Thaïra J C Openneer1, Dennis van der Meer2,3, Jan-Bernard C Marsman4, Natalie J Forde1,5, Sophie E A Akkermans5,6, Jilly Naaijen5,6, Jan K Buitelaar5,6,7, Pieter J Hoekstra1, Andrea Dietrich1. 1. Department of Child and Adolescent Psychiatry, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. 2. NORMENT, KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Oslo, Norway. 3. Faculty of Health, Medicine and Life Sciences, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands. 4. Neuroimaging Center, Department of Neuroscience, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. 5. Karakter Child and Adolescent Psychiatry University Centre, Nijmegen, The Netherlands. 6. Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, The Netherlands. 7. Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands.
Abstract
OBJECTIVES: Tourette syndrome (TS) is characterised by the presence of sudden, rapid movements and vocalizations (tics). The nature of tics suggests impairments in inhibitory control. However, findings of impaired inhibitory control have so far been inconsistent, possibly due to small sample sizes, wide age ranges, or not taking medication use or attention-deficit/hyperactivity disorder (ADHD) comorbidity into account. METHODS: We investigated group differences in response inhibition using an fMRI-based stop-signal task in 103 8 to 12-year-old children (n = 51 with TS, of whom n = 28 without comorbid ADHD [TS - ADHD] and n = 23 with comorbid ADHD [TS + ADHD]; and n = 52 healthy controls), and related these measures to tic and ADHD severity. RESULTS: We observed an impaired response inhibition performance in children with TS + ADHD, but not in those with TS - ADHD, relative to healthy controls, as evidenced by a slower stop-signal reaction time, slower mean reaction times, and larger variability of reaction times. Dimensional analyses implicated ADHD severity as the driving force in these findings. Neural activation during failed inhibition was stronger in the inferior frontal gyrus and temporal and parietal areas in TS + ADHD compared to healthy controls. CONCLUSIONS: Impaired inhibitory performance and increased neural activity in TS appear to manifest predominantly in relation to ADHD symptomatology.
OBJECTIVES: Tourette syndrome (TS) is characterised by the presence of sudden, rapid movements and vocalizations (tics). The nature of tics suggests impairments in inhibitory control. However, findings of impaired inhibitory control have so far been inconsistent, possibly due to small sample sizes, wide age ranges, or not taking medication use or attention-deficit/hyperactivity disorder (ADHD) comorbidity into account. METHODS: We investigated group differences in response inhibition using an fMRI-based stop-signal task in 103 8 to 12-year-old children (n = 51 with TS, of whom n = 28 without comorbid ADHD [TS - ADHD] and n = 23 with comorbid ADHD [TS + ADHD]; and n = 52 healthy controls), and related these measures to tic and ADHD severity. RESULTS: We observed an impaired response inhibition performance in children with TS + ADHD, but not in those with TS - ADHD, relative to healthy controls, as evidenced by a slower stop-signal reaction time, slower mean reaction times, and larger variability of reaction times. Dimensional analyses implicated ADHD severity as the driving force in these findings. Neural activation during failed inhibition was stronger in the inferior frontal gyrus and temporal and parietal areas in TS + ADHD compared to healthy controls. CONCLUSIONS: Impaired inhibitory performance and increased neural activity in TS appear to manifest predominantly in relation to ADHD symptomatology.