Motor cortex excitability in restless legs syndrome

Background and purpose: A review of the literature shows that the transcranial magnetic stimulation (TMS) is a useful neurophysiological tool to investigate the pathophysiology of the restless legs syndrome (RLS). In this study we used TMS to define motor cortical excitability in RLS subjects. Patients and methods: Six RLS patients and two healthy control subjects underwent TMS (single and paired) examination using two protocols: (1) the evaluation of motor cortical excitability changes occurring at various times after a repetitive finger movement task; (2) the evaluation of the time course of intracortical motor activity tested with pairs of magnetic stimuli applied at inter-stimulus intervals of 1–6 ms. Results: Subjects affected by RLS do not show the normal fluctuations of motor cortical excitability usually found after a bimanual finger movement task. The intracortical inhibition was reduced in RLS subjects. Conclusions: These results compared with the other studies suggest a modification in the central circuits and suppose a reduction or alteration in the cortical plasticity.