Neural representations of statistical and rule-based predictions in Gilles de la Tourette syndrome.

Gilles de la Tourette syndrome (GTS) is a disorder characterised by motor and vocal tics, which may represent habitual actions as a result of enhanced learning of associations between stimuli and responses (S-R). In this study, we investigated how adults with GTS and healthy controls (HC) learn two types of regularities in a sequence: statistics (non-adjacent probabilities) and rules (predefined order). Participants completed a visuomotor sequence learning task while EEG was recorded. To understand the neurophysiological underpinnings of these regularities in GTS, multivariate pattern analyses on the temporally decomposed EEG signal as well as sLORETA source localisation method were conducted. We found that people with GTS showed superior statistical learning but comparable rule-based learning compared to HC participants. Adults with GTS had different neural representations for both statistics and rules than HC adults; specifically, adults with GTS maintained the regularity representations longer and had more overlap between them than HCs. Moreover, over different time scales, distinct fronto-parietal structures contribute to statistical learning in the GTS and HC groups. We propose that hyper-learning in GTS is a consequence of the altered sensitivity to encode complex statistics, which might lead to habitual actions.

Agreement between self-, mother and father proxy-reports on health-related quality of life in adolescents with Tourette syndrome.

This study aimed to investigate agreement and discrepancies between parent proxy- and adolescent self-reports on assessments of adolescents' health-related quality of life (HRQoL), and the role that individual factors may play in parent-adolescent agreement, in a sample of adolescents with Tourette syndrome (TS) compared to a control group of healthy adolescents. Adolescents aged 12-18 years diagnosed with TS were recruited with their parents from primary and secondary referral centres. Adolescent healthy controls were matched for gender and age. Adolescents and each of their parents completed a set of questionnaires including a HRQoL evaluation of adolescent, the 'Vécu et Santé Perçue de l'Adolescent'. Mother-adolescent, father-adolescent and mother-father agreements on adolescents' HRQoL scores were investigated at individual and group level, both in TS and control groups. Data were available for 75 adolescents, 75 mothers and 63 fathers, in the TS group. Agreement between mother, father proxy-reports and TS adolescents self-reports of HRQoL varied from poor to good, without significant difference with the control group. In TS group, mothers and fathers underestimated adolescents' HRQoL in 'Psychological well-being' subscale and mothers underestimated it in 'Physical 'well-being' subscale, while controls overestimated adolescents' HRQoL in these subscales. Larger mother-adolescent discrepancies for 'Psychological well-being' and 'Physical well-being' subscales were associated with internalizing symptoms. Regarding future studies, comprehensive evaluation of the various dimensions of adolescents' HRQoL with TS requires the integration of the perspectives of both adolescents, mothers and fathers. Clinicians should take into account this point to provide comprehensive care and services.

Cannabis-based medicine in treatment of patients with Gilles de la Tourette syndrome.

