Impact of Transcutaneous Spinal Stimulation on Blood Pressure and Orthostasis in Spinal Cord Injury: Short and Long-Term Effects - Individuals with a spinal cord injury (SCI) in the cervical or high thoracic (≥T6) regions often experience unstable low blood pressure (BP) and orthostatic hypotension (OH), a sudden BP drop upon moving to an upright position. OH can cause dizziness, blurred vision, syncope, and falls, negatively impacting quality of life (QOL) and increasing long-term cardiovascular (CV) risks and cognitive impairment. Current therapies have limited efficacy, with significant barriers to long-term use due to side effects and dosage restrictions. While spinal cord stimulation (epidural and transcutaneous) shows initial promise for improving BP in chronic SCI, questions remain about long-term benefits. This grant aims to generate preliminary data to better understand the immediate effects of spinal cord transcutaneous stimulation (scTS) on BP (Aim 1) and to evaluate whether scTS produces lasting improvements in BP regulation and subsequently, daily function (Aims 2 and 3). This approach may indicate autonomic nervous system adaptation rather than merely providing temporary BP elevation. The novelty of our approach lies in offering a non-invasive, feasible, and accessible intervention, making it broadly applicable to a larger population. The study will recruit 10 individuals at least 1-year post-SCI, with OH and low BP, for 20 30-minute scTS- CV training sessions. Assessments will be conducted before, immediately after, and bi-weekly for two months post-training, using personalized stimulation parameter mapping (e.g., site, frequency), and focusing on CV and person-centered outcomes. Aim 1 will assess the immediate BP response to scTS-CV during a 70° tilt test. We hypothesize that stimulation will minimize the BP drop, reduce OH symptoms, and prolong tilt duration compared to a tilt without stimulation. Aim 2 will assess the long-term effects of 20 scTS-CV sessions (‘training’) on BP. Post-training, we expect: (a) reduced BP drop, fewer symptoms, and longer tilt duration during a 70° tilt test; (b) higher, more stable BP during a 30-minute seated assessment; and (c) decreased frequency and severity of OH events in 24-hour ambulatory BP monitoring (ABPM). Effects are expected to gradually diminish over the 2-month follow-up. Aim 3 will assess the long-term impact of training on daily function and community participation. We hypothesize post-training improvements in repeated assessments over the two months, including the self-reported Autonomic Dysfunction Following SCI (ADFSCI) and SCI-QOL, and the clinician-administered Canadian Occupational Performance Measure (COPM), with these effects gradually lessening over time. The investigation aims to demonstrate the feasibility and durability of scTS-CV training as a non-invasive BP regulation intervention for SCI patients. Preliminary findings will inform a future R01 application, exploring training regimens and underlying mechanisms for sustained BP control. The long-term goal is to advance SCI care, improve daily function and community participation, and enhance CV health outcomes.
