Neurobehavioral aspects, pathophysiology, and management of Tourette syndrome

Scoping Review of Multidisciplinary Care in Tourette Syndrome

Objective

To review current multidisciplinary care practices in patients with Tourette syndrome (TS).

Background

Individuals with TS can have multiple symptoms and comorbidities and require treatment to encompass all of their needs. A multidisciplinary research or care model approaches the situation/problem from all sides and uses multiple perspectives.

Methods

A database search of Medline (using Pubmed), PsychINFO, and Scopus was performed using keywords related to multidisciplinary care and TS. The authors then screened the results for relevant information using a standardized extraction form to collect data. Next, relevant codes from text analysis were extracted with a final list agreed on with author consensus. Finally, we inferred common themes.

Results

The search revealed 2304 citations, and 87 were selected for full-text analysis. One additional article was identified by manual search. Thirty-one citations were deemed relevant. Multidisciplinary team members typically included a psychiatrist or child psychiatrist, a neurologist or child neurologist, and a psychologist or therapist at the core. Four primary benefits were associated with multidisciplinary care: establishing the diagnosis, managing the complexity of TS and its associated comorbidities, averting complications, and evaluating advanced therapies. Limitations include possible poor team dynamics and rigidity in the approach leading to an algorithmic treatment plan.

Conclusions

A multidisciplinary care model for TS is the preferred model advocated by patients, physicians, and organizations. This scoping review reveals that the impetus for multidisciplinary care rests on four primary benefits, but there is a lack of empirical evidence for defining and evaluating its use.

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part III: pharmacological treatment

In 2011, the European Society for the Study of Tourette Syndrome (ESSTS) published the first European guidelines for Tourette Syndrome (TS). We now present an update of the part on pharmacological treatment, based on a review of new literature with special attention to other evidence-based guidelines, meta-analyses, and randomized double-blinded studies. Moreover, our revision took into consideration results of a recent survey on treatment preferences conducted among ESSTS experts. The first preference should be given to psychoeducation and to behavioral approaches, as it strengthens the patients' self-regulatory control and thus his/her autonomy. Because behavioral approaches are not effective, available, or feasible in all patients, in a substantial number of patients pharmacological treatment is indicated, alone or in combination with behavioral therapy. The largest amount of evidence supports the use of dopamine blocking agents, preferably aripiprazole because of a more favorable profile of adverse events than first- and second-generation antipsychotics. Other agents that can be considered include tiapride, risperidone, and especially in case of co-existing attention deficit hyperactivity disorder (ADHD), clonidine and guanfacine. This view is supported by the results of our survey on medication preference among members of ESSTS, in which aripiprazole was indicated as the drug of first choice both in children and adults. In treatment resistant cases, treatment with agents with either a limited evidence base or risk of extrapyramidal adverse effects might be considered, including pimozide, haloperidol, topiramate, cannabis-based agents, and botulinum toxin injections. Overall, treatment of TS should be individualized, and decisions based on the patient's needs and preferences, presence of co-existing conditions, latest scientific findings as well as on the physician's preferences, experience, and local regulatory requirements.

Treatment-refractory Tourette Syndrome

Tourette Syndrome (TS) is a complex neurodevelopmental condition marked by tics and frequently associated with psychiatric comorbidities. While most cases are mild and improve with age, some are treatment-refractory. Here, we review strategies for the management of this population. We begin by examining the diagnosis of TS and routine management strategies. We then consider emerging treatments for refractory cases, including deep brain stimulation (DBS), electroconvulsive therapy (ECT), repetitive transcranial magnetic stimulation (rTMS), and novel pharmacological approaches such as new vesicular monoamine transporter type 2 inhibitors, cannabinoids, and anti-glutamatergic drugs.

The anarchic brain in action: the contribution of task-based fMRI studies to the understanding of Gilles de la Tourette syndrome

PURPOSE OF REVIEW

Gilles de la Tourette syndrome (GTS) is a frequent neurological disorder characterized by the production of tics, and frequently associated with obsessive-compulsive disorder or attention-deficit hyperactivity disorder. The aim of this article is to summarize the contribution of imaging activation techniques to the study of the syndrome.

