromedial thalamus has been the preferred target, but more recently the globus pallidus internus has also gained some notoriety. The mechanism by which DBS is effective on tics and other symptoms in TS is not yet understood. As refractory TS is not common, even reference centers have difficulties in performing large controlled trials. However, studies that reproduce the current results in larger and multicenter randomized controlled trials to improve our knowledge so as to support the best target and stimulation settings are still lacking. This article will discuss the selection of the candidates, DBS targets and mechanisms on TS, and clinical evidence to date reviewing current literature about the use of DBS in the treatment of TS.

Paediatric Moyamoya Disease and Tourette's Syndrome: An Unusual Association Responding Favourably to Direct and Indirect Cerebral Revascularisation Surgery

BACKGROUND

Moyamoya disease, an uncommon chronic intra-cerebral arteriopathy asymmetrically affecting the proximal vasculature, is rarely associated with clinical features pertaining to movement disorders.

CASE DESCRIPTION

A 5-year-and-9-month-old boy developed repetitive episodic involuntary winking of the right eye along with ipsilateral shoulder shrugging movements in an absolutely conscious state, associated with paroxysmal shouts and loud laughs and punctuated with abusive verbal expressions (coprolalia). These episodic features, over the course of the next 1.5 years, got progressively accentuated by situations which evoked stress. In addition, there was progressive regression of verbal and cognitive milestones, emotional lability and aspects of attention deficit hyperkinetic disorder. The child was evaluated by a neurologist with magnetic resonance imaging of the brain, which showed characteristic ischaemic areas involving the basal ganglia and fronto-parietal cortical areas along the middle cerebral artery territory, predominantly on the left side. Subsequent cerebral angiography revealed extensive stenosis of bilateral (predominantly left-sided) internal cerebral arteries and middle cerebral arteries with evidence of diffuse leptomeningeal collaterals. The electroencephalography was reported to be normal. He was eventually diagnosed to be suffering from Moyamoya disease with associated Tourette's syndrome. Subsequently, the child underwent left-sided superficial temporal artery to middle cerebral artery anastomosis along with encephalo-duro-arterio-myo-synangiosis. Significant clinico-radiological improvement was noted after 3 months. The clinical deficiencies had dramatically resolved. There was evidence of excellent development of both direct and indirect surgical collaterals along the left middle cerebral artery territory. He could go back to school.

CONCLUSION

Ours is probably the first case reporting an association of paediatric Moyamoya disease with Tourette's syndrome, which significantly resolved after cerebral revascularisation surgery.

Association of Affected Neurocircuitry With Deficit of Response Inhibition and Delayed Gratification in Attention Deficit Hyperactivity Disorder: A Narrative Review

The neural networks that constitute corticostriatothalamocortical circuits between prefrontal cortex and subcortical structure provide a heuristic framework for bridging gaps between neurocircuitry and executive dysfunction in attention deficit hyperactivity disorder (ADHD). “Cool” and “Hot” executive functional theory and the models of dual pathway are supposed to be applied within the neuropsychology of ADHD. The theoretical model elaborated response inhibition and delayed gratification in ADHD. We aimed to review and summarize the literature about the circuits on ADHD and ADHD-related comorbidities, as well as the effects of neurocircuitry on the executive dysfunction in ADHD.

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.

Therapeutic potential of medicinal marijuana: an educational primer for health care professionals

With the proposed Canadian July 2018 legalization of marijuana through the Cannabis Act, a thorough critical analysis of the current trials on the efficacy of medicinal marijuana (MM) as a treatment option is necessary. This review is particularly important for primary care physicians whose patients may be interested in using MM as an alternative therapy. In response to increased interest in MM, Health Canada released a document in 2013 for general practitioners (GPs) as an educational tool on the efficacy of MM in treating some chronic and acute conditions. Although additional studies have filled in some of the gaps since the release of the Health Canada document, conflicting and inconclusive results continue to pose a challenge for physicians. This review aims to supplement the Health Canada document by providing physicians with a critical yet concise update on the recent advancements made regarding the efficacy of MM as a potential therapeutic option. An update to the literature of 2013 is important given the upcoming changes in legislation on the use of marijuana. Also, we briefly highlight the current recommendations provided by Canadian medical colleges on the parameters that need to be considered prior to authorizing MM use, routes of administration as well as a general overview of the endocannabinoid system as it pertains to cannabis. Lastly, we outline the appropriate medical conditions for which the authorization of MM may present as a practical alternative option in improving patient outcomes as well as individual considerations of which GPs should be mindful. The purpose of this paper is to offer physicians an educational tool that provides a necessary, evidence-based analysis of the therapeutic potential of MM and to ensure physicians are making decisions on the therapeutic use of MM in good faith.

