Newsletter
Restoring Hand Function in Stroke Survivors
Issue: Fall 2008
As a key researcher in IIT’s Center for Integrative Neuroscience and Neuroengineering, Derek Kamper brings to his work dual expertise as assistant professor of biomedical engineering and senior research scientist and director of the Coleman Hand Rehabilitation Laboratory at RIC. Kamper’s research program combines his background in robotics, control theory, and neuromechanics to improve patient recovery of motor function following neurological injuries, particularly neuromuscular injury that affects the hand.
The Actuated Hand Exoskeleton: Created at IIT as a test bed for the various hand rehabilitation strategies for stroke survivors
Research Expertise
More than 700,000 people in the United States suffer from a stroke each year; the American Heart Association reports a resulting current stroke population of roughly 3 million. Hand impairment is a prevalent outcome of stroke, with finger extension as the most common motor function impairment. Although hand is fundamental to all activities of daily living, diminished motor control of the hand following stroke, or due to cerebral palsy or other similar conditions, has not been widely studied. Capitalizing on his joint faculty appointment with IIT and RIC, Kamper has targeted his research in three main areas. The first entails a detailed analysis of the underlying mechanisms of impairment of the hand. This effort necessitates a second research area to describe how the hand functions when unimpaired. The final area uses the knowledge gained in the other two areas to develop devices and techniques to guide hand rehabilitation.
Applications in Stroke Rehabilitation
Repetitive practice has been shown to lead to functional improvement following a stroke. Unfortunately, many stroke survivors do not possess sufficient sensorimotor control to practice the desired movements. Kamper and other researchers have recently developed a number of new mechatronic devices to facilitate hand rehabilitation in these patients. How best to use these devices remained to be determined. To help answer this fundamental question, Kamper and collaborators at Northwestern University and Vanderbilt University have been developing a test bed for various rehabilitation strategies.
At the forefront of this initiative is a prototype for a novel robotic hand rehabilitation system—the Actuated Hand Exoskeleton (AHX). Unlike any existing hand robotic system, the AHX provides the flexibility necessary to create different environments that may be beneficial for rehabilitation [see graphic]. Designed to allow control of the thumb and index finger, the two most functionally important digits, AHX controls each joint in these digits independently with high torque and speed production. The device also allows free movement of the arm such that reach-to-grasp can be performed.
Based on recently developed hybrid system theory, the AHX incorporates an intelligent control mechanism that provides a mathematical framework to model both continuous dynamics and discreet event dynamics in a unified manner. This novel controller will permit exploration of a number of intervention strategies to find the one that best facilitates retraining of hand function.