Tourette Syndrome: Update

Gilles de la Tourette syndrome as a paradigmatic neuropsychiatric disorder

Gilles de la Tourette syndrome is a chronic and complex tic disorder accompanied by specific behavioral problems in the majority of patients. With its multifaceted interplay between motion and emotion, this condition is a paradigmatic example of the science and art of clinical neuropsychiatry. This review article encompasses the clinical phenomenology of motor and vocal tics and associated sensory experiences (premonitory urges), as well as the behavioral spectrum of the most common comorbidities, including obsessive-compulsive disorder, attention-deficit and hyperactivity disorder, affective symptoms, and impulsivity. Knowledge of the contributions of both tics and behavioral problems to patients' health-related quality of life across the lifespan should assist treating clinicians in formulating a targeted management plan. Although the exact pathophysiology of Gilles de la Tourette syndrome remains elusive, research into therapeutic interventions has expanded the range of available interventions across multiple domains. A thorough understanding of the neurology and psychiatry of this condition is of key importance to meet the needs of this patient population, from the formulation of an accurate diagnosis to the implementation of effective treatment strategies.

Acute Worsening of Tics on Varenicline

OBJECTIVE

The aim of this study was to report worsening of Tourette syndrome (TS) in 2 patients treated with varenicline.

BACKGROUND

Abnormal dopaminergic signaling is likely involved in the pathophysiology of TS. Varenicline is a partial α4β2 nicotinic acetylcholine agonist that enhances dopamine release. Therefore, the use of varenicline may influence tics in patients with TS.

METHOD

We analyzed and described 2 case studies on patients with significant worsening of tics after treatment with varenicline.

RESULTS

Patient 1 had motor tics in childhood, which completely resolved by the age of 20 years. At the age of 25 years, he started varenicline and stopped smoking. Within 2 weeks, he developed motor followed by vocal tics that persisted despite stopping varenicline and restarting smoking. The tics were complex, medically refractory, and caused severe disability at work and school (Yale Global Tic Severity Scale score, 86). Patient 2 developed motor and vocal tics in adolescence that persisted into her 20s and caused significant disability in association with psychiatric comorbidities. At the age of 31 years, she started varenicline to quit smoking, which led to a marked increase in tic frequency and severity. Varenicline was discontinued after 3 weeks with improvement to baseline tic severity (Yale Global Tic Severity Scale score, 94). Ultimately, both patients successfully underwent deep brain stimulation to bilateral centromedian/parafascicular complex thalamic nuclei for medically refractory TS.

CONCLUSIONS

We report 2 patients with motor and/or vocal tics that had severe worsening of tics after varenicline use. This may be due to varenicline-induced increased striatal dopamine in conjunction with nicotine cessation, influencing dopamine receptor sensitivity in TS. Providers should be cautious in prescribing varenicline to patients with TS.

Global network modulation during thalamic stimulation for Tourette syndrome

Background and objectives

Deep brain stimulation (DBS) of the thalamus is a promising therapeutic alternative for treating medically refractory Tourette syndrome (TS). However, few human studies have examined its mechanism of action. Therefore, the networks that mediate the therapeutic effects of thalamic DBS remain poorly understood.

Methods

Five participants diagnosed with severe medically refractory TS underwent bilateral thalamic DBS stereotactic surgery. Intraoperative fMRI characterized the blood oxygen level-dependent (BOLD) response evoked by thalamic DBS and determined whether the therapeutic effectiveness of thalamic DBS, as assessed using the Modified Rush Video Rating Scale test, would correlate with evoked BOLD responses in motor and limbic cortical and subcortical regions.

Results

Our results reveal that thalamic stimulation in TS participants has wide-ranging effects that impact the frontostriatal, limbic, and motor networks. Thalamic stimulation induced suppression of motor and insula networks correlated with motor tic reduction, while suppression of frontal and parietal networks correlated with vocal tic reduction. These regions mapped closely to major regions of interest (ROI) identified in a nonhuman primate model of TS.

Conclusions

Overall, these findings suggest that a critical factor in TS treatment should involve modulation of both frontostriatal and motor networks, rather than be treated as a focal disorder of the brain. Using the novel combination of DBS-evoked tic reduction and fMRI in human subjects, we provide new insights into the basal ganglia-cerebellar-thalamo-cortical network-level mechanisms that influence the effects of thalamic DBS. Future translational research should identify whether these network changes are cause or effect of TS symptoms.