Advances, challenges, and promises in pediatric neuroimaging of neurodevelopmental disorders

Recent years have witnessed the proliferation of neuroimaging studies of neurodevelopmental disorders (NDDs), particularly of children with autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and Tourette's syndrome (TS). Neuroimaging offers immense potential in understanding the biology of these disorders, and how it relates to clinical symptoms. Neuroimaging techniques, in the long run, may help identify neurobiological markers to assist clinical diagnosis and treatment. However, methodological challenges have affected the progress of clinical neuroimaging. This paper reviews the methodological challenges involved in imaging children with NDDs. Specific topics include correcting for head motion, normalization using pediatric brain templates, accounting for psychotropic medication use, delineating complex developmental trajectories, and overcoming smaller sample sizes. The potential of neuroimaging-based biomarkers and the utility of implementing neuroimaging in a clinical setting are also discussed. Data-sharing approaches, technological advances, and an increase in the number of longitudinal, prospective studies are recommended as future directions. Significant advances have been made already, and future decades will continue to see innovative progress in neuroimaging research endeavors of NDDs.

Aripiprazole Selectively Reduces Motor Tics in a Young Animal Model for Tourette's Syndrome and Comorbid Attention Deficit and Hyperactivity Disorder

Tourette’s syndrome (TS) is a neurodevelopmental disorder characterized primarily by motor and vocal tics. Comorbidities such as attention deficit and hyperactivity disorder (ADHD) are observed in over 50% of TS patients. We applied aripiprazole in a juvenile rat model that displays motor tics and hyperactivity. We additionally assessed the amount of ultrasonic vocalizations (USVs) as an indicator for the presence of vocal tics and evaluated the changes in the striatal neurometabolism using in vivo proton magnetic resonance spectroscopy (1H-MRS) at 11.7T. Thirty-one juvenile spontaneously hypertensive rats (SHRs) underwent bicuculline striatal microinjection and treatment with either aripiprazole or vehicle. Control groups were sham operated and sham injected. Behavior, USVs, and striatal neurochemical profile were analyzed at early, middle, and late adolescence (postnatal days 35 to 50). Bicuculline microinjections in the dorsolateral striatum induced motor tics in SHR juvenile rats. Acute aripiprazole administration selectively reduced both tic frequency and latency, whereas stereotypies, USVs, and hyperactivity remained unaltered. The striatal neurochemical profile was only moderately altered after tic-induction and was not affected by systemic drug treatment. When applied to a young rat model that provides high degrees of construct, face, and predictive validity for TS and comorbid ADHD, aripiprazole selectively reduces motor tics, revealing that tics and stereotypies are distinct phenomena in line with clinical treatment of patients. Finally, our 1H-MRS results suggest a critical revision of the striatal role in the hypothesized cortico-striatal dysregulation in TS pathophysiology.

Review of the evidence for the management of co-morbid Tic disorders in children and adolescents with attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder in children and adolescents, with prevalence ranging between 5% and 12% in the developed countries. Tic disorders (TD) are common co-morbidities in paediatric ADHD patients with or without pharmacotherapy treatment. There has been conflicting evidence of the role of psychostimulants in either precipitating or exacerbating TDs in ADHD patients. We carried out a literature review relating to the management of TDs in children and adolescents with ADHD through a comprehensive search of MEDLINE, EMBASE, CINAHL and Cochrane databases. No quantitative synthesis (meta-analysis) was deemed appropriate. Meta-analysis of controlled trials does not support an association between new onset or worsening of tics and normal doses of psychostimulant use. Supratherapeutic doses of dextroamphetamine have been shown to exacerbate TD. Most tics are mild or moderate and respond to psychoeducation and behavioural management. Level A evidence support the use of alpha adrenergic agonists, including Clonidine and Guanfacine, reuptake noradrenenaline inhibitors (Atomoxetine) and stimulants (Methylphenidate and Dexamphetamines) for the treatment of Tics and comorbid ADHD. Priority should be given to the management of co-morbid Tourette’s syndrome (TS) or severely disabling tics in children and adolescents with ADHD. Severe TDs may require antipsychotic treatment. Antipsychotics, especially Aripiprazole, are safe and effective treatment for TS or severe Tics, but they only moderately control the co-occurring ADHD symptomatology. Short vignettes of different common clinical scenarios are presented to help clinicians determine the most appropriate treatment to consider in each patient presenting with ADHD and co-morbid TDs.

