Recent fitting strategies for nonlinear amplification

Recently, more hearing aids that incorporate nonlinear signal processing are being dispensed. Until recently, prescriptive formulas have not been available for audiologists to assess if the performance provided by hearing aids using nonlinear signal processing is appropriate for the hearing loss of the patient. In the past few years, several prescriptive formulae for nonlinear signal processing have been introduced. In this article, three of the newer prescriptive procedures for nonlinear signal processing (DSL [i/o], FlG6, and NAL-NL1) are reviewed. In addition, some of the recent research findings analyzing differences in performance provided by the DSL [i/o] and FlG6 procedures are reported. The NAL-NL1 procedure was only very recently introduced, and research on this prescriptive formula is not currently available.