Investigating the relationship between directional microphones, compression, and working memory in realistic spatial conditions

Project: Research project

Project Details


Hearing aids have specialized features to improve access to sounds for the hearing-impaired listener. Two such features available in most modern hearing aids are wide dynamic range compression (WDRC) and microphone directionality. During a routine hearing aid fitting, audiologists must prescribe settings for these features but the choice of the right settings is complicated due to potential interaction between these features. Further complicating the hearing aid fitting process are patient variables such as working memory capacity that may also affect the benefit from these features both in isolation and in combination. Currently, working memory capacity is not routinely measured in the clinic. But research has shown that low working memory capacity limits the benefits that can be gained from WDRC at low signal-to-noise ratios (SNR). One potential way to help individuals with low working memory capacity “unlock” the benefits of fast WDRC is to use directional microphones to improve SNRs. However, directional microphones may not be the best option in certain environmental conditions (e.g., speech arriving from multiple directions). The goal of this research is to help audiologists understand how to prescribe the appropriate directionality and WDRC settings for individuals with low working memory capacity faced with realistic speech and noise scenarios. Specific Aim 1 will characterize the effect of microphone directionality on benefit with WDRC across spatial conditions. Hearing-impaired listeners will identify speech in spatially separated noise. Wearable hearing aids will be used to change signal processing in two dimensions – WDRC speed and microphone directionality. Specific Aim 2 will determine the relationship between behavioral outcomes and acoustic signal fidelity metrics when microphone directionality is combined with WDRC. The proposed work is in alignment with the mission of NIDCD to conduct an support behavioral research and research training in interventions that substitute for lost/impaired sensory and communication function. The K01 award will enable the PI to build upon her existing research and clinical experience with hearing aids and provide structured training in the following areas: a) focused research on the impact of directional microphones on individual hearing aid outcomes in realistic spatial conditions, b) designing a clinical trial with wearable hearing aids, and c) advancing scientific communication skills. Research and training will take place at Northwestern University under the mentorship of Dr. Pamela Souza and Dr. Richard Freyman.
Effective start/end date12/1/1911/30/22


  • National Institute on Deafness and Other Communication Disorders (5K01DC018324-03)


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