Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill and North Carolina State University, Raleigh, NC, United States of America.
J Neural Eng. 2018 Aug;15(4):046005. doi: 10.1088/1741-2552/aabd5d. Epub 2018 Apr 11.
Haptic perception of a prosthetic limb or hand is a crucial, but often unmet, need which impacts the utility of the prostheses. In this study, we seek to evaluate the feasibility of a non-invasive transcutaneous nerve stimulation method in generating haptic feedback in a transradial amputee subject as well as intact able-bodied subjects.
An electrode grid was placed on the skin along the medial side of the upper arm beneath the short head of the biceps brachii, in proximity to the median and ulnar nerves. Varying stimulation patterns were delivered to different electrode pairs, in order to emulate different types of sensations (Single Tap, Press-and-Hold, Double Tap) at different regions of the hand. Subjects then reported the magnitude of sensation by pressing on a force transducer to transform the qualitative haptic perception into a quantitative measurement.
Altering current stimulations through electrode pairs on the grid resulted in repeatable alterations in the percept regions of the hand. Most subjects reported spatial coverage of individual fingers or phalanges, which can resemble the whole hand through different pairs of stimulation electrodes. The different stimulation patterns were also differentiable by all subjects. The amputee subject also reported haptic sensations similar to the able-bodied subjects.
Our findings demonstrated the capabilities of our transcutaneous stimulation method. Subjects were able to perceive spatially distinct sensations with graded magnitudes that emulated tapping and holding sensation in their hands. The elicitation of haptic sensations in the phantom hand of an amputee is a significant step in the development of our stimulation method, and provides insight into the future adaptation and implementation of prostheses with non-invasive sensory feedback to the users.
假肢或手部的触觉感知是一个至关重要但经常未得到满足的需求，它会影响假肢的实用性。在这项研究中，我们试图评估一种非侵入性的经皮神经刺激方法在桡骨截肢受试者以及健全的受试者中产生触觉反馈的可行性。
在肱二头肌短头下方的上臂内侧皮肤放置一个电极网格，靠近正中神经和尺神经。通过向不同的电极对施加不同的刺激模式，模拟不同类型的感觉（单点触摸、按压保持、双击）在手部的不同区域。然后，受试者通过按压力传感器报告感觉的大小，将定性的触觉感知转化为定量测量。
通过网格上的电极对改变电流刺激会导致手部感知区域的可重复改变。大多数受试者报告了单个手指或指骨的空间覆盖范围，通过不同的刺激电极对可以模拟整个手。所有受试者也可以区分不同的刺激模式。截肢受试者也报告了类似于健全受试者的触觉感觉。
我们的发现证明了我们经皮刺激方法的能力。受试者能够感知到具有不同幅度的空间上不同的感觉，模拟手部的敲击和保持感觉。在截肢者的幻肢中诱发出触觉感觉是我们刺激方法发展的重要一步，并为未来向使用者提供非侵入性感觉反馈的假肢的适应和实施提供了深入了解。
