Tourette syndrome. Phenomenology and classification of tics

Itching Frequency and Neuroanatomic Correlates in Frontotemporal Lobar Degeneration

Importance

Itching is common in geriatric populations and is frequently linked to dermatological or systemic conditions. Itching engages specific brain regions that are implicated in the pathogenesis of frontotemporal lobar degeneration spectrum disorders (FTLD-SD). Thus, itching of undetermined origin (IUO) may indicate the presence of a neurodegenerative process.

Objective

To compare the frequency of itching in FTLD-SD and Alzheimer disease (AD) and to determine the neuroanatomical underpinnings of IUO.

Design, Setting, and Participants

This case-control study evaluated data and brain magnetic resonance images (MRIs) for participants with FTLD-SD or AD. Participants of a research study on FTLD-SD at the University of California, San Francisco, Memory and Aging Center were evaluated from May 1, 2002, to December 31, 2021. The exposure group underwent structural brain MRI within 6 months of initial diagnosis. Research visit summaries were reviewed to validate qualitative details and accurately identify itching with undetermined origin (IUO).

Exposures

Symptoms suggestive of FTLD-SD or AD.

Main Outcomes and Measures

Frequency of itching in FTLD-SD and AD and neuroanatomic correlates.

Results

A total of 2091 research visit summaries were reviewed for 1112 patients exhibiting symptoms indicative of FTLD-SD or AD. From 795 records where itching or a related phrase was endorsed, 137 had IUO. A total of 454 participants were included in the study: 137 in the itching group (mean [SD] age, 62.7 [9.9] years; 74 [54%] females and 63 males [46%]) and 317 in the nonitching group (mean [SD] age, 60.7 [10.8] years; 154 [49%] females and 163 males [51%]). Groups were similar in age, sex, and disease severity. More frequent itching was found in FTLD-SD (95/248 patients [38%], of which 44 [46%] had behavioral variant frontotemporal dementia [bvFTD]) compared with the AD group (14/77 patients [18%]; P = .001). The odds of itching were 2.4 (95% CI, 1.48-3.97) times higher for FTLD-SD compared with all other cases of dementia. Compared with healthy controls, the group with IUO exhibited greater gray matter atrophy bilaterally in the amygdala, insula, precentral gyrus, and cingulum, as well as in the right frontal superior gyrus and thalamus. Among patients with bvFTD and itching vs bvFTD without itching, itching was associated with right-lateralized gray matter atrophy affecting the insula, thalamus, superior frontal gyrus, and cingulum.

Conclusions and Relevance

Among individuals with IUO, FTLD-SD was disproportionately represented compared with AD. In FTLD-SD, dysfunction in the right anterior insula and its connected regions, including the right precentral gyrus, cingulum, and bilateral amygdala, contribute to dysregulation of the itching-scratching networks, resulting in uncontrollable itching or skin picking. Awareness among physicians about the relationship between neurodegeneration and itching may help in the management of itch in older individuals. Further studies are needed to determine the best treatments for these symptoms in patients with neurodegenerative disorders.

Deep brain stimulation for Tourette's syndrome

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the efficacy and harm of deep brain stimulation for motor symptoms, with psychiatric and behavioural comorbidities, either individually or in combination, in adults and adolescents with Tourette's syndrome compared to placebo, sham intervention, or the best available behavioural and pharmacological treatment.

When the interoceptive and conceptual clash: The case of oppositional phenomenal self-modelling in Tourette syndrome

Tourette syndrome (TS) has been associated with a rich set of symptoms that are said to be uncomfortable, unwilled, and effortful to manage. Furthermore, tics, the canonical characteristic of TS, are multifaceted, and their onset and maintenance is complex. A formal account that integrates these features of TS symptomatology within a plausible theoretical framework is currently absent from the field. In this paper, we assess the explanatory power of hierarchical generative modelling in accounting for TS symptomatology from the perspective of active inference. We propose a fourfold analysis of sensory, motor, and cognitive phenomena associated with TS. In Section 1, we characterise tics as a form of action aimed at sensory attenuation. In Section 2, we introduce the notion of epistemic ticcing and describe such behaviour as the search for evidence that there is an agent (i.e., self) at the heart of the generative hierarchy. In Section 3, we characterise both epistemic (sensation-free) and nonepistemic (sensational) tics as habitual behaviour. Finally, in Section 4, we propose that ticcing behaviour involves an inevitable conflict between distinguishable aspects of selfhood; namely, between the minimal phenomenal sense of self-which is putatively underwritten by interoceptive inference-and the explicit preferences that constitute the individual's conceptual sense of self. In sum, we aim to provide an empirically informed analysis of TS symptomatology under active inference, revealing a continuity between covert and overt features of the condition.

How to face the hemifacial spasm: challenges and misconceptions

Hemifacial spasm (HFS) is characterised by intermittent, brief or sustained, repetitive contractions of the muscles innervated by one facial nerve. It is one of the most frequent movement disorders affecting the face. However common and allegedly straightforward to diagnose, it might reveal as a challenge for clinicians in various situations. Indeed, it often needs prior exclusion of many other movement disorders affecting the face, with frequent phenomenological overlaps with blepharospasm, post-facial palsy, facial motor tics, etc. The clinical diagnosis shall be supported by modern brain imaging techniques, and sometimes electromyography, as some particular aetiologies may require specific treatment. Primary forms are associated with vascular compression of the ipsilateral seventh cranial nerve, whereas secondary forms can be caused by any injury occurring on the facial nerve course. This article proposes a global and organised approach to the diagnosis, and the ensuing therapeutic options, as many practitioners still use some inefficient medications when they encounter a case of facial spasm.

The Dysfunctional Mechanisms Throwing Tics: Structural and Functional Changes in Tourette Syndrome

Tourette Syndrome (TS) is a high-incidence multifactorial neuropsychiatric disorder characterized by motor and vocal tics co-occurring with several diverse comorbidities, including obsessive-compulsive disorder and attention-deficit hyperactivity disorder. The origin of TS is multifactorial, with strong genetic, perinatal, and immunological influences. Although almost all neurotransmettitorial systems have been implicated in TS pathophysiology, a comprehensive neurophysiological model explaining the dynamics of expression and inhibition of tics is still lacking. The genesis and maintenance of motor and non-motor aspects of TS are thought to arise from functional and/or structural modifications of the basal ganglia and related circuitry. This complex wiring involves several cortical and subcortical structures whose concerted activity controls the selection of the most appropriate reflexive and habitual motor, cognitive and emotional actions. Importantly, striatal circuits exhibit bidirectional forms of synaptic plasticity that differ in many respects from hippocampal and neocortical plasticity, including sensitivity to metaplastic molecules such as dopamine. Here, we review the available evidence about structural and functional anomalies in neural circuits which have been found in TS patients. Finally, considering what is known in the field of striatal plasticity, we discuss the role of exuberant plasticity in TS, including the prospect of future pharmacological and neuromodulation avenues.

Premonitory Urge and Tic Severity, Comorbidities, and Quality of Life in Chronic Tic Disorders

BACKGROUND

Tics are intimately associated with premonitory urges (PU) but knowledge about urges is still limited, with small sample sizes often limiting the generalizability of findings.

OBJECTIVES

This study addressed the following open questions: (1) is tic severity associated with urge severity, (2) how common is relief, (3) which comorbidities are associated with urges, (4) are urges, tics, and comorbidities associated with lower quality of life, and (5) can complex and simple, motor and vocal tics be differentiated based on PU?

METHODS

N = 291 patients who reported a confirmed diagnosis of chronic primary tic disorder (age = 18-65, 24% female) filled out an online survey assessing demographic data, comorbid conditions, location, quality and intensity of PU, as well as quality of life. Every tic was recorded, and whether the patient experienced a PU, the frequency, intensity, and quality of that urge.