RECENT FINDINGS

GTS has been studied with a variety of functional MRI (fMRI)/PET activation paradigms to characterize the origin of tics or their suppression, and how they compare physiologically with voluntary actions or response inhibitions. Current studies indicate overactivations of prefrontal and premotor cortices, including the supplementary motor area, and subcortical structures. Resting state functional connectivity studies complement activation studies in showing perturbed connectivity of cortico-subcortical networks. Several such findings correlate with the severity of the disease.

SUMMARY

fMRI activation techniques are contributing a system-level neurophysiological description of GTS and bridge the gap between animal models and clinical observations. fMRI clarifies brain networks involved in different aspects of GTS phenomenology with some good clinical face validity. A future generation of fMRI studies should have higher ambitions and contribute, for example, to treatment optimization including the identification of ideal targets for deep brain stimulation in drug-resistant cases; however, such goals will be achieved only through controlled large-scale cooperative studies.

Investigation of a Possible Role for the Histidine Decarboxylase Gene in Tourette Syndrome in the Chinese Han Population: A Family-Based Study

Tourette syndrome (TS) is a polygenic neuropsychiatric disease. Previous studies have indicated that dysregulation in the histaminergic system may play a crucial role in disease onset. In this study, we investigated the role of the histidine decarboxylase gene (HDC) in TS susceptibility in the Chinese Han population. After genotyping 241 TS nuclear families trios, we analyzed three tag HDC single nucleotide polymorphisms (rs854150, rs854151, and rs854157) in a family-based study using the transmission disequilibrium test (TDT) and haplotype relative risk (HRR). TDT showed no over-transmission in these SNPs across the HDC region (for rs854150: χ² = 0.472, P = 0.537, OR = 1.097, 95%CI = 0.738–1.630; for rs854151: χ² = 0.043, P = 0.889, OR = 1.145, 95%CI = 0.767–1.709; for rs854157:χ² = 0.984, P = 0.367, OR = 1.020, 95%CI = 0.508–2.049). HRR also showed the same tendency (for rs854150: χ² = 0.211, P = 0.646, OR = 1.088, 95%CI = 0.759–1.559; for rs854151: χ² = 0.134, P = 0.714, OR = 0.935, 95%CI = 0.653–1.339; for rs854157:χ² = 0.841, P = 0.359, OR = 1.206, 95%CI = 0.808–1.799). Additionally, the haplotype-based haplotype relative risk showed a negative association. Although these findings indicate an unlikely association between HDC and TS in the Chinese Han population, a potential role for HDC cannot be ruled out in TS etiology. Future research should investigate this more thoroughly using different populations and larger samples.

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.

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.

Functional reversal of (-)-Stepholidine analogues by replacement of benzazepine substructure using the ring-expansion strategy

(-)-Stepholidine is an active ingredient of the Chinese herb Stephania and naturally occurring tetrahydroprotoberberine alkaloid with mixed dopamine receptor D1 agonistic and dopamine receptor D2 antagonistic activities. In this work, a series of novel hexahydrobenzo[4,5]azepino [2,1-a]isoquinolines were designed and synthesized as ring-expanded analogues of (-)-Stepholidine. Initial pharmacological assays demonstrated that a benzazepine replacement was associated with significant increase in selectivity and functional reversal at dopamine receptor D1 . Compound-(-)-15e (Ki  = 5.32 ± 0.01 nm) is more potent than (-)-Stepholidine (Ki  = 13 nm) and was identified as a selective dopamine receptor D1 antagonist (IC50  = 0.14 μm). Moreover, molecular modeling suggested that (-)-15e might exert its dopamine receptor D1 antagonistic activities through interacting with the transmembrane helix 7 of dopamine receptor D1 .

The International Deep Brain Stimulation Registry and Database for Gilles de la Tourette Syndrome: How Does It Work?

