Physiological Transformations One Decade After Spinal Cord Injury Plus Unilateral Brachial Plexus Avulsion

This case study examines the long-term effects of > 2 years of non-invasive transcutaneous spinal cord stimulation (tSCS) combined with activity-based neurorehabilitation therapy (ABNT) in an individual with a chronic, complete T4/T5 spinal cord injury (SCI) and right brachial avulsion followed by a two-nerve transfer within 6 months of the injury. Beginning 9 to 11 years post-injury, the participant completed 60-minute sessions that combined tSCS and an Ekso NeuroRehabilitation (EksoNR) device. Electromyography (EMG) recordings were taken from bilateral tibialis anterior (TA) and soleus (SOL) muscles, analyzing only trials where the EksoNR provided full assistance. Over time, gait abilities, including gait speed, swing time, and step length, improved significantly (r² >0.50, p < 0.001). Muscle activity was quantified across five sessions that were two to five months apart, showed that mean EMG activity increased over time, with each session averaging a 16% increase compared to the first session of EMG collection. There were differences between bilateral muscles and their coordination (p < 0.05). These results indicate that prolonged intervention enables spinal and supraspinal networks to progressively improve stepping by modulating the amplitude and timing of excitation patterns within specific motor pools. Clinically, this raises questions about how to achieve necessary control through different network combinations for efficient stepping, highlighting the importance of understanding activity-dependent adaptations underlying learning and motor control.