Fig. 3.

Fast target reaching (extension) task for the assessment of motor impairments. a Subject are instructed to move their index finger as fast as possible from a starting position (30${}^{\circ }$ flexion from the MCP joint neutral position) to a target position (10${}^{\circ }$ extension from the MCP joint neutral position) in a single, ballistic movement. The outcome measure is the maximum velocity reached during that movement. b The task has good reliability (ICC$>0.70$) on the less affected and excellent reliability (ICC $>0.90$) on the more affected side. c There is a high agreement (80%) in impairment classification between the task metric and the clinical measure of upper-limb motor impairments FMA. d The box plot indicates a tendency of decreasing robotic task performance with increasing stroke severity (mild: FMA$>=54$, moderate: $54>$FMA$>=35$, severe: FMA$<35$). There is a significant difference between control (N=62) and all stroke sub-groups—severe (N=14), moderate (N=8) and mild (N=8). Acronyms - D: dominant, LA: less affected, A: affected, FMA: Fugl-Meyer Upper Limb Motor Assessment, ICC: intraclass correlation coefficient, SRD: smallest real difference. Statistical significance: p-value<0.05: *, p-value<0.01: **, p-value<0.001: ***