Biomarkers of tic severity in children with Tourette syndrome: Motor cortex inhibition measured with transcranial magnetic stimulation.
Mitchell A Batschelett, David A Huddleston, Deana Crocetti and 3 others
PMID 36938698WHAT IT FOUND
Tourette syndrome children did not show different brain inhibition compared to typically developing peers.
However, within the Tourette group, worse tics linked to lower inhibition in the motor cortex. This suggests motor cortex activity reflects tic severity, not just the diagnosis.
Key findings
01There was no significant difference in motor cortex inhibition (SICI) or facilitation (ICF) between children with Tourette syndrome and typically developing children.
02In children with Tourette syndrome, greater tic severity was associated with reduced short-interval intracortical inhibition (SICI).
03Severity of ADHD symptoms, particularly hyperactivity, was associated with altered motor cortex inhibition and facilitation across the whole sample.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The study is cross-sectional, so it cannot determine if changes in brain inhibition cause tics or result from them. Medication use was not controlled for or analyzed, which can significantly affect motor cortex physiology. The sample size was small (60 children), limiting the generalizability of the findings. Urge data was missing for some participants due to the difficulty of administering the scale to this age group.
Declared interests
The authors declared no conflicts of interest. The study was supported by the National Institutes of Health.
The easy way to misread this
Do not interpret the lack of difference between groups as evidence that motor cortex inhibition is unrelated to Tourette syndrome. The study found that within the Tourette group, worse tics correlated with lower inhibition, suggesting the measure reflects symptom severity rather than diagnosis.