1,666 research outputs found

    Tourette syndrome research highlights from 2016 [version 1; referees: 3 approved, 1 approved with reservations]

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    This article presents highlights chosen from research that appeared during 2016 on Tourette syndrome and other tic disorders. Selected articles felt to represent meaningful advances in the field are briefly summarized

    Tourette syndrome research highlights 2015 [version 1; referees: 3 approved]

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    We present selected highlights from research that appeared during 2015 on Tourette syndrome and other tic disorders. Topics include phenomenology, comorbidities, developmental course, genetics, animal models, neuroimaging, electrophysiology, pharmacology, and treatment. We briefly summarize articles whose results we believe may lead to new treatments, additional research or modifications in current models of TS

    Sense of agency disturbances in movement disorders: A comprehensive review

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    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

    Impaired forward model updating in young adults with Tourette syndrome

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    Current theories of motor control emphasise how the brain may use internal models of the body to ensure accurate planning and control of movements. One such internal model - a forward model - is thought to generate an estimate of the next motor state and/or the sensory consequences of an upcoming movement, thereby allowing movement errors to be monitored. In addition, forward models may provide a means by which to determine a sense of agency, i.e., the (conscious) sense of authorship and control over our actions. Tourette syndrome is a developmental neurological condition characterised by the occurrence of motor and phonic tics. The involuntary (or voluntary) nature of tics has been the subject of considerable debate, and it was recently argued that the presence of tics in Tourette syndrome could result in a blurring of any subjective boundary between voluntary and involuntary movements. In particular, it was proposed that the level of sensorimotor noise that accompanies tics may be particularly high in Tourette syndrome, and this may contribute to less efficient forward models used to determine agency. We investigated whether the internal monitoring of movements is impaired in individuals with Tourette syndrome, relative to a matched group of typically-developing individuals, using a task that involved executing double-step aiming movements using a hand-held robot manipulandum. Participants were required on each trial to execute two movements in turn, each directed to a remembered target location without visual feedback. Importantly, we assumed that to perform accurately on the second (return) movement it would be necessary to update any forward model to take account errors made during the first (outward) movement. Here we demonstrate that while the Tourette syndrome group were equally accurate, and no more variable, than the matched control group in executing aiming movements to the first (outward) target location. They were significantly less accurate, and exhibited greater movement variability, than controls when executing the second (return) movement. Furthermore, we show that for the return movement only, movement accuracy and movement variability were significantly predicted by the Tourette syndrome group’s clinical severity scores. We interpret these findings as consistent with the view that individuals with Tourette syndrome may experience a reduction in the precision of the forward model estimates thought necessary for the accurate planning and control of movements

    Postural control anomalies in children with Tourette syndrome

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    The goal of the present study was to determine whether postural control is affected in Gilles-de-la-Tourette syndrome (TS). Center of pressure (COP) displacements were recorded in children with TS and unaffected siblings (7-16 yrs) in three conditions using a force platform: 1) Eyes-Open, 2) Eyes-Closed, 3) One-Leg standing with eyes open. The COP range and velocity were higher in children with TS than in unaffected siblings in all conditions. These differences could not be attributed to age, present tic severity, comorbidities (hyperactivity and compulsions) or medication. The data suggest that sub-clinical postural control anomalies are present in TS

    A randomized controlled trial comparing behavioral, educational, and pharmacological treatments in youths with chronic tic disorder or Tourette syndrome

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    Context: The existing literature on the treatment of pediatric chronic tic disorder (CTD) and Tourette syndrome (TS) indicates that both behavioral therapy (BT) and pharmacotherapy (PT) are effective for reducing symptoms. Objective: To evaluate the efficacy of BT compared to psychoeducation (PE) or PT for reducing tics and co-occurring symptoms and for improving quality of life (QoL) in a sample of youths with CTD and TS. Design: A 10 weeks, 2 sites (Catania, Rome) randomized controlled trial. Participants were randomized to receive one of the following treatments: BT, PE, or PT. Participants: 110 outpatients aged between 8 and 17 years affected by CTD or TS. Results: Patients in the BT and PT groups showed a significant reduction in the severity of tic symptoms, while the PE group did not show any improvement. PT was more effective for reducing obsessive compulsive symptoms than BT, while PE group did not show any improvement. Both BT and PT groups showed an improvement in most QoL domains, whereas no differences were found in the PE group. Conclusions: BT is as effective as pharmacological therapy in the treatment of tic disorders in children and adolescents, thus offering an alternative to medications for CTD and TS

    Neurobiology of the premonitory urge in Tourette’s syndrome:pathophysiology and treatment implications

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    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 Phenomenon of Exquisite Motor Control in Tic Disorders and its Pathophysiological Implications

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    The unifying characteristic of movement disorders is the phenotypic presentation of abnormal motor outputs, either as isolated phenomena or in association with further clinical, often neuropsychiatric, features. However, the possibility of a movement disorder also characterized by supranormal or enhanced volitional motor control has not received attention. Based on clinical observations and cases collected over a number of years, we here describe the intriguing clinical phenomenon that people with tic disorders are often able to control specific muscle contractions as part of their tic behaviors to a degree that most humans typically cannot. Examples are given in accompanying video documentation. We explore medical literature on this topic and draw analogies with early research of fine motor control physiology in healthy humans. By systematically analyzing the probable sources of this unusual capacity, and focusing on neuroscientific accounts of voluntary motor control, sensory feedback, and the role of motor learning in tic disorders, we provide a novel pathophysiological account explaining both the presence of exquisite control over motor output and that of overall tic behaviors. We finally comment on key questions for future research on the topic and provide concluding remarks on the complex movement disorder of tic behaviors
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