MINT conditioning to improve post-stroke gait

Stroke is one of the most common causes of long-term disability. About 60% of stroke survivors have impaired leg movement, leading to reduced walking speed and quality of life. One contributor to leg impairment appears to be abnormal co-activation of leg muscles, especially hip adductors and knee extensors. This is similar to the abnormal co-activation (a.k.a. abnormal synergies) that contributes to impaired arm movement after stroke. We have developed a Myoelectric Interface for NeurorehabiliTation (MINT) paradigm to counteract abnormal co-activation. Our prior work and preliminary results have shown that MINT conditioning to reduce co- activation can improve arm movement even in chronic stroke survivors, and that an early wearable version had relatively high adherence and enjoyment. The long-term goal of this research is to develop an inexpensive, robust, wearable device for home-based MINT conditioning and translate it into clinical use for improving movement in both arm and leg. The objectives of this proposal are 1) to build robust, completely wireless EMG sensors and more engaging games to enable user-friendly, home-based therapy, 2) to test MINT conditioning’s ability to reduce leg muscle co-activation and improve gait in chronic stroke survivors, and 3) to determine the mechanisms behind the response to MINT conditioning. Our preliminary results show that MINT conditioning can be used in the leg and can improve gait kinematics and walking speed, a key goal of locomotor recovery. We hypothesize that MINT conditioning will improve leg function and walking in stroke survivors. We will achieve our objectives via the following specific aims: 1) develop a robust MINT system using wireless electrodes and more engaging games; 2) test the impact of MINT conditioning on leg movement; and 3) investigate mechanisms of changes from MINT conditioning. This proposal’s innovative combination of inexpensive, completely wireless, wearable devices and engaging, commercial-quality games will improve robustness and enhance translational potential. Achieving our objectives will be significant because it will establish that abnormal co-activation of hip adductors and knee extensors impairs gait. It will also facilitate the development of an enhanced, rehabilitative therapy to improve function after stroke that could be used widely and potentially could help severely impaired stroke survivors. The enhanced therapy will increase enjoyment and enable use in any location, both of which are critical to increasing the dose of, and engagement with, therapy, which in turn increase the likelihood of recovery. We expect that MINT conditioning will be synergistic with existing therapies, given its novel mechanism of action (reducing abnormal co-activation using myoelectric signals). The research will also provide fundamental understanding of the mechanism of improvement due to MINT conditioning—specifically, where in the CNS changes occur due to rehabilitation after a stroke. Finally, this project will provide critical results that will enable us to quickly translate this research into pivotal clinical trials.