Measurement of electrode current pulses from cochlear implants

The experimental setup for the measurement of the current pulses generated at the different electrodes of a cochlear implant is presented. The electrical stimuli were modulated by ad hoc software, transferred through a custom-made cochlear-implant programming interface to the speech processor, encoded as radio frequency (RF) signals, delivered via coil to the implant receiver/stimulator, and hence sent as current pulses to the electrode array of the implant. In the measurement procedure, each electrode of the implant array is connected to an external port, and the current waveform at any single electrode can be measured by a probe and a digital oscilloscope. It was shown that the nucleus cochlear implant delivers current pulses according to specifications with emulated clinical load resistances within the physiological range.