Research Article

The comparison of changes in hearing thresholds and insertion losses due to occlusion induced by ear impression in sound field assessment

Abstract

Background and Aim: The methods of determining the amount of sound attenuation by ear mold, earplug or any other foreign body that placed in or out of the ear canal, is divided in subjective and objective. Due to the contradictory results in the studies in this field, this study aimed to use more audiometric frequencies considering the strengths and weaknesses of previous studies.
Methods: This study was conducted on 30 individuals with normal hearing in the age range of 21-26-year-old. First the impression mold was prepared from both ears. The evaluating real ear unaided response and the real ear occluded response. In the next step, hearing thresholds were assessed by sound field with a precision of 1 dB, once in both open ear and once in both closed ears. Finally, the insertion loss due to mold placement at each frequency was compared with the amount of behavioral threshold changes at the same frequency.
Results: By using paired t-test at frequencies of 400, 500, 800, 1000, 1500, 1600, 2000, 2500, 3000, 4000, 5000, 6000, 6300 and 8000 Hz, the difference in behavioral hearing thresholds with and without molding was greater than the amount of the insertion loss (p < 0.001).
Conclusion: The insertion loss due to impression for behavioral assessment at all of the tested frequencies were more than the attenuation in real ear evaluation (p < 0.001). In this regard, consequently the standard deviation of insertion loss due to impression in behavioral threshold condition was more than real ear measurement.

1. Nelisse H, Cocq CL, Boutin J, Voix J, Laville F, editors. Comparison of subjective and objective methods for the measurements of hearing protector devices attenuation and occlusion effect. Acoustical Society of America; 2013 2 - 7 June; Montreal, Canada.
2. Biabani A, Golmohammadi R, Aliabadi M. [Study of noise reduction rate of hearing protection devices based on microphone in real ear (MIRE) under laboratory conditions]. J Ergo. 2016;4(2):17-25. Persian. doi: 10.21859/joe-040249
3. Biabani A, Golmohammadi R, Aliabadi M. [Study of the performance of acoustic fixture for using in noise reduction rate tests of hearing protection devices]. J Occup Hyg. 2016;3(1):60-6. Persian. doi: 10.21859/johe-03018.
4. Kusy A, Châtillon J. Real-world attenuation of custom-moulded earplugs: Results from industrial in situ F-MIRE measurements. Appl Acoust. 2012;73(6-7):639-47. doi: 10.1016/j.apacoust.2012.02.001
5. Kabe I, Kochi T, Tsuruoka H, Tonegawa T, Denda I, Nonogi M, et al. Noise attenuation of earplugs as measured by hREAT and F-MIRE methods in a Japa¬nese metal manufacturing plant. J Occup Health. 2012;54(4):310-5. doi: 10.1539/joh.11-0217-fs
6. Neitzel R, Somers S, Seixas N. Variability of real-world hearing protector attenuation measurements. Ann Occup Hyg. 2006;50(7):679-91. doi: 10.1093/annhyg/mel025
7. Berger EH, editor Preferred Methods for Measuring Hearing Protector Attenuation. International Congress on Noise Control Engineering 2005 (INTERNOISE 2005); 2005 07-10 August; Rio de Janeiro- Brazil: Enviromental Noise Control.
8. Berger EH. Methods of measuring the attenuation of hearing protection devices. J Acoust Soc Am. 1986;79(6):1655-87. doi: 10.1121/1.393228
9. Berger EH, Kerivan JE. Influence of physiological noise and the occlusion effect on the measurement of real-ear attenuation at threshold. J Acoust Soc Am. 1983;74(1):81-94. doi: 10.1121/1.389621
10. Berger EH, Franks JR, Lindgren F. International review of field studies of hearing protector attenuation. In: Axelsson A, Borchgrevink HM, Hamernik RP, Hellstrom P, Henderson D, Salvi RJ, editors. Scientific basis of noise-induced hearing loss. New York: Thieme Medical Publishers; 1996. p. 361-77.
11. Zera J, Mlynski R, editors. Determination of earmuff transmittance with the use of MIRE technique and with artificial test fixtures. 20th International Congress on Acoustics ICA; 2010 August; Sydney, Australia.
12. Casali J, Mauney D, Burks JA. Physical vs. psychophysical measurement of hearing protector attenuation—a.k.a. MIRE vs. REAT. Sound Vibrat. 1995;29:20-7.
13. Searchfield GD, Purdy SC. Probe microphone placement for real ear measurement. Am J Audiol. 1997;6(2):49-54. doi: 10.1044/1059-0889.0602.49
14. Frye G. Real ear measures. In: Metz MJ, editor. Sandlin's textbook of hearing aid amplification: technical and clinical considerations. 3rd ed. San Diego: Plural Publishing, Inc; 2014. p. 519-42.
Files
IssueVol 29 No 2 (2020) QRcode
SectionResearch Article(s)
DOI https://doi.org/10.18502/avr.v29i2.2788
Keywords
Sound field assessment; insertion loss; real ear occluded response; ear impression; probe microphone measurement; real ear measurement
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Creative Commons License This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
How to Cite
1.
Hosseini SH, Rahbar N, Sameni SJ. The comparison of changes in hearing thresholds and insertion losses due to occlusion induced by ear impression in sound field assessment. Aud Vestib Res. 2020;29(2):76-84.