Tourette Syndrome (TS) is a neuropsychiatric disease characterized by a combination of motor and vocal tics. Deep brain stimulation (DBS), already widely utilized for Parkinson's disease and other movement disorders, is an emerging therapy for select and severe cases of TS that are resistant to medication and behavioral therapy. Over the last two decades, DBS has been used experimentally to manage severe TS cases. The results of case reports and small case series have been variable but in general positive. The reported interventions have, however, been variable, and there remain non-standardized selection criteria, various brain targets, differences in hardware, as well as variability in the programming parameters utilized. DBS centers perform only a handful of TS DBS cases each year, making large-scale outcomes difficult to study and to interpret. These limitations, coupled with the variable effect of surgery, and the overall small numbers of TS patients with DBS worldwide, have delayed regulatory agency approval (e.g., FDA and equivalent agencies around the world). The Tourette Association of America, in response to the worldwide need for a more organized and collaborative effort, launched an international TS DBS registry and database. The main goal of the project has been to share data, uncover best practices, improve outcomes, and to provide critical information to regulatory agencies. The international registry and database has improved the communication and collaboration among TS DBS centers worldwide. In this paper we will review some of the key operation details for the international TS DBS database and registry.

Dopamine and T cells: dopamine receptors and potent effects on T cells, dopamine production in T cells, and abnormalities in the dopaminergic system in T cells in autoimmune, neurological and psychiatric diseases

Dopamine, a principal neurotransmitter, deserves upgrading to 'NeuroImmunotransmitter' thanks to its multiple, direct and powerful effects on most/all immune cells. Dopamine by itself is a potent activator of resting effector T cells (Teffs), via two independent ways: direct Teffs activation, and indirect Teffs activation by suppression of regulatory T cells (Tregs). The review covers the following findings: (i) T cells express functional dopamine receptors (DRs) D1R-D5R, but their level and function are dynamic and context-sensitive, (ii) DR membranal protein levels do not necessarily correlate with DR mRNA levels, (iii) different T cell types/subtypes have different DR levels and composition and different responses to dopamine, (iv) autoimmune and pro-inflammatory T cells and T cell leukaemia/lymphoma also express functional DRs, (v) dopamine (~10(-8) M) activates resting/naive Teffs (CD8(+) >>>CD4(+) ), (vi) dopamine affects Th1/Th2/Th17 differentiation, (vii) dopamine inhibits already activated Teffs (i.e. T cells that have been already activated by either antigen, mitogen, anti-CD3 antibodies cytokines or other molecules), (viii) dopamine inhibits activated Tregs in an autocrine/paracrine manner. Thus, dopamine 'suppresses the suppressors' and releases the inhibition they exert on Teffs, (ix) dopamine affects intracellular signalling molecules and cascades in T cells (e.g. ERK, Lck, Fyn, NF-κB, KLF2), (x) T cells produce dopamine (Tregs>>>Teffs), can release dopamine, mainly after activation (by antigen, mitogen, anti-CD3 antibodies, PKC activators or other), uptake extracellular dopamine, and most probably need dopamine, (xi) dopamine is important for antigen-specific interactions between T cells and dendritic cells, (xii) in few autoimmune diseases (e.g. multiple sclerosis/SLE/rheumatoid arthritis), and neurological/psychiatric diseases (e.g. Parkinson disease, Alzheimer's disease, Schizophrenia and Tourette), patient's T cells seem to have abnormal DRs expression and/or responses to dopamine or production of dopamine, (xiii) drugs that affect the dopaminergic system have potent effects on T cells (e.g. dopamine=Intropin, L-dopa, bromocriptine, haloperidol, quinpirole, reserpine, pergolide, ecopipam, pimozide, amantadine, tetrabenazine, nomifensine, butaclamol). Dopamine-induced activation of resting Teffs and suppression of Tregs seem beneficial for health and may also be used for immunotherapy of cancer and infectious diseases. Independently, suppression of DRs in autoimmune and pro-inflammatory T cells, and also in cancerous T cells, may be advantageous. The review is relevant to Immunologists, Neurologists, Neuroimmunologists, Hematologists, Psychiatrists, Psychologists and Pharmacologists.