Single-unit activity of the anterior Globus pallidus internus in Tourette patients and posterior Globus pallidus internus in dystonic patients

OBJECTIVES

Our goal was to provide a detailed analysis of neurons' electrophysiological activity recorded in sub-territories of Globus pallidus internus (GPi) used as Deep Brain Stimulation (DBS) targets for these clinical conditions to potentially assist electrode targeting.

METHODS

We used intra-operative microelectrode recording during stereotactic neurosurgery to guide implantation of DBS lead.

RESULTS

Units in the medial anterior part of GPi of 7 Tourette's syndrome patients under general anesthesia were firing at mean and median rate of 32.1 and 21 Hz respectively (n = 101), with 45% of spikes fired during bursts and 21.3 bursts per minute. In the latero-posterior part of GPi of 7 dystonic patients under local anesthesia the mean and median activity were 46.1 and 30.6 Hz respectively (n = 27), and a mean of 21.7 bursts per minute was observed, with 30% of all spikes occurring during these bursts.

CONCLUSION

Units activity pattern - slow-regular, fast-irregular or fast-regular were present in different proportions between the two targets.

SIGNIFICANCE

The electrophysiological characteristics of the medial-anterior part of GPi and its latero-posterior portion can be used to assist DBS electrode targeting and also support the refinement of pathophysiological models of Tourette's syndrome and Dystonia.

The 5 choice continuous performance test (5C-CPT): A novel tool to assess cognitive control across species

BACKGROUND

Neurodevelopmental disorders including Tourette's syndrome (TS) and attention deficit hyperactivity disorder (ADHD) are characterized by significant impairment in attention and cognitive control. These cognitive deficits persist throughout development, contribute significantly to socio-occupational impairment, and are relatively impervious to available treatment. A critical challenge in pro-cognitive drug discovery is translatability of findings across species, underscoring the need for developing valid and reliable cross-species cognitive tasks.

NEW METHOD

Here we describe a cross-species 5 choice continuous performance task that was developed to measure cognitive control processes of attention, vigilance, and response inhibition, enabling the translation of findings for pro-cognitive drug discovery across species and delineate neural mechanisms underlying cognitive control construct.

RESULTS

Construct validity of 5C-CPT has been verified by multiple cross-species studies. Several lines of evidence report consistent findings across species including, deficits resulting from 36-h sleep deprivation studies, engagement of parietal cortex in human brain imaging and rodent lesion studies, and vigilance decrements over time.

COMPARISON WITH EXISTING METHOD

Unlike the widely used rodent 5 choice serial reaction time task (5CSRTT) and the sustained attention task (SAT), the rodent 5C-CPT includes both target and non-target stimuli that allow measuring of cognitive control elements including response inhibition, an ability to inhibit pre-potent response during non-target trials, detect vigilance decrement and calculate signal detection parameters in rodents analogous to human CPT.

CONCLUSION

The cross-species 5C-CPT is a robust translational tool to characterize the neurobiological substrates underlying cognitive control deficits in clinical population including, ADHD and TS and develop targeted pro-cognitive therapeutics.

