Effects of Untrained Earmold Impression Taking on Custom Hearing Protector Device Performance

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1 Effects of Untrained Earmold Impression Taking on Custom Hearing Protector Device Performance Melinda F. Bryan, Ph.D., CCC-A Louisiana Tech University, Ruston, LA Kelly Pack, Au.D., CCC-A Professional Hearing Services, Texarkana, TX

2 A Note of Thanks I would like to thank Westone for their support in this project, including assessment and production of the earmold impressions and financial support for this project.

3 Introduction Custom made hearing protection devices (HPDs) are currently available for purchase through the internet. Impression is made by the consumer, and sent in via mail service to be cast into custom HPD.

4 Importance of this Research Internet accessibility is reaching an all time high: 74% of American adults report having access to and using the internet (Rainie, 2010). 75%-80% of internet users report using the internet to research healthcare information (Fox, 2008). In 2007 research estimated 49% of American adults had made one or more online purchases, a 27% increase from 2000 (Horrigan, 2008) online purchases were $127 billion dollars (U.S. Census Bureau, 2010).

5 Importance for this Research Any reduction in attenuation could leave the HPD user vulnerable to the damaging effects of noise. Currently no research exists on the efficacy of custom HPDs made from do-it-yourself impression kits. Currently no law preventing impressions from being taken by untrained impression takers.

6 Review of Literature Effects of Noise on Hearing: Significant change in outer hair cell emission can occur in a short exposure to impulse noise (Olszewski, Miłoński, Sułkowski, Majak, and Olszewski, 2005). Permanent loss in hearing acuity has been shown from exposure to gun blast impulse noise (Balatsouras, Homisoglou, & Danielidis, 2005). Permanent cochlear damage could happen at a moderate level of steady-state noise in a relatively short amount of time (Sliwinska- Kowalska and Jedlinska, 1998). Permanent damage can happen in short exposure times.

7 Review of Literature Impression Techniques and Impact on Attenuation: Impressions must reach the 2 nd bend of the ear canal to create a good seal and create an effective HPD (Pirzanski & Berge, 2005). Movement of the jaw during impression taking may negatively effect the effectiveness of HPD (Pirzanski, Chasin, Klenk, Maye & Purdy, 2000). Impression material that does not sufficiently expand the ear canal in the area of the second bend may not produce an effective seal (Pirzanski & Berge, 2005).

8 Review of Literature Kimball (2008) DIY Impression Taking Earmold impressions were taken by untrained impression takers. Impressions were sent to two different earmold laboratories to be evaluate and graded. Grading was based on criteria that these labs have previously evaluated as important for effective HPD earmolds. On a Scale of 1 to 5, 80% of untrained earmold impressions were under 3; 50% were under 2. Indicating earmold impressions taken by untrained earmold impression takers may not be able to provide the necessary attributes needed to create an effective HPD.

9 Purpose To compare the performance of HPDs produced from do-it-yourself earmold impressions to HPD performance made from impressions taken by trained professionals. Real Ear Measures Occluded Threshold Measures Assessment of Impressions

10 Methods and Procedures Participants: Research Group 10 individuals Criteria for candidacy include: - age 18 years or older - no prior training in methods of taking earmold impressions. Control Group 3 licensed audiologists - Criteria for candidacy include: - age 18 or older, - previous formal training in creating earmold impressions, and - an active, licensed audiologist.

11 Methods and Procedures Research Group Safety Self report patient history screened for contraindications. - Pain, tenderness or recent drainage - HIV/ diabetes Otoscopic exam by licensed Audiologist for contraindications prior to impression taking. - Excessive cerumen - Abrasions - Unhealthy appearing ear canals or tympanic membranes Visual evaluation of otoblock placement by a licensed Audiologist to determine safety of amateur impression taking. *Best case scenario not like real-world conditions

12 Methods and Procedures Replicated a Do-It Yourself Impression Kit, purchased from Internet*: The kit included: 1) 1 Covidien brand blunt tipped plastic Monoject 35 ml syringe, 2) 3 double tipped cotton swabs, 3) 3 blue, medium sized, foam ear dams with cotton removal strings, 4) 3 small, black foam ear dams with cotton removal strings, 5) 3 containers of pre-measured one-to-one silicone earmold impression materials and 6) 1 set of directions for making earmold impressions using the provided kit. *Earplug Superstore (2010)

13 Methods and Procedures Each Participant had: 1 set of earmold impressions made by an amateur impression taker and 1 set of earmold impressions made by a professional impression taker.

14 Each impression made into: Full-shell Westone brand model 40 custom-fit high noise multi-purpose ear plugs. Silicone OtoBlast material. NRR 29. Methods and Procedures

15 Methods and Procedures Evaluations: Real Ear Measurements Occluded Thresholds Visual Assessment of Impressions by Westone

16 Methods and Procedures Real Ear Measurements Measured Real Ear Unoccluded Resepose (REUR) taken twice per ear*. Measured Real Ear Occluded Response (REOR) 3 times per ear with each HPD*. Between each REOR, administrator removed and reinserted HPD. Measurements averaged per condition and per ear. *Measurements completed in soundproof booth. Made measurements with Audioscan RM500SL & 50 db HL white noise signal.