The International Deep Brain Stimulation Registry and Database for Gilles de la Tourette Syndrome: How Does It Work?

Tourette Syndrome (TS) is a neuropsychiatric disease characterized by a combination of motor and vocal tics. Deep brain stimulation (DBS), already widely utilized for Parkinson's disease and other movement disorders, is an emerging therapy for select and severe cases of TS that are resistant to medication and behavioral therapy. Over the last two decades, DBS has been used experimentally to manage severe TS cases. The results of case reports and small case series have been variable but in general positive. The reported interventions have, however, been variable, and there remain non-standardized selection criteria, various brain targets, differences in hardware, as well as variability in the programming parameters utilized. DBS centers perform only a handful of TS DBS cases each year, making large-scale outcomes difficult to study and to interpret. These limitations, coupled with the variable effect of surgery, and the overall small numbers of TS patients with DBS worldwide, have delayed regulatory agency approval (e.g., FDA and equivalent agencies around the world). The Tourette Association of America, in response to the worldwide need for a more organized and collaborative effort, launched an international TS DBS registry and database. The main goal of the project has been to share data, uncover best practices, improve outcomes, and to provide critical information to regulatory agencies. The international registry and database has improved the communication and collaboration among TS DBS centers worldwide. In this paper we will review some of the key operation details for the international TS DBS database and registry.

Narcissistic vulnerability is a common cause for depression in patients with Gilles de la Tourette syndrome

The aim of this study was to assess for the first time different dimensions of narcissistic self-regulation in a large cohort of adult patients with Gilles de la Tourette syndrome (GTS) (n=50). From preliminary studies it is suggested that narcissistic personality trait and disorder, respectively, are relatively uncommon and occur in only 6-10% of GTS patients. In this study we used the Narcissism Inventory (NI), a 163-items questionnaire that measures four different dimensions of narcissism. The main result was that the prevalence of narcissism strongly depends on the subtype of narcissism: while the vulnerable narcissism ("threatened self" and "hypochondriac self") was common, the "classic narcissistic self" (grandiose narcissism) was rare. From our data an association between comorbid depression and increased values of the "threatened self" and comorbid OCD with increased values of the "hypochondriac self" is suggested. Narcissism correlated positively with the personality domain neuroticism and had a significantly negative impact on patients' quality of life. Therefore it can be speculated that vulnerable narcissism is - among several others - one cause for depression in patients with GTS. These findings may open new psychotherapeutic perspectives in the treatment of depression in patients with GTS.

Astroglial glutamate transporter deficiency increases synaptic excitability and leads to pathological repetitive behaviors in mice

An increase in the ratio of cellular excitation to inhibition (E/I ratio) has been proposed to underlie the pathogenesis of neuropsychiatric disorders, such as autism spectrum disorders (ASD), obsessive-compulsive disorder (OCD), and Tourette's syndrome (TS). A proper E/I ratio is achieved via factors expressed in neuron and glia. In astrocytes, the glutamate transporter GLT1 is critical for regulating an E/I ratio. However, the role of GLT1 dysfunction in the pathogenesis of neuropsychiatric disorders remains unknown because mice with a complete deficiency of GLT1 exhibited seizures and premature death. Here, we show that astrocyte-specific GLT1 inducible knockout (GLAST(CreERT2/+)/GLT1(flox/flox), iKO) mice exhibit pathological repetitive behaviors including excessive and injurious levels of self-grooming and tic-like head shakes. Electrophysiological studies reveal that excitatory transmission at corticostriatal synapse is normal in a basal state but is increased after repetitive stimulation. Furthermore, treatment with an N-methyl-D-aspartate (NMDA) receptor antagonist memantine ameliorated the pathological repetitive behaviors in iKO mice. These results suggest that astroglial GLT1 has a critical role in controlling the synaptic efficacy at corticostriatal synapses and its dysfunction causes pathological repetitive behaviors.