Habituation is altered in neuropsychiatric disorders-A comprehensive review with recommendations for experimental design and analysis

Abnormalities in the simplest form of learning, habituation, have been reported in a variety of neuropsychiatric disorders as etiologically diverse as Autism Spectrum Disorder, Fragile X syndrome, Schizophrenia, Parkinson's Disease, Huntington's Disease, Attention Deficit Hyperactivity Disorder, Tourette's Syndrome, and Migraine. Here we provide the first comprehensive review of what is known about alterations in this form of non-associative learning in each disorder. Across several disorders, abnormal habituation is predictive of symptom severity, highlighting the clinical significance of habituation and its importance to normal cognitive function. Abnormal habituation is discussed within the greater framework of learning theory and how it may relate to disease phenotype either as a cause, symptom, or therapy. Important considerations for the design and interpretation of habituation experiments are outlined with the hope that these will aid both clinicians and basic researchers investigating how this simple form of learning is altered in disease.

Purposeless oral activity induced by meta-chlorophenylpiperazine (m-CPP): Undefined tic-like behaviors?

BACKGROUND

The pathophysiological hypothesis underlying tic disorders in Tourette syndrome (TS) is that basal ganglia are not capable of properly filtering cortical information, leading patients with difficulties in inhibiting unwanted behaviors or impulses. One of the main challenges for furthering such a hypothesis is to find appropriate animal models summarizing some aspects of the disease.

METHODS

It has been established for more than 25 years in rodents that the prototypical serotonin (5-HT) agonist meta-chlorophenylpiperazine (m-CPP) elicits purposeless oral movements including chewing behavior. These bouts of oral movements, originally thought to mimic human oral dyskinesia consequent to long-term administration of antipsychotic drugs or parkinsonian tremor, could correspond to an undefined form of tics. Here, we describe the nature of the purposeless oral movements triggered by m-CPP and other agonists which could be associated with obsessive compulsive disorders. We report the pharmacology of this response with a focus on the 5-HT_2C receptor subtype and the degree to which the dopaminergic and cholinergic systems are involved. The orofacial dyskinetic effects are related to the action of these compounds in associative/limbic territories of the basal ganglia, rather than sensorimotor ones, as expected from the human disease.

CONCLUSION

In spite of the low translational value of these oral movements, the neurobiological analysis of these oral movements could help to a better understanding of the pathophysiology of tics and compulsive disorders often cormorbid with TS.

Comprehension of direct and indirect sarcastic remarks in children and adolescents with Tourette's syndrome

Previous research has reported that aspects of social cognition such as nonliteral language comprehension are impaired in adults with Tourette's syndrome (TS), but little is known about social cognition in children and adolescents with TS. The present study aims to evaluate a measure of sarcasm comprehension suitable for use with children and adolescents (Experiment 1), and to examine sarcasm comprehension in children and adolescents with TS-alone or TS and attention deficit hyperactivity disorder (ADHD; Experiment 2). In Experiment 1, the measure of sarcasm comprehension was found to be sensitive to differences in nonliteral language comprehension for typically-developing children aged 10 to 11 years old compared to children aged 8 to 9 years old; the older group performed significantly better on the comprehension of scenarios ending with either direct or indirect sarcastic remarks, whereas the two age groups did not differ on the comprehension of scenarios ending with sincere remarks. In Experiment 2, both the TS-alone and TS+ADHD groups performed below the level of the control participants on the comprehension of indirect sarcasm items but not on the comprehension of direct sarcasm items and sincere items. Those with TS+ADHD also performed below the level of the control participants on measures of interference control and fluency. The findings are discussed with reference to the possible contribution of executive functioning and mentalizing to the patterns of performance.

Developing a 3-choice serial reaction time task for examining neural and cognitive function in an equine model

BACKGROUND

Large animal models of human neurological disorders are advantageous compared to rodent models due to their neuroanatomical complexity, longevity and their ability to be maintained in naturalised environments. Some large animal models spontaneously develop behaviours that closely resemble the symptoms of neural and psychiatric disorders. The horse is an example of this; the domestic form of this species consistently develops spontaneous stereotypic behaviours akin to the compulsive and impulsive behaviours observed in human neurological disorders such as Tourette's syndrome. The ability to non-invasively probe normal and abnormal equine brain function through cognitive testing may provide an extremely useful methodological tool to assess brain changes associated with certain human neurological and psychiatric conditions.

NEW METHOD

An automated operant system with the ability to present visual and auditory stimuli as well as dispense salient food reward was developed. To validate the system, ten horses were trained and tested using a standard cognitive task (three choice serial reaction time task (3-CSRTT)).

