Finger force enslaving and surplus in spinal cord injury patients

This study investigated the phenomena of finger enslaving, involuntary finger actions by non-intended fingers, and force deficit, smaller maximum force by all four fingers than the sum of individual finger maximum forces in individuals with cervical spinal cord injuries (SCI). A total of 16 subjects participated in this study: 8 with a cervical spinal cord injury and 8 controls. Each of the injured subjects had one paralyzed finger. The results showed that the efforts to produce force using any individual finger induced force production in all other fingers, suggesting finger force enslaving. The maximum force during the four-finger task was greater than the sum of the individual finger forces during single-finger tasks in the SCI group, which was reflected by positive force deficit, “force surplus”. One may utilize these findings for rehabilitation of paralyzed fingers caused by cervical spinal injuries.