title: The effect of multi-channel wide dynamic range compression, noise reduction, and the directional microphone on horizontal localization performance in hearing aid wearers.
abstract: This study examined the effect that signal processing strategies used in modern hearing aids, such as multi-channel WDRC, noise reduction, and directional microphones have on interaural difference cues and horizontal localization performance relative to linear, time-invariant amplification. Twelve participants were bilaterally fitted with BTE devices. Horizontal localization testing using a 360 degrees loudspeaker array and broadband pulsed pink noise was performed two weeks, and two months, post-fitting. The effect of noise reduction was measured with a constant noise present at 80 degrees azimuth. Data were analysed independently in the left/right and front/back dimension and showed that of the three signal processing strategies, directional microphones had the most significant effect on horizontal localization performance and over time. Specifically, a cardioid microphone could decrease front/back errors over time, whereas left/right errors increased when different microphones were fitted to left and right ears. Front/back confusions were generally prominent. Objective measurements of interaural differences on KEMAR explained significant shifts in left/right errors. In conclusion, there is scope for improving the sense of localization in hearing aid users.
authors.affiliation: National Acoustic Laboratories, Chatswood, NSW, Australia. gitte.keidser@nal.gov.au
authors.forename: Gitte
authors.initials: G
authors.lastname: Keidser
authors.forename: Kristin
authors.initials: K
authors.lastname: Rohrseitz
authors.forename: Harvey
authors.initials: H
authors.lastname: Dillon
authors.forename: Volkmar
authors.initials: V
authors.lastname: Hamacher
authors.forename: Lyndal
authors.initials: L
authors.lastname: Carter
authors.forename: Uwe
authors.initials: U
authors.lastname: Rass
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Convery
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006310:Hearing Aids; D006319:Hearing Loss, Sensorineural / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012044:Regression Analysis; D013017:Sound Localization; D013067:Speech Perception; D016896:Treatment Outcome