A New Hearing Aid Fitting Strategy for Severe to Profound Hearing Loss

A new fitting strategy for severe to profound hearing loss is proposed. This fitting strategy is based on the Cambridge Formula for multichannel compression [2]. The formula has been modified so that it takes into account that amplification may not support or even hamper hearing at certain frequencies. The new fitting strategy was evaluated by aided speech intelligibility tests. For 35 subjects, the new fitting strategy was compared with the subjects' own hearing aids through speech intelligibility tests. The same tests were performed with 20 ears of severe hearing-impaired test subjects outside of a clinical setting. For these ears, the new fitting strategy was compared with NAL-NL 1 implemented on the same dynamic compression algorithm and with own hearing aids. The new fitting strategy performs well for the profound hearing impaired. For the severe hearing impaired, however, no improvement could be found. Some shortcomings of the new fitting strategy have been identified and improvements are suggested.