RESULTS

PU and tic severity were significantly associated, and 85% of urge-related tics were followed by relief. A diagnosis of attention deficit/hyperactivity disorder (ADHD) or depression, female gender, and older age increased the likelihood of experiencing PU, while more obsessive compulsive (OCD) symptoms and younger age were associated with higher urge intensities. PU, complex vocal tics, ADHD, OCD, anxiety, and depression were related to lower quality of life. Motor and vocal, complex and simple tics did not differ regarding PU intensity, frequency, and quality, or relief.

CONCLUSIONS

The results shed light on the relationship between PU, tics, comorbidities, age, gender, and quality of life in tic disorders.

Oromandibular tics associated with Tourette syndrome

BACKGROUND

Tourette syndrome (TS) is the most common cause of chronic tics. Patients with TS frequently manifest motor tics involving the eyes and face but oromandibular (OM) tics have been rarely studied.

MATERIALS AND METHODS

We reviewed the medical records and video-recordings of 155 consecutive patients with TS in our movement disorders clinic. In addition, we studied 35 patients with classic tardive dyskinesia (TD) and compared their clinical and demographic features with those with TS.

RESULTS

We identified 41 patients with OM tics (26.5%). Although patients with OM tics had a greater overall tic severity and higher frequency of.complex motor and phonic tics, in the bivariate analysis, only comorbid dystonic tics (P = 0.001), greater number of affected body parts (P = 0.012) and more frequent eye-rolling tics (P = 0.059) were included in the final regression model after controlling for other variables. When compared with patients with OM tics, patients with classic TD had more frequently masticatory movements (sensitivity, 0.86; specificity, 0.95), continuous tongue movements (sensitivity, 0.71; specificity, 1.0) and continuous OM movements (sensitivity, 0.4; specificity, 1.0).

CONCLUSIONS

OM tics are common and often troublesome or even disabling symptoms in patients with TS. They may be difficult to differentiate from TD, but the latter is typically manifested by continuous orolingual and masticatory movements.

Motor stereotypies in autism spectrum disorder: Clinical randomized study and classification proposal

LAY ABSTRACT

Motor stereotypies are one of the most frequent features in children with a diagnosis of autism spectrum disorder. They may disrupt children's functioning and development and be a potential source of stress for families. Several factors, including sex, age, cognitive ability, and severity of autism spectrum disorder, may influence the presence and intensity of stereotypies. The present study aimed to identify the prevalence of motor stereotypies in a group of children with autism spectrum disorder. In addition, it sought to investigate whether sex, age, cognitive ability, verbal language, neurological comorbidities, and severity of autism spectrum disorder were associated with an increased probability and higher number, duration, and variability of stereotypies. A total of 134 participants aged 2.3-17.6 years underwent a clinical protocol with standardized video-recorded sessions. Stereotypies were identified and classified by two independent evaluators. The prevalence of stereotypies was 56.7%, and a total of 1198 motor stereotypies were captured. Children who were younger, nonverbal, and had higher severity of autism spectrum disorder had an increased probability of presenting stereotypies. Being nonverbal or having higher severity of autism spectrum disorder was also associated with presenting a higher number of stereotypies. Children with developmental delay, intellectual disability, or epilepsy displayed longer stereotypies, and children with developmental delay or intellectual disability additionally presented more diverse stereotypies. As part of the study, the authors present a clinical classification model, a glossary, and video samples of motor stereotypies. The findings of this study suggest that children who are younger, nonverbal, have lower cognitive ability, and have higher severity of autism spectrum disorder may have a higher burden of stereotypies. Earlier intervention and monitoring of these children have the potential to improve their long-term outcomes.

Tourette syndrome: clinical features, pathophysiology, and treatment

Tourette syndrome is a chronic neurodevelopmental disorder characterised by motor and phonic tics that can substantially diminish the quality of life of affected individuals. Evaluating and treating Tourette syndrome is complex, in part due to the heterogeneity of symptoms and comorbidities between individuals. The underlying pathophysiology of Tourette syndrome is not fully understood, but recent research in the past 5 years has brought new insights into the genetic variations and the alterations in neurophysiology and brain networks contributing to its pathogenesis. Treatment options for Tourette syndrome are expanding with novel pharmacological therapies and increased use of deep brain stimulation for patients with symptoms that are refractory to pharmacological or behavioural treatments. Potential predictors of patient responses to therapies for Tourette syndrome, such as specific networks modulated during deep brain stimulation, can guide clinical decisions. Multicentre data sharing initiatives have enabled several advances in our understanding of the genetics and pathophysiology of Tourette syndrome and will be crucial for future large-scale research and in refining effective treatments.

Overcoming the phenomenological Perpetuum mobile in clinical cognitive neuroscience for the benefit of replicability in research and the societal view on mental disorders

Cognitive neuroscience comes in many facets, and a particularly large branch of research is conducted in individuals with mental health problems. This article outlines why it is important that cognitive neuroscientists re-shape their role in mental health research and re-define directions of research for the next decades. At present, cognitive neuroscience research in mental health is too firmly rooted in categorial diagnostic definitions of mental health conditions. It is discussed why this hampers a mechanistic understanding of brain functions underlying mental health problems and why this is a problem for replicability in research. A possible solution to these problems is presented. This solution affects the strategy of research questions to be asked, how current trends to increase replicability in research can or cannot be applied in the mental health field and how data are analyzed. Of note, these aspects are not only relevant for the scientific process, but affect the societal view on mental disorders and the position of affected individuals as members of society, as well as the debate on the inclusion of so-called WEIRD and non-WEIRD people in studies. Accordingly, societal and science political aspects of re-defining the role of cognitive neuroscientists in mental health research are elaborated that will be important to shape cognitive neuroscience in mental health for the next decades.

Magnetic Resonance Imaging Demonstrates Gyral Abnormalities in Tourette Syndrome

Tourette syndrome (TS) is a neurological disorder characterized by involuntary and repetitive movements known as tics. A retrospective analysis of magnetic resonance imaging (MRI) scans from 39 children and adolescents with TS was performed and subsequently compared to MRI scans from 834 neurotypical controls. The purpose of this study was to identify any differences in the regions of motor circuitry in TS to further our understanding of their disturbances in motor control (i.e., motor tics). Measures of volume, cortical thickness, surface area, and surface curvature for specific motor regions were derived from each MRI scan. The results revealed increased surface curvature in the opercular part of the inferior frontal gyrus and the triangular part of the inferior frontal gyrus in the TS group compared to the neurotypical control group. These novel findings offer some of the first evidence for surface curvature differences in motor circuitry regions in TS, which may be associated with known motor and vocal tics.

We Move or Are We Moved? Unpicking the Origins of Voluntary Movements to Better Understand Semivoluntary Movements

The capacity for voluntary control is seen as essential to human movements; the sense that one intended to move (willing) and those actions were self-generated (self-agency) gives the sense of voluntariness and of being in control. While the mechanisms underlying voluntary movement have long been unclear, recent neuroscientific tools have identified networks of different brain areas, namely, the prefrontal cortex, supplementary motor area, and parietal cortex, that underlie voluntary action. Dysfunction in these brain areas can result in different forms of semivoluntary movement as the borderland of voluntary and involuntary movement where a person may experience a disordered sense of will or agency, and thus the movement is experienced as unexpected and involuntary, for an otherwise voluntary-appearing movement. Tics, functional movement disorders, stereotypies, perseveration, compulsions, utilization behaviors, and motor mannerism have been described elsewhere in the context of psychoses, and are often mistaken for each other. Yet, they reflect an impairment of prefrontal cortices and related circuits rather than simple motor systems, which results in the absence of subjective recognition of the movements, in contrast to other neurological movement disorders where principal abnormalities are located within the basal ganglia and its connections. Therefore, their recognition is clinically important since they are usually associated with neurodevelopmental and neurodegenerative disorders. In this review, we first defined a conceptual framework, from both a neuroanatomical and a neurophysiological point of view, for the generation of voluntary movement. We then examined the evidence linking dysfunctions in different motor pathways to each type of movement disorder. We looked at common semivoluntary movement disorders providing an overview, where possible, of their phenomenology and brain network abnormalities for each condition. We also emphasized important clinical feature similarities and differences to increase recognition of each condition in practice.

