TMS-evoked potentials provide novel neurophysiological features of Tourette syndrome

Summary

Gilles de la Tourette syndrome (TS) is a neuropsychiatric disorder linked to abnormal activity in cortico-striatal-thalamo-cortical circuits and the dopaminergic system. This study measured TMS-evoked potentials (TEPs) from selected networks to examine changes in cortical excitation and inhibition in adults with TS.

Study design

• Participants: 33 adults with TS and 18 healthy controls.
• Symptom severity was rated with the YGTSS (tics), PUTS (premonitory urge), Y-BOCS (OCD), CAARS (ADHD), BDI (depression) and BAI (anxiety).
• TEPs were recorded after stimulation of the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC) and primary visual cortex (V1).

Key findings

• Patients with TS showed a delayed P180 latency in M1 compared with controls (p = 0.006).
• A lower early TEP amplitude after DLPFC stimulation (50–70 ms) and a delayed DLPFC P180 latency were associated with higher tic severity (p = 0.001 and p = 0.003).
• Early M1 amplitude (50–70 ms) differentiated patients with mild to moderate tics from those with severe tics (p = 0.003).
• Early V1 amplitude (15–45 ms) correlated with the severity of anxiety.

Authors' conclusions

The authors suggest that distinct TEP patterns after DLPFC, M1 and V1 stimulation may shed light on the pathophysiology of TS, and that these patterns are associated with tic severity and comorbidities.

Read the full article

Lassman S, Zifman N, Fogel H, Hassin-Baer S, Anis S. TMS-evoked potentials provide novel neurophysiological features of Tourette syndrome. Parkinsonism & Related Disorders. 2025;130:107217. doi:10.1016/j.parkreldis.2024.107217

Summary prepared by QuantalX from the published abstract. All results are as reported by the authors. The full text is available from the publisher.