Botulinum toxin for motor and phonic tics in Tourette's syndrome

BACKGROUND

Gilles de la Tourette syndrome, or Tourette's syndrome, is defined as the presence of both motor and vocal (phonic) tics for more than 12 months, that manifest before the age of 18 years, in the absence of secondary causes. Treatment of motor and phonic tics is difficult and challenging.

OBJECTIVES

To determine the safety and effectiveness of botulinum toxin in treating motor and phonic tics in people with Tourette's syndrome, and to analyse the effect of botulinum toxin on premonitory urge and sensory tics.

SEARCH METHODS

We searched the Cochrane Movement Disorders Group Trials Register, CENTRAL, MEDLINE, and two trials registers to 25 October 2017. We reviewed reference lists of relevant articles for additional trials.

SELECTION CRITERIA

We considered all randomised, controlled, double-blind studies comparing botulinum toxin to placebo or other medications for the treatment of motor and phonic tics in Tourette's syndrome for this review. We sought both parallel group and cross-over studies of children or adults, at any dose, and for any duration.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods to select studies, assess risk of bias, extract and analyse data. All authors independently abstracted data onto standardized forms; disagreements were resolved by mutual discussion.

MAIN RESULTS

Only one randomised placebo-controlled, double-blind cross-over study met our selection criteria. In this study, 20 participants with motor tics were enrolled over a three-year recruitment period; 18 (14 of whom had a diagnosis of Tourette's syndrome) completed the study; in total, 21 focal motor tics were treated. Although we considered most bias domains to be at low risk of bias, the study recruited a small number of participants with relatively mild tics and provided limited data for our key outcomes. The effects of botulinum toxin injections on tic frequency, measured by videotape or rated subjectively, and on premonitory urge, are uncertain (very low-quality evidence). The quality of evidence for adverse events following botulinum toxin was very low. Nine people had muscle weakness following the injection, which could have led to unblinding of treatment group assignment. No data were available to evaluate whether botulinum injections led to immunoresistance to botulinum.

AUTHORS' CONCLUSIONS

We are uncertain about botulinum toxin effects in the treatment of focal motor and phonic tics in select cases, as we assessed the quality of the evidence as very low. Additional randomised controlled studies are needed to demonstrate the benefits and harms of botulinum toxin therapy for the treatment of motor and phonic tics in patients with Tourette's syndrome.

Benchmarking Treatment Response in Tourette's Disorder: A Psychometric Evaluation and Signal Detection Analysis of the Parent Tic Questionnaire

This study assessed the psychometric properties of a parent-reported tic severity measure, the Parent Tic Questionnaire (PTQ), and used the scale to establish guidelines for delineating clinically significant tic treatment response. Participants were 126 children ages 9 to 17 who participated in a randomized controlled trial of Comprehensive Behavioral Intervention for Tics (CBIT). Tic severity was assessed using the Yale Global Tic Severity Scale (YGTSS), Hopkins Motor/Vocal Tic Scale (HMVTS) and PTQ; positive treatment response was defined by a score of 1 (very much improved) or 2 (much improved) on the Clinical Global Impressions - Improvement (CGI-I) scale. Cronbach's alpha and intraclass correlations (ICC) assessed internal consistency and test-retest reliability, with correlations evaluating validity. Receiver- and Quality-Receiver Operating Characteristic analyses assessed the efficiency of percent and raw-reduction cutoffs associated with positive treatment response. The PTQ demonstrated good internal consistency (α = 0.80 to 0.86), excellent test-retest reliability (ICC = .84 to .89), good convergent validity with the YGTSS and HM/VTS, and good discriminant validity from hyperactive, obsessive-compulsive, and externalizing (i.e., aggression and rule-breaking) symptoms. A 55% reduction and 10-point decrease in PTQ Total score were optimal for defining positive treatment response. Findings help standardize tic assessment and provide clinicians with greater clarity in determining clinically meaningful tic symptom change during treatment.