Compromised reactive but intact proactive inhibitory motor control in Tourette disorder

Tourette disorder (TD) is characterized by tics, which are sudden repetitive involuntary movements or vocalizations. Deficits in inhibitory control in TD patients remain inconclusive from the traditional method of estimating the ability to stop an impending action, which requires careful interpretation of a metric derived from race model. One possible explanation for these inconsistencies is that race model's assumptions of independent and stochastic rise of GO and STOP process to a fixed threshold are often violated, making the classical metric to assess inhibitory control less robust. Here, we used a pair of metrics derived from a recent alternative model to address why stopping performance in TD is unaffected despite atypical neural circuitry. These new metrics distinguish between proactive and reactive inhibitory control and estimate them separately. When these metrics in adult TD group were contrasted with healthy controls (HC), we identified robust deficits in reactive control, but not in proactive control in TD. The TD group exhibited difficulty in slowing down the speed of movement preparation, which they rectified by their intact ability to postpone the movement.

"I'm in pain and I want help": An online survey investigating the experiences of tic-related pain and use of pain management techniques in people with tics and tic disorders

OBJECTIVES

Tic disorders (TDs) are complex neurological conditions characterized by involuntary, persistent vocalizations and motor movements called tics. Tics involve brief muscle movements and can impair many aspects of daily functioning and quality of life in patients - and their physical nature can cause pain. Understanding individuals' experiences of tic-related pain and pain management could help explore this under-researched area and identify additional support needs for this population. The aim of this study was to investigate experiences of pain and use of pain management techniques in people with tic disorders.

METHODS

An online survey consisting of multiple choice and open-ended questions exploring experiences of tic-related pain, help-seeking behavior for tic-related pain, and use of pain relief techniques for tic-related pain, was circulated online via international Tourette syndrome patient associations, and one online support group for Tourette syndrome. The online survey was open to adults (≥16 years) with self-reported tics. Open-ended questions were analyzed using thematic analysis.

RESULTS

One hundred eighty-one participants (16-71 years; 58.0% female) from 18 countries completed the online survey. Several aspects of tics were associated with pain, including the physical effort of motor tics (n = 177, 97.8%), repetitive tics (n = 141, 77.9%) and the consequences of tics (n = 131, 72.4%). Nearly two-thirds (n = 118, 64.6%) had sought professional help for tic-related pain. Distraction techniques (n = 126, 69.6%), taking pain relief medication (n = 125, 69.1%) and altering tics (n = 111, 61.3%) were the most commonly-reported methods used to relieve and cope with tic-related pain. Thematic analysis found an interrelated complex relationship between participants' tics, pain, and pain management techniques, reflected in four themes: the "tic-pain" cycle, the impact of pain, the importance of support, and the perceived successfulness of pain management techniques.

CONCLUSIONS

Tic-related pain was reported to have a significant physical and psychological impact which impacted aspects of daily living in people with tic disorders. The findings add to limited research suggesting tic-related pain is a dominant issue for individuals with tic disorders, potentially impacting upon their quality of life. Increased understanding of tic-related pain and its influence may be helpful in the long-term management of tic disorders, both in terms of clinical management and patients' self-management.

Tonic Tics in Gilles de la Tourette Syndrome

AIM

Tonic tics (TTs) are a part of a clinical picture of Gilles de la Tourette syndrome (GTS) and manifest themselves as sustained and isometric contraction of a muscle group devoid of the movement effect or accompanied by only slight visible motion. The aim of this study was to evaluate the prevalence and phenomenology of TTs, and to assess the clinical associations of TTs with tic severity and comorbidities in patients with GTS.

METHODS

We performed a one-time registration study in a cohort of 241 consecutive outpatients with GTS aged 5 to 50 years (188 males, 153 patients under the age of 18 years). All patients were personally interviewed and examined.

RESULTS

TTs occurred in 85.2% of adults and 63.9% of children and adolescents. Most frequently reported types of TTs were tensing of the abdomen (58.7%), neck (52.7%), and upper limbs (50.3%). Multivariate statistical analysis showed a significant correlation between TTs and the total number of simple tics, total number of complex tics, and age at evaluation. In the group of children and adolescents, an additional significant variable was the duration of GTS. In the group of adults, significant parameters were total number of simple tics, total number of complex tics, peak tic severity ever experienced, premonitory urges, and the presence of dystonic tics.

CONCLUSION

TTs belong to the tic spectrum, common and early symptoms of GTS, are associated with overall a greater number of tics which are more severe, and with more comorbidities.

Induction of Ticlike Involuntary Movements in Rats by Striatotomy and Subsequent Neurochemical Sensitization

OBJECTIVE

It has been proposed that Tourette syndrome is associated with dysfunction in widespread cortical areas and globus pallidus externus hyperactivity secondary to dopaminergic hyperactivity and serotonergic/dynorphinergic hypoactivity. The main objective of this study was to test this hypothesis by developing an animal model of Tourette syndrome via striatotomy, followed by administration of drugs that mimic the neurotransmitter environment, so as to induce globus pallidus externus hyperactivity.

METHODS

Rats were assigned to 3 groups: stereotactic striatotomy (STT) and striatal sham -lesion (SHAM) groups, treated with anterior and posterior striatum procedures in both hemispheres, and a group of nonoperated animals (NAIVE). Postoperatively, all rodents were blindly administered 3 drug protocols: levodopa/benserazide; levodopa/benserazide/ergotamine/naloxone (MIX); and saline. The animals were filmed at the peak action of these drugs. The videos were evaluated by a single blinded researcher.

RESULTS

Six types of involuntary movements (IMs) were observed: cephalic, trunk jerks, oromandibular, forepaw jerks, dystonic, and locomotive. The number of animals with IM and the mean number of IM after both levodopa/benserazide and MIX was significantly higher in the STT compared with the SHAM and NAIVE groups. In the SHAM and NAIVE, MIX was superior to levodopa/benserazide in the induction of IM. In the STT, MIX was superior to levodopa/benserazide in the induction of trunk jerks. Appendicular IM were more common after posterior than after anterior striatotomy.

CONCLUSIONS

These results show that striatotomy, followed by administration of levodopa/benserazide alone or associated with ergotamine and naloxone, is efficacious in inducing IM, supporting the hypothesis that led to this study.

Cognitive Tic-Like Phenomena in Gilles de la Tourette Syndrome

Coprolalia and echophenomena repeated in the patients’ mind (CTPh—cognitive tic-like phenomena) have been rarely recognized as part of Gilles de la Tourette syndrome (GTS) symptomatology and their assignment to tics, OCD or other psychopathologies has not been settled. The aim of the paper was to assess the incidence and clinical associations of CTPh in GTS, and to establish if CTPh belong to the tic spectrum. We performed a prospective, one-registration study on a cohort of 227 consecutive patients with GTS. CTPh were diagnosed during the interview and defined as brief, sudden, involuntary thoughts that had corresponding complex vocal tics. CTPh occurred at some point in the lives of 34 (15.0%) patients. The median age at onset of CTPh was 14.5 years (IQR: 10.5–17.5). CTPh were found more frequently in adults, with the most frequent onset in adolescence (44.1%). Four mental phenomena resembling tics were recognized: echolalia (n = 17), coprolalia (n = 16), palilalia (n = 13) and repeating of words in the mind (n = 7). The older the age of patients, the more severe tics, and anxiety disorder significantly correlated with CTPh. CTPh may be considered as a part of tic spectrum with a substantial impact of anxiety disorder. CTPh are a late and age-related symptom of GTS.