INTRODUCTION: Gilles de la Tourette syndrome (GTS) is a childhood onset disorder characterised by the presence of motor and vocal tics. The guidelines of both the American Academy of Neurology (AAN) as well as the European Society for the Study of Tourette Syndrome (ESSTS) recommend behavioural therapy and pharmacotherapy, mainly with antipsychotics, as first line treatments for tics. In spite of these well-established therapeutic approaches, a significant number of patients are dissatisfied because of insufficient tic reduction or intolerable side effects. Previous studies have suggested that cannabis-based medicine (CBM) might be an alternative treatment in these patients. MATERIAL AND METHODS: Two reviewers (KS, NS) searched the electronic database of PubMed on 1 July, 2021 for relevant studies using the search terms: ('Tourette syndrome' [MeSH Terms] OR 'Gilles de la Tourette syndrome' [MeSH Terms] OR 'tic disorders' [MeSH Terms] OR 'tics' [MeSH Terms] OR 'tic disorders'[Title/Abstract]) AND ('cannabis-based medicine' [Title/Abstract] OR 'cannabis' [Title/Abstract] OR 'dronabinol' [Title/Abstract] OR 'nabiximols' [Title/Abstract] OR 'tetrahydrocannabinol' [Title/Abstract] OR 'THC' [Title/Abstract] OR 'cannabidiol' [Title/Abstract], limit: 'humans'. These studies were further reviewed for additional relevant citations. The titles and abstracts of the studies obtained through this search were examined by two reviewers (KS, NS) in order to determine article inclusion. Discrepancies were addressed by the reviewers through discussion and eventually conversation with the senior reviewer (KMV). RESULTS: Although the amount of evidence supporting the use of CBM in GTS is growing, the majority of studies are still limited to case reports, case series, and open uncontrolled studies. To date, only two small randomised controlled trials (RCTs) using tetrahydrocannabinol (THC, dronabinol) have been published demonstrating the safety and efficacy of this intervention in the treatment of tics in patients with GTS. On the other hand, another RCT with Lu AG06466 (formerly known as ABX-1431), a modulator of endocannabinoid neurotransmission, has failed to prove effective in the therapy of GTS. Accordingly, under the guidelines of both the ESSTS and the AAN, treatment with CBM is categorised as an experimental intervention that should be applied to patients who are otherwise treatment-resistant. CONCLUSIONS: Increasing evidence suggests that CBM is efficacious in the treatment of tics and psychiatric comorbidities in patients with GTS. The results of ongoing larger RCTs, such as CANNA-TICS (ClinicalTrials.gov Identifier: NCT03087201), will further clarify the role of CBM in the treatment of patients with GTS.

Lower-level associations in Gilles de la Tourette syndrome: Convergence between hyperbinding of stimulus and response features and procedural hyperfunctioning theories.

Gilles de la Tourette syndrome (GTS) can be characterized by enhanced cognitive functions related to creating, modifying and maintaining connections between stimuli and responses (S-R links). Specifically, two areas, procedural sequence learning and, as a novel finding, also event file binding, show converging evidence of hyperfunctioning in GTS. In this review, we describe how these two enhanced functions can be considered as cognitive mechanisms behind habitual behaviour, such as tics in GTS. Moreover, the presence of both procedural sequence learning and event file binding hyperfunctioning in the same disorder can be treated as evidence for their functional connections, even beyond GTS. Importantly though, we argue that hyperfunctioning of event file binding and procedural learning are not interchangeable: they have different time scales, different sensitivities to potential impairment in action sequencing and distinguishable contributions to the cognitive profile of GTS. An integrated theoretical account of hyperbinding and hyperlearning in GTS allows to formulate predictions for the emergence, activation and long-term persistence of tics in GTS.

Increased perception-action binding in Tourette syndrome.

Gilles de la Tourette syndrome is a multifaceted neurodevelopmental disorder characterized by multiple motor and vocal tics. Research in Tourette syndrome has traditionally focused on the motor system. However, there is increasing evidence that perceptual and cognitive processes play a crucial role as well. Against this background it has been reasoned that processes linking perception and action might be particularly affected in these patients with the strength of perception-action binding being increased. However, this has not yet been studied experimentally. Here, we investigated adult Tourette patients within the framework of the 'Theory of Event Coding' using an experimental approach allowing us to directly test the strength of perception-action binding. We included 24 adult patients with Tourette syndrome and n = 24 healthy control subjects using a previously established visual-motor event file task with four levels of feature overlap requiring repeating or alternating responses. Concomitant to behavioural testing, EEG was recorded and analysed using temporal signal decomposition and source localization methods. On a behavioural level, perception-action binding was increased in Tourette patients. Tic frequency correlated with performance in conditions where unbinding processes of previously established perception-action bindings were required with higher tic frequency being associated with stronger perception-action binding. This suggests that perception-action binding is intimately related to the occurrence of tics. Analysis of EEG data showed that behavioural changes cannot be explained based on simple perceptual or motor processes. Instead, cognitive processes linking perception to action in inferior parietal cortices are crucial. Our findings suggest that motor or sensory processes alone are less relevant for the understanding of Tourette syndrome than cognitive processes engaged in linking and restructuring of perception-action association. A broader cognitive framework encompassing perception and action appears well suited to opening new routes for the understanding of Tourette syndrome.

