ADAPTIVE FITTING OF HEARING INSTRUMENTS BY CATEGORY LOUDNESS SCALING (SCALADAPT)

The introduction of programmable as well as non-linear hearing instrum ents has shown that audiogram-based fitting procedures are inappropria te for meeting the individual needs of hearing aid users with sensorin eural loss. Particularly the present and Future development of hearing instruments with advanced analog and digital signal processing requir es suitable fitting procedures. In this context, we developed an adapt ive fitting strategy (ScalAdapt) using category loudness scaling. In t his paper the procedure is described and tested using programmable 3-c hannel AGC instruments. However, it can be modified for any other hear ing aid design. The underlying idea is to normalize the aided loudness perception for two input levels, one around the most comfortable leve l (MCL) and the other just below the uncomfortable level (UCL), as anc hor points in each channel by interactive fine-tuning of the fitting p arameters (channel gain, compression onset, compression ratio, etc.). The benefits of ScalAdapt have been evaluated by a field test study in 17 experienced hearing aid users. The results showed that ScalAdapt p rovides consistently higher objective (speech recognition in noise) an d subjective benefits (self-assessment inventory) than for instance NA L-based fittings.