Probing the subjective response to a five-parameter electrocutaneous stimulus has revealed a noisy perceptual space. A method for reducing the noise is hypothesized and experimentally tested by comparing the intensity discrimination thresholds along and off the energy gradient. Preliminary results show a reduction of the threshold of up to 60% when stimulating along the gradient. The method is exploited to implement an optimal intensity control in an electrotactile vision-substitution device.