Microsurgery and Neuromodulation for Facial Spasms

Facial spasms are of various types. Hemifacial spasm (HFS) is characterized by unilateral tonic-clonic contractions of facial muscles, following a specific pattern of disease progression. It has well-delineated clinical, radiological and electrophysiological features. We have conducted an extensive review of existing literature on the subject, as regards etiopathogenesis, clinical features, investigations and management options for facial spasms. Primary Hemifacial spasm (HFS) may be treated using pharmacotherapy, botulinum toxin injections or microvascular decompression surgery. Microvascular decompression has the potential to reverse the pathological changes of the disease and has proved to be the most successful of all treatment options. Other facial spasms are exceedingly difficult to treat and may need neuromodulation as an option. The following article attempts to review the clinical features and therapeutic approaches to managing patients with facial spasms.

A Comprehensive Review of Tic Disorders in Children

Tics are characterized by sudden, rapid, recurrent, nonrhythmic movement or vocalization, and are the most common movement disorders in children. Their onset is usually in childhood and tics often will diminish within one year. However, some of the tics can persist and cause various problems such as social embarrassment, physical discomfort, or emotional impairments, which could interfere with daily activities and school performance. Furthermore, tic disorders are frequently associated with comorbid neuropsychiatric symptoms, which can become more problematic than tic symptoms. Unfortunately, misunderstanding and misconceptions of tic disorders still exist among the general population. Understanding tic disorders and their comorbidities is important to deliver appropriate care to patients with tics. Several studies have been conducted to elucidate the clinical course, epidemiology, and pathophysiology of tics, but they are still not well understood. This article aims to provide an overview about tics and tic disorders, and recent findings on tic disorders including history, definition, diagnosis, epidemiology, etiology, diagnostic approach, comorbidities, treatment and management, and differential diagnosis.

Blocking Tics in Gilles de la Tourette Syndrome

Introduction: Patients with Gilles de la Tourette syndrome (GTS) may experience blocking tics (BTs) defined as recurrent, brief cessations of motor acts. The aim of this study was to assess the prevalence, age of onset, and clinical correlates of BTs in GTS patients.

Materials and Methods: We performed a one-time registration study in a cohort of 195 consecutive GTS patients aged 5–66 years (mean age: 15.0 ± 9.2; 47 females, 24.1%). All patients were personally interviewed and examined.

Results: At least one BT occurred at some point in the lifetime of 73 patients (37.4%) with a mean age of onset of 10.4 ± 5.9 years. BTs occurred an average of 4.8 ± 5.3 years after tic onset. The most common BT was cessation of walking (n = 59, 80.8%), followed by speech (n = 19, 26.0%), running (n = 18, 24.7%), and writing (n = 9, 12.3%). Most of the patients (n = 52, 71.2%) reported cessation of only one activity. Clinical associations of BTs included more severe tics, overall greater number of tics, and, to a lesser extent, higher age at evaluation and comorbid obsessive-compulsive disorder.

Conclusions: BTs represent complex tics, early and common symptoms of GTS, and are associated with a more severe form of GTS.

Language evolution: examining the link between cross-modality and aggression through the lens of disorders

We demonstrate how two linguistic phenomena, figurative language (implicating cross-modality) and derogatory language (implicating aggression), both demand a precise degree of (dis)inhibition in the same cortico-subcortical brain circuits, in particular cortico-striatal networks, whose connectivity has been significantly enhanced in recent evolution. We examine four cognitive disorders/conditions that exhibit abnormal patterns of (dis)inhibition in these networks: schizophrenia (SZ), autism spectrum disorder (ASD), synaesthesia and Tourette's syndrome (TS), with the goal of understanding why the two phenomena altered reactive aggression and altered cross-modality cluster together in these disorders. Our proposal is that enhanced cross-modality (necessary to support language, in particular metaphoricity) was a result, partly a side-effect, of self-domestication (SD). SD targeted the taming of reactive aggression, but reactive impulses are controlled by the same cortico-subcortical networks that are implicated in cross-modality. We further add that this biological process of SD did not act alone, but was engaged in an intense feedback loop with the cultural emergence of early forms of language/grammar, whose high degree of raw metaphoricity and verbal aggression also contributed to increased brain connectivity and cortical control. Consequently, in conjunction with linguistic expressions serving as approximations/'fossils' of the earliest stages of language, these cognitive disorders/conditions serve as confident proxies of brain changes in language evolution, helping us reconstruct certain crucial aspects of early prehistoric languages and cognition, as well as shed new light on the nature of the disorders. This article is part of the theme issue 'Reconstructing prehistoric languages'.

Correlates and clinical implications of tic suppressibility

Purpose of review

Tic disorders are common in the pediatric population and are differentiated from other movement disorders by tic suppressibility. Understanding the mechanism of tic suppression may provide new insights to the pathophysiology of tic disorders. This article highlights clinical phenomenology and neuronal correlates of tic suppressibility.

Recent findings

Recent studies suggest that tic suppressibility exists in children shortly after onset of their tics. Moreover, those who are better able to suppress their tics have better tic outcomes. Interoceptive awareness and automatic action inhibition may be involved in tic suppression.

Summary

We illustrate a possible underlying mechanism of tic suppressibility and its clinical correlations and implications. New concepts such as interoceptive awareness and action inhibition may help explain tic disorders. Further study will be useful to fill remaining knowledge gaps.

A Review of Cognitive and Behavioral Interventions for Tic Disorder

OBJECTIVES

Tic disorder is a neurodevelopmental disorder characterized by multiple involuntary movements of muscles or vocalization. Although tic symptoms subside as the patient ages, some patients suffer from significant functional impairments related to severe tic symptoms. This manuscript aimed to review the latest scientific evidences for the effect of cognitive-behavioral interventions on tic disorder.

METHODS

The relevant studies were identified by searching medical research databases. We focused our search on studies published between 2000 and 2020 in order to reflect the latest scientific evidence. A total of 821 articles were identified in the initial database search and 27 articles were finally included for the review after the exclusion of duplicated and irrelevant articles.

RESULTS

Behavioral therapies including habit reversal training, Comprehensive Behavioral Intervention for Tics, and exposure and response prevention were the most widely studied interventions for tic disorder and are recommended as first-line treatments for tic disorders with high confidence. Cognitive psychophysiologic approaches were also reported to be effective.

CONCLUSION

Further studies are needed to support the future treatment of tics with low-cost and more widely available treatments, in order to ensure better treatment outcomes.

One-year outcome of manualised behavior therapy of chronic tic disorders in children and adolescents

BACKGROUND

Chronic tic disorders are neurodevelopmental disorders that can be treated with Habit Reversal Training (HRT) and Exposure Response Prevention (ERP). Intermediate and long-term effects have been examined after individual treatment with HRT, whereas evaluation of long-term outcome after an initial treatment with ERP, or a combination of HRT and ERP is lacking. The present study examines the long-term effect after a combined treatment with HRT and ERP delivered in an individual or a group setting METHODS: Fifty-nine children and adolescents diagnosed with a chronic tic disorder were randomised to manualised treatment combining HRT and ERP as individual or group training. Forty-seven were re-examined 1 year after acute outcome. Outcome measures included Total Tic Severity score (TTS) measured by the Yale Global Tic Severity Scale (YGTSS) and Beliefs About Tics Scale (BATS) RESULTS: In a mixed model, it was shown that the initial improvement with both individual and group treatment was maintained throughout the follow-up period. There were no significant differences between the two methods of treatment delivery. Of all participants completing the 12 months evaluation, 74.4% were considered responders. There was a significant positive association between the reduction of TTS and the reduction in BATS. In a latent class post-treatment trajectory analysis, two classes were identified, where high baseline severity increased the likelihood of being in the lesser responder class. Similar, but only as a trend, having ADHD, planning difficulties or hypersensitivity increased the risk of a lesser response.