Sense of agency disturbances in movement disorders: A comprehensive review.

Sense of agency refers to the experience that one's self-generated action causes an event in the external environment. Here, we review the behavioural and brain evidence of aberrant experiences of agency in movement disorders, clinical conditions characterized by either a paucity or an excess of movements unrelated to the patient's intention. We show that specific abnormal agency experiences characterize several movement disorders. Those manifestations are typically associated with structural and functional brain abnormalities. However, the evidence is sometimes conflicting, especially when considering results obtained through different agency measures. The present review aims to create order in the existing literature on sense of agency investigations in movement disorders and to provide a coherent overview framed within current neurocognitive models of motor awareness.

Tics in patients with encephalitis.

BACKGROUND: Movement disorders have been described in the context of different types of encephalitis. Among hyperkinetic manifestations, tics have sporadically been reported in cases of encephalitis resulting from a range of aetiologies. OBJECTIVE: This review aimed to assess the prevalence and characteristics of tics in patients with encephalitis. METHODS: We conducted a systematic literature review of original studies on the major scientific databases, according to the standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: In addition to the established association between tics and encephalitis lethargica, our literature search identified reports of tics in patients with immune-mediated pathologies (including autoimmune encephalitides affecting the N-methyl-D-aspartate receptor, voltage-gated potassium channels, and glycine receptors) and infective processes (ranging from relatively common viral pathogens, such as herpes simplex, to prions, as in Creutzfeldt-Jakob disease). Tics were most commonly reported in the post-encephalitic period and involvement of the basal ganglia was frequently observed. DISCUSSION: The association of new-onset tics and encephalitis, in the background of other neuropsychiatric abnormalities, has practical implications, potentially improving the detection of encephalitis based on clinical features. Future research should focus on the categorisation and treatment of hyperkinetic movement disorders associated with encephalitis.

"Spreading the word of the master": the contribution of Italian physicians in the early dissemination of Jean-Martin Charcot's theories.

Jean-Martin Charcot (1825-1893) laid the foundations of modern neurology. The lectures he gave at La Salpêtrière Hospital in Paris attracted a large number of visitors from all over the world. Some of them transcribed these clinical lessons, translating and publishing them when returning home. This article discusses the contribution of some Italian physicians (Gaetano Rummo, 1853-1917; Domenico Miliotti; Giulio Melotti, 1857-19?; and Augusto Tebaldi, 1833-1895), who were pioneers in disseminating the ideas and discoveries of Charcot. The early Italian translations were based on personal handwritten notes and memories, not relying on official French versions personally revised or edited by Charcot himself. As such, their veracity cannot always be verified, particularly in the lack of other independent works reporting details on the same lectures. However, the Italian transcriptions providing information which cannot be found elsewhere in Charcot's corpus of works represent an invaluable and a unique source for fully understanding some theories by the French neurologist. Furthermore, they are the first documents providing original materials related to Charcot's teaching translated in a foreign language. The first Italian publications that included photographs of patients were deeply influenced by and clearly modeled on the famous volumes of the Iconographie photographique de la Salpêtrière and further contributed to the early dissemination of Charcot's theories.

Dystonic tics in patients with Gilles de la Tourette syndrome.

