Spinal Cord Treatment Through Stimulation

 

            Our ability to move our bodies from our fingers to our toes comes from the nerves within the spinal cord. Each year thousands of individuals damage their spinal cord or another part of their spine resulting in spinal cord injuries that could lead to the permanent loss of sensation, mobility, or overall function. In hopes of reversing spinal cord damage, many have been researching different treatments that could help the thousands who have lost their ability to move or feel a part(s) of their body.

            One group that has made significant strides in developing a potential treatment for spinal cord injuries is Dr. Monica Perez and Dr. Hang Jin Jo. In their article “Corticospinal-motor neuronal plasticity promotes exercise mediated recovery in humans with spinal cord injury”, they studied paired corticospinal motor neuronal stimulation (PCMS) as a way to activate spinal synapses in patients with varying degrees of spinal injuries to improve functional recovery of the neurons. Through using transcranial magnetic stimulation (TMS) they were able to deliver stimuli over the primary motor cortex to specific superficial neurons depending on the individual’s injuries. Dr. Perez took 25 patients with incomplete spinal cord injuries, meaning there were some functioning neurons present at the site of injury, into either the group with PCMS and exercise or the placebo group with sham-PCMS and exercise. The patients completed ten sessions of either PCMS or sham-PCMS followed by exercise over the course of three weeks. Additionally, another group of 13 patients were exposed to PCMS without exercise to learn the effects of the PCMS alone. The experimental treatment of PCMS coupled with or without exercise showed an increase by 40-50% in the voluntary contraction of muscles that were affected by the spinal cord injuries. Incredibly, the group that coupled exercise and PCMS saw the improvement last for 6 months after completing the treatment.

            Another group that studied a potential treatment for spinal cord injuries is Dr. Edmund Hodkin, Dr. Yuming Lei, and others. In an effort to address two problems in one, the researchers worked to develop a treatment for both spinal cord injuries and strokes that suffered from upper limb weakness. In their article, “Automated FES for Upper Limb Rehabilitation following Stroke & Spinal Cord Injury” focused on the ability to improve neural plasticity through functional electrical stimulation (FES). FES applied peripheral stimulation to selected neurons in the injured upper arm as the subject performed a reach-to-grasp movement.  The movement is broken into two components. First, transporting the hand to the object. Second, the formation of the hand to grasp the object, and ending with grasping the object. Dr. Hodkin and Dr. Lei delivered the FES through a closed-loop device in order to enhance movement in 11 subjects with either stroke or spinal cord injuries. An admitted issue with the device developed by the researchers is that it does not offer the same flexibility as a physical therapy session with a therapist helping the patient. This reduced the amount of distance the patient is able to perform as they are self-starting the movement in an area that is limited due to injury. After two weeks of this training with FES, the researchers found mild changes within the patients that benefited them. However, this study does not investigate the long-term effects, like Dr. Perez’s study. More research will need to be done in order to understand the long-term effects that FES has on neural plasticity and connections with the upper limbs.

Thousands are left immobile every year from spinal cord injuries and strokes. Upon analyzing both studies, it is clear that electrical stimulation in junction with movement plays a crucial role in the lasting treatment in these types of injuries. Dr. Perez’s study showed the ability that electrical stimulation had to induce long-term changes in neural plasticity within the spinal cord. Dr. Hodkin’s study gives insight into the ability to pair electrical stimulation with self-generated movement in patients with upper limb impairments.

 

Bibliography

E. F. Hodkin et al., "Automated FES for Upper Limb Rehabilitation Following Stroke and Spinal Cord Injury," in IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 26, no. 5, pp. 1067-1074, May 2018, doi: 10.1109/TNSRE.2018.2816238.

 

Hang Jin Jo, Monica A Perez, Corticospinal-motor neuronal plasticity promotes exercise-mediated recovery in humans with spinal cord injury, Brain, Volume 143, Issue 5, May 2020, Pages 1368–1382, https://doi.org/10.1093/brain/awaa052