Fitting of hearing aids with different technical parameters to a patient with dead regions

The purpose of the study was to determine an optimal hearing aid fitting procedure for a patient with well diagnosed high-frequency ‘dead regions’ in both cochleas. The patient reported non-symmetrical hearing problems of sensorineural origin. For binaural amplification two similar independent hearing aids were used as well as a pair of dependent devices with an ear-to-ear function. Two fitting methods were used: DSLi/o and NAL-NL1, and four different strategies of fitting were tested: the initial fitting based on the DSLi/o or NAL-NL1 method with necessary loudness corrections, the second fitting taking into account all the available functions of hearing instruments, the third fitting (based on the second one) but with significantly reduced amplification well above one octave of frequency inside dead region, and the final fitting with significantly reduced gain slightly below one octave inside dead regions. The results of hearing aids fitting were assessed using an APHAB procedure.