CLINICAL RATIONALE FOR THE STUDY: Gilles de la Tourette syndrome (GTS) is a childhood onset disorder characterised by motor and vocal tics. Different types of motor tics may occur in GTS, including dystonic tics (DTs). Although DTs have been recognised as part of GTS symptomatology, little is known about their risk factors or about how often and at what age they appear in affected individuals. AIM OF THE STUDY: The aim of our study was to investigate lifetime prevalence and clinical correlations of DTs in a Polish cohort of GTS patients. MATERIAL AND METHODS: We performed a prospective, one-registration study in a cohort of 207 consecutive ambulatory patients (mean age: 16.5 ± 9.4 years, 131 children, 162 males) with GTS. Duration of GTS was 9.0 ± 8.0 years (range: 1-39 years). DTs were diagnosed during the interview. DTs were defined as slower and lasting longer than typical clonic tics, abnormal dystonia-like movements that led to a sustained, but not fixed, posture. RESULTS: DTs occurred at some point in the lifetime of 73.9% (n = 153) of patients. The prevalence of DTs in adults and children was almost the same (p = 0.963). Age at onset of DTs was 9.9 ± 5.2 years with the most frequent onset in children (7-11 years, 74.4%, n = 64), followed by adolescence (12-18 years; 17.4%, n = 15) and adulthood (≥ 18 years, 8.1%, n = 7). DTs occurred 3.7 ± 4.2 years after tic onset. On average, patients suffered from 1.8 ± 1.7 types of DTs. The most frequent manifestations of DTs were: eyes (tightening resembling blepharospasm 84.3%, n = 129 and oculogyric crisis 45.8%, n = 70), trunk (dystonic postures 59.5%, n = 91), jaw (bruxism 34.6%, n = 53), neck (30.7%, n = 47), upper limb (26.1%, n = 40), and foot (20.9%, n = 32). Multivariate logistic regression analysis showed significant associations of DTs with the total number of simple, and the total number of complex, tics. CONCLUSIONS AND CLINICAL IMPLICATIONS: DTs are early and frequent symptoms of GTS. They tend to localise in the facial area. DTs occur more frequently in individuals with a higher number of tics and probably add to the global impairment caused by tics.

Intact automatic motor inhibition in patients with tourette syndrome.

BACKGROUND: Behavioral disinhibition has been proposed as a key mechanism in Tourette syndrome. Yet classic inhibition tasks have yielded inconsistent results, likely reflecting interference by strategies compensating for tic release. METHODS: We examined a core inhibitory function that is immune to such interference because it suppresses movements automatically. We measured automatic motor inhibition behaviorally in 21 adults with Tourette syndrome and 21 healthy controls via the negative compatibility effect. When a motor response is activated, for example, by a subliminal prime stimulus, but execution is delayed, activation turns into inhibition, increasing reaction time and error. Diminished automatic inhibition could underlie tic release. RESULTS: Both controls and patients showed strong automatic motor inhibition with no significant group difference. Bayesian statistics, allowing inference on the absence of effects, favored intact inhibition in patients. Our study was well powered. CONCLUSIONS: Automatic motor inhibition in Tourette syndrome is neither impaired nor harnessed by compensation. © 2018 International Parkinson and Movement Disorder Society.

Pathological glutamatergic neurotransmission in Gilles de la Tourette syndrome.

