An evaluation of several rationales for selecting hearing aid gain

The present study evaluates the rationales underlying several hearing aid selection procedures. The first portion of the evaluation confirms that the gain-selection rationales result in the selection of different hearing aids for a given patient. Nine different audiometric configurations representing varying degrees of flat, sloping, and rising sensorineural hearing loss were considered. The second phase of the evaluation considered how well each procedure achieved the goal of maximizing speech recognition. This analysis made use of the Articulation Index and was applied to each of the nine audiometric configurations. The results of this analysis suggested that, given the ability to adjust the overall gain over a typical range available through most volume controls, any of the procedures could produce optimal aided speech recognition performance. The final portion of the evaluation examined the ability of each procedure to prescribe absolute gain and relative gain (frequency response) that corresponded to that preferred by hearing aid wearers. The data for preferred insertion gain came from a recent investigation by Leijon, Eriksson-Mangold, and Beck-Karlsen (1984). The results of this evaluation suggested that some procedures prescribe gain values closer to those preferred by listeners than others. More data are needed on preferred gain values for a variety of configurations, however, before any one procedure can be recommended over another.