Speech intelligibility and hearing aid benefit in a living room: Comparison of real and simulated acoustics

For hearing-impaired patients, a disparity between hearing aid benefit determined by conventional audiological assessment and observed in everyday life has been reported. Hence, ecologically valid testing methods to better reflect performance in real-world scenarios are required. Hereby, the living room is a highly relevant (home) environment for speech communication involving various target and interfering sources. This study examines speech intelligibility in an average German living room with a connected kitchen and acoustic reproductions of the real room using loudspeakers. Speech recognition thresholds were measured using the Oldenburg Sentence Test (OLSA) and a male-transformed version of the ISTS (International Speech Test Signal) as a masker. Aided and unaided hearing-impaired listeners, as well as a normal-hearing control group, participated. Three target positions were investigated, with the most challenging target position in the adjacent kitchen with an obstructed direct sound path. Interactive room acoustics simulation (allowing for head movements) was used to replicate the living room via a small-scale (four) loudspeaker array, as applicable in the clinical environment, and a large-scale, three-dimensional array with 86 loudspeakers. The study discusses the impact of room acoustics on speech intelligibility at different target positions and the relationship between real and simulated environments regarding hearing aid benefit.