Using Microphone Technology to Improve Speech Perception in Noise in Children with Cochlear Implants

Abstract

Cochlear implant (CI) users are affected more than their normal hearing (NH) peers by the negative consequences of background noise on speech understanding. Research has shown that adult CI users can improve their speech recognition in challenging listening environments by using dual-microphone beamformers, such as adaptive directional microphones (ADMs) and wireless remote microphones (RMs). The suitability of these microphone technologies for use in children with CIs is not well-understood nor widely accepted.To assess the benefit of ADM or RM technology on speech perception in background noise in children and adolescents with cochlear implants (CIs) with no previous or current use of ADM or RM.Mixed, repeated measures design.Twenty (20) children, ten (10) CI users (mean age 14.3 yrs) who used Advanced Bionics HiRes90K implants with research Naida processors, and ten (10) NH age-matched controls participated in this prospective study.CI users listened with an ear-canal level microphone, T-Mic (TM), an ADM, and a wireless RM at different audio-mixing ratios. Speech understanding with five microphone settings (TM 100%, ADM, RM + TM 50/50, RM + TM 75/25, RM 100%) was evaluated in quiet and in noise.Speech perception ability was measured using children’s spondee words to obtain a speech recognition threshold for 80% accuracy (SRT80%) in 20-talker babble where the listener sat in a sound booth 1 m (3.28′) from the target speech (front) and noise (behind) to test five microphone settings (TM 100%, ADM, RM + TM 50/50, RM + TM 75/25, RM 100%). Group performance-intensity functions were computed for each listening condition to show the effects of microphone configuration with respect to signal-to-noise ratio (SNR). A difference score (CI Group minus NH Group) was computed to show the effect of microphone technology at different SNRs relative to NH. Statistical analysis using a repeated-measures analysis of variance evaluated the effects of the microphone configurations on SRT80% and performance at SNRs. Between-groups analysis of variance was used to compare the CI group with the NH group.The speech recognition was significantly poorer for children with CI than children with NH in quiet and in noise when using the TM alone. Adding the ADM or RM provided a significant improvement in speech recognition for the CI group over use of the TM alone in noise (mean dB advantage ranged from 5.8 for ADM to 16 for RM100). When children with CI used the RM75 or RM100 in background babble, speech recognition was not statistically different from the group with NH.Speech recognition in noise performance improved with the use of ADM and RM100 or RM75 over TM-only for children with CIs. Alhough children with CI remain at a disadvantage as compared with NH children in quiet and more favorable SNRs, microphone technology can enhance performance for some children with CI to match that of NH peers in contexts with negative SNRs.

Application of Digital Remote Wireless Microphone Technology in Single-Sided Deaf Cochlear Implant Recipients

“…The accessory mixing ratio controls the relative strength of the input signals from the audio accessory and the hearing device microphone(s). Johnstone et al (2018) 12 measured speech recognition in quiet and noise in bilaterally hearingimpaired pediatric CI recipients (mean age 14 years) using the T-Mic™, the adaptive directional microphone (ADM) Ultrazoom as well as the omnidirectional remote microphone (Pho-nak RemoteMic). Speech recognition significantly improved with the application of both ADM and remote microphone in quiet and noise compared with T-Mic™T-Mic™?A3B2 ek?> alone.…”

“…Speech recognition significantly improved with the application of both ADM and remote microphone in quiet and noise compared with T-Mic™T-Mic™?A3B2 ek?> alone. Even though there was a benefit with ADM and remote microphone, the CI children performed poorer than the NH children (Johnstone et al, 2018 12 ). Wolfe and Schafer (2008) 31 assessed the influence of the mixing ratio on speech recognition in noise in bilaterally hearing-impaired unilateral CI users.…”

Remote Microphone Systems for Cochlear Implant Recipients in Small Group Settings

“…[1][2][3][4] Remote microphone technologies, with one microphone to capture the talker of interest and deliver it wirelessly to the CI recipient's sound processor, are the most effective means to improve CI recipients' speech recognition in noise. 3,[5][6][7] In previous speech recognition studies with commonly-encountered SNRs (0 to þ10 dB SNR), using remote microphone systems improved speech recognition by 30 to 60 percentage points relative to the CI alone. 3,4,[8][9][10][11] Given the single microphone, traditional remote microphone systems are not ideal in small group settings with multiple talkers of interest.…”

Why do many children who are hard of hearing not use remote microphones to compensate for their hearing loss?

“…Remote microphones (RM) are wireless technologies used as assistive devices for children who are hard of hearing (HoH). They were originally developed to limit the negative effects of noise on understanding speech for hearing-aid users in challenging listening environments, and they are now also compatible with cochlear implants [ 6 ].…”