Shirley Ryan Ability Lab, Northwestern University, Chicago, IL 60611, United States of America; Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL 60611, United States of America.
Shirley Ryan Ability Lab, Northwestern University, Chicago, IL 60611, United States of America; Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL 60611, United States of America; Edward Hines, Jr. VA Hospital, Hines, IL 60141, United States of America.
Exp Neurol. 2021 Aug;342:113722. doi: 10.1016/j.expneurol.2021.113722. Epub 2021 Apr 28.
Spinal cord injuries (SCI) disrupt neural pathways between the brain and spinal cord, causing impairment of motor function and loss of independent mobility. Spontaneous plasticity in spared neural pathways improves function but is often insufficient to restore normal function. One unique approach to augment plasticity in spinal synaptic pathways is acute intermittent hypoxia (AIH), meaning brief exposure to mild bouts of low oxygen, interspersed with normoxia. While the administration of AIH elicits rapid plasticity and enhances volitional somatic motor output in the lower-limbs of people with incomplete SCI, it is not known if AIH-induced neuroplasticity is equally prevalent in spinal motor pathways regulating upper-extremity motor-function. In addition, how long the motor effects are retained following AIH has not yet been established. The goal of this research was to investigate changes in hand strength and upper-limb function elicited by episodic hypoxia, and to establish how long these effects were sustained in persons with incomplete cervical SCI. We conducted a randomized, blinded, placebo-controlled and cross-over design study consisting of a single AIH or sham AIH session in 14 individuals with chronic, incomplete cervical SCI. In a subset of six participants, we also performed a second protocol to determine the cumulative effects of repetitive AIH (i.e., two consecutive days). In both protocols, hand dynamometry and clinical performance tests were performed pre- and post-exposure. We found that a single AIH session enhanced bilateral grip and pinch strength, and that this effect peaked ~3 h post-intervention. The strength change was substantially higher after AIH versus sham AIH. These findings demonstrate the potential of AIH to improve upper-extremity function in persons with chronic SCI, although follow-up studies are needed to investigate optimal dosage and duration of effect.
脊髓损伤 (SCI) 破坏了大脑和脊髓之间的神经通路，导致运动功能受损和独立移动能力丧失。未受损神经通路中的自发可塑性会改善功能，但通常不足以恢复正常功能。增强脊髓突触通路可塑性的一种独特方法是急性间歇性低氧 (AIH)，即短暂暴露于轻度低氧，间歇性地与正常氧合交替。虽然 AIH 的给药会在不完全性 SCI 患者的下肢中引发快速的可塑性并增强随意躯体运动输出，但尚不清楚 AIH 诱导的神经可塑性在调节上肢运动功能的脊髓运动通路上是否同样普遍。此外，AIH 后运动效应能持续保留多长时间尚未确定。本研究的目的是研究间歇性低氧引起的手部力量和上肢功能变化，并确定其在不完全性颈髓 SCI 患者中的持续时间。我们进行了一项随机、双盲、安慰剂对照和交叉设计研究，该研究包括 14 名慢性、不完全性颈髓 SCI 患者的单次 AIH 或假 AIH 治疗。在 6 名参与者的亚组中，我们还进行了第二个方案，以确定重复 AIH（即连续两天）的累积效应。在这两个方案中，手部测力计和临床表现测试均在暴露前和暴露后进行。我们发现，单次 AIH 治疗可增强双侧握力和捏力，并且这种效应在干预后约 3 小时达到峰值。与假 AIH 相比，AIH 后的力量变化明显更高。这些发现表明 AIH 有可能改善慢性 SCI 患者的上肢功能，尽管需要进一步的研究来探讨最佳剂量和作用持续时间。
