Abstract: An electrode array for use with a cochlear implant is disclosed, which has electrodes selectively spaced to better target selected regions of the cochlea. In one form, the spacing between adjacent electrodes decreases towards an apical end of the array allowing the electrodes to better target receptors on the inner wall of the scala timpani of the cochlea.

Abstract: There is provided a system for predicting the characteristic frequency of each electrode of an implanted cochlear electrode array from electrode position data contained in an image of the implanted cochlea. There is also provided a system for setting the frequency range to electrode map of a cochlear prosthesis.

Abstract: An evoked response audiometer for sleeping subjects comprising a function generator for supplying to a sleeping patient an auditory signal consisting of a carrier frequency which is periodically modulated at frequencies in excess of 60 Hz, the frequency of modulation being varied in a generally increasing manner for auditory signals of higher frequencies such that the stimulus is frequency specific, a detector for sampling and analyzing brain potentials evoked by said signal, a low-pass filter providing a time window which samples the brain potentials for a predetermined interval to provide sets of fourier analysis samples containing amplitude and phase data in narrow bands centered on the modulation frequency and its second harmonic, a computer for analyzing the Fourier analysis samples to extract means values of the amplitudes and phase angles of the signals, and for extracting from the means values of the phase angles the probabilities that the distributions of the phase angles could have occurred by chang