User Testing for Performance and Brain Engagement With the Hope Hand Exoskeleton for Individuals With Spasticity Due to Brain Injury

Hand spasticity and hypertonia are common in individuals who have sustained an upper motor neuron (UMN) injuries due to stroke and traumatic brain injury. While rehabilitation robots and hand exoskeleton-based therapy treatments have shown great promise of improving motor function, the frequency of use and the nature of the repetitive therapeutic tasks can limit the promotion of neuroplasticity. The use of an assistive hand exoskeleton, meant to help the user perform activities of daily living (ADL), leverages the principals of neuroplasticity regarding increased frequency of use and increased specificity in doing functional tasks, to further improve neuroplasticity. Therefore, the use of an assistive hand exoskeleton may have neurorehabilitative benefits. The HOPE Hand - hand orthosis with powered finger extension - was designed to provide active finger flexion and extension of the fingers in the presence of increased muscle tone to assist individuals to perform ADLs. User testing was conducted with 3 control subjects and 2 subjects with hand spasticity and hypertonia due to a traumatic brain injury (TBI) and a stroke, respectively. This user test evaluated the user's ability to perform a functional task with the hand exoskeleton as well as their brain's engagement in the task using functional near-infrared spectroscopy (fNIRS) towards understanding neurorehabilitation benefits of assistive exoskeleton use. Results show the impaired subjects performed the functional water bottle task in significantly less time with the exoskeleton than without it. The fNIRS data showed that their motor cortex and speech centers of the brain were activating despite sustaining damage. By combining performance metrics and neuroimaging, we can further evaluate the HOPE Hand and other assistive exoskeletons to study their potential for promoting neurorehabilitation.