1. Hearing Conservation Metrics Theresa Y. Schulz, PhD. Lt. Col. USAF (ret.)

2. Topics Leading vs Lagging IndicatorsMotivating Workers Audiometric Testing Earplug Fit Testing Continuous Monitoring

3. Indicators for Hearing Loss: Standard Threshold Shift Temporary Threshold Shift Recordable Hearing Loss Dosimetry In-ear Dosimetry Personal Attenuation Level (PAR) Hearing Loss Compensation Hearing Conservation Metrics

4. Lagging Indicators vs. Leading Indicators Hearing Conservation Metrics

5. Indicators for Hearing Loss: Standard Threshold Shift Temporary Threshold Shift Recordable Hearing Loss Dosimetry In-ear Dosimetry Personal Attenuation Level (PAR) Hearing Loss Compensation Hearing Conservation Metrics

6. Ototoxic by themselves Synergistic effect with noise Large differences in sensitivity Recommend: increased frequency of audiometric testing Synergistic Ototoxics Carbon Monoxide Hydrogen Cyanide NOISE Hazardous Noise Ototoxic Chemicals Confirmed Ototoxics Ethyl Benzene Lead and inorganic compounds (as Pb) Styrene Toluene Trichloroethylene Possible Carbon disulfide n-Hexane Xylene Hearing Conservation Metrics

7. Conduct audiometric testing during the work shift TTS vs PTS Hearing Conservation Metrics

8. Percentage of exposed workers with STS/year Affected by: Duration of employment, Demographics Recent analysis of large database: 1980-present: 1.5% per year In non-noise exposed employees: roughly 1% Current corporate policy: 1% rate per year, or equivalent to internal non-occupationally exposed population- ?Best Practice? Hearing Conservation Metrics

9. Use Early Warning Flags Identify individuals at risk for significant loss in future Identify problem jobs/work areas Hearing Conservation Metrics

10. Age-Corrected STS Represents Significant Hearing Loss! Study of industrial workers: 52% of OSHA recordable STS cases (new definition) had compensable hearing impairment (AAOHNS criteria)! Median time to develop recordable STS: approx. 10 years* Hearing Conservation Metrics * Rabinowitz et al. Impact of OSHA rule: recording hearing loss JOEM 2003

11. So….. Age-Corrected STS is NOT an “Early Flag”! Hearing Conservation Metrics

12. Candidate “Early flags” (indicators) 10 dB shift from baseline in avg 2,3,4KHz (not age-corrected) 15dB shift from baseline (at least one frequency 1-6KHz) (Department of Defense) 15dB shift from baseline (at least one frequency 1-6KHz) confirmed on second test (NIOSH) Others: 7dB shift 2,3,4KHz? 5dB shift 2,3,4KHz? Hearing Conservation Metrics

13. Compensable Hearing Impairment: How many workers have absolute loss of >25dB avg 500,1K,2K,3KHz? Useful for workers comp liability as well as need for workplace accommodation, etc. Noise Levels- trends over time for individual departments. Hearing Conservation Metrics

14. Fit Testing In-Ear Dosimetry Hearing Conservation Metrics

15. How much noise is reaching the ear of the worker ? That is completely unknown … Noise Level = 100 dB Noise Reduction Rating = 30 dB (55 – 104 dB) Earplug Fit Testing

16. How much protection? 0 dB >33 dB EAR #1 EAR #2 EAR #3 Earplug Fit Testing

17. -10 125 250 5001000 20003150400063008000 Frequency in Hz 90 80 70 60 50 40 30 20 10 0 Attenuation in dB Max Poor Fit NRR = 0dB Max Good Fit NRR = 33dB Good Fit vs Bad Fit Earplug Fit