CONCLUSIONS

The present study compares the efficacy in individualised and group treatment of providing manualised therapy for child and adolescent tic disorders using two behavioural methods (combined HRT and ERP) both of which have been shown to have acute benefits but only one of which has been validated for longer term effectiveness. In the present study, both individualised and group treatments showed benefit throughout a 1-year follow-up period with several potential confounds affecting outcomes, while the relative benefits of either HRT and ERP were not addressed. Trial registration NCT04594044, 1-10-72-216-15, registered 19th October 2020, retrospectively registered, https://register.clinicaltrials.gov/prs/app/template/Home.vm?uid=U0005BW2&ts=9&sid=S000ABEY&cx=-wlx7vb The study is approved by the National Ethical Committee (1-10-72-216-15) and the Danish Data Protection Agency (1-16-02-490-15), registered 12 October 2015.

Clinical features and neuropsychiatric comorbidities in pediatric patients with tic disorders: a retrospective chart review study from South Korea

BACKGROUND

Tic disorders are childhood-onset neuropsychiatric disorders characterized by multiple motor or vocal tics with frequent comorbidities and a broad spectrum of phenotypic presentations. In this study, we aimed to investigate the clinical characteristics and comorbid neuropsychiatric conditions in pediatric patients with tic disorders.

METHODS

We retrospectively reviewed the medical records of 119 pediatric patients (89 males, 30 females) who were diagnosed with tic disorders according to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) at Uijeongbu St. Mary's Hospital, Republic of Korea, between January 2012 and July 2019.

RESULTS

The mean age of tic onset was 6.9 years (range, 1-14) and the mean age at diagnosis was 8 years (range, 1-17). The mean lag between tic onset and diagnosis was 13.3 months (range, 0.25-132). The most common, first-presenting tics were eye blinking (50.4%), followed by jaw or lip movement (29.4%) and throat clearing (29.4%). Thirty-seven (31.1%) patients had at least one co-occurring neuropsychiatric disorder at the time of tic diagnosis. Subtypes of tic disorders, types of initial tics, and presence of neuropsychiatric comorbidities were not associated with tic severity. Tic severity was associated with greater functional impairment and tic noticeability (p < 0.05). A relatively shorter time to diagnosis was associated with tic severity (Spearman's ρ = - 0.14, p = 0.11).

CONCLUSIONS

The evolving nature of tic expression and severity, high prevalence of neuropsychiatric comorbidities, and associated functional impairments emphasize the importance of comprehensive assessment during the disease course for determining and prioritizing goals of treatment.

Tics and Tourette's syndrome

Tics and Tourette's syndrome are common hyperkinetic movement disorders seen mostly in the pediatric age group. Tics are defined as sudden, rapid, recurrent, nonrhythmic motor movements or vocalization, generally preceded by urge. Tourette's syndrome is defined as the presence of both motor and phonic tics for more than 1 year in patients with onset less than 18 years old. Most of these hyperkinetic movement disorders improve in adulthood. This review emphasizes the clinical pearls in the diagnosis and distinguishing it from other movement disorders. The treatment ranges from behavioral therapies, medical management, and also surgical treatment such as deep brain stimulation that is limited to refractory patients.

Clinical Features of Tourette Syndrome

Tourette syndrome is a multifaceted disorder characterized by multiple motor and at least one vocal tics that start in childhood, persist for at least 1 year, and cannot be attributed to another medical condition or exposure to medications/drugs. Clinical diagnostic criteria are available, and identification of tics is typically straightforward based on characteristic appearance and features. Diagnostic uncertainty can rarely arise in cases of mild tics, atypical features, certain psychiatric comorbidities, and other non-tic movement disorders. Comorbid psychopathology, including attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive behaviors/obsessive-compulsive disorder, affects the majority of patients and is correlated with disease severity and the presence of additional psychiatric behaviors. The severity of tics often improves after adolescence, whereas psychiatric symptoms typically persist. The subset of patients in whom tics persist into adulthood experience higher rates of anxiety, and lower self-esteem, socioeconomic status, and quality of life; the relative contribution of motor tics and psychopathology is not fully understood. This article summarizes the clinical features of Tourette syndrome, including major diagnostic criteria, unique features of tics, and key aspects that differentiate tics from common mimics and chameleons. Comorbid psychiatric conditions and their impact on phenotype and quality of life are described. Finally, current understanding of the natural history is summarized, including limited research in adults with Tourette syndrome.

From Physical Aggression to Verbal Behavior: Language Evolution and Self-Domestication Feedback Loop

We propose that human self-domestication favored the emergence of a less aggressive phenotype in our species, more precisely phenotype prone to replace (reactive) physical aggression with verbal aggression. In turn, the (gradual) transition to verbal aggression and to more sophisticated forms of verbal behavior favored self-domestication, with the two processes engaged in a mutually reinforcing feedback loop, considering that verbal behavior entails not only less violence and better survival but also more opportunities to interact longer and socialize with more conspecifics, ultimately enabling the emergence of more complex forms of language. Whereas in the case of self-domestication, sexual selection has been proposed to work against physical aggression traits, in the case of verbal insult, the selection has been proposed to work in favor of verbal aggression. The tension between these two seemingly opposing forces gets resolved/alleviated by a tendency to replace physical aggression with verbal aggression and with verbal behavior more generally. This also helps solve the paradox of the Self-Domestication Hypothesis regarding aggression, more precisely why aggression in humans has been reduced only when it comes to reactive aggression, but not when it comes to proactive aggression, the latter exhibiting an increase in the advent of modern language. We postulate that this feedback loop was particularly important during the time period arguably between 200 and 50 kya, when humans were not fully modern, neither in terms of their skull/brain morphology and their behavior/culture nor in terms of their self-domestication. The novelty of our approach lies in (1) giving an active role to early forms of language in interacting with self-domestication processes; (2) providing specific linguistic details and functions of this early stage of grammar (including insult and humor); (3) supplying neurobiological, ontogenetic, and clinical evidence of a link between (reactive) aggression and (reactive) verbal behavior; (4) identifying proxies of the earlier stages in evolution among cognitive disorders; and (5) identifying specific points of contact and mutual reinforcement between these two processes (self-domestication and early language evolution), including reduction in physical aggression and stress/tension, as well as sexual selection.

Nerve Compression Syndromes in the Posterior Cranial Fossa

BACKGROUND

Nerve compression syndromes in the posterior cranial fossa can severely impair patients' quality of life. There is often uncertainty about the best treatment. In this article, we provide an overview of these conditions and the corresponding treatment strategies.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed and on a scientific analysis of the authors' patient collective.

RESULTS

These syndromes are caused by compression of a cranial nerve by an artery or vein at the zone of the nerve's entry to or exit from the brainstem. The best-known neurovascular compression syndrome is trigeminal neuralgia, followed by hemifacial spasm. Less well known are glossopharyngeal neuralgia, nervus intermedius neuralgia, and vestibular paroxysmia. The initial treatment of trigeminal neuralgia is medical: the first line of treatment is with sodium-blocking anticon- vulsants, such as carbamazepine. For patients with hemifacial spasm, botulinum toxin injection is the recommended initial treatment and often leads to a satisfactory regression of the spasms. If these treatments fail, a microvascular decompression operation is indicated. The aim of the procedure is to separate the irritating vessel from the nerve and to keep these structures apart permanently. There is hardly any available evidence on these treatment strategies from randomized controlled trials.

