Improving Grip Control Using a Dynamic Speed-Accuracy Tradeoff Protocol

Nam H. Kim1, Steven Escaldi2 , Adam Shain1 , Michael Wininger1, and William Craelius1
 1 Department of Biomedical Engineering, Rutgers, The State University of New Jersey
Piscataway, NJ  
2 JFK Johnson Institute for Rehabilitation, Edison, NJ


Restoring fine motor control in persons with chronic hemiparesis remains a challenge for rehabilitation engineers.  The present study introduces an ergonomic grip force detection device, Gripper, for the biofeedback-based motor rehabilitation of hemiparesis in chronic stroke patients.  Using the Gripper, we were able to validate Fitts’ speed-accuracy tradeoff (SAT) in dynamic grasping tasks in non-neurologically impaired persons, and assess the restoration of motor function in a cohort of chronic stroke patients over time according to their SAT parameters.  A pilot study with eight healthy subjects revealed that the speed of force production and its accuracy to match a force target are log-linearly related.  Four chronic stroke patients exhibited significant improvements in their adherence to a Fitts’-like relationship following a 6-week training programme with the Gripper.


Stroke, grip, grasp, motor control,  biofeedback.


This study was funded by the National Institute on Disability and Rehabilitation Research (NIDRR) SBIR grant to Nian-Crae Inc., Somerset, NJ.  Technical assistance was provided by Carey Glass, CPO.

Author Contact Information:

Nam H. Kim, PhD, Rutgers University, 599 Taylor Road, Piscataway, NJ 08854, Office Phone (732) 445-1178  EMAIL: