D2 MARS Development Project:
Bringing Hand Rehabilitation into New Environments
Executive Summary of Aims:
The goal of this project is to develop technology to facilitate therapeutic training of individuals with hand impairment following stroke. As the hand performs a vast repertoire of movements and the degree of impairment varies widely in stroke survivors, it is unlikely that a single device could provide optimal therapy across this wide spectrum. Paradoxically, users with greater hand impairment may benefit more from technologically simpler devices which focus on less precise movements (e.g., spherical grasp and release) but which can be taken home for greater practice. Users with less impairment may require more complex devices which can provide for independent actuation of digits and can interface with other devices. In the previous grant cycle we developed and evaluated two different platforms for hand therapy: one self-actuated through cables and another externally actuated through pneumatics under computer control1,2. In our pilot study of therapeutic training of grasp-and-release3, modest but significant functional improvements were seen across subjects (average 10-sec decrease in performance time per task for the Wolf Motor Function Test4, similar to the absolute change seen in the EXCITE constraint-induced study5). We believe we can improve upon these results by better matching appropriate technology to the clients’ needs; the cable platform seems well suited to clients with more severe hand impairment while the pneumatic platform seems suited for clients with moderate impairment.
Thus, for this project we propose the following three aims:
- Creation of an actuated glove to assist hand opening. Building from our current cable device, we will develop an externally actuated orthosis to allow the user to independently control gross extension of the digits by any of a number of input mechanisms which we will design. This device is relatively simple, and targeted at more severely impaired patients who need to work on spherical grasp and release. Because the device will be easy to use and entirely portable, therapy trials will be performed in the home in accordance with a regimen established by our research occupational therapist.
- Generation of a system for training finger individuation. While some stroke survivors may be able to perform gross finger extension with a majority of the digits, extension of certain digits may still be problematic. Additionally, isolated movement of individual digits may prove difficult. Using the pneumatic platform, we have developed a prototype to control the flexion of each digit independently under computer control6. Extension can be assisted in those digits in need while flexion can be resisted to help train digit individuation. This device can be used in conjunction with a virtual reality (VR) environment. We will refine the prototype and develop our VR environments to optimize the rehabilitation experience.
- Coordination of the pneumatic system with the arm robot VRROOM. One of the fundamental functional activities of the upper extremity is the reach-to-grasp movement. Even stroke survivors who are able to perform grasp-and-release with the hand in a static posture may have difficulty when coordinating arm and hand movement. We will combine the pneumatic device with the robotic arm system (VRROOM) developed by Drs. Patton and Kenyon to provide a research platform for the evaluation of full reach-to-grasp training.