Two-point discrimination threshold as a function of frequency and polarity at fingertip by electrical stimulation

The effect of frequencies and current polarity of electrical stimulation to fingertip was investigated toward realizing electrocutaneous display. We measured the two-point discrimination threshold of electrical stimulation with 1.0 mm diameter electrodes spaced by 2.0 mm. The waveform pattern with the smallest two-point discrimination threshold was anode at frequencies from 200 to 400 Hz; most subjects could clearly discriminate the physical separation of 4 mm, some of them could discriminate 2 mm with optimized electrical stimulation.