Aberrant cortical associative plasticity associated with severe adult Tourette syndrome.

ABSTRACT

BACKGROUND: Recent studies have shown altered cortical plasticity in adult patients with Tourette syndrome. However, the clinical significance of this finding remains elusive. METHODS: Motor cortical plasticity was evaluated in 15 adult patients with severe Tourette syndrome and 16 healthy controls using the paired associative stimulation protocol by transcranial magnetic stimulation. Associations between paired associative stimulation-induced plasticity and relevant clinical variables, including cortical excitability, psychiatric comorbidities, drug treatment and tic severity, were assessed. RESULTS: Motor cortical plasticity was abnormally increased in patients with Tourette syndrome compared with healthy subjects. This abnormal plasticity was independently associated with tic severity. CONCLUSION: Patients with severe Tourette syndrome display abnormally increased cortical associative plasticity. This aberrant cortical plasticity was associated with tic severity, suggesting an underlying mechanism for tic pathophysiology.