Mesias Luis, Gormez M Akif, Tyler Dustin J, Makowski Nathaniel S, Graczyk Emily L, Fu Michael J
Human Fusions Institute, Case Western Reserve University (CWRU), Cleveland, OH, United States of America.
Department of Electrical, Computer, and Systems Engineering, CWRU, Cleveland, OH, United States of America.
J Neural Eng. 2023 Dec 21;20(6). doi: 10.1088/1741-2552/ad0563.
This study's objective is to understand distally-referred surface electrical nerve stimulation (DR-SENS) and evaluates the effects of electrode placement, polarity, and stimulation intensity on the location of elicited sensations in non-disabled individuals.A two-phased human experiment was used to characterize DR-SENS. In Experiment One, we explored 182 electrode combinations to identify a subset of electrode position combinations that would be most likely to elicit distally-referred sensations isolated to the index finger without discomfort. In Experiment Two, we further examined this subset of electrode combinations to determine the effect of stimulation intensity and electrode position on perceived sensation location. Stimulation thresholds were evaluated using parameter estimation by sequential testing and sensation locations were characterized using psychometric intensity tests.We found that electrode positions distal to the wrist can consistently evoke distally referred sensations with no significant polarity dependency. The finger-palm combination had the most occurrences of distal sensations, and the different variations of this combination did not have a significant effect on sensation location. Increasing stimulation intensity significantly expanded the area of the sensation, moved the most distal sensation distally, and moved the vertical centroid proximally. Also, a large anodic-leading electrode at the elbow mitigated all sensation at the anodic-leading electrode site while using symmetric stimulation waveforms. Furthermore, this study showed that the most intense sensation for a given percept can be distally referred. Lastly, for each participant, at least one of the finger-palm combinations evaluated in this study worked at both perception threshold and maximum comfortable stimulation intensities.These findings show that a non-invasive surface electrical stimulation charge modulated haptic interface can be used to elicit distally-referred sensations on non-disabled users. Furthermore, these results inform the design of novel haptic interfaces and other applications of surface electrical stimulation based haptic feedback on electrodes positioned distally from the wrist.
本研究的目的是了解远端传导性表面电神经刺激（DR-SENS），并评估电极放置、极性和刺激强度对非残疾个体诱发感觉位置的影响。采用两阶段人体实验来表征DR-SENS。在实验一中，我们探索了182种电极组合，以确定最有可能诱发仅局限于食指的远端传导性感觉且无不适感的电极位置组合子集。在实验二中，我们进一步研究了该电极组合子集，以确定刺激强度和电极位置对感觉位置感知的影响。使用序贯测试的参数估计来评估刺激阈值，并使用心理测量强度测试来表征感觉位置。我们发现，手腕远端的电极位置能够始终如一地诱发远端传导性感觉，且不存在显著的极性依赖性。指-掌组合诱发远端感觉的情况最多，并且该组合的不同变体对感觉位置没有显著影响。增加刺激强度会显著扩大感觉区域，使最远端的感觉向远端移动，并使垂直质心向近端移动。此外，在使用对称刺激波形时，肘部的大阳极引导电极可减轻阳极引导电极部位的所有感觉。此外，本研究表明，给定感知的最强烈感觉可以是远端传导性的。最后，对于每个参与者，本研究中评估的指-掌组合中至少有一个在感知阈值和最大舒适刺激强度下均有效。这些发现表明，一种非侵入性的表面电刺激电荷调制触觉接口可用于在非残疾用户身上诱发远端传导性感觉。此外，这些结果为新型触觉接口的设计以及基于手腕远端电极的表面电刺激触觉反馈的其他应用提供了参考。
