PP309 - Comparison of Over-the-Counter Hearing Aid Fitting Between Self-Fit and Professional-Fit

Abstract:
This study investigated the over-the-counter (OTC) hearing aid fitting differences (self- vs. professional-fit). 84 adults with mild-to-moderate SNHL participated; 20 in the self-fit feasibility study; 64 underwent fitting, wearing aids for one month, and outcome validation for comparisons. Results revealed significantly higher gain/outputs at 2000Hz and 4000Hz for the professional fit. Both groups had aided benefits for QuickSIN. Professional fit indicated relatively higher self-perceived aided benefits for APHAB and SSQ12. The thresholds were higher at 500Hz from the OTC-app compared to those from audiometer. Most of the threshold differences were within 10dB. More information was reported/discussed providing valuable insights for OTC fitting.

Summary:
To reduce the cost and increase the accessibility of hearing aids (HAs), over-the-counter (OTC) HAs have been approved to be fit for adults with mild to moderate hearing loss (HL) without the presence of a healthcare professional. Studies have been focused on the validation of self-fitting and found comparable aided benefits between self- and professional-fit on sound quality, preference, and speech intelligibility (e.g., De Sousa et al., 2023), although self-fit showed less effective (e.g., Humes et al., 2017). Studies also examined the hearing threshold accuracy from the OTC app and audiometer with inconsistent findings (e.g., Chen, et al., 2021; Keidser & Convery, 2016). No study has considered all fitting essentials in the comparison. This study followed the audiology best practice fitting process including comparisons on audiometric results and verification of HA operation, physical fit, and real ear measures, in addition to the validation of aided benefits between self- and professional-fit of OTC aids.

84 adults with a mild to moderate sensorineural HL completed this study. 20 participated in the human factor study from unboxing and fitting aids to turn off the aids, to verify the feasibility of self-fitting. The whole procedure was timed for further data analysis. Each participant also completed a self-identification questionnaire. 64 participated in the clinical study, randomly assigned into self-fit or professional-fit group (32 each). All underwent three stages: fitting, wearing aids for one month, and outcome validation. Quick Speech in Noise (QuickSIN), the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech, Spatial and Qualities of Hearing Scale (SSQ12) questionnaires were used to validate aided benefit. Real ear aided gain and output, hearing test results from OTC app and audiometer, and participant operation performance were also recorded for further comparison. Data collected were analyzed using Matlab and JMP pro.
    
Results revealed significantly higher gain/outputs at 2000Hz and 4000Hz for the professional-fit compared to the self-fit (p < .0001) and for those with higher technology level (p < .0001) and for those with HA history compared to those without HA (p=.03). Also, the gain/output increased with age (p=.001). Both groups had aided benefit for QuickSIN. The professional-fit had more benefit at MCL, whereas the self-fit had relatively more benefit at 70dB HL. Both groups indicated self-perceived aided benefit, more for professional-fit for all conditions for APHAB and SSQ12. There was no significantly statistical difference of the aided benefits across group, gender, hearing loss, technology level, HA history, although the young group perceived significantly more benefit than other groups for SSQ12 (p=.0025). The average threshold differences (OTC app vs. audiometer) were all withing 10dB. The thresholds were higher at 500Hz from the app compared to those from audiometer in soundbooth. Most of the threshold differences were within 10dB, with some exceptions of 15 to 35dB differences. More information regarding self-fit feasibility, HA operation, etc. will be reported/discussed.

Information obtained from this study provides valuable insights for OTC fitting, which will help both audiology professionals and patients achieve better rehabilitation outcomes.