17 Methods and Procedures Occluded Threshold Measures Unoccluded thresholds obtained twice at.25,.5, 1, 2, 4, 6 and 8 khz*. Occluded thresholds (i.e.,.25,.5, 1, 2, 4, 6 and 8 khz ) performed with both amateur and professional sets of HPDs - three times each condition*. HPDs were removed and replaced between threshold measurements by the administrator. *Measurements completed in soundfield (soundproof booth) w/ participant placed 1 meter from the speaker. Used pulsed, warbled tone using ascending/descending method

18 Methods and Procedures Visual Assessment Earmold impressions photographed from 5 angles. Assessed by 3 earmold impression experts using 4 attributes known to affect HPD fit and attenuation. sufficient canal length sufficient amount of material in the canal sufficient fill of concha, helix and anti-helix areas, and evidence that the impression material had been pressed into the ear. Assigned one of the following classification: Acceptable for manufacture Unacceptable for manufacture Acceptable for manufacture, but remakes would require a new impression to be made.

19 No significant difference between right or left ears. Results: Real Ear Measurements Right ear Left ear Both amateur and professional occluded ears showed significantly more attenuation than unoccluded ear canals. Amateur HPD occluded ears showed significantly less attenuation than professional HPD occluded ears.

20 Results: Occluded Thresholds Both amateur and professional occluded ear showed significantly more attenuation than unoccluded ear canal. Amateur occluded ears showed significantly less attenuation than professional occluded ears.

21 Results: Visual Assessment Typical Impression Amateur Typical Impression Professional

22 Results: Visual Assessment Criteria Amateur Impressions Professional Impressions Sufficient Material in Canal 0 (0%) 20 (100%) Sufficient Canal Length 2 (10%) 20 (100%) Sufficient Fill of Concha, Helix & Anti-Helix Areas Evidence of impression material pressed into the ear 7 (35%) 20 (100%) 20 (100%) 0 (0%) Rated as. Acceptable for Manufacture 0 (0%) 14 (70%) Unacceptable for Manufacture 15 (75%) 0 (0%) Acceptable for Manufacture but Remakes require New Impression. 5 (25%) 6 (30%)

23 Discussion HPDs made from professionally made earmold impressions have significantly higher attenuation as showed through real ear measures and occluded threshold compared to those made from amateur made earmold impressions.

24 Discussion This study was a best case scenario Contraindications were controlled for Safety was monitored by a licensed Audiologist Otoblock placement was monitored by a licensed audiologist. (4 were repositioned) While Westone would have rejected most amateur impressions, it is unknown if all manufacturers would have the same high standards.

25 Discussion Previous research shows impression material needs to reach the second bend of the ear canal to create a proper seal and effectively attenuate noise (Pirzanski & Berge, 2005). Visual grading showed - 18 of 20 amateur impressions had insufficient canal length - 0 professional impressions had insufficient canal length. Deep placement of the otoblock and impression material can be uncomfortable for both the impression taker as well as the patient. This could be the reason amateur impressions were not as long and attenuation was lower.

26 Discussion Previous research found that jaw position during impression taking had a significant impact on attenuation (Pirzanski, Chasin, Klenk, Maye & Purdy, 2000). Position of the jaw can have significant impact on the diameter of the impression between the first and second bend, ultimately effecting attenuation. The amateur impression taker may be unaware that jaw movement during impression taking may reduce how snugly the HPD fits inside the canal resulting in a decrease of attenuations.

27 Clinical Implications HPDs should be made by a trained professional for optimal attenuation. Do-it-yourself earmold impression kits should be removed from the market as a safety concern. - Do not screen for contraindications. - Possibility of tympanic membrane perforation. - Increased risk of noise exposure due to reduced attenuation of subsequent HPD.

28 Clinical Implications Internet HPD providers could contract or refer to a trained healthcare provider for earmold impressions.

29 Questions or For More Information? Melinda Bryan:

30 References Balatsouras, D.G., Homisoglou, E., & Danielidis, V. (2005). Extended High Frequency audiometry in patients with acoustic trauma. Clinical Otolaryngology, 30, Earplug Superstore. (2010). Retrieved from on November 5, Fox, S. (2008). The engaged e-patient population. Pew Internet & American Life Project. Washington, D.C.: Pew Research Center. Retrieved from Horrigan, J.B. (2008).Online shopping: Internet users like the convenience but worry about the security of their financial information. The Pew Internet & American Life Project. Washington, D.C.: Pew Research Center. Retrieved from Shopping.pdf. on October 31, Kimball, S.H. (2008). Making earmold impressions at home: How well can untrained consumers do it? The Hearing Journal, 61(4), Olszewski. J., Milonski, J., Sulkowski, W., Majak, J., & Olszewski, S. (2005). Temporary hearing threshold shift measured by otoacoustic emissions in subjects exposed to short-term impulse noise. International Journal of Occupational Medicine and Environmental Health, 18(4), Pirzanski, C., & Berge, B. (2005) Ear canal dynamics: Facts versus perception. The Hearing Journal, 58(10), Pirzanski, C., Chasin, M., Klenk, M., Maye, V. & Purdy, J. (2000). Attenuation variables in earmolds for hearing protection devices. The Hearing Journal, (53)6, Rainie, L. (2010). Internet, broadband and cell phone statistics. Pew Internet & American Life Project. Washington, D.C.: Pew Research Center. Retrieved from on October 31, 2010.

31 References Sliwinska-Kowalska, M., & Jedlinska, U. (1998). Prolonged exposure to industrial noise: Cochlear Pathology does not correlate with the degree of permanent threshold shift, but is related to duration of exposure. The Journal of Occupational Health, 40, U.S. Census Bureau (2010). E-stats Retrieved from on November 11, 2010.

Do It Yourself Custom Hearing Protection

Do It Yourself Custom Hearing Protection Evan Mattice, B.S. Au.D. Candidate, University of Texas at Dallas Ross Roeser, Ph.D. University of Texas at Dallas Thank you to NHCA donors and scholarship foundation