VISIT-TS: A multimedia tool for population studies on tic disorder

Population-based assessment of Tourette syndrome (TS) and other tic disorders produces a paradox. On one hand, ideally diagnosis of tic disorders requires expert observation. In fact, diagnostic criteria for TS explicitly require expert assessment of tics for a definite diagnosis. On the other hand, large-scale population surveys with expert assessment of every subject are impracticable. True, several published studies have successfully used expert assessment to find tic prevalence in a representative population (e.g. all students in a school district). However, extending these studies to larger populations is daunting. We created a multimedia tool to demonstrate tics to a lay audience, discuss their defining and common attributes, and address features that differentiate tics from other movements and vocalizations. A first version was modified to improve clarity and to include a more diverse group in terms of age and ethnicity. The result is a tool intended for epidemiological research. It may also provide additional benefits, such as more representative minority recruitment for other TS studies and increased community awareness of TS

Hippocampal volume in Provisional Tic Disorder predicts tic severity at 12-month follow-up

Previous studies have investigated differences in the volumes of subcortical structures (e.g., caudate nucleus, putamen, thalamus, amygdala, and hippocampus) between individuals with and without Tourette syndrome (TS), as well as the relationships between these volumes and tic symptom severity. These volumes may also predict clinical outcome in Provisional Tic Disorder (PTD), but that hypothesis has never been tested. This study aimed to examine whether the volumes of subcortical structures measured shortly after tic onset can predict tic symptom severity at one-year post-tic onset, when TS can first be diagnosed. We obtained T1-weighted structural MRI scans from 41 children with PTD (25 with prospective motion correction (vNavs)) whose tics had begun less than 9 months (mean 4.04 months) prior to the first study visit (baseline). We re-examined them at the 12-month anniversary of their first tic (follow-up), assessing tic severity using the Yale Global Tic Severity Scale. We quantified the volumes of subcortical structures using volBrain software. Baseline hippocampal volume was correlated with tic severity at the 12-month follow-up, with a larger hippocampus at baseline predicting worse tic severity at follow-up. The volumes of other subcortical structures did not significantly predict tic severity at follow-up. Hippocampal volume may be an important marker in predicting prognosis in Provisional Tic Disorder

Publications

Posters, preprints, paper

MPDP: Public

Public information about the MPDP study

Functional tic-like presentations differ strikingly from Provisional Tic Disorder

Objective: Recent years have seen a dramatic increase in new “tic” cases in teens and young adults. These individuals often present with fulminant onset of symptoms not commonly seen in Tourette syndrome (TS), and are often diagnosed with Functional Neurological Symptom Disorder (FND-tic). However, some authors have questioned whether this illness truly differs from typical Provisional Tic Disorder (PTD) and TS. We sought to test whether the presenting symptoms of FND-tic differ substantially from those in patients later diagnosed with TS. Method: We compared retrospective comparison of data from a longitudinal study of PTD to data summarized from published reports of FND-tic. The longitudinal study of PTD included 89 children with tics beginning less than 9 months ago (median 3.6 months), nearly all of whom were diagnosed with TS at follow-up. We discuss clinical features thought to support a diagnosis of FND-tic, including symptom characteristics, course, severity and comorbidity. Features were selected before reviewing data for this comparison, but after data were collected. Results: Several clinical features dramatically distinguish the patients diagnosed with FND-tic from those with typical PTD. For example, coprophenomena are reported at or shortly after symptom onset in over half of FND-tic patients, whereas coprophenomena had occurred in only 1 of 89 children with PTD at a median of 3.6 months. Six clinical features each have a positive predictive value over 90% for FND-tic diagnosis, if prior probability is 50%. Conclusion: These new data provide strong evidence supporting the diagnostic validity of FND-tic as distinct from TS

Functional tic-like presentations differ strikingly from Provisional Tic Disorder [version 2; peer review: 2 approved]

Background: Recent years have seen a dramatic increase in new “tic” cases in teens and young adults. These individuals often present with fulminant onset of symptoms not commonly seen in Tourette syndrome (TS) and are often diagnosed with Functional Neurological Symptom Disorder (FND-tic). However, some authors have questioned whether this illness truly differs from typical Provisional Tic Disorder (PTD) and TS. Previous studies have compared FND-tic, usually a few months after symptom onset, to patients with TS, usually years after symptom onset. We sought to test whether the presenting symptoms of FND-tic differ substantially from those in patients at a similar duration of symptoms who are later diagnosed with TS. Methods: This comparative study examines clinical features summarized from published reports of FND-tic with novel data from a longitudinal study of PTD. This study came from a referral center for TS and tic disorders and included 89 children with tics whose first tic occurred a median of 3.6 months earlier, nearly all of whom were diagnosed with a chronic tic disorder at follow-up. Specifically, we examine clinical features identified in a recent literature review as supporting a diagnosis of FND-tic, including symptom characteristics, course, severity and comorbidity. Results: Several clinical features dramatically distinguish the patients diagnosed with FND-tic from those diagnosed with typical PTD. For example, coprophenomena are reported at or shortly after symptom onset in over half of FND-tic patients, whereas even several months after onset, coprophenomena had occurred in only 1 of 89 children with PTD. Six clinical features each have a positive predictive value over 90% for FND-tic diagnosis if prior probability is 50%. Conclusions: These new data provide strong evidence supporting the diagnostic validity of FND-tic as distinct from TS

