Evaluating sound localization cues for premium hearing aids across multiple manufacturers

Modern hearing aids employ complex signal processing to improve signal-to-noise ratios for people with impaired hearing. Some of this processing, however, can reduce interaural level differences (ILD), which could reduce sound localization abilities and thus interfere with communication in complex acoustic scenes. It has been speculated that interaural time differences (ITD) are also distorted by amplification, perhaps due to even very brief signal processing delays or multi-path acoustics. Previously we found little ITD distortion for a single set of hearing aids, except when “strong” directional microphones were enabled. To extend and replicate these results, premium hearing aids from four major manufacturers were compared. Aids were set to low-gain amplification and a range of different signal processing algorithms were systematically activated in a manner consistent with clinical practice. Binaural acoustical recordings were measured using an acoustic manikin on which the hearing aids were attached as...