CONCLUSION

Nerve compression syndromes in the posterior cranial fossa can generally be treated nonsurgically at first. Over the course of the condition, however, treatment failure or intolerable side effects may arise. In such cases, a microvascu- lar decompression operation is indicated. This is a causally directed form of treat- ment that generally yields very good results.

Predictors of therapeutic treatment outcome in adolescent chronic tic disorders

BACKGROUND

Chronic tic disorders may have a major impact on a child's function. A significant effect has been shown for combined habit reversal training (HRT) and exposure response prevention (ERP) treatment delivered in an individual and group setting.

AIMS

The present study examines predictors and moderators of treatment outcome after an acute therapeutic intervention.

METHOD

Fifty-nine children and adolescents were randomised to manualised treatment combining HRT and ERP as individual or group training. Age, gender, baseline tic severity, Premonitory Urge for Tics Scale (PUTS) scores, Beliefs about Tic Scale (BATS) scores, hypersensitivity and comorbid psychiatric symptoms were analysed as predictors of outcome. The same characteristics were examined as moderators for individual versus group treatment. Outcome measures included the change in total tic severity (TTS) score and functional impairment score (as measured by the Yale Global Tic Severity Scale (YGTSS)).

RESULTS

Internalising symptoms predicted a lesser decrease in functional impairment. The occurrence of obsessive-compulsive symptoms predicted a larger decrease in TTS. Baseline hypersensitivity and high scores on depressive symptoms favoured individual treatment. High baseline PUTS scores favoured group therapy.

CONCLUSIONS

This is the first study examining factors predicting and moderating perceived functional impairment following a therapeutic intervention. The study adds to the knowledge on predictors and moderators of TTS. Furthermore, this is the first study examining the effect of the BATS score. The study points towards factors that may influence treatment outcome and that require consideration when choosing supplemental treatment. This applies to comorbid anxiety and depressive symptoms, and to the child's belief about their tics and premonitory urge.

DECLARATION OF INTEREST

None.

The urge to blink in Tourette syndrome

Functional neuroimaging studies have attempted to explore brain activity that occurs with tic occurrence in subjects with Tourette syndrome (TS). However, they are limited by the difficulty of disambiguating brain activity required to perform a tic, or activity caused by the tic, from brain activity that generates a tic. Inhibiting ticcing following the urge to tic is important to patients' experience of tics and we hypothesize that inhibition of a compelling motor response to a natural urge will differ in TS subjects compared to controls. This study examines the urge to blink, which shares many similarities to premonitory urges to tic. Previous neuroimaging studies with the same hypothesis have used a one-size-fits-all approach to extract brain signal putatively linked to the urge to blink. We aimed to create a subject-specific and blink-timing-specific pathophysiological model, derived from out-of-scanner blink suppression trials, to eventually better interpret blink suppression fMRI data. Eye closure and continuously self-reported discomfort were reported during five blink suppression trials in 30 adult volunteers, 15 with a chronic tic disorder. For each subject, data from four of the trials were used with an empirical mathematical model to predict discomfort from eye closure observed during the remaining trial. The blink timing model of discomfort during blink suppression predicted observed discomfort much better than previously applied models. Combining this approach with observed eye closure during fMRI blink suppression trials should therefore extract brain signal more tightly linked to the urge to blink. The simple mean of time-discomfort curves from each subject's other trials also outperformed older models. The TS group blinked more than twice as often during the blink suppression block, and reported higher baseline discomfort, smaller excursion from baseline to peak discomfort during the blink suppression block, and slower return of discomfort to baseline during the recovery block.

A Bayesian Account of the Sensory-Motor Interactions Underlying Symptoms of Tourette Syndrome

Tourette syndrome is a hyperkinetic movement disorder. Characteristic features include tics, recurrent movements that are experienced as compulsive and "unwilled"; uncomfortable premonitory sensations that resolve through tic release; and often, the ability to suppress tics temporarily. We demonstrate how these symptoms and features can be understood in terms of aberrant predictive (Bayesian) processing in hierarchical neural systems, explaining specifically: why tics arise, their "unvoluntary" nature, how premonitory sensations emerge, and why tic suppression works-sometimes. In our model, premonitory sensations and tics are generated through over-precise priors for sensation and action within somatomotor regions of the striatum. Abnormally high precision of priors arises through the dysfunctional synaptic integration of cortical inputs. These priors for sensation and action are projected into primary sensory and motor areas, triggering premonitory sensations and tics, which in turn elicit prediction errors for unexpected feelings and movements. We propose experimental paradigms to validate this Bayesian account of tics. Our model integrates behavioural, neuroimaging, and computational approaches to provide mechanistic insight into the pathophysiological basis of Tourette syndrome.

Combined habit reversal training and exposure response prevention in a group setting compared to individual training: a randomized controlled clinical trial

Chronic tic disorders may have a huge influence on quality of life. Habit reversal training (HRT) and exposure response prevention (ERP) are effective treatments. In a blinded assessed, open trial, this study evaluates the effectiveness of a newly developed Scandinavian tic treating manual designed to treat adolescents with a chronic tic disorder, combining HRT and ERP. The study compared the efficacy of treatment based on the same manual delivered either individually or in groups. The study was an open randomized controlled clinical trial in which adolescents were randomized to either individual or group therapy. Both therapies included nine sessions. The parents were offered group-based psycho-education. The exclusion criteria were chosen to design a study that would be close to clinical practice. This is the first Scandinavian study that examines the effectiveness of a treatment manual combining HRT and ERP delivered in an individual and group setting. The study showed a significant reduction of the Total Tic score on the Yale Global Tic Severity Scale both in the individual (effect size 1.21) and group setting (effect size 1.38). A total of 66.7% of participants were considered responders. There was no statistical significant difference between the individual and group setting apart from the functional impairment score. The reductions were comparable with those shown in other studies. The participants applied both HRT and ERP, and the majority (36/59) reported an increased post-treatment experience of control. The newly designed Scandinavian manual was equally effective in the individual and group setting with effect sizes comparable with those shown in other studies.

[Neuronal plasticity and neuromodulation in pediatric neurology]

BACKGROUND

Neuronal plasticity is a core mechanism for learning and memory. Abnormal neuronal plasticity has emerged as a key mechanism in many neurological and neuropediatric diseases.

OBJECTIVE

Chances and perspectives of neuromodulation techniques in neurological and neuropediatric diseases with altered neuronal plasticity.

MATERIAL AND METHODS

Presentation and discussion of own results of neuronal plasticity investigations in patients with neurodevelopmental disorders including RASopathies, autism spectrum disorders (ASD) and Gilles de la Tourette syndrome (GTS).

RESULTS

The results of neuronal plasticity studies in patients with RASopathies, ASD and GTS underline the pathophysiological relevance of abnormal neuronal plasticity in these diseases. Transcranial magnetic stimulation (TMS) is a useful tool to examine and also induce neuronal plasticity in these patients.

CONCLUSION

Neuronal plasticity appears to be an important pathophysiological factor in neuronal developmental disorders and can be investigated using TMS. New and innovative techniques may offer novel approaches for individualized TMS applications, particularly in children with neuropediatric conditions.

Distinctive tics suppression network in Gilles de la Tourette syndrome distinguished from suppression of natural urges using multimodal imaging

Background and objectives

Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder characterized by tics. A hallmark of GTS is the ability to voluntarily suppress tics. Our aim was to distinguish the neural circuits involved in the voluntary suppression of ocular tics in GTS patients from blink suppression in healthy subjects.

