PP1341 - The Impact of Various Beamformer Configurations on Listening Effort for Off-Axis Speech

The majority of the time, conversations happen in front of us.  But according to Walden et al. (2004) approximately 20% of the time, speech is on the side or behind us and we don’t want to or can’t move our head.  This is when an automatic program with steered beamforming is beneficial.  Ecological momentary assessment (EMA) apps can help gather data while participants are in the real-world.  In this poster a study comparing current and legacy beamformer settings and the impact on listening effort will be discussed as well as data from retrospective surveys from EMA. 

Summary:

The primary purpose of this investigation is to evaluate which microphone mode provided a lower perceived listening effort with speech from the side and the back in noisy situations with adults who have moderate to moderately severe hearing loss during a lab session using realistic overall noise levels and signal to noise ratios.  A secondary purpose was to gather qualitative data on listening effort and hearing aid satisfaction via daily retrospective surveys, as well as quantitative data on hearing handicap and aided speech intelligibility. 

Fourteen experienced hearing aid users from the Aurora, IL area with moderate to moderately severe hearing loss were assessed using two different hearing aids in the lab using AZ Bio sentences for the target speech.  A subjective listening effort questionnaire with a 10-point scale that includes some questions from the Speech, Spatial and Qualities of hearing Scale (SSQ; Gatehouse & Noble, 2004) was given after each condition.  The participants also indicated which device (i.e., beamformer) they preferred.  The speech intelligibility scores were also recorded. 

For speech from the side, the investigator compared a fixed directional microphone setting hearing aid to a narrow binaural directional microphone mode device.  For speech to the back, an omnidirectional microphone mode designed to restore the natural directivity pattern of the outer ear was compared to a narrow binaural directional microphone mode. 

During a two-week home trial, participants received daily retrospective surveys via the EMA app on the smartphone. 

In the lab, participants showed a significant improvement in overall listening effort with the steered beamformer, as well as a significant preference for the steered beamforming behavior over the static behavior.  Additionally, a total of 163 daily in-field surveys were returned from the two-week home trial, giving a daily assessment of their listening effort in noisy environments and their satisfaction with their hearing instruments throughout the day.  Surveys also captured open-ended feedback from participants (in written or voice-note format) to provide context for their categorical responses.  A plurality of daily responses (31%) report not experiencing noisy environments at all during the day, with the remaining responses distributed mostly over the low end of the categorical scale.  Participants were overwhelmingly satisfied with the instruments, with 90% of all daily surveys reporting satisfaction.

Results show that a steered beamformer offers benefits to listening effort and speech intelligibility in the lab environment, and EMA results overall show a high degree of satisfaction with hearing instruments using such a beamformer.  A wide range of subjective listening effort experienced by participants during daily life were reported with a preponderance of participants indicating not experiencing noisy situations at all during the day.  Results also show a high degree of satisfaction with hearing instruments, measured daily over a two-week period. 

In conclusion, the results of this investigation provides evidence to support that a hearing aid with steered beamforming provides a lower perceived listening effort when speech is from the side and back in a noisy environment compared to a hearing aid with a static beamformer.