Stability of low-frequency residual hearing in patients who are candidates for combined acoustic plus electric hearing.

The purpose of this study was to investigate the stability over time of low-frequency auditory thresholds to better determine if the new technique of using a short-electrode cochlear implant that preserves residual low-frequency acoustic hearing can be a long-term solution for those with severe-to-profound hearing loss at high frequencies. The present study determined the long-term rate of decline in acoustic hearing in patients who have a preexisting hearing loss yet have not been implanted with a cochlear implant. A retrospective analysis of patients' audiograms that fit into the range for candidacy for the short-electrode device was performed to calculate the rate of change of threshold over time. The analysis of adult patients' data indicated that there was an average of only 1.05 dB hearing deterioration per year in the low frequencies and that presbycusis accounted for approximately one third to one half of this decline. The average deterioration of hearing threshold for pediatric patients was 1.2 dB per year; however, the rates of change in pediatric patients were considerably more variable (across individuals and across frequencies) than in adults. These data provide support for the idea that the short-electrode cochlear implant may be a practical solution for most adults in the long run, but this may not be the case for all pediatric patients.