Reflex responses generated by cutaneous mechanoreceptors of the plantar foot are important for the maintenance of balance during postural tasks and gait. With aging, reflex generation, particularly from fast adapting type I receptors, is reduced, which likely contributes to impaired postural stability in this population. Therefore, improving reflex generation from these receptors may serve as a tool to improve balance performance. A mechanism to enhance reflexes may lie in the phenomenon of stochastic resonance, whereby the addition of certain intensities and frequencies of noise stimuli improves the performance of a system. This study was conducted to determine whether tactile noise stimuli could improve cutaneous reflex generation. In 12 healthy young adults, we evoked cutaneous reflex responses using a 0–50 Hz Gaussian noise vibration applied to the plantar heel. Concurrently, we applied one of six subthreshold intensities of electrical tactile noise to the plantar heel [0%, 20%, 40%, 60%, 80% or 100% (threshold)] and were able to analyze data from 0%, 20% and 40% trials. Across participants, it was found that the addition of a 20% perceptual threshold (PT) noise resulted in enhanced reflex responses when analyzed in both the time and frequency domains. These data provide evidence that cutaneous reflex generation can be enhanced via a stochastic resonance effect and that 20% PT is the optimal intensity of noise to do so. Therefore, the addition of noise stimuli may be a valuable clinical intervention to improve reflex responses associated with postural balance in populations with impairments.

中文翻译：

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应用于足底的阈下电噪声可增强下肢皮肤反射的产生

足底的皮肤机械感受器产生的反射反应对于在姿势任务和步态过程中保持平衡很重要。随着年龄的增长，反射的产生，特别是来自快速适应的 I 型受体的反射减少，这可能导致该人群的姿势稳定性受损。因此，改善这些受体的反射生成可以作为提高平衡性能的工具。增强反射的机制可能存在于随机共振现象中，由此增加某些强度和频率的噪声刺激可以提高系统的性能。进行这项研究是为了确定触觉噪声刺激是否可以改善皮肤反射的产生。在 12 名健康的年轻人中，我们使用应用于足底跟的 0-50 Hz 高斯噪声振动引起皮肤反射反应。同时，我们将六个亚阈值电触觉噪声强度之一应用于足跟 [0%、20%、40%、60%、80% 或 100%（阈值）]，并能够分析来自 0%、20 % 和 40% 试验。在所有参与者中，发现在时域和频域中进行分析时，增加 20% 的感知阈值 (PT) 噪声会导致反射反应增强。这些数据提供的证据表明，可以通过随机共振效应增强皮肤反射的产生，并且 20% PT 是这样做的最佳噪声强度。因此，添加噪声刺激可能是一种有价值的临床干预措施，可改善与受损人群姿势平衡相关的反射反应。