Noninvasive Spinal Cord Stimulation for Recovery of Autonomic Function After Spinal Cord Injury: Moving from Mechanisms to Clinical Practice

Objective: Our goal is to improve AUTONOMIC FUNCTIONs (e.g., blood pressure control, urinary bladder, bowel, and sexual function) in individuals with spinal cord injury (SCI). Autonomic functions are bodily functions that happen automatically without specifically choosing or thinking about it. We propose to test an available non-invasive method (e.g., does not enter the body), to stimulate the spinal cord by applying electrodes to the skin over the mid back or lower back for recovery of these crucial functions.

Rationale: After cervical or high thoracic SCI, majority of people experience urinary bladder, bowel, and sexual dysfunctions. These individuals either have low blood pressure when they are seated (known as orthostatic hypotension) or sudden extreme increase of blood pressure (known as autonomic dysreflexia) during regular daily activities such as bladder and bowel management or sexual activities. Unlike paralysis (a loss of movement) which can be seen, these autonomic dysfunctions are 'invisible' to the general public, but are rated among highest priorities for quality of life for Veterans and civilians with SCI. The hospital re-admission for management of these autonomic dysfunctions increases medical care and cost for Veterans with SCI.

Although various medications and therapeutic strategies are in use for management of autonomic dysfunctions after SCI, to date majority of these strategies have proven to be largely ineffective and have numerous side-effects. During the last decade, our team and others have shown that spinal cord stimulation (using surgically implanted or noninvasive/over the skin electrodes) dramatically improves the recovery of not only motor, but also autonomic functions in individuals with chronic SCI.

Ultimate Applicability and Impact: Individuals with cervical/high-thoracic chronic SCI is the target population in this proposal. In comparison to the surgically placed electrodes, proposed non-invasive stimulation using conventional, self-adhesive electrodes is low cost and is considered non-significant risk by the Food and Drug Administration. We are confident that this new non-invasive treatment for autonomic functions can move from the research phase to application in the clinical and home environments within 4-6 years.

We propose a translational project that combines animal and human studies (a pilot clinical trial) to test the effect of noninvasive spinal cord stimulation on recovery of the blood pressure control (e.g., episodes of low and high blood pressure) as well as bladder, bowel, and sexual functions in individuals with chronic SCI.

Using animal studies, we will investigate how stimulation impacts the nervous system and how we can change the stimulation factors for more beneficial effect on autonomic functions in individuals with SCI.

We will also conduct a pilot clinical trial among individuals with chronic SCI in order to serve as a basis for future, multicenter clinical trials, making this therapy option readily available to be used by healthcare providers and individuals with SCI. The trial aims to establish the most effective individualized stimulation positions and intensity (e.g., specific to physique or injury severity). Using these parameters, person-related outcomes (recovery of autonomic functions) will be tested using either short-term (in real time) or long-term (8 weeks) spinal cord stimulation.

Contribution to Field of SCI Research, Patient Care, and/or Quality of Life: Based on our promising initial data from both animal and human studies as well as the extensive expertise of our team consisting of basic scientists, clinicians, and persons with lived experience in SCI, we are confident that the proposed innovative therapy will improve the crucial autonomic functions that determine the quality of life in individuals with SCI. These findings will establish the safety evidence necessary for developing clinical practice guidelines of non-invasive stimulation for medical professionals. The proposed non-invasive approach will not require surgery and will allow easy repositioning of the electrode to target multiple functions. We predict that this therapy will offer a cost-effective solution administered in out-patient clinics and home environments.