RESULTS

All animals achieved total learning criterion and performed six probe sessions. Learning criterion was met within 16.30±0.79 sessions over a three day period. During six probe sessions, level of performance was maintained at 80.67±0.57% (mean±SEM) accuracy.

COMPARISON WITH EXISTING METHOD(S)

This is the first mobile fully automated system developed to examine cognitive function in the horse.

CONCLUSIONS

A fully-automated operant system for mobile cognitive function of a large animal model has been designed and validated. Horses pose an interesting complementary model to rodents for the examination of human neurological dysfunction.

An initial study of family accommodation in children and adolescents with chronic tic disorders

This initial study examined the nature, incidence, and clinical correlates of family accommodation in youth with tic disorders, and validated a brief self-report measure of tic-related family accommodation, the Tic Family Accommodation Scale (TFAS). Seventy-five youth aged 6-18 who were diagnosed with a tic disorder and their parent completed a diagnostic clinical interview, and clinician and parent-report measures of tic severity, depressive symptoms, anxiety symptoms, behavioral problems, family accommodation and impairment. An exploratory factor analysis of the TFAS showed a two-factor structure, with good internal consistency for the Total score, Modification of Child Environment and Modification of Parent Environment subscales (α = 0.88, 0.86, and 0.81, respectively). Family accommodation was not associated with tic severity. Family accommodation was associated with increased anxiety and depressive symptoms, higher externalizing, rule breaking, aggressive behaviors and social problems, and with greater tic-related functional impairment. Anxiety and externalizing problems (but not depressive symptoms) predicted family accommodation when controlling for tic severity. Family accommodation predicted high levels of functional impairment over and above the effect of tic severity, anxiety, depression and externalizing problems. Family accommodation is a common phenomenon for youth with tic disorders, with modifications typically encompassing changes to the child and/or parent environments. Accommodation was not associated with tic severity, but was related to higher levels of anxiety, depressive symptoms, externalizing symptoms, aggression, and rule breaking behaviors. Results suggest that other emotional symptoms are more likely to drive accommodation practices than the tic symptoms per se.

"I'm not being rude, I'd want somebody normal": Adolescents' Perception of their Peers with Tourette's Syndrome: an Exploratory Study

Tourette's syndrome (TS) is a highly stigmatised condition, and typically developing adolescents' motives and reasons for excluding individuals with TS have not been examined. The aim of the study was to understand how TS is conceptualised by adolescents and explore how individuals with TS are perceived by their typically developing peers. Free text writing and focus groups were used to elicit the views of twenty-two year ten students from a secondary school in South East England. Grounded theory was used to develop an analytical framework. Participants' understanding about the condition was construed from misconceptions, unfamiliarity and unanswered questions. Adolescents who conceived TS as a condition beyond the individual's control perceived their peers as being deprived of agency and strength and as straying from the boundaries of normalcy. People with TS were viewed as individuals deserving pity, and in need of support. Although participants maintained they had feelings of social politeness towards those with TS, they would avoid initiating meaningful social relationships with them due to fear of 'social contamination'. Intergroup anxiety would also inhibit a close degree of social contact. Participants that viewed those with TS as responsible for their condition expressed a plenary desire for social distance. However, these behavioural intentions were not limited to adolescents that elicited inferences of responsibility to people with TS, indicating that attributional models of stigmatisation may be of secondary importance in the case of TS. Implications for interventions to improve school belonging among youth with TS are discussed.

Globus Pallidus Interna in Tourette Syndrome: Decreased Local Activity and Disrupted Functional Connectivity

Globus pallidus interna (GPi) is an effective deep brain stimulation site for the treatment of Tourette syndrome (TS), and plays a crucial role in the pathophysiology of TS. To investigate the functional network feature of GPi in TS patients, we retrospectively studied 24 boys with 'pure' TS and 32 age-/education-matched healthy boys by resting state functional magnetic resonance images. Amplitude of low-frequency fluctuation (ALFF) and functional connectivity were used to estimate the local activity in GPi and its functional coordinate with the whole brain regions, respectively. We found decreased ALFF in patients' bilateral GPi, which was also negatively correlated with clinical symptoms. Functional connectivity analysis indicated abnormal regions within motor and motor-control networks in patients (inferior part of sensorimotor area, cerebellum, prefrontal cortex, cingulate gyrus, caudate nucleus, and brain stem). Transcranial magnetic stimulation sites defined by previous studies ("hand knob" area, premotor area, and supplementary motor area) did not show significantly different functional connectivity with GPi between groups. In summary, this study characterized the disrupted functional network of GPi and provided potential regions-of-interest for further basic and clinical studies on TS.

