Poletto Christopher J, Van Doren Clayton L
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44109, USA.
IEEE Trans Biomed Eng. 2002 Oct;49(10):1221-4. doi: 10.1109/TBME.2002.803563.
Electrocutaneous stimulation is a potentially useful communication tool for applications in virtual reality, sensory substitution, and sensory augmentation. Many of these applications require the use of arrays of small electrodes. Stimulation through small electrodes is often painful, however, limiting the practicality of such arrays. The purpose of this study was to test a method for elevating the pain threshold to electrocutaneous stimulation through small (1-mm diameter) electrodes on the fingertip. We hypothesized that long, subthreshold, depolarizing prepulses (PP) would elevate the pain threshold so that a subsequent stimulus pulse (SP) would be less likely to be painful. We used psychophysical methods to measure the probability that an SP would be perceived as painful both by itself and when preceded by a PP that was 2, 4, 6, 8, or 10 dB lower in amplitude than the SP. We found that the PPs significantly increased the pain threshold, reducing the likelihood that the SP was painful (p < .0001). The dose effect of PP amplitude was also highly significant (p < .0001), with larger PPs elevating pain thresholds more. To our knowledge, this is the first report of PPs being used to elevate electrical stimulation thresholds in humans. PPs may be useful for selective inactivation of neural subpopulations in many human neuroprosthetic applications.
皮肤电刺激是一种在虚拟现实、感官替代和感官增强应用中可能有用的通信工具。这些应用中的许多都需要使用小型电极阵列。然而，通过小型电极进行刺激通常会很疼，这限制了此类阵列的实用性。本研究的目的是测试一种提高通过指尖上直径为1毫米的小型电极进行皮肤电刺激的疼痛阈值的方法。我们假设，长时、阈下、去极化预脉冲（PP）会提高疼痛阈值，从而使随后的刺激脉冲（SP）不太可能引起疼痛。我们使用心理物理学方法测量SP单独出现时以及在其之前出现幅度比SP低2、4、6、8或10分贝的PP时被感知为疼痛的概率。我们发现PP显著提高了疼痛阈值，降低了SP引起疼痛的可能性（p < .0001）。PP幅度的剂量效应也非常显著（p < .0001），更大的PP能更有效地提高疼痛阈值。据我们所知，这是关于PP用于提高人类电刺激阈值的首次报告。PP可能在许多人类神经假体应用中对选择性失活神经亚群有用。
