Grip force. Representative example of mean grip force profiles of one control subject (a) and one patient (b). A sold line, long dashed double-dotted line, and dashed line indicate sandpaper, suede, and silk conditions, respectively. The zero of x-axis (dotted vertical line) represents the starting time of lifting movement. Averaged grip forces of three conditions in the controls (c) and patients (d). Error bars denote ± 1.0SE.