Published September 11, 2024 | Version 1.1
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Cortical thickness in provisional and chronic tic disorder

Description

Background: Structural MRI studies have found thinner cortex in Tourette syndrome (TS) than in tic-free controls (TFC) in several cortical regions. Whether this thinning precedes or follows the first tic is unknown. Cortical thickness has not been reported in patients with a tic disorder less than one year in duration (Provisional Tic Disorder, PTD).

Objectives: Compare regional cortical thickness in TS, PTD and TFC.

Methods: T1-weighted brain MRI was acquired in 391 children 5-10 years old: 83 with PTD, 103 with TS, and 205 TFC. FreeSurfer measured cortical thickness in 34 cortical regions in each hemisphere. An ANCOVA compared regional cortical thickness between groups, controlling for age, sex, handedness and intracranial volume and correcting for multiple comparisons with Holm’s method.

Results: Brain volume and mean cortical thickness differed significantly among groups (TS < PTD < TFC). That pattern was observed in 34 of 68 cortical regions, including in the subset of highest quality images acquired with prospective motion correction. The typical developmental cortical thinning from age 5.0-11.0 occurred 2–3 times faster in the tic groups. Predicted cortical thickness in the PTD group at tic onset was identical to the TFC group, but diminished over time to match the TS group at one year after tic onset.

Conclusion: These data from one of the largest imaging studies of tic disorders suggest that the thinner cortex in TS develops after rather than before tics begin. As such, it is more likely  to represent a consequence rather than a cause of tics. We hypothesize that it may reflect earlier maturation of inhibitory circuits because of  extended experience suppressing tics.

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Additional details

Funding

Training Investigators in Neuroimaging and Neuropsychiatry of Movement Disorders K24MH087913
National Institute of Mental Health
The New Tics Study: A Novel Approach to Pathophysiology and Cause of Tic Disorders R01MH104030
National Institute of Mental Health
Tourette Syndrome genetics and neuroimaging international collaborative study R01MH126213
National Institute of Mental Health
Tracking Neurodegeneration in Early Wolfram Syndrome R01HD070855
Eunice Kennedy Shriver National Institute of Child Health and Human Development
EARLY PREDICTORS OF BRAIN HEALTH AND DEVELOPMENT IN YOUTH WITH T1DM R01DK064832
National Institute of Diabetes and Digestive and Kidney Diseases
PREDICTING OUTCOME IN CHILDREN WITH NEW-ONSET TICS USING NEUROIMAGING DATA R21NS091635
National Institute of Neurological Disorders and Stroke
PREDICTING OUTCOME IN CHILDREN WITH TIC DISORDERS USING NEUROIMAGING DATA K01MH104592
National Institute of Mental Health
Cancer Center Support Grant P30CA091842
National Cancer Institute
WASHINGTON UNIVERSITY INTELLECTUAL AND DEVELOPMENTAL DISABILITIES RESEARCH CENTER U54HD087011
Eunice Kennedy Shriver National Institute of Child Health and Human Development
Washington University Institute of Clinical and Translational Sciences UL1RR024992
National Institutes of Health
Washington University Institute of Clinical and Translational Sciences UL1TR000448
National Center for Advancing Translational Sciences
Washington University Institute of Clinical and Translational Sciences UL1TR002345
National Center for Advancing Translational Sciences
Neuroimaging Laboratories Research Center of the Mallinckrodt Institute of Radiology and Washington University 1
Washington University in St. Louis

Dates

Created
2024-09-06
Updated
2024-09-11
Added Amel Lilic as author