Li Suzhou, Triolo Ronald J, Charkhkar Hamid
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States.
Louis Stokes Cleveland Veteran Affairs Medical Center, Cleveland, OH, United States.
Front Neurosci. 2023 Sep 25;17:1276308. doi: 10.3389/fnins.2023.1276308. eCollection 2023.
Individuals with lower limb loss experience an increased risk of falls partly due to the lack of sensory feedback from their missing foot. It is possible to restore plantar sensation perceived as originating from the missing foot by directly interfacing with the peripheral nerves remaining in the residual limb, which in turn has shown promise in improving gait and balance. However, it is yet unclear how these electrically elicited plantar sensation are integrated into the body's natural sensorimotor control reflexes. Historically, the H-reflex has been used as a model for investigating sensorimotor control. Within the spinal cord, an array of inputs, including plantar cutaneous sensation, are integrated to produce inhibitory and excitatory effects on the H-reflex.
In this study, we characterized the interplay between electrically elicited plantar sensations and this intrinsic reflex mechanism. Participants adopted postures mimicking specific phases of the gait cycle. During each posture, we electrically elicited plantar sensation, and subsequently the H-reflex was evoked both in the presence and absence of these sensations.
Our findings indicated that electrically elicited plantar sensations did not significantly alter the H-reflex excitability across any of the adopted postures.
This suggests that individuals with lower limb loss can directly benefit from electrically elicited plantar sensation during walking without disrupting the existing sensory signaling pathways that modulate reflex responses.
下肢缺失者跌倒风险增加，部分原因是缺失的足部缺乏感觉反馈。通过直接与残肢中残留的周围神经连接，可以恢复被感知为源自缺失足部的足底感觉，这反过来已显示出改善步态和平衡的前景。然而，目前尚不清楚这些电诱发的足底感觉是如何整合到身体的自然感觉运动控制反射中的。历史上，H反射一直被用作研究感觉运动控制的模型。在脊髓内，一系列输入，包括足底皮肤感觉，被整合以对H反射产生抑制和兴奋作用。
在本研究中，我们描述了电诱发的足底感觉与这种内在反射机制之间的相互作用。参与者采用模仿步态周期特定阶段的姿势。在每个姿势期间，我们电诱发足底感觉，随后在有和没有这些感觉的情况下诱发H反射。
我们的研究结果表明，在任何采用的姿势中，电诱发的足底感觉都不会显著改变H反射兴奋性。
这表明下肢缺失者在行走过程中可以直接从电诱发的足底感觉中受益，而不会破坏调节反射反应的现有感觉信号通路。
