Gait and balance disorders are common among individuals who have experienced a traumatic brain injury (TBI). Prior studies have shown that individuals with TBI tend to walk slower, take smaller steps, and have increased mediolateral sway. However, symptoms and severity vary considerably between subjects, making the neuropathology of gait difficult to characterize and to inform targeted interventions. Traditional rehabilitation protocols provide little improvement after the first few months post-injury, leaving many individuals with chronic balance impairments. Interventions that can accelerate neuroplasticity or enhance sensorimotor integration are desperately needed to improve motor function in individuals with a prior TBI.

This dissertation examines changes in the neuromuscular control of gait as a result of a mild to moderate traumatic brain injury and explores targeted neurorehabilitation modalities that may improve motor function. The first two chapters characterize neuromuscular coordination in chronic TBI patients and examine relationships between these quantitative motor control metrics and clinical assessments of gait function. The third chapter tests the hypothesis that neuromuscular coordination of gait can be fundamentally altered by using noninvasive neuromodulation to enhance plasticity during gait and balance rehabilitation exercises. The fourth chapter documents an exploratory study of gait and balance using sub-sensory vibratory stimulation to enhance somatosensation when visual information is disrupted. This dissertation demonstrates the potential application of noninvasive neuromodulation to improve gait and balance for individuals with a prior TBI.