Hodgkiss Daniel D, Williams Alison M M, Shackleton Claire S, Samejima Soshi, Balthazaar Shane J T, Lam Tania, Krassioukov Andrei V, Nightingale Tom E
School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom.
International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada.
Front Neurosci. 2024 Aug 29;18:1435716. doi: 10.3389/fnins.2024.1435716. eCollection 2024.
Cervical or upper-thoracic spinal cord injury (SCI, ≥T6) often leads to low resting blood pressure (BP) and impaired cardiovascular responses to acute exercise due to disrupted supraspinal sympathetic drive. Epidural spinal cord stimulation (invasive, ESCS) and transcutaneous spinal cord stimulation (non-invasive, TSCS) have previously been used to target dormant sympathetic circuits and modulate cardiovascular responses. This case series compared the effects of cardiovascular-optimised ESCS and TSCS versus sham ESCS and TSCS on modulating cardiovascular responses and improving submaximal upper-body exercise performance in individuals with SCI. Seven males with a chronic, motor-complete SCI between C6 and T4 underwent a mapping session to identify cardiovascular responses to spinal cord stimulation. Subsequently, four participants (two ESCS and two TSCS) completed submaximal exercise testing. Stimulation parameters (waveform, frequency, intensity, epidural electrode array configuration, and transcutaneous electrode locations in the lumbosacral region) were optimised to elevate cardiovascular responses (CV-SCS). A sham condition (SHAM-SCS) served as a comparison. Participants performed arm-crank exercise to exhaustion at a fixed workload corresponding to above ventilatory threshold, on separate days, with CV-SCS or SHAM-SCS. At rest, CV-SCS increased BP and predicted left ventricular cardiac contractility and total peripheral resistance. During exercise, CV-SCS increased time to exhaustion and peak oxygen pulse (a surrogate for stroke volume), relative to SHAM-SCS. Ratings of perceived exertion also tended to be lower with CV-SCS than SHAM-SCS. Comparable improvements in time to exhaustion with ESCS and TSCS suggest that both approaches could be promising ergogenic aids to support exercise performance or rehabilitation, along with reducing fatigue during activities of daily living in individuals with SCI.
颈段或上胸段脊髓损伤（SCI，≥T6）常因脊髓上的交感神经驱动中断，导致静息血压降低以及对急性运动的心血管反应受损。硬膜外脊髓刺激（侵入性，ESCS）和经皮脊髓刺激（非侵入性，TSCS）此前已被用于靶向休眠的交感神经回路并调节心血管反应。本病例系列比较了心血管优化的ESCS和TSCS与假ESCS和TSCS对调节脊髓损伤个体心血管反应及改善次最大负荷上身运动表现的影响。7名患有C6至T4之间慢性、运动完全性脊髓损伤的男性接受了一次定位检查，以确定对脊髓刺激的心血管反应。随后，4名参与者（2名接受ESCS，2名接受TSCS）完成了次最大负荷运动测试。优化刺激参数（波形、频率、强度、硬膜外电极阵列配置以及腰骶部经皮电极位置）以提高心血管反应（CV-SCS）。假刺激条件（SHAM-SCS）作为对照。参与者在不同日期，在对应于高于通气阈值的固定工作量下，进行手臂曲柄运动直至疲劳，同时接受CV-SCS或SHAM-SCS。静息时，CV-SCS可升高血压，并预测左心室心肌收缩力和总外周阻力。运动期间，相对于SHAM-SCS，CV-SCS可延长疲劳时间并提高峰值氧脉搏（每搏输出量的替代指标）。与SHAM-SCS相比，CV-SCS时的主观用力感觉评分也往往更低。ESCS和TSCS在疲劳时间方面的类似改善表明，这两种方法都可能是有前景的促力辅助手段，可支持运动表现或康复，同时减少脊髓损伤个体日常生活活动中的疲劳。