Methods

Fifteen GTS patients and 22 healthy control subjects were included in a multimodal study using eye-tracker recordings during functional MRI (fMRI). The ability to suppress tics/blinks was compared both on subjective (self-rating) and objective (eye-tracker) performance. For fMRI analysis we used a novel designed performance-adapted block design analysis of tic/blink suppression and release based on eye-tracker monitoring.

Results

We found that the subjective self-reported ability to suppress tics or blinks showed no significant correlation with objective task performance. In GTS during successful suppression of tics, the dorsal anterior cingulate cortex and associated limbic areas showed increased activation. During successful suppression of eye blinks in healthy subjects, the right ventrolateral prefrontal cortex and supplementary and cingulate motor areas showed increased activation.

Conclusions

These findings demonstrate that GTS patients use a characteristic limbic suppression strategy. In contrast, control subjects use the voluntary sensorimotor circuits and the classical ‘stop’ network to suppress natural urges. The employment of different neural suppression networks provides support for cognitive behavioral therapy in GTS.

•

Neural networks of tic suppression are specific and differ from blink suppression.

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Tourette patients employ a limbic suppression strategy to suppress tics.

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Controls use sensorimotor circuits and ‘stop’ networks for blink suppression.

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Objective task performance is highly recommended during functional MRI of tics.

Associative plasticity in supplementary motor area - motor cortex pathways in Tourette syndrome

The important role of the supplementary motor area (SMA) in the generation of tics and urges in Gilles de la Tourette syndrome (GTS) is underscored by an increased SMA-motor cortex (M1) connectivity. However, whether plasticity is also altered in SMA-M1 pathways is unclear. We explored whether SMA-M1 plasticity is altered in patients with Tourette syndrome. 15 patients with GTS (mean age of 33.4 years, SD = 9.9) and 19 age and sex matched healthy controls were investigated with a paired association stimulation (PAS) protocol using three transcranial magnetic stimulation (TMS) coils stimulating both M1 and the SMA. Standard clinical measures for GTS symptoms were collected. There was a significant PAS effect showing that MEP amplitudes measured in blocks during and after PAS were significantly higher compared to those in the first block. However, the degree of PAS was not differentially modulated between patients and controls as shown by a Bayesian data analysis. PAS effects in GTS correlated positively with the YGTSS motor tic severity. Plasticity previously reported to be altered in sensorimotor pathways in GTS is normal in SMA-M1 projections suggesting that the dysfunction of the SMA in GTS is not primarily related to altered plasticity in SMA-M1 connections.

Social cognition and self-other distinctions in neuropsychiatry: Insights from schizophrenia and Tourette syndrome

Impairments in social cognition may reflect dysfunction of disorder specific or disorder general mechanisms. Although cross-disorder comparison may prove insightful, few studies have compared social cognition in different neuropsychiatric disorders. Parallel investigation of schizophrenia and Tourette syndrome (TS) is encouraged by similarities including the presence of problematic social behavior, echophenomena, emotional dysregulation and dopamine dysfunction. Focusing on tests of social cognition administered in both disorders, this review aims to summarize behavioral, neurophysiological and neuroimaging findings, before exploring how these may contribute to clinical symptoms. Studies investigating social cognition (imitation, emotion recognition, and understanding of beliefs or intentions) in patients with schizophrenia or TS were identified through Web of Science and PubMed searches. Although findings indicate that social cognitive deficits are more apparent in schizophrenia, adults with TS can exhibit similar task performance to patients with paranoia. In both disorders, behavioral and neuroimaging findings raise the possibility of increased internal simulation of others' actions and emotions, in combination with a relative under-application of mentalizing. More specifically, dysfunction in neurobiological substrates such as temporo-parietal junction and inferior frontal gyrus may underlie problems with self-other distinctions in both schizophrenia and TS. Difficulties in distinguishing between actions and mental states linked to the self and other may contribute to a range of psychiatric symptoms, including emotional dysregulation, paranoia, social anhedonia and socially disruptive urges. Comparing different patient populations could therefore reveal common neuro-cognitive risk factors for the development of problematic social behaviors, in addition to markers of resilience, coping strategies and potential neuro-compensation mechanisms.

Centrality of prefrontal and motor preparation cortices to Tourette Syndrome revealed by meta-analysis of task-based neuroimaging studies

Tourette Syndrome (TS) is a neurodevelopmental condition characterized by chronic multiple tics, which are experienced as compulsive and 'unwilled'. Patients with TS can differ markedly in the frequency, severity, and bodily distribution of tics. Moreover, there are high comorbidity rates with attention deficit hyperactivity disorder (ADHD), obsessive compulsive disorder (OCD), anxiety disorders, and depression. This complex clinical profile may account for apparent variability of findings across neuroimaging studies that connect neural function to cognitive and motor behavior in TS. Here we crystalized information from neuroimaging regarding the functional circuitry of TS, and furthermore, tested specifically for neural determinants of tic severity, by applying activation likelihood estimation (ALE) meta-analyses to neuroimaging (activation) studies of TS. Fourteen task-based studies (13 fMRI and one H2O-PET) met rigorous inclusion criteria. These studies, encompassing 25 experiments and 651 participants, tested for differences between TS participants and healthy controls across cognitive, motor, perceptual and somatosensory domains. Relative to controls, TS participants showed distributed differences in the activation of prefrontal (inferior, middle, and superior frontal gyri), anterior cingulate, and motor preparation cortices (lateral premotor cortex and supplementary motor area; SMA). Differences also extended into sensory (somatosensory cortex and the lingual gyrus; V4); and temporo-parietal association cortices (posterior superior temporal sulcus, supramarginal gyrus, and retrosplenial cortex). Within TS participants, tic severity (reported using the Yale Global Tic Severity Scale; YGTSS) selectively correlated with engagement of SMA, precentral gyrus, and middle frontal gyrus across tasks. The dispersed involvement of multiple cortical regions with differences in functional reactivity may account for heterogeneity in the symptomatic expression of TS and its comorbidities. More specifically for tics and tic severity, the findings reinforce previously proposed contributions of premotor and lateral prefrontal cortices to tic expression.

How Much Do We Know about Adult-onset Primary Tics? Prevalence, Epidemiology, and Clinical Features

BACKGROUND

Tic disorders are generally considered to be of pediatric onset; however, reports of adult-onset tics exist in the literature. Tics can be categorized as either primary or secondary, with the latter being the larger group in adults. Primary or idiopathic tics that arise in adulthood make up a subset of tic disorders whose epidemiologic and clinical features have not been well delineated.

METHODS

Articles to be included in this review were identified by searching PubMed, SCOPUS, and Web of Science using the terms adult- and late-onset tics, which resulted in 120 unique articles. Duplicates were removed. Citing references were identified using Google Scholar; all references were reviewed for relevance.

RESULTS

The epidemiologic characteristics, clinical phenomenology, and optimal treatment of adult-onset tics have not been ascertained. Twenty-six patients with adult-onset, primary tics were identified from prior case reports. The frequency of psychiatric comorbidities may be lower in adults than in children, and obsessive compulsive disorder was the most common comorbidity. Adult-onset primary tics tend to wax and wane, occur predominantly in males, are often both motor and phonic in the same individual, and are characterized by a poor response to treatment.

DISCUSSION

We know little about adult-onset tic disorders, particularly ones without a secondary association or cause. They are not common, and from the limited data available, appear to share some but not all features with childhood tics. Further research will be important in gaining a better understanding of the epidemiology and clinical manifestations of this disorder.

