We intend to perform two studies on overall 90 subjects. One study will assess the affected upper limb in 15 patients with unilateral focal dystonia, 15 patients with CRPS and 15 patients with focal dystonia and CRPS, while the second study will test the affected lower limb in 15 patients with unilateral focal dystonia, 15 patients with CRPS and 15 patients with focal dystonia and CRPS in the lower limb.