Extracorporeal 'phantom' tics in Tourette's syndrome

Premonitory Urges Reconsidered: Urge Location Corresponds to Tic Location in Patients With Primary Tic Disorders

Objective

In patients with Tourette syndrome and other primary tic disorders (PTDs), tics are typically preceded by premonitory urges (PUs). To date, only a few studies have investigated the location and frequency of PUs, and contrary to clinical experience, the results suggest that PUs are not located in the same anatomic region as the tics. This study aimed to further explore PU location and frequency in detail, differentiating the kind and complexity of the corresponding tics, in a large sample of patients with PTD.

Methods

A total of 291 adult (≥ 18 years) patients with a confirmed diagnosis of chronic PTD were included. The study was conducted online, assement included tics and the general characterization of PUs and a sophisticated body drawing for locating PUs.

Results

We found that PUs were located in the same body area as, or in direct proximity to, the corresponding tic. Most frequently, PUs were located in the face and at the head (62.1%). Compared with simple tics, complex (motor and vocal) tics were more often preceded by a PU; but there was no difference in PU frequency observed between motor tics and vocal tics. PUs were more often experienced at the front than at the back of the body (73% vs. 27%), while there was no difference between the right and left sides (41.6% vs. 41.3%).

Conclusion

The strong association between PU and tic location further supports the hypothesis that PUs represent the core of PTD. Accordingly, future therapies should focus on treating PUs to achieve greater tic reduction.

Tourette syndrome in children: An update

Tourette syndrome (TS) causes academic, social, emotional, physical, and functional problems. Most TS patients also have comorbid neuropsychological conditions. The purpose of this review is to provide updated information to the clinician about phenomenology, epidemiology, comorbidities, pathophysiology and management strategies for tics (a hallmark of TS) and TS. Recent findings suggest that TS is likely due to a combination of several different genes and environmental factors, with possible involvement of the cortical-basal ganglia-thalamocortical circuit and related multiple neurotransmitters. First-line management includes psychoeducation for families, patients, and school personnel, as well as behavioral therapy. Non-medicine treatment for tics is advancing to include younger children and increase access via remote service applications. Pharmacotherapy is used if appropriate and several new medicines are under investigation (e.g., Tetrabenazine, valbenazine, deutetrabenazine, ecopipam, cannabinoids). Deep brain stimulation and Mouthguard therapy can be used for children with intractable illness.

Sensory symptoms in body-focused repetitive behaviors, restless legs syndrome, and Tourette syndrome: An overlap?

Tourette syndrome (TS) is a neurodevelopmental condition characterized by multiple tics. Sensory symptoms play a key role in the clinical phenomenology and pathophysiology of TS, as most patients report premonitory urges driving tic expression. Interestingly, sensory symptoms have also been reported in other conditions characterized by repeated behaviors. This review explores the nature of sensory symptoms reported by patients with body focused repetitive behaviors (BFRBs, especially trichotillomania and skin picking disorder) and restless legs syndrome (RLS) in comparison to TS. A sense of mounting inner tension and reinforcement mechanisms driven by gratification and relief on expression of the tic or repetitive behavior appear to be implicated across all conditions. Subjective urges can be temporarily suppressed by patients with TS and selected BFRBs, whereas patients with RLS tend to report dysesthesia more frequently than a suppressible urge to move. The observed similarities in the phenomenology of sensory symptoms across these conditions raise the possibility of a comparable underlying pathophysiology. Preliminary findings suggest an overlap of neural pathways encompassing the insula, basal ganglia (putamen), and posterior cingulate cortex.

The Use of Deep Brain Stimulation in Tourette Syndrome

Tourette syndrome (TS) is a childhood neurobehavioural disorder, characterised by the presence of motor and vocal tics, typically starting in childhood but persisting in around 20% of patients into adulthood. In those patients who do not respond to pharmacological or behavioural therapy, deep brain stimulation (DBS) may be a suitable option for potential symptom improvement. This manuscript attempts to summarise the outcomes of DBS at different targets, explore the possible mechanisms of action of DBS in TS, as well as the potential of adaptive DBS. There will also be a focus on the future challenges faced in designing optimized trials.

Sensory aspects of movement disorders

Movement disorders, which include disorders such as Parkinson's disease, dystonia, Tourette's syndrome, restless legs syndrome, and akathisia, have traditionally been considered to be disorders of impaired motor control resulting predominantly from dysfunction of the basal ganglia. This notion has been revised largely because of increasing recognition of associated behavioural, psychiatric, autonomic, and other non-motor symptoms. The sensory aspects of movement disorders include intrinsic sensory abnormalities and the effects of external sensory input on the underlying motor abnormality. The basal ganglia, cerebellum, thalamus, and their connections, coupled with altered sensory input, seem to play a key part in abnormal sensorimotor integration. However, more investigation into the phenomenology and physiological basis of sensory abnormalities, and about the role of the basal ganglia, cerebellum, and related structures in somatosensory processing, and its effect on motor control, is needed.

