Clin Exp Otorhinolaryngol.  2022 May;15(2):135-143. 10.21053/ceo.2021.01004.

Electroacoustic Evaluation of Smartphone-Based Hearing Aid Applications

• Nguyen W
• Koo M
• Lee JH
• Oh SH
• Park MK

• KMID: 2530159
• DOI: http://doi.org/10.21053/ceo.2021.01004

Abstract

Objectives
. This study evaluated the electroacoustic characteristics of smartphone-based hearing aid applications (apps).
Methods
. We investigated hearing aid apps based on processing delay measurements, hearing instrument testing, simulated real ear measurements, and a head-and-torso simulator.
Results
. Many apps exceeded the recommended level for processing delay. Hearing instrument testing showed the highest amplification characteristics and the best sound quality when a hearing aid was used, followed by the high-end apps and then the low-end apps. The simulated real ear measurements results showed that the high-end apps had a better ability to match the amplification targets than the low-end apps, but there was no consistent pattern among apps when controlling the output. Only a few apps could improve the signal-to-noise ratio in the head-and-torso simulator.
Conclusion
. Most of the apps showed relatively poor electroacoustic performance in comparison with hearing aids. Generalizing access to hearing care through hearing aid apps induces a wide diversity of hearing performance with no fixed standard for reliability. However, we expect their overall quality to improve over the next few years.

Keyword

Hearing Aid Apps; Smartphone; Electroacoustic; Hearing Aids; Hearing Disability

Figure

• 

  Fig. 1. Flowchart of the applications (apps) selection method.

• 

  Fig. 2. Processing delays of the 14 hearing aid applications (apps) according to their operating system (Android and iOS).

• 

  Fig. 3. Maximum OSPL90 values of 14 hearing aid apps and a hearing aid (Siya 1). OSPL, output sound pressure level; app, application.

• 

  Fig. 4. HFA OSPL90 values of 14 hearing aid apps and a hearing aid (Siya 1). HFA, high-frequency average; OSPL, output sound pressure level; app, application.

• 

  Fig. 5. HFA FOG values of the 14 hearing aid apps and a hearing aid (Siya 1). HFA, high-frequency average; FOG, full on gain; app, application.

Reference

1. American National Standards Institute. Specification of hearing aid characteristics. United States patent. ANSI S3. 22-1987. 1987 Jun 2.

2. American National Standards Institute. Specification of hearing aid characteristics. United States patent. ANSI S3. 22-2003. 2003 Aug 28.

3. IEC. Electroacoustics-hearing aid. Part 7: measurement of the performance characteristics of hearing aids for production, supply and delivery quality assurance purposes. IEC 60118-7:2005. Ed 2.0. Geneva: IEC;2005.

4. Callaway SL, Punch JL. An electroacoustic analysis of over-the-counter hearing aids. Am J Audiol. 2008; Jun. 17(1):14–24.

5. Amlani AM, Taylor B, Levy C, Robbins R. Utility of smartphone-based hearing aid applications as a substitute to traditional hearing aids. Hear Rev. 2013; 20(13):16–8.

6. Medwetsky L, Kelly K, Bakke M. Earphone models for iPhones: surprising results when used with a hearing app. Hearing Review. 2020.

7. De Sousa KC, Moore DR, Motlagh-Zadeh L, Myburgh HC, Swanepoel DW. Do smartphone hearing aid apps work. Hear J. 2019; Nov. 72(11):34–7.

8. Stone MA, Moore BC. Tolerable hearing aid delays. I. Estimation of limits imposed by the auditory path alone using simulated hearing losses. Ear Hear. 1999; Jun. 20(3):182–92.

9. Voss A, Oeding K, Bankaitis AU, Pumford J, Valente M. Coupler and real-ear performance between PSAPs and hearing aids. Hear Rev. 2018; 25(11):10–8.

10. Holube I, Fredelake S, Vlaming M, Kollmeier B. Development and analysis of an International Speech Test Signal (ISTS). Int J Audiol. 2010; Dec. 49(12):891–903.

11. British Society of Audiology. Guidance on the use of real ear measurement (REM) to verify the fitting of digital signal processing hearing aids 2007 [Internet]. Seafield: British Society of Audiology;2007 [citied 2021 Sep 6]. Available from: https://www.thebsa.org.uk/resources/guidance-use-real-ear-measurement-verify-fitting-digital-signal-processing-hearing-aids/.

12. Heurig R, Chalupper J. Acceptable processing delay in digital hearing aids. Hear Rev. 2010; 17(1):28–31.

13. Stone MA, Moore BC, Meisenbacher K, Derleth RP. Tolerable hearing aid delays. V. Estimation of limits for open canal fittings. Ear Hear. 2008; Aug. 29(4):601–17.

14. van Buuren RA, Festen JM, Houtgast T. Peaks in the frequency response of hearing aids: evaluation of the effects on speech intelligibility and sound quality. J Speech Hear Res. 1996; Apr. 39(2):239–50.

15. Agnew J. The causes and effects of distortion and internal noise in hearing AIDS. Trends Amplif. 1998; Sep. 3(3):82–118.

16. Thompson SC. Internal noise in hearing aid microphones: its causes and consequences. Hear J. 2003; Oct. 56(10):46–7.

17. Kuk FK, Paludan-Muller C. Noise-management algorithm may improve speech intelligibility in noise. Hear J. 2006; Apr. 59(4):62.