Figure 1

Hand paths, including the speed, curvature, and jerk profiles were evaluated in four representative participants. Panels A, B, C and D show the respective hand paths. The hand path is projected on a plane composed of the first principal component (main movement direction: left to right correspond to table to mouth) and the second principal component (lower side in general corresponds to being proximal while upper corresponds to being distal from the body). Panels E, F, G, and H show speed (tangential velocity); panels I, J, K, and L show curvature profiles for the patients with SIAS scores of 2 (patient P5), 3 (patient P9), 4 (patient P10), and the healthy volunteer (H1), respectively. Panels M, N, O, and P show the same curvature profiles as in panels I, J, K, and L, but are zoomed around the low curvature values between 0 and 0.05 (1/mm). Panels Q, R, S, T show the jerk profiles computed by Equation (2).