Noise analysis of real-life listening situations for maximal speech audibility in hearing aid fitting.

This study attempts to prescribe hearing aid characteristics for one listening environment selected by an individual hearing aid user in order to provide better speech intelligibility than standard insertion gain prescriptions. The procedure is based on acoustic analyses of noise recorded by the user. The main purpose is to show the feasibility of the measurement and analysis procedure as a tool to investigate the consequences of the noise characteristics of everyday hearing aid use. The Speech Intelligibility Index (SII) is used as a criterion to optimize the insertion gain frequency response of the hearing aid. The results indicate that realistic background noise information is essential to achieve the best possible speech audibility. Maximizing the SII required higher insertion gain above 5000 Hz than assumed in conventional fitting procedures. Different insertion gain frequency responses are required for different listening conditions. The measurement procedure could identify acoustic listening conditions where hearing instruments would probably give no benefit.