The effect of equating loudness on audibility-based hearing aid selection procedures.

Recently the articulation index (AI) has received a great deal of attention as a means to select hearing aid characteristics and to evaluate the merits of different hearing aid selection methods. These evaluations were based on the seldom modified assumption that the listening condition producing the largest AI is the best condition. The negative consequences of the differences in hearing aid conditions were seldom considered. In this paper it is shown that higher AIs are often achieved at the cost of substantially greater loudness. When gain adjustments are made to equate loudness across conditions, very different conclusions are reached about the relative merits of selection methods and the value of certain frequency-gain response modifications.