Spinal Cord Stimulation and Autonomic Response in People With SCI.

Despite being studied less than half as frequently, autonomic dysfunction is a greater priority than walking again in spinal cord injury. One autonomic condition after spinal cord injury is orthostatic hypotension, where blood pressure dramatically declines when patients assume the upright posture. Orthostatic hypotension is associated with all-cause mortality and cardiovascular incidents as well as fatigue and cognitive dysfunction, and it almost certainly contributes to an elevated risk of heart disease and stroke in people with spinal cord injury. In addition, autonomic dysfunction leads to bladder, bowel, sexual dysfunctions, which are major contributors to reduced quality and quantity of life. Unfortunately, the available options for treating this condition, are primarily limited to pharmacological options, which are not effective and are associated with various side effects. It has been recently demonstrated that spinal cord stimulation can modulate autonomic circuits and improve autonomic function in people living with spinal cord injury. Neuroanatomically, the thoracolumbar sympathetic pathways are the primary spinal cord segments involved in blood pressure control. Recently, a pilot study has been published demonstrating that transcutaneous spinal cord stimulation of thoracolumbar afferents can improve cardiovascular function. However, some studies have shown that lumbosacral transcutaneous spinal cord stimulation can also elicit positive cardiovascular effects. Therefore, there is no consensus on the optimal strategy in order to deliver transcutaneous spinal cord stimulation to improve the function of the autonomic system, and it may be that lumbosacral (i.e. the stimulation site being used most commonly for restoring leg function is sufficient). Another key knowledge gap in terms of transcutaneous spinal cord stimulation is whether or not the current is directly or indirectly activating these spinal circuits. Last but not least, the effects of epidural sp