Gilles de la Tourette syndrome is a hereditary, neuropsychiatric movement disorder with reported abnormalities in the neurotransmission of dopamine and γ-aminobutyric acid (GABA). Spatially focalized alterations in excitatory, inhibitory and modulatory neurochemical ratios within specific functional subdivisions of the basal ganglia, may lead to the expression of diverse motor and non-motor features as manifested in Gilles de la Tourette syndrome. Current treatment strategies are often unsatisfactory thus provoking the need for further elucidation of the underlying pathophysiology. In view of (i) the close spatio-temporal synergy exhibited between excitatory, inhibitory and modulatory neurotransmitter systems; (ii) the crucial role played by glutamate (Glu) in tonic/phasic dopaminergic signalling; and (iii) the interdependent metabolic relationship exhibited between Glu and GABA via glutamine (Gln); we postulated that glutamatergic signalling is related to the pathophysiology of Gilles de la Tourette syndrome. As such, we examined the neurochemical profile of three cortico-striato-thalamo-cortical regions in 37 well-characterized, drug-free adult patients and 36 age/gender-matched healthy control subjects via magnetic resonance spectroscopy at 3 T. To interrogate the influence of treatment on metabolite concentrations, spectral data were acquired from 15 patients undergoing a 4-week treatment with aripiprazole. Test-retest reliability measurements in 23 controls indicated high repeatability of voxel localization and metabolite quantitation. We report significant reductions in striatal concentrations of Gln, Glu + Gln (Glx) and the Gln:Glu ratio, and thalamic concentrations of Glx in Gilles de la Tourette syndrome in comparison to controls. ON-treatment patients exhibited no significant metabolite differences when compared to controls but significant increases in striatal Glu and Glx, and trends for increases in striatal Gln and thalamic Glx compared to baseline measurements. Multiple regression analysis revealed a significant negative correlation between (i) striatal Gln and actual tic severity; and (ii) thalamic Glu and premonitory urges. Our results indicate that patients with Gilles de la Tourette syndrome exhibit an abnormality in the flux of metabolites in the GABA-Glu-Gln cycle, thus implying perturbations in astrocytic-neuronal coupling systems that maintain the subtle balance between excitatory and inhibitory neurotransmission within subcortical nuclei.

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.

The neuropsychiatry of Gilles de la Tourette syndrome: The état de l'art.

Gilles de la Tourette syndrome (GTS) is a chronic tic disorder characterised by the presence of multiple motor and vocal tics with onset during development. Tics are the most common hyperkinetic symptoms in childhood and co-morbid behavioural conditions (especially obsessive-compulsive disorder, attention-deficit and hyperactivity disorder, affective symptoms, and impulsivity) are present in the majority of patients. Although GTS is no longer considered a rare medical curiosity, its exact pathophysiology remains elusive. Recent research on the brain correlates of the subjective 'urge to tic' has highlighted the role of extra-motor pathways within the brain mechanisms of tic generation. Advances in our understanding of the pathophysiology of GTS can pave the way to the implementation of more effective treatment strategies for this heterogeneous neurobehavioral condition. Finally, the development of GTS-specific instruments for the assessment of health-related quality of life has allowed more standardised assessments across the lifespan, capturing the impact of both tics and behavioural co-morbidities.

Aripiprazole in treatment of Gilles de la Tourette syndrome - New therapeutic option.

Aripiprazole is a dopamine D2- and serotonin 5-hydroxytryptamine (5-HT)1A receptor partial agonist and 5-HT2A receptor antagonist primarily used for the treatment of schizophrenia, bipolar disorder or depression with psychotic ideation. However, recently a number of new possible indications have been suggested, among them Gilles de la Tourette syndrome (GTS). In two randomized, double-blind, placebo-controlled studies in children and adolescents with GTS has been confirmed the efficacy of aripiprazole in tic reduction. In comparison to other neuroleptics, aripiprazole seems to be similarly effective. What is more, the number and profile of possible adverse effects is also favorable. As a consequence, aripiprazole had been registered by Food and Drug Administration (FDA) for the treatment of tics and represents new therapeutic option in treatment of GTS.

A tug of war: antagonistic effective connectivity patterns over the motor cortex and the severity of motor symptoms in Gilles de la Tourette syndrome.

