颈椎水平的经皮脊髓刺激(tSCS)可能有助于改善四肢不完全瘫痪患者的上肢功能。虽然临床试验正在进行中,关于传播途径以及适当的刺激参数仍有很多争论。这项研究旨在探讨宫颈tSCS在离散的上肢运动池中诱导单突触反射的程度,并研究改变刺激位置和强度的影响。
方法:14名神经系统完整的参与者完成了两次实验室检查,在此期间,通过施加在颈椎上的3×3阴极矩阵诱发后根肌反射(PRMR)。最初在C7椎骨水平进行增量募集曲线,以达到每条肌肉的静息运动阈值(RMT)。随后在两个强度(RMT和RMT+20%)下以0.25Hz的频率在所有九个阴极位置上递送成对脉冲(Ims平方单相,脉冲间间隔为50ms)。在四个上肢肌肉中记录了对第一(PRMR1)和第二(PRMR2)刺激的诱发反应。
结果:对于PRMR1,在所有肌肉中都观察到脊髓水平的显着影响,尾端记录到更大的反应。对侧刺激显著增加肱二头肌PRMR1(p<0.05,F=4.9,η2=0.29),桡骨腕屈肌(p<0.05,F=4.9,η2=0.28)和截骨外展肌(p<0.01,F=8.9,η2=0.89)。对侧刺激后激活抑郁(PAD)也显着增加肱二头肌(p=0.001,F=9.3,η2=0.44),肱三头肌(p<0.05,F=5.4,η2=0.31)和桡骨腕屈肌(p<0.001,F=17.4,η2=0.59)。
结论:通过改变宫颈tSCS过程中的刺激强度和位置,可以达到单侧运动池选择性水平。优化这些参数可以提高这种神经调节方法在临床队列中的功效。
Transcutaneous spinal cord stimulation (
tSCS) at the cervical level may facilitate improved upper-limb function in those with incomplete tetraplegia. While clinical trials are ongoing, there is still much debate regarding the transmission pathway as well as appropriate stimulation parameters. This study aimed to explore the extent to which cervical
tSCS can induce mono-synaptic reflexes in discrete upper-limb motor pools and examine the effects of altering stimulus location and intensity.
METHODS: Fourteen participants with intact nervous systems completed two laboratory visits, during which posterior root-muscle reflexes (PRMRs) were evoked via a 3 × 3 cathode matrix applied over the cervical spine. An incremental recruitment curve at the C7 vertebral level was initially performed to attain resting motor threshold (RMT) in each muscle. Paired pulses (1 ms square monophasic with inter-pulse interval of 50 ms) were subsequently delivered at a frequency of 0.25 Hz at two intensities (RMT and RMT + 20%) across all nine cathode positions. Evoked responses to the 1st (PRMR1) and 2nd (PRMR2) stimuli were recorded in four upper-limb muscles.
RESULTS: A significant effect of the spinal level was observed in all muscles for PRMR1, with greater responses being recorded caudally. Contralateral stimulation significantly increased PRMR1 in Biceps Brachii (p < 0.05, F = 4.9, η2 = 0.29), Flexor Carpi Radialis (p < 0.05, F = 4.9, η2 = 0.28) and Abductor Pollicis Brevis (p < 0.01, F = 8.9, η2 = 0.89). Post-activation depression (PAD) was also significantly increased with contralateral stimulation in Biceps Brachii (p = 0.001, F = 9.3, η2 = 0.44), Triceps Brachii (p < 0.05, F = 5.4, η2 = 0.31) and Flexor Carpi Radialis (p < 0.001, F = 17.4, η2 = 0.59).
CONCLUSIONS: A level of unilateral motor pool selectivity may be attained by altering stimulus intensity and location during cervical
tSCS. Optimising these parameters may improve the efficacy of this neuromodulation method in clinical cohorts.