Performance of Dual-Microphone In-the-Ear Hearing Aids

Fifty subjects with mild to moderate-severe sensorineural hearing loss and prior experience with binaural amplification were evaluated at two sites (25 subjects at each site). Signal-to-noise ratios (SNRs) were measured using the Hearing in Noise Test (HINT) after each subject wore binaural in-the-ear hearing aids programmed for omnidirectional and dual-microphone performance, for 4 weeks. Both microphone conditions were evaluated under "ideal" (signal at 0°; noise at 180°) and "diffuse" (signal at 0°; correlated noise at 45°, 135°, 225°, and 315°) listening conditions. Results revealed statistically significant mean improvements in SNRs between 3.7 and 3.5 dB at Site I and 3.2 and 2.7 dB at Site II for the ideal and diffuse listening conditions, respectively, for the dual-microphones in comparison to the performance provided by the omnidirectional microphone. Abbreviations: Dl = directivity index, HINT = Hearing in Noise Test, NAL-R = National Acoustic Laboratory-Revised, REIG = real-ear insertion gain, SAV = select-a-vent, SC+aRT = super compression with adaptive release time