Atypical Sensory behaviours in children with Tourette's Syndrome and in children with Autism Spectrum Disorders

Certain visual disturbances make it difficult to read text and have been attributed to visual stress, also called "pattern-related visual stress". 12 Children with ASD, 12 children with Tourette's syndrome and without ASD and 12 controls, all matched on age and non verbal ability, participated in an experiment exploring sensory behaviours and visual stress. Reading rate and accuracy were assessed with the Wilkins Rate of Reading test with and without the Intuitive Overlays. Both the children with Tourette's and the children with ASD showed a higher prevalence of atypical sensory behaviours and symptoms of visual stress than the typically developing control children. Six out of twelve children with Tourette's syndrome (50%) read more accurately and over 15% more quickly with a coloured overlay. Four of the 12 children with ASD and none of the control children read over 15% more quickly with an overlay. The findings are discussed in relation to problems in sensory modulation.

Stigma in youth with Tourette's syndrome: a systematic review and synthesis

Tourette's syndrome (TS) is a childhood onset neurodevelopmental disorder, characterised by tics. To our knowledge, no systematic reviews exist which focus on examining the body of literature on stigma in association with children and adolescents with TS. The aim of the article is to provide a review of the existing research on (1) social stigma in relation to children and adolescents with TS, (2) self-stigma and (3) courtesy stigma in family members of youth with TS. Three electronic databases were searched: PsycINFO, PubMed and Web of Science. Seventeen empirical studies met the inclusion criteria. In relation to social stigma in rating their own beliefs and behavioural intentions, youth who did not have TS showed an unfavourable attitude towards individuals with TS in comparison to typically developing peers. Meanwhile, in their own narratives about their lives, young people with TS themselves described some form of devaluation from others as a response to their disorder. Self-degrading comments were denoted in a number of studies in which the children pointed out stereotypical views that they had adopted about themselves. Finally, as regards courtesy stigma, parents expressed guilt in relation to their children's condition and social alienation as a result of the disorder. Surprisingly, however, there is not one study that focuses primarily on stigma in relation to TS and further studies that examine the subject from the perspective of both the 'stigmatiser' and the recipient of stigma are warranted.

Self-initiated coping with Tourette's syndrome: Effect of tic suppression on QOL

OBJECTIVE

Because of the semi-voluntary nature of tics, patients with Tourette' syndrome (TS) often report self-initiated coping with tics. Our goals were to understand the experiences of self-initiated coping with tics by individuals with TS (e.g., suppression frequency, suppression ability, and side effects of tic suppression), and investigate the effects of tic control on quality of life (QOL).

METHOD

One hundred participants with TS (38 children and 62 adults) answered a questionnaire concerning tic control, QOL, and other clinical characteristics.

RESULT

Fifty-eight percent of the participants always or frequently tried to suppress tics daily. In contrast, over 90% felt uncomfortable or incomplete when they suppressed tics and needed concentration or extra effort to suppress them. Thirty-four percent could suppress tics for less than one minute and 65% could suppress tics for less than 10min. Higher subjective satisfaction with tic control was positively correlated with life satisfaction and QOL.

CONCLUSION

Individuals with TS often attempt self-initiated coping in their daily lives, especially through tic suppression, despite experiencing subjective discomfort and being aware that the duration of tic suppression is often limited. Moreover, it was found that their subjective satisfaction with tic control and effective tic suppression might have a positive influence on their life satisfaction and QOL. Thus, self-initiated coping with tics is vital for improving the QOL of individuals with TS and intervention aimed at enhancing subjective satisfaction with tic control could help manage TS.