Jian-Pi-Zhi-Dong-Decoction regulates the expression of glutamate transporters to attenuate glutamate excitotoxicity and exerts anti-tics effects in Tourette syndrome model rats

PURPOSE

This study explored whether Jian-Pi-Zhi-Dong-Decoction (JPZDD) could regulate the metabolism of glutamate (GLU) and its transporters in the striatum to exert anti-tics effects in Tourette syndrome (TS) rats.

MATERIALS AND METHODS

We randomly assigned 56 Sprague Dawley rats into four groups, each with 14 rats: control, model, tiapride (Tia), and JPZDD. TS groups (model, Tia, and JPZDD) received intraperitoneal injection of 3,3'-iminodipropionitrile for 7 days to establish TS model. Thereafter, rats in the four groups were treated differently once a day for 6 weeks. Behavioral evaluation was performed each week by using stereotypy recording and autonomic activity test. The level of GLU in the striatum was examined by high-performance liquid chromatography. Expression of EAAT1 and VGLUT1 were measured by quantitative real-time PCR (qRT-PCR) and laser scanning confocal microscope.

RESULTS

Compared with the model group, the stereotypy score and autonomic activity were decreased in Tia and JPZDD groups. Notably, the model group had increased concentration of GLU, which decreased after JPZDD and Tia treatments. In the model group, EAAT1 and glial cells were highly co-expressed and the relative fluorescence intensity (FI) of EAAT1 was significantly lower than that in the control group. Treatment with JPZDD and Tia increased the relative FI of EAAT1. The mRNA level of EAAT1 decreased in the model group compared to that in the control group, although it was significantly elevated following JPZDD or Tia treatment. In the model group, there was low co-expression of VGLUT1 and axon cells and the FI of VGLUT1 was remarkably increased relative to that in the control group and reduced following treatment with JPZDD and Tia. A similar trend was observed in the mRNA and protein expression of VGLUT1, although it was not statistically significant.

CONCLUSION

The mechanism by which JPZDD alleviated behavioral dysfunction of TS rats may be associated with maintaining normal GLU transport by upregulating EAAT1 and down-regulating VGLUT1 in the striatum.

A Single Case of Tourette's Syndrome Treated with Traditional Chinese Medicine

The objective of this case study was to investigate the effectiveness of Chinese medicine in treating Tourette's syndrome. Tourette's syndrome is a childhood- onset disorder that is characterized by sudden, involuntary movements or tics. The participant in this study was a 33-year-old male who had been diagnosed with Tourette's syndrome at the age of 9 years. His major complaints included facial tics, shoulder shrugging, and clearing the throat. Using a combination of acupuncture, herbs, Gua-Sha, and lifestyle changes once a week for 35 treatments, all the symptoms were reduced by 70%, as reported by the patient. In this case, the results indicated that Chinese medicine was able to minimize the symptoms of Tourette's syndrome. Further investigation is needed to support this argument. Tourette's syndrome, which was first described in 1885 by a French physician named Gilles de la Tourette, is characterized by facial tics, involuntary body movements from the head to the extremities, or vocal tics, and it usually has its onset in childhood. It is a neuropsychiatric disorder. The treatment for Tourette's syndrome is based on pharmacological treatment, behavior treatment, and deep brain stimulation. Unfortunately, none of these could completely control the symptoms; furthermore, antipsychiatric drugs might cause additional side effects, such as Parkinson symptoms, tardive dyskinesia, and metabolic disturbances. Finding acupuncture and oriental medicine literature on treatment of Tourette's syndrome was difficult, especially that written in English. Some research papers that have been translated into English indicated that Chinese herbs and acupuncture could reduce the tics significantly. For example, a study by Dr Pao-Hua Lin reported the significant effects of using acupuncture and oriental medicine in treating 1000 Tourette's syndrome cases. This case was treated to further investigate the principles of Dr Lin's study.

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.

Neurobiology of the Premonitory Urge in Tourette's Syndrome: Pathophysiology and Treatment Implications

Motor and vocal tics are relatively common motor manifestations identified as the core features of Tourette's syndrome (TS). Although traditional descriptions have focused on objective phenomenological observations, such as anatomical location, number and frequency of tics, patients' first-person accounts have consistently reported characteristic subjective correlates. These sensory phenomena are often described as a feeling of mounting inner tension or urge to move ("premonitory urge"), which is transiently relieved by tic expression. This article reviews the existing literature on the clinical and neurobiological aspects of the premonitory urge in patients with TS, with focus on its pathophysiology and possible treatment implications.