We tested the hypothesis that Gilles de la Tourette syndrome (GTS) is characterized by perturbed connectivity within cortico-subcortical motor networks. To this end, we performed a dynamic causal modelling (DCM) analysis of fMRI data collected during a finger opposition task in 24 normal controls and 24 GTS patients. The DCM analysis allowed us to assess whether any GTS-specific patterns of brain activity were related to intrinsic and/or to task-dependent connectivity. While no abnormalities were found for task-dependent connectivity, intrinsic connectivity was abnormally increased in the premotor network, with stronger connections from the supplementary motor area (SMA), from the dorsolateral premotor cortex and from the putamen to the right superior frontal gyrus, an area where GTS showed over-activation in a previous univariate analysis. We also found a positive correlation between the connectivity strength from the right basal ganglia to the right primary motor cortex (M1) and disease severity measured by the Yale Global Tic Severity Scale (YGTSS). This pattern was mirrored by a negative correlation between the connection strength from the right SMA to the right area M1 and the YGTSS score. These two reverse correlation effects showed a specific relationship with individual disease severity: the greater the imbalance between subcortical and premotor connectivity towards area M1, the higher the YGTSS score. These results reveal the existence of perturbed intrinsic connectivity patterns in the motor networks of GTS patients with two competing forces operating in a tug of war-like mechanism: aberrant subcortical afferents to M1, compensated for by inputs from the premotor cortex.

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.

Health-related quality of life, anxiety and depression in parents of adolescents with Gilles de la Tourette syndrome: a controlled study.

Our objectives were to assess health-related quality of life (HRQoL), anxiety, depression of Gilles de la Tourette syndrome (GTS) adolescents' parents compared to controls; to assess GTS adolescents' HRQoL compared to controls; to investigate which parental and adolescent variables are associated with poorer parental HRQoL. The controlled study involved GTS outpatients and their parents, adolescent healthy controls matched for gender and age and their parents. Parents' HRQoL was assessed using SF-36 and WHOQOL-BREF; anxiety, depression using HADS. Adolescents' HRQoL was assessed by adolescents using VSP-A instrument and by their parents using VSP-P. A total of 75 GTS adolescents, 75 mothers, 63 fathers were compared to 75 control adolescents, 75 mothers, 62 fathers. GTS mothers had worse HRQoL than controls on 5 of the 8 SF-36 dimensions and 1 of the 4 WHOQOL-BREF dimensions, while GTS fathers had worse HRQoL on 2 of the WHOQOL-BREF dimensions. GTS mothers had poorer HRQoL than fathers. GTS mothers had more depression than control mothers and GTS fathers had more anxiety than control fathers. GTS adolescents had worse HRQoL than controls on 5 of the 9 VSP-A dimensions. Factors significantly related to parental HRQoL were anxiety, depression, GTS adolescents' HRQoL and, concerning mothers, behavioural and emotional adolescents' problems; concerning fathers, severity of vocal tics, duration since first symptoms. This study provides a better understanding of poorer HRQoL and psychiatric morbidity of GTS adolescents' parents. Clinicians should pay attention to their emotional well-being and HRQoL and be aware that mothers and fathers are differently affected.

A functional magnetic resonance imaging investigation of motor control in Gilles de la Tourette syndrome during imagined and executed movements.

The current study investigated the neural correlates of voluntary motor control in 24 adult Gilles de la Tourette (GTS) patients. We examined whether imagination and the execution of the same voluntary movement - finger oppositions with either hand - were associated with specific patterns of activation. We also explored whether these patterns correlated with the severity of the syndrome, as measured by the Yale Global Tic Severity Scale (YGTSS) for motor tics. The presence of brain morphometric abnormalities was also assessed using voxel-based morphometry. Crucial to our experiment was the manipulation of the presence of an explicit motor outflow in the tasks. We anticipated a reduction in the ticking manifestation during the explicit motor task and brain activation differences between GTS patients and 24 age/gender-matched normal controls. The anticipated differences were all evident in the form of hyperactivations in the GTS patients in the premotor and prefrontal areas for both motor tasks for both hands; however, the motor imagery hyperactivations also involved rostral pre-frontal and temporo-parietal regions of the right hemisphere. The blood oxygen level-dependent responses of the premotor cortices during the motor imagery task were significantly correlated with the YGTSS scores. In contrast, no significant brain morphometric differences were found. This study provides evidence of a different neurofunctional organisation of motor control between adult patients with GTS and healthy controls that is independent from the actual execution of motor acts. The presence of an explicit motor outflow in GTS mitigates the manifestation of tics and the need for compensatory brain activity in the brain regions showing task-dependent hyperactivations.