Putting the Pieces Together in Gilles de la Tourette Syndrome: Exploring the Link Between Clinical Observations and the Biological Basis of Dysfunction

Gilles de la Tourette syndrome is a complex, idiopathic neuropsychiatric disorder whose pathophysiological mechanisms have yet to be elucidated. It is phenotypically heterogeneous and manifests more often than not with both motor and behavioral impairment, although tics are its clinical hallmark. Tics themselves present with a complex profile as they characteristically wax and wane and are often preceded by premonitory somatosensory sensations to which it is said a tic is the response. Highly comorbid with obsessive-compulsive disorder and attention deficit-hyperactivity disorder, it is purported to be an epigenetic, neurodevelopmental spectrum disorder with a complex genetic profile. It has a childhood onset, occurs disproportionately in males, and shows spontaneous symptomatic attenuation by adulthood in the majority of those afflicted. Although not fully understood, its neurobiological basis is linked to dysfunction in the cortico-basal ganglia-thalamo-cortical network. Treatment modalities for Tourette syndrome include behavioral, pharmacological and surgical interventions, but there is presently no cure for the disorder. For those severely affected, deep brain stimulation (DBS) has recently become a viable therapeutic option. A key factor to attaining optimal results from this surgery is target selection, a topic still under debate due to the complex clinical profile presented by GTS patients. Depending on its phenotypic expression and the most problematic aspect of the disorder for the individual, one of three brain regions is most commonly chosen for stimulation: the thalamus, globus pallidus, or nucleus accumbens. Neurophysiological analyses of intra- and post-operative human electrophysiological recordings from clinical DBS studies suggest a link between tic behavior and activity in both the thalamus and globus pallidus. In particular, chronic recordings from the thalamus have shown a correlation between symptomatology and (1) spectral activity in gamma band power and (2) theta/gamma cross frequency coherence. These results suggest gamma oscillations and theta/gamma cross correlation dynamics may serve as biomarkers for dysfunction. While acute and chronic recordings from human subjects undergoing DBS have provided better insight into tic genesis and the neuropathophysiological mechanisms underlying Tourette syndrome, these studies are still sparse and the field would greatly benefit from further investigations. This review reports data and discoveries of scientific and clinical relevance from a wide variety of methods and provides up-to-date information about our current understanding of the pathomechanisms underlying Tourette syndrome. It gives a comprehensive overview of the current state of knowledge and addresses open questions in the field.

Aripiprazole Improves Associated Comorbid Conditions in Addition to Tics in Adult Patients with Gilles de la Tourette Syndrome

Gilles de la Tourette Syndrome (GTS) is characterized by motor and vocal tics, as well as associated comorbid conditions including obsessive-compulsive disorder (OCD), attention deficit/hyperactivity disorder (ADHD), depression, and anxiety which are present in a substantial number of patients. Although randomized controlled trials including a large number of patients are still missing, aripiprazole is currently considered as a first choice drug for the treatment of tics. The aim of this study was to further investigate efficacy and safety of aripiprazole in a group of drug-free, adult patients. Specifically, we investigated the influence of aripiprazole on tic severity, comorbidities, premonitory urge (PU), and quality of life (QoL). Moreover, we were interested in the factors that influence a patient's decision in electing for-or against- pharmacological treatment. In this prospective uncontrolled open-label study, we included 44 patients and used a number of rating scales to assess tic severity, PU, comorbidities, and QoL at baseline and during treatment with aripiprazole. Eighteen out of fortyfour patients decided for undergoing treatment for their tics with aripiprazole and completed follow-up assessments after 4–6 weeks. Our major findings were (1) aripiprazole resulted in significant reduction of tics, but did not affect PU; (2) aripiprazole significantly improved OCD and showed a trend toward improvement of other comorbidities including depression, anxiety, and ADHD; (3) neither severity of tics, nor PU or QoL influenced patients' decisions for or against treatment of tics with aripiprazole; instead patients with comorbid OCD tended to decide in favor of, while patients with comorbid ADHD tended to decide against tic treatment; (4) most frequently reported adverse effects were sleeping problems; (5) patients' QoL was mostly impaired by comorbid depression. Our results suggest that aripiprazole may improve associated comorbid conditions in addition to tics in patients with GTS. It can be hypothesized that these beneficial effects are related to aripiprazole's adaptive pharmacological profile, which exhibits an influence on the dopaminergic as well as a number of other neurotransmitter systems. For the first time, our data provide evidence that patients' decision making process for or against medical treatment is influenced by other factors than tic severity and QoL.

A Review and Update on Tourette Syndrome: Where Is the Field Headed?

Tourette syndrome (TS) is a childhood onset neurologic disorder with manifestations including multiple motor and phonic tics, and in most cases a variety of behavioral comorbidities such as attention deficit hyperactivity disorder, obsessive compulsive disorder, and other impulse control disorders. Although it is considered a hereditary disorder, likely modified by environmental factors, genetic studies have yet to uncover relevant causative genes and there is no animal model that mimics the broad clinical phenomenology of TS. There has been a marked increase in the number of neurophysiological, neuroimaging, and other studies on TS. The findings from these studies, however, have been difficult to interpret because of small sample sizes, variability of symptoms across patients, and comorbidities. Although anti-dopaminergic drugs are the most widely used medications in the treatment of TS, there has been increasing interest in other drugs, behavioral therapies, and surgical approaches including deep brain stimulation. Herein, we review the current literature and discuss the complexities of TS and the challenges in understanding its pathophysiology and in selecting the most appropriate treatment. We also offer an expert's view of where the field of TS may be headed.

Fragile X syndrome: A review of clinical management

The fragile X mental retardation 1 gene, which codes for the fragile X mental retardation 1 protein, usually has 5 to 40 CGG repeats in the 5' untranslated promoter. The full mutation is the almost always the cause of fragile X syndrome (FXS). The prevalence of FXS is about 1 in 4,000 to 1 in 7,000 in the general population although the prevalence varies in different regions of the world. FXS is the most common inherited cause of intellectual disability and autism. The understanding of the neurobiology of FXS has led to many targeted treatments, but none have cured this disorder. The treatment of the medical problems and associated behaviors remain the most useful intervention for children with FXS. In this review, we focus on the non-pharmacological and pharmacological management of medical and behavioral problems associated with FXS as well as current recommendations for follow-up and surveillance.

Dystonic tics induced by deep brain stimulation of the posterior subthalamic area for essential tremor

OBJECTIVE The posterior subthalamic area (PSA) is a promising target of deep brain stimulation (DBS) for medication-refractory essential tremor (ET). This case series describes a novel adverse effect manifesting as dystonic tics in patients with ET undergoing DBS of the PSA. METHODS Six patients with ET received electrode implants for DBS of the dorsal and caudal zona incerta subregions of the PSA. RESULTS Five of the 6 patients developed dystonic tics soon after clinical programming. These tics were of varying severity and required reduction of the electrical stimulation amplitude. This reduction resolved tic occurrence without significantly affecting ET control. Dystonic tics were not observed in 39 additional patients who underwent DBS of the same brain regions for controlling non-ET movement disorders. CONCLUSIONS The pathophysiology of tic disorders is poorly understood and may involve the basal ganglia and related cortico-striato-thalamo-cortical circuits. This series is the first report of DBS-induced tics after stimulation of any brain target. Although the PSA has not previously been implicated in tic pathophysiology, it may be a candidate region for future studies.

A Case of Adult Onset Tic Disorder Following Carbon Monoxide Intoxication

Background:

Adult onset tic disorders are usually secondary in origin. We report a case of adult onset tic disorder following carbon monoxide (CO) intoxication with typical magnetic resonance imaging features.

Case Report:

A 36-year-old woman developed temporarily suppressible patterned movements on her face, neck, and shoulder associated with sensory discomfort after CO poisoning. Magnetic resonance images showed bilateral symmetric cavitary changes in the globus pallidus. Clonazepam relieved much of her symptoms.

Conclusion:

Our patient developed a mono-symptomatic tic disorder following CO intoxication. This further supports that altered outflow signals from the basal ganglia, especially the globus pallidus, may contribute to the development of tic disorders.