The Effectiveness of Aripiprazole for Tics, Social Adjustment, and Parental Stress in Children and Adolescents with Tourette's Disorder

OBJECTIVE

Tourette's syndrome (TS) frequently results in a negative impact on multiple functional domains. This prospective open-label study investigated the potential effectiveness of aripiprazole for tics, social adjustment, and parental stress in children and adolescents with TS.

METHODS

Study participants consisted of 26 patients (mean age 10.4 ± 3.0 years; 22 boys and 4 girls) who were prescribed aripiprazole, with each dose ranging from 2.5 to 15 mg/day. At baseline and 2, 4, and 8 weeks from baseline, tic symptoms, social adjustment, and parenting stress were assessed using the Yale Global Tic Severity Scale (YGTSS), the Social Adjustment Inventory for Children and Adolescents (SAICA), and the Parenting Stress Index (PSI). Aripiprazole could be optionally titrated from 2.5 to 30 mg/day at each visit.

RESULTS

Of the 26 patients at the initial visit, 22 (84.6%) completed the study. The mean dose of aripiprazole at the endpoint was 8.0 ± 4.0 mg/day. During the 8-week aripiprazole treatment period, motor tics, phonic tics, and impairment on the YGTSS all showed significant improvement. Home behaviors on the SAICA and child domain on the PSI also showed significant improvement. Patients' phonic tics, but not motor tics, showed a positive correlation with their school function and peer relationships. The child domain on the PSI was positively correlated with motor tics, phonic tics, and impairment, as measured by the YGTSS.

CONCLUSIONS

An 8-week aripiprazole treatment program for children and adolescents with TS was beneficial to their tic symptoms, behaviors at home, and caregivers' stress with regard to fulfilling parenting roles. A long-term placebo-controlled trial with larger samples is warranted to confirm the effectiveness of aripiprazole for social adjustment and parental stress.

Advances in management of movement disorders in children

Movement disorders in children are causally and clinically heterogeneous and present in a challenging developmental context. Treatment options are broad ranging, from pharmacotherapy to invasive neuromodulation and experimental gene and stem cell therapies. The clinical effects of these therapies are variable and often poorly sustained, and only a few of the management strategies used in paediatric populations have been tested in randomised controlled studies with age-appropriate cohorts. Identification of the most appropriate treatment is uniquely challenging in children because of the incomplete knowledge about the pathophysiology of movement disorders and their influence on normal motor development; thus, effective therapeutic options for these children remain an unmet need. It is vital to transfer the expanding knowledge of the movement disorders into the development of novel symptomatic or, ideally, disease-modifying treatments, and to assess these therapeutic strategies in appropriately designed and well done trials.

New treatment models for compulsive disorders

Obsessive compulsive disorder (OCD) as well as related disorders such as body dysmorphic disorder, tic disorder, and trichotillomania are all common and often debilitating. Although treatments are available, more effective approaches to these problems are needed. Thus this review article presents what is currently known about OCD and related disorders and suggests that understanding OCD more broadly as a compulsive disorder may allow for more effective treatment options. Toward that goal, the review presents new models of psychopharmacology and psychotherapy, as well as new brain stimulation strategies. Treatment advances, grounded in the neuroscience, have promise in advancing treatment response for OCD as well as other disorders of compulsivity.

Clinical Neurophysiological Evaluation for Simple Motor Tics

Objective

To demonstrate the usefulness of neurophysiological evaluation to distinguish simple motor tics and functional myoclonus.

Methods

Careful clinical assessments, multichannel surface EMG, and EEG-EMG jerk-locked back-averaging were performed.

Results

Urge to move and ability to voluntarily suppress the movement were reported. EMG bursts showed variable duration and triphasic pattern of the antagonist muscles mimicking voluntary movements. Only the late component of the Bereitschaftspotential (BP2) was present prior to the involuntary movement onset.

Conclusion

Combination of the isolated late BP, premonitory urge, and suppressibility leads to the diagnosis of simple motor tics rather than functional myoclonus.

Significance

The physiological approach in addition to careful clinical assessment is helpful to support the diagnosis of tic.