Psychometric Properties of a Self-Report Instrument for the Assessment of Tic Severity in Adults With Tic Disorders

The gold-standard measure of tic severity in tic disorders (TD), the Yale Global Tic Severity Scale (YGTSS), is a semistructured clinician-administered interview that can be time consuming and requires highly trained interviewers. Moreover, the YGTSS does not provide information regarding frequency and intensity of specific tics because all motor and all vocal tics are rated as a group. The aim of the present study is to describe and test the Adult Tic Questionnaire (ATQ), a measure for the assessment of tic severity in adults, and to report its preliminary psychometric properties. The ATQ is a brief self-report questionnaire that provides information regarding frequency, intensity, and severity of 27 specific tics. In addition, the ATQ produces total frequency, intensity, and severity scores for vocal and motor tics, as well as a global total tic severity score. Results showed that the ATQ demonstrated very good internal consistency and temporal stability. The total, vocal, and motor tic severity scales of the ATQ showed strong correlation with corresponding subscales of the YGTSS, indicating strong convergent validity. Weak correlations with measures of severity of obsessive-compulsive disorder and attention deficit/hyperactivity disorder, indicated strong discriminant validity. The ATQ, a promising measure for the assessment of tic severity in adults with TD, may be a valuable supplement to the current recommended assessment battery for TD. Furthermore, the ATQ enables clinicians and researchers to track changes in the frequency and intensity of specific tics, which is important given their complex and dynamic nature.

Deep Brain Stimulation during Pregnancy and Delivery: Experience from a Series of "DBS Babies"

Introduction

Deep brain stimulation (DBS) is widely used to improve quality of life in movement disorders (MD) and psychiatric diseases. Even though the ability to have children has a big impact on patients’ life, only a few studies describe the role of DBS in pregnancy.

Objective

To describe risks and management of women treated by DBS for disabling MD or psychiatric diseases during pregnancy and delivery.

Methods

We report a retrospective case series of women, followed in two DBS centers, who became pregnant and went on to give birth to a child while suffering from disabling MD or psychiatric diseases [Parkinson’s disease, dystonia, Tourette’s syndrome (TS), Obsessive Compulsive Disorder (OCD)] treated by DBS. Clinical status, complications and management before, during, and after pregnancy are reported. Two illustrative cases are described in greater detail.

Results

DBS improved motor and behavioral disorders in all patients and allowed reduction in, or even total interruption of disease-specific medication during pregnancy. With the exception of the spontaneous early abortion of one fetus in a twin pregnancy, all pregnancies were uneventful in terms of obstetric and pediatric management. DBS parameters were adjusted in five patients in order to limit clinical worsening during pregnancy. Implanted material limited breast-feeding in one patient because of local pain at submammal stimulator site and led to local discomfort related to stretching of the cable with increasing belly size in another patient whose stimulator was implanted in the abdominal wall.

Conclusion

Not only is it safe for young women with MD, TS and OCD who have a DBS-System implanted to become pregnant and give birth to a baby but DBS seems to be the key to becoming pregnant, having children, and thus greatly improves quality of life.

Deep Brain Stimulation in Tourette's Syndrome

Objective

Tourette’s syndrome (TS) is defined by 1 year of persistent motor and vocal tics. Often, the tics are refractory to conventional pharmacologic and psychobehavioral interventions. In these patients, deep brain stimulation (DBS) may be an appropriate intervention. This paper reviews different DBS targets in TS, discusses existing evidence on the efficacy of DBS in TS, highlights adverse effects of the procedure, discusses indications and patient selection as well as future directions for DBS in TS.

Methods

A literature review searching PubMed database entries between 2000 and 2015. Search terms included “DBS in Tourette Syndrome”, “Deep brain stimulation in Tourette syndrome,” and “Surgical management of Tourette Syndrome.”

Results

Though there are no universally accepted guidelines defining ideal DBS candidates for TS, age, tic severity, and treatment refractoriness are important factors to consider in patient selection. A variety of targets exist for DBS in TS, but thalamic targets and GPi are the most widely studied. Psychiatric side effects that are target specific should be monitored closely and it is possible that these adverse effects may be resolved with programing. Small randomized controlled trials support the efficacy of DBS in TS.

Conclusion

DBS for TS is safe and feasible, but large multi-center clinical trials are needed to determine the ideal target and optimal location within a particular target.