Median nerve stimulation for treatment of tics: A 4-week, open trial with ecological momentary assessment

Median nerve stimulation (MNS) at 10-12 Hz was recently proposed as a potential treatment for tics in Tourette syndrome and other chronic tic disorders (TS/CTD). Here we report on 31 people ages 15-64 with TS/CTD who participated in a 4-week open label study of MNS. We provide individual participant data. Participants were recruited from participants in a randomized controlled trial of MNS and were given a transcutaneous electrical nerve stimulation (TENS) unit to use for MNS for 4 weeks. They were instructed to use the device as desired. Participants were instructed to complete surveys each time they began or ended stimulation, as well as twice daily at random times when prompted by a text message. These surveys contained information on tic frequency, tic intensity, and stimulation discomfort, when applicable. Participants also completed a more extensive final survey at the conclusion of the 4 weeks. 27 participants completed the study. Median device use was 1.5 days per week (interquartile range [IQR] =1.4) and 50 minutes per day used (median, IQR= 93 minutes). Tic frequency improved during MNS (mean improvement 1.0 on a 0-5 scale, p<0.001), as did tic intensity (mean improvement 0.9, p <0.001). Mean discomfort during stimulation was mild (1.2 on a 3-point scale). 21 participants (78%) reported they planned to continue using the device after the study ended. Participants’ results in this study did not correlate significantly with their results in the preceding blinded, randomized, controlled trial. One of the most common suggestions by participants was for a more unobtrusive device. Although 4 participants did not complete the study, in the remainder we found median nerve stimulation to improve tic frequency and intensity with minimal side effects. Most participants plan to continue using the device

Median Nerve Stimulation for Treatment of Tics: A 4-Week Open Trial with Ecological Momentary Assessment

Median nerve stimulation (MNS) at 10–12 Hz was recently proposed as a treatment for Tourette syndrome and other chronic tic disorders (TS/CTD). We report on 31 participants ages 15–64 with TS/CTD in an open-label, comparative (within-group, several time points) study of MNS (ClinicalTrials.gov registration number NCT05016765). Participants were recruited from completers of a randomized controlled trial (RCT) of MNS and were given a transcutaneous electrical nerve stimulation (TENS) unit to use as desired for 12 Hz MNS for 4 weeks. Participants were instructed to complete surveys regarding tic symptoms and stimulation discomfort before and after stimulation, as well as twice daily when randomly prompted by text message. Participants also completed an extensive final survey. Twenty-seven participants completed the study. Median device use was 1.5 days per week and 50 min per day used. Tic frequency improved during MNS (mean improvement: 1.0 on a 0–5 scale, p p < 0.001). Mean discomfort was mild (1.2 on a 3-point scale). In total, 21 participants (78%) planned to continue using the device. Participants’ results in this study did not correlate significantly with their results in the blinded RCT. We found MNS to improve tic frequency and intensity with minimal side effects

Reward enhances tic suppression in children within months of tic disorder onset.

Tic disorders are childhood onset neuropsychiatric disorders characterized by motor and/or vocal tics. Research has demonstrated that children with chronic tics (including Tourette syndrome and Chronic Tic Disorder: TS/CTD) can suppress tics, particularly when an immediate, contingent reward is given for successful tic suppression. As a diagnosis of TS/CTD requires tics to be present for at least one year, children in these tic suppression studies had been living with tics for quite some time. Thus, it is unclear whether the ability to inhibit tics is learned over time or present at tic onset. Resolving that issue would inform theories of how tics develop and how behavior therapy for tics works. We investigated tic suppression in school-age children as close to the time of tic onset as possible, and no later than six months after onset. Children were asked to suppress their tics both in the presence and absence of a contingent reward. Results demonstrated that these children, like children with TS/CTD, have some capacity to suppress tics, and that immediate reward enhances that capacity. These findings demonstrate that the modulating effect of reward on inhibitory control of tics is present within months of tic onset, before tics have become chronic

Reward enhances tic suppression in children within months of tic disorder onset

Tic disorders are childhood onset neuropsychiatric disorders characterized by motor and/or vocal tics. Research has demonstrated that children with chronic tics (including Tourette syndrome and Chronic Tic Disorder: TS/CTD) can suppress tics, particularly when an immediate, contingent reward is given for successful tic suppression. As a diagnosis of TS/CTD requires tics to be present for at least one year, children in these tic suppression studies had been living with tics for quite some time. Thus, it is unclear whether the ability to inhibit tics is learned over time or present at tic onset. Resolving that issue would inform theories of how tics develop and how behavior therapy for tics works. We investigated tic suppression in school-age children as close to the time of tic onset as possible, and no later than six months after onset. Children were asked to suppress their tics both in the presence and absence of a contingent reward. Results demonstrated that these children, like children with TS/CTD, have some capacity to suppress tics, and that immediate reward enhances that capacity. These findings demonstrate that the modulating effect of reward on inhibitory control of tics is present within months of tic onset, before tics have become chronic