Effect of Jian-Pi-Zhi-Dong Decoction on striatal glutamate and γ-aminobutyric acid levels detected using microdialysis in a rat model of Tourette syndrome

BACKGROUND

Jian-Pi-Zhi-Dong Decoction (JPZDD) is a dedicated treatment of Tourette syndrome (TS). The balance of neurotransmitters in the cortico-striato-pallido-thalamo-cortical network is crucial to the occurrence of TS and related to its severity. This study evaluated the effect of JPZDD on glutamate (Glu) and γ-aminobutyric acid (GABA) and their receptors in a TS rat model.

MATERIALS AND METHODS

Rats were divided into four groups (n=12 each). TS was induced in three of the groups by injecting them with 3,3'-iminodipropionitrile for 7 consecutive days. Two model groups were treated with tiapride (Tia) or JPZDD, while the control and the remaining model group were gavaged with saline. Behavior was assessed by stereotypic score and autonomic activity. Striatal Glu and GABA contents were detected using microdialysis. Expressions of N-methyl-D-aspartate receptor 1 and GABAA receptor (GABAAR) were observed using Western blot and real-time polymerase chain reaction.

RESULTS

Tia and JPZDD groups had decreased stereotypy compared with model rats; however, the JPZDD group showed a larger decrease in stereotypy than the Tia group at a 4-week time point. In a spontaneous activity test, the total distance of the JPZDD and Tia groups was significantly decreased compared with the model group. The Glu levels of the model group were higher than the control group and decreased with Tia or JPZDD treatment. The GABA level was higher in the model group than the control group. Expressions of GABAAR protein in the model group were higher than in the control group. Treatment with Tia or JPZDD reduced the expression of GABAAR protein. In the case of the mRNA expression, only Tia reduced the expression of N-methyl-D-aspartate receptor 1, compared with the model group.

CONCLUSION

JPZDD could alleviate impairments in behavior and dysfunctional signaling by downregulating GABAAR in the striatum. We suggest that this acts to maintain the balance of Glu and GABA.

Enhanced habit formation in Gilles de la Tourette syndrome

Tics are sometimes described as voluntary movements performed in an automatic or habitual way. Here, we addressed the question of balance between goal-directed and habitual behavioural control in Gilles de la Tourette syndrome and formally tested the hypothesis of enhanced habit formation in these patients. To this aim, we administered a three-stage instrumental learning paradigm to 17 unmedicated and 17 antipsychotic-medicated patients with Gilles de la Tourette syndrome and matched controls. In the first stage of the task, participants learned stimulus-response-outcome associations. The subsequent outcome devaluation and ‘slip-of-action’ tests allowed evaluation of the participants’ capacity to flexibly adjust their behaviour to changes in action outcome value. In this task, unmedicated patients relied predominantly on habitual, outcome-insensitive behavioural control. Moreover, in these patients, the engagement in habitual responses correlated with more severe tics. Medicated patients performed at an intermediate level between unmedicated patients and controls. Using diffusion tensor imaging on a subset of patients, we also addressed whether the engagement in habitual responding was related to structural connectivity within cortico-striatal networks. We showed that engagement in habitual behaviour in patients with Gilles de la Tourette syndrome correlated with greater structural connectivity within the right motor cortico-striatal network. In unmedicated patients, stronger structural connectivity of the supplementary motor cortex with the sensorimotor putamen predicted more severe tics. Overall, our results indicate enhanced habit formation in unmedicated patients with Gilles de la Tourette syndrome. Aberrant reinforcement signals to the sensorimotor striatum may be fundamental for the formation of stimulus-response associations and may contribute to the habitual behaviour and tics of this syndrome.

Therapeutic Developments for Tics and Myoclonus

Tics and myoclonus are phenomenologically similar given that both are jerk-like movements, but, in contrast to myoclonus, tics are often preceded by premonitory sensations and are typically associated with a variety of behavioral comorbidities, including attention deficit and obsessive-compulsive disorder. There are many other clinical features that help differentiate these two hyperkinetic disorders. Whereas behavioral and antidopaminergic therapies are most effective in the management of tics, clonazepam, other anticonvulsants, and serotonergic drugs are often used to control myoclonic movements. Botulinum toxin may also be helpful in focal tics and in segmental forms of myoclonus. DBS plays an increasingly important role in the treatment of these disorders, particularly when they are generalized and are disabling despite optimal medical therapy.