Impacts of selected stimulation patterns on the perception threshold in electrocutaneous stimulation

Abstract

BackgroundConsistency is one of the most important concerns to convey stable artificially induced sensory feedback. However, the constancy of perceived sensations cannot be guaranteed, as the artificially evoked sensation is a function of the interaction of stimulation parameters. The hypothesis of this study is that the selected stimulation parameters in multi-electrode cutaneous stimulation have significant impacts on the perception threshold.MethodsThe investigated parameters included the stimulated location, the number of active electrodes, the number of pulses, and the interleaved time between a pair of electrodes. Biphasic, rectangular pulses were applied via five surface electrodes placed on the forearm of 12 healthy subjects.ResultsOur main findings were: 1) the perception thresholds at the five stimulated locations were significantly different (p < 0.0001), 2) dual-channel simultaneous stimulation lowered the perception thresholds and led to smaller variance in perception thresholds compared to single-channel stimulation, 3) the perception threshold was inversely related to the number of pulses, and 4) the perception threshold increased with increasing interleaved time when the interleaved time between two electrodes was below 500 μs.ConclusionsTo maintain a consistent perception threshold, our findings indicate that dual-channel simultaneous stimulation with at least five pulses should be used, and that the interleaved time between two electrodes should be longer than 500 μs. We believe that these findings have implications for design of reliable sensory feedback codes.

Sensory and Motor Thresholds of Transcutaneous Electrical Stimulation Are Influenced by Gender and Age

“…These findings are in accordance with a study that found significantly lower thresholds at 10 Hz compared to 75 Hz [3]. Nevertheless, another study [24] reported a sensory threshold inversely related to the frequency, a finding diverging from ours, although the sample assessed by the author was small. These results may be associated with a greater perception of painful stimuli in elderly subjects, since the frequency of 5 HZ excites the afferent fibers A‐δ and C, which convey low‐frequency stimuli, whereas afferent fibers A‐β convey higher frequencies.…”

Evaluation of sensation evoked by electrocutaneous stimulation on forearm in nondisabled subjects

“…A logarithmic relationship was found between the pulse number and the sensation magnitude. In the previous study on the effects of pulse number on PT, an inverse relationship was found between PT and the pulse number: PT = c + d/n [29]. This may imply that the PT is negatively related to the sensation magnitude in a nonlinear fashion.…”

Evaluation of sensitivity, motor and pain thresholds across the menstrual cycle through medium-frequency transcutaneous electrical nerve stimulation

“…Specifically, the shorter the phase duration, the greater the amplitude required to reach these thresholds (38,39). Our results showed that sensitivity increased in the premenstrual phase (P5) for all of the examined physical parameters.…”