Response inhibition and interference control in obsessive-compulsive spectrum disorders

Over the past 20 years, motor response inhibition and interference control have received considerable scientific effort and attention, due to their important role in behavior and the development of neuropsychiatric disorders. Results of neuroimaging studies indicate that motor response inhibition and interference control are dependent on cortical–striatal–thalamic–cortical (CSTC) circuits. Structural and functional abnormalities within the CSTC circuits have been reported for many neuropsychiatric disorders, including obsessive–compulsive disorder (OCD) and related disorders, such as attention-deficit hyperactivity disorder, Tourette’s syndrome, and trichotillomania. These disorders also share impairments in motor response inhibition and interference control, which may underlie some of their behavioral and cognitive symptoms. Results of task-related neuroimaging studies on inhibitory functions in these disorders show that impaired task performance is related to altered recruitment of the CSTC circuits. Previous research has shown that inhibitory performance is dependent upon dopamine, noradrenaline, and serotonin signaling, neurotransmitters that have been implicated in the pathophysiology of these disorders. In this narrative review, we discuss the common and disorder-specific pathophysiological mechanisms of inhibition-related dysfunction in OCD and related disorders.

Atomoxetine decreases vulnerability to develop compulsivity in high impulsive rats

BACKGROUND

The factors contributing to the development and severity of obsessive-compulsive spectrum disorders such as obsessive-compulsive disorder, Tourette's syndrome, pathological gambling, and addictions remain poorly understood, limiting the development of therapeutic and preventive strategies. Recent evidence indicates that impulse-control deficits may contribute to the severity of compulsivity in several of these disorders. This suggests that impulsivity may be a transnosological endophenotype of vulnerability to compulsivity. However, the precise nature of the link between impulsivity and compulsivity in anxiety-related compulsive disorders remains unknown.

METHODS

We investigated the relationship between impulsivity and the development of a compulsive behavior in rats, which captures the hallmarks of compulsivity as defined in the DSM-IV--namely, that it is maladaptive, excessive, repetitive, and anxiolytic.

RESULTS

We demonstrate that a high-impulsivity trait, as measured in the five-choice serial reaction time task, predicts an increased propensity to develop compulsivity as measured in a schedule-induced polydipsia procedure. Trait impulsivity and compulsivity were nonlinearly related. This impulsivity-compulsivity relationship was lost after the development of compulsivity or under chronic treatment with atomoxetine, a noradrenergic reuptake inhibitor used to treat attention-deficit/hyperactivity disorder. Atomoxetine treatment both decreased impulsivity and prevented the development of compulsivity in high-impulsive animals.

CONCLUSIONS

These observations provide insight into the reciprocal influence of impulsivity and compulsivity in compulsive disorders and suggest that atomoxetine may be a useful treatment for patients suffering from obsessive-compulsive spectrum disorders with high impulsivity.

The thalamostriatal system in normal and diseased states

Because of our limited knowledge of the functional role of the thalamostriatal system, this massive network is often ignored in models of the pathophysiology of brain disorders of basal ganglia origin, such as Parkinson's disease (PD). However, over the past decade, significant advances have led to a deeper understanding of the anatomical, electrophysiological, behavioral and pathological aspects of the thalamostriatal system. The cloning of the vesicular glutamate transporters 1 and 2 (vGluT1 and vGluT2) has provided powerful tools to differentiate thalamostriatal from corticostriatal glutamatergic terminals, allowing us to carry out comparative studies of the synaptology and plasticity of these two systems in normal and pathological conditions. Findings from these studies have led to the recognition of two thalamostriatal systems, based on their differential origin from the caudal intralaminar nuclear group, the center median/parafascicular (CM/Pf) complex, or other thalamic nuclei. The recent use of optogenetic methods supports this model of the organization of the thalamostriatal systems, showing differences in functionality and glutamate receptor localization at thalamostriatal synapses from Pf and other thalamic nuclei. At the functional level, evidence largely gathered from thalamic recordings in awake monkeys strongly suggests that the thalamostriatal system from the CM/Pf is involved in regulating alertness and switching behaviors. Importantly, there is evidence that the caudal intralaminar nuclei and their axonal projections to the striatum partly degenerate in PD and that CM/Pf deep brain stimulation (DBS) may be therapeutically useful in several movement disorders.