The NAL-NL1 Non-linear Hearing Aid Fitting Procedure: Characteristics and Comparisons with Other Procedures Denis Byrne, Harvey
Dillon, Teresa Ching, Richard Katsch and Gitte Keidser The prescriptions of the NAL-NL1 non-linear hearing aid fitting procedure are illustrated for a sample of varied audiograms. These prescriptions are compared with those of the DSL [i/o], FIG6, and a threshold version of IHAFF procedures. For an average speech input level the NAL-NL1 prescriptions are very similar to those of the well-established NAL-RP procedure. Compared with the other procedures, NAL-NL1 prescribes less low-frequency gain for flat and upward sloping audiograms. It prescribes less high-frequency gain for steeply sloping high-frequency hearing losses and may indicate that amplification is of no value at some frequencies because they cannot contribute to speech intelligibility. NAL-NL1 tends to prescribe less compression than the other procedures. All procedures differ considerably from one another for some audiograms. |