Inhibitory Control in Children with Tourette Syndrome Is Impaired in Everyday Life but Intact during a Stop Signal Task.

Melanie Ritter,Signe Allerup Vangkilde,Julie Hagstrøm,Kerstin Jessica Plessen,Anne Katrine Pagsberg,Katrine Maigaard

doi:10.3390/jcm11020309

Abstract

Tourette Syndrome (TS) has previously been associated with deficits in inhibitory control (IC). However, studies on IC in individuals with TS have produced conflicting results. In the present study, we investigated IC, comparing the Stop Signal Reaction Time (SSRT) measure with parent and teacher ratings of daily life IC in 169 children aged 8–12 (60 with TS, 60 typically developing controls, 27 with attention-deficit/hyperactivity disorder (ADHD), and 22 with TS + ADHD). We further investigated associations of IC with TS and ADHD symptom severity. Children with TS showed intact SSRT performance, but impairments in daily life IC, as reported by parents and teachers. For the latter, we observed a staircase distribution of groups, with the healthy controls presenting with the best IC, followed by TS, TS + ADHD, and finally ADHD. Dimensional analyses indicated a strong association between ADHD severity and both measures of IC. Our results indicate that children with TS are not impaired in a laboratory-based measure of IC, although some difficulties were evident from measures of everyday behaviour, which may in part be due to parents and teachers interpreting tics as disinhibited behaviour. Comorbid ADHD or the severity of subthreshold ADHD symptomatology appeared to account for IC deficits.

Highlights

Tourette Syndrome (TS) is a neurodevelopmental disorder, characterized by multiple motor tics and a minimum of one vocal tic, presenting before the age of 18 and lasting for at least one year [1,2]
We observed a staircase distribution of daily life Inhibitory control (IC), with the healthy control group presenting with the highest scores, followed by TS, TS + attention-deficit/hyperactivity disorder (ADHD), and the ADHD group, children with TS and the healthy controls did not differ significantly regarding the performance-based Stop Signal Reaction Time (SSRT), in accordance with previous findings [14,17,33,34,35,36]
Children with ADHD showed a significant impairment in SSRT compared to healthy controls and children with TS

Summary

Introduction

Tourette Syndrome (TS) is a neurodevelopmental disorder, characterized by multiple motor tics and a minimum of one vocal tic, presenting before the age of 18 and lasting for at least one year [1,2]. Inhibitory control (IC) is an executive function defined as the ability to inhibit cognition and/or behaviour that is irrelevant or inappropriate to the execution of goal-oriented actions and adaptive behaviour [3,4]. Cognitive and behavioural inhibition is central to in Habit Reversal Training (HRT) and Exposure and Response Prevention (ERP), which are the most effective behavioural treatment options for TS [11]. Both treatment types require the patients to inhibit their tics, which further emphasizes the need for investigating the extent of inhibitory difficulties in children with TS

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Results

Conclusion