Overview
The goal of this study is to investigate the suitability and effectiveness of the AirPod Pro 2nd generation (AP2) as hearing assistive technology for individuals with mild-to-moderate hearing loss when listening in noisy environments. Researchers will compare four types of assistive technology: hearing aids (HAs), AP2, dedicated wireless remote microphones, and Smartphone wireless remote microphone.
The main questions it aims to answer are:
- Which assistive technology provides the greatest benefit for speech recognition in noisy environments?
- How do these devices impact listening effort, as measured by reaction time in a dual-task activity and changes in pupil size?
- What are participants' preferences for each device based on how easy it is to understand speech and their overall satisfaction? Participants will visit the lab for a single 3-hour session. They will listen to sentences using each device and repeat what they hear. During this task, their reaction times for the secondary task and changes in pupil size will be measured.
Description
A total of 24 participants will be recruited from the Callier Center, local audiology offices, support groups, and senior centers and will first undergo a pure-tone hearing test in a sound booth. The preferred ear tip for the Airpod Pro 2nd generation (AP2) will be selected based on participant's comfort, ensuring it passes the ear tip fit test in the iPhone operating system. Similarly, the appropriate ear tip for the receiver-in-the canal Phonak Paradise hearing aid will be selected. The devices will be fit bilaterally and programmed for the individual's hearing loss using the smartphone or computer. Real-ear measurements will be then conducted with both the HAs and the AP2s to verify that their amplification reaches the The National Acoustic Laboratories non-linear version 2 (NAL-NL2) target level bilaterally (± 5 decibels) for the individual's degree of hearing loss, using Audioscan Verifit 2 (version 4.26.3).
The speech recognition threshold (SRT) at 70.7% will first be measured using the AP2 and a 2-down-1-up adaptive procedure, adjusting the signal-to-noise ratio (SNR) of babble noise using Hearing in Noise Test (HINT). The sentence will be presented at 65 dBA constant level from Knowles Electronics Manikin for Acoustic Research (KEMAR) with a mouth simulator positioned 1 meter at 0 degrees azimuth. The noise will be presented from the two speakers positioned 1 meter at 90- and 270-degrees azimuth. The participant must repeat the key words correctly. The SNR step size will initially be set to 4 dB for the first three reversals to enable rapid convergence, then reduced to 2 dB to refine the threshold measurement. This procedure will continue until six to eight reversals are obtained to ensure threshold stability. This approach will provide a reliable measurement of the SRT with the AP2 and allow enough range for improvements to comparison with other assistive technologies.
Next, the participants will complete a dual-task paradigm at the SNR that resulted in 70.7% performance with AP2, both without assistive technology and with technology including HA, AP2, dedicated wireless remote microphones (DRM), or Smartphone wireless remote microphone (SRM). The target speech will be presented through KEMAR with a mouth simulator positioned 1 meter at 0 degrees azimuth, with babble noise from two speakers positioned 1 meter at 90- and 270-degrees azimuth. The primary task will involve sentence recognition in babble noise using different AzBio sentence lists mentioned above. The secondary task will utilize a working memory task from PALETA (www.paleta.fob.usp.br). While listening to and repeating the AzBio sentence aloud, participants will simultaneously look at the screen, memorize, and click the sequence of colors. Listening effort will be measured by calculating the difference in response time (RT) for the secondary task between the dual-task condition (primary and secondary) and single-task (secondary only) condition.
Following this, the pupil diameter will be measured while participants repeat sentences presented, serving as an additional measure to more reliably assess listening effort under consistent same speaker, SRT and device settings. The AzBio sentence list (Spahr et al., 2012), consisting of 20 sentences, will be used with each assistive technology condition, totaling five sets. Pupil diameter will be captured using the Tobii Pro Lab Analyzer software (version 1.217, Tobii Technology AB, Stockholm, Sweden) positioned 1 meter in front of the participant. This measure will provide two key insights: listening effort and speech recognition ability. We will then compare listening effort and speech recognition with and without each assistive device to determine which assistive technology provides the greatest benefit for speech recognition and listening effort in noisy environments.
Finally, participants will complete a questionnaire to evaluate their experience with each assistive technology. During the pupillometry session, they will rate the difficulty of the sentence recognition task immediately after using each device. At the end of the session, participants will select their preferred assistive technology with the reason for their choice.
Eligibility
Inclusion Criteria:
- Adults aged 18 to 60 years.
- Native English speakers.
- Mild-to-moderate hearing loss confirmed by a pure-tone hearing test (average hearing threshold screening 25 to 55 dB HL across octave frequencies from 250 to 8000 Hz).
- Individuals with no prior hearing aid experience.
Exclusion Criteria:
- Normal hearing.
- Hearing loss worse than moderate.
- Neurological, psychiatric, or ophthalmological conditions that might alter the pupil response.
- Non-native English speakers.
- Individuals with prior hearing aid experience.