Militskova, Alena

Background/Objectives: Traumatic spinal cord (SC) injury (SCI) is a debilitating neurological condition. Minimally invasive approaches to monitor in real time the functional state of the neuromotor apparatus in animal models of SCI (at rest and movement) to assess effectiveness of therapy are needed in preclinical studies. We aimed to develop such a bioethically acceptable platform for SCI studies on non-human primates (Rhesus macaques). Methods: Epidural and myographic electrode implantation (EI) (wireless and wired, connected via a head plug) was performed. After EI, motor responses caused by electrical stimulation of the SC at the level of the cervical and lumbar thickening were recorded; electromyography of the limb muscles was recorded during quadrupedal movement of the animal on a treadmill with simultaneous assessment of movements’ kinematic parameters. Five weeks after EI, three animals underwent lateral hemisection of the SC in the C4–C5 segment under the control of a surgical microscope and intraoperative recording of motor- and sensory-evoked potentials. Results: Within 30 days after SCI, during treadmill testing, a decrease in electromyographic activity of the limb muscles and the volume of angular movement in the joints on the side of the injury was detected. Electrical stimulation at the L2–S1 segments of the SC at a frequency of 30 Hz led to the appearance of a locomotor pattern in the muscles of the hind limbs and an increase in the range of motion. Conclusions: Our platform can be used for pathophysiological studies of various neuromodulation modes and as a basis for the development of control neurointerfaces.

Abstract In this study the effect of transcutaneous (tSCS) and epidural electrical spinal cord stimulation (EES) to facilitate volitional movements, balance, and non-motor functions was consecutively tested in two subjects with motor complete spinal cord injury (SCI). We hypothesized that tSCS and EES have different but complimentary effects on restoration after SCI. In both subjects tSCS demonstrated minimal improvement in volitional movements critical to initiate tSCS-enabled rehabilitation. Compared to tSCS, following EES demonstrated immediate restoration of volitional movements, while tSCS was more effective in improving balance. Continuous improvement in non-motor functions was found during tSCS-enabled and then EES-enabled rehabilitation. These results show significant difference in effect of tSCS and EES on recovery of neurologic functions and demonstrate advantages of consecutive tSCS and EES therapy of SCI. Proposed approach will help to select responsive to neuromodulation subjects and early initiate therapy, particularly for motor complete SCI with minimal effect from conventional rehabilitation.