ESTRACE--1: a stethoscope for functional checking of electrostimulators and low cost body surface mapping system

In a project on the mapping of body surface potentials evoked by implanted spinal cord stimulators and transcutaneous electrostimulators, a simple device was developed for use in polyclinical practice for easy checking of the function of these stimulators. The device is an electrical stethoscope and consists of an instrumentation amplifier, bandpass filter, a distortion circuit and a headphone. In vivo measurements demonstrate the generation of an amplitude-dependent tone by the distortion circuit. The apparatus is in many aspects similar to a stethoscope: simple to understand and a practical tool for a fast Go/No-Go test. The device can be optionally connected with a PC and enables body surface mapping documentation within a few minutes.