Tic disorders and obsessive compulsive disorder: where is the link?

Over the last years evidence on the overlap between tic-disorders (TD) and obsessive compulsive behavior/disorder (OCB/OCD) has increased. The main focus of research have been the phenomenological and epidemiological similarities and differences in samples of different age, primary diagnosis (TD vs. OCD) including the co-occurrence of both. Unfortunately, only a minority of studies included all three groups (TD, TD + OCD, OCD). Nevertheless, new insight concerning possible subtypes for both TD and OCD has been gained. While some authors concentrated on OCD with/without tics we will summarize the field of TD and OCB/OCD from the viewpoint of tics, since OCB plays an important role in patients with TD. Thereby we will not only sharpen the clinicans' awareness of known differences in phenomenology, epidemiology, genetics and neurobiology, aimed to improve their diagnoses and treatment but also highlight the gaps of knowledge and discuss possibilities for further research in this field.

Sensorimotor integration in movement disorders

Although current knowledge attributes movement disorders to a dysfunction of the basal ganglia-motor cortex circuits, abnormalities in the peripheral afferent inputs or in their central processing may interfere with motor program execution. We review the abnormalities of sensorimotor integration described in the various types of movement disorders. Several observations, including those of parkinsonian patients' excessive reliance on ongoing visual information during movement tasks, suggest that proprioception is defective in Parkinson's disease (PD). The disturbance of proprioceptive regulation, possibly related to the occurrence of abnormal muscle-stretch reflexes, might be important for generating hypometric or bradykinetic movements. Studies with somatosensory evoked potentials (SEPs), prepulse inhibition, and event-related potentials support the hypothesis of central abnormalities of sensorimotor integration in PD. In Huntington's disease (HD), changes in SEPs and long-latency stretch reflexes suggest that a defective gating of peripheral afferent input to the brain might impair sensorimotor integration in cortical motor areas, thus interfering with the processing of motor programs. Defective motor programming might contribute to some features of motor impairment in HD. Sensory symptoms are frequent in focal dystonia and sensory manipulation can modify the dystonic movements. In addition, specific sensory functions (kinaesthesia, spatial-temporal discrimination) can be impaired in patients with focal hand dystonia, thus leading to a "sensory overflow." Sensory input may be abnormal and trigger focal dystonia, or defective "gating" may cause an input-output mismatch in specific motor programs. Altogether, several observations strongly support the idea that sensorimotor integration is impaired in focal dystonia. Although elemental sensation is normal in patients with tics, tics can be associated with sensory phenomena. Some neurophysiological studies suggest that an altered "gating" mechanism also underlies the development of tics. This review underlines the importance of abnormal sensorimotor integration in the pathophysiology of movement disorders. Although the physiological mechanism remains unclear, the defect is of special clinical relevance in determining the development of focal dystonia.

Is it a tic or Tourette's? Clues for differentiating simple from more complex tic disorders

Tics are characterized by sterotyped, purposeless, and irregularly repetitive movements and usually can be classified as chronic motor or vocal tic disorders, transient tic disorders, or Tourette's syndrome. The latter is a complex disorder associated with multiple tics and often accompanied by other conditions, such as ADHD and obsessive-compulsive disorder. Treatment can be difficult, and drug therapy should begin with agents least likely to cause problems for the patient. Education of the patient and family and support from the physician and other care providers are essential elements of effective management.

Tourette syndrome. Phenomenology and classification of tics

Motor and phonic tics represent the clinic hallmark of Tourette syndrome. Since there is no diagnostic test for tics, the clinical recognition of phenomenology is essential for proper diagnosis. Some, and possibly most, motor tics are preceded by a premonitory urge or sensation that is relieved by the execution of the tic and thus can be difficult to differentiate from compulsions, hence the term compulsive tic. In the schema of categorization of movements, most tics can be classified as either unvoluntaryin response to an inner sensory stimulus or to an unwanted feeling compulsionor involuntarytics that are usually suppressible. Further studies are needed to elucidate the clinical, anatomical, and physiologic substrates for the different forms of tics. Finally, the relationship between tics and comorbid conditions, such as obsessive-compulsive disorder and attention deficit with hyperactivity needs to be further explored.