Altered structural connectivity of cortico-striato-pallido-thalamic networks in Gilles de la Tourette syndrome.

Gilles de la Tourette syndrome is a childhood-onset syndrome characterized by the presence and persistence of motor and vocal tics. A dysfunction of cortico-striato-pallido-thalamo-cortical networks in this syndrome has been supported by convergent data from neuro-pathological, electrophysiological as well as structural and functional neuroimaging studies. Here, we addressed the question of structural integration of cortico-striato-pallido-thalamo-cortical networks in Gilles de la Tourette syndrome. We specifically tested the hypothesis that deviant brain development in Gilles de la Tourette syndrome could affect structural connectivity within the input and output basal ganglia structures and thalamus. To this aim, we acquired data on 49 adult patients and 28 gender and age-matched control subjects on a 3 T magnetic resonance imaging scanner. We used and further implemented streamline probabilistic tractography algorithms that allowed us to quantify the structural integration of cortico-striato-pallido-thalamo-cortical networks. To further investigate the microstructure of white matter in patients with Gilles de la Tourette syndrome, we also evaluated fractional anisotropy and radial diffusivity in these pathways, which are both sensitive to axonal package and to myelin ensheathment. In patients with Gilles de la Tourette syndrome compared to control subjects, we found white matter abnormalities in neuronal pathways connecting the cerebral cortex, the basal ganglia and the thalamus. Specifically, striatum and thalamus had abnormally enhanced structural connectivity with primary motor and sensory cortices, as well as paracentral lobule, supplementary motor area and parietal cortices. This enhanced connectivity of motor cortex positively correlated with severity of tics measured by the Yale Global Tics Severity Scale and was not influenced by current medication status, age or gender of patients. Independently of the severity of tics, lateral and medial orbito-frontal cortex, inferior frontal, temporo-parietal junction, medial temporal and frontal pole also had enhanced structural connectivity with the striatum and thalamus in patients with Gilles de la Tourette syndrome. In addition, the cortico-striatal pathways were characterized by elevated fractional anisotropy and diminished radial diffusivity, suggesting microstructural axonal abnormalities of white matter in Gilles de la Tourette syndrome. These changes were more prominent in females with Gilles de la Tourette syndrome compared to males and were not related to the current medication status. Taken together, our data showed widespread structural abnormalities in cortico-striato-pallido-thalamic white matter pathways in patients with Gilles de la Tourette, which likely result from abnormal brain development in this syndrome.

Health-related quality of life in patients with Gilles de la Tourette syndrome at the transition between adolescence and adulthood.

Gilles de la Tourette syndrome (GTS) is a neurodevelopmental condition characterised by tics and co-morbid behavioural problems, affecting predominantly male patients. Tic severity typically fluctuates over time, with a consistent pattern showing improvement after adolescence in a considerable proportion of patients. Both tics and behavioural co-morbidities have been shown to have the potential to affect patients' health-related quality of life (HR-QoL) in children and adults with persisting symptoms. In this study, we present the results of the first investigation of HR-QoL in patients with Gilles de la Tourette syndrome at the transition between adolescence and adulthood using a disease-specific HR-QoL measure, the Gilles de la Tourette Syndrome-Quality of Life-Children and Adolescents scale. Our results showed that patients with GTS and more severe co-morbid anxiety symptoms reported lower HR-QoL across all domains, highlighting the impact of anxiety on patient's well-being at a critical stage of development. Routine screening for anxiety symptoms is recommended in all patients with GTS seen at transition clinics from paediatric to adult care, to implement effective behavioural and pharmacological interventions as appropriate.