Excitation characteristic of a bipolar stimulus for broadband stimulation in measurements of electrically evoked auditory potentials.

OBJECTIVE: The aim of this study was to determine the optimum electrical stimulation mode for the measurement of electrically evoked potentials. To quantify the broadband excitation electrically evoked compound action potentials were recorded in cochlear implant recipients. The full width half maximum was determined for spread of excitation along the electrode array.

DESIGN: Prospective clinical study.

STUDY SAMPLE: The study sample consisted of 20 adult cochlear implant users.

RESULTS: The applied alternating, intracochlear stimulation mode leads to neural excitation along approximately 80% of the length of the electrode array. The median of the full width at half maximum values covered the range of 18 electrodes on the implant array.

CONCLUSION: The bipolar, alternating, and intracochlear stimulation mode would provide a sufficient, broadband excitation of the spiral ganglion to measure electrically evoked auditory potentials.