Accuracy of an Automated Hearing Aid Fitting Using Real Ear Measures Embedded in a Manufacturer Fitting Software

Abstract

Background Hearing aid fitting guidelines recommend real ear measures (REM) to verify hearing aid performance. Unfortunately, approximately 70 to 80% of clinicians do not use REM, but instead download manufacturer first-fit. Studies report differences in performance between first-fit and programmed-fit with greatest differences in the higher frequencies. Recently, hearing aid and real ear analyzer (REA) manufacturers allow REA communication with hearing aid software feature to automatically program hearing aids to target. Little research is available reporting the accuracy of this feature.

Purpose The aim of the study is to examine whether differences exist at 50, 65, and 80 dB SPL between two ReSound first-fit formulae (Audiogram+ and NAL-NL2) using ReSound AutoREM and Aurical NAL-NL2

Research Design The study design is of repeated measure type.

Study Sample The study sample includes 48 ears.

Data Collection and Analysis For the two fitting formulae, AutoREM real ear insertion gain (REIG) was measured at 50, 65, and 80 dB SPL and compared with measures from Aurical NAL-NL2.

Results Mean AutoREM REIG for ReSound NAL-NL2 was 3 to 8 dB below Aurical NAL-NL2 for 50 dB SPL, within 1 to 3 dB for 65 dB SPL and 1 to 5 dB above for 80 dB SPL. Mean AutoREM REIG for Audiogram + was 1 to 12 dB below Aurical NAL-NL2 for 50 dB SPL, within 2 to 5 dB for 65 dB SPL and 1 to 7 dB above NAL-NL2 for 80 dB SPL.

Conclusion Relative to the Aurical NAL-NL2, AutoREM REIG₅₀ for Audiogram + and ReSound NAL-NL2 was lower. Relative to the Aurical NAL-NL2, AutoREM REIG₆₅ for Audiogram + was higher at 1,000 Hz and lower at 4,000 to 6,000 Hz and for ReSound NAL-NL2 it was lower at 500 Hz and 4,000 Hz and higher at 3,000 Hz. Relative to the Aurical NAL-NL2, AutoREM REIG₈₀ for Audiogram + was higher at 500 to 3,000 Hz and 6,000 Hz and ReSound NAL-NL2 was higher at 500 to 6,000 Hz. Because of wide intersubject variability clinicians should continue to use REM as a “check and balance” when using AutoREM.

Keywords

AutoREM - real ear insertion gain - real ear measures

• References

• 1 ASHA Ad Hoc Committee on Hearing Aid Selection and Fitting. Guidelines for hearing aid fitting for adults. Am J Audiol 1998; 7 (01) 5-13
• 2 American Academy of Audiology. Guidelines for the audiologic management of adult hearing impairment. 2006 . Accessed January 12, 2021 at: http://audiology.org/resources/documentlibrary/documents/haguidelines.pdf
• 3 British Society of Audiology. Guidance on the use of real-ear measurements to verify the fitting of digital signal processing hearing aids. 2007 . Accessed January 12, 2021 at: http://www.thebsa.org.uk/wp-content/uploads/2014/04/REM.pdf
• 4 Consumer Reports. Hear well in a noisy world: hearing aids, hearing protection & more. Consum Rep 2009; 74 (07) 32-37
• 5 Mueller G, Picou E. Survey examines popularity of real-ear probe-microphone measures. Hear J 2010; 63 (05) 27-32
• 6 Keidser G, Dillon H, Carter L, O'Brien A. NAL-NL2 empirical adjustments. Trends Amplif 2012; 16 (04) 211-223
• 7 Boymans M, Dreschler WA. Audiologist-driven versus patient-driven fine tuning of hearing instruments. Trends Amplif 2012; 16 (01) 49-58
• 8 Leavitt R, Flexer C. The importance of audibility in successful amplification of hearing loss. Hear Rev 2012; 19 (13) 20-23
• 9 Abrams HB, Chisolm TH, McManus M, McArdle R. Initial-fit approach versus verified prescription: comparing self-perceived hearing aid benefit. J Am Acad Audiol 2012; 23 (10) 768-778
• 10 Sanders J, Stoody T, Weber J, Mueller HG. Manufacturers' NAL-NL2 fittings fail real-ear verification. Hear Rev 2015; 21 (03) 24-32
• 11 Munro KJ, Puri R, Bird J, Smith M. Using probe-microphone measurements to improve the match to target gain and frequency response slope, as a function of earmould style, frequency, and input level. Int J Audiol 2016; 55 (04) 215-223
• 12 Killion MC, Niquette PA, Gudmundsen GI, Revit LJ, Banerjee S. Development of a quick speech-in-noise test for measuring signal-to-noise ratio loss in normal-hearing and hearing-impaired listeners. J Acoust Soc Am 2004; 116 (4 Pt 1): 2395-2405
• 13 Byrne D, Dillon H. The National Acoustic Laboratories' (NAL) new procedure for selecting the gain and frequency response of a hearing aid. Ear Hear 1986; 7 (04) 257-265
• 14 Cox RM, Alexander GC. The abbreviated profile of hearing aid benefit. Ear Hear 1995; 16 (02) 176-186
• 15 Valente M, Oeding K, Brockmeyer A, Smith S, Kallogjeri D. Differences in word and phoneme in quiet, sentence recognition in noise and subjective outcomes between manufacturer first fit and hearing aids programmed to NAL-NL2. J Am Acad Audiol 2018; 29: 706-721
• 16 Baumann J, Powers T, Branda E. Validity, reliability and efficiency if the Signia autofit procedure. Hear Rev 2018; 25 (09) 26-30
• 17 Denys S, Matthias L, Francart T, Wouters J. A preliminary investigation into hearing aid fitting based on automated real-ear measurements integrated in the fitting software: test–retest reliability, matching accuracy and perceptual outcomes. Int J Audiol 2018; 58 (02) 1-9
• 18 Folkeard P, Pumford J, Abbasalipour P, Willis N, Scollie S. A comparison of automated real-ear and traditional hearing aid fitting methods. Hear Rev 2018; 25 (11) 28-32
• 19 Mueller G, Ricketts T. 20Q: Hearing aid verification-will AutoREM fit move the sticks?. 2018 . Accessed January 20, 2021 at: www.audiologyonline.com
• 20 Allen JB, Hall JL, Jeng PS. Loudness growth in 1/2-octave bands (LGOB)—a procedure for the assessment of loudness. J Acoust Soc Am 1990; 88 (02) 745-753
• 21 Holube I, Fredelake S, Vlaming M, Kollmeier B. Development and analysis of the international speech test signal (ISTS). Int J Audiol 2010; 49 (12) 891-903
• 22 Koehler E, Kulkarni S. Fast and easy fitting and verification with integrated real-ear measurement. Hear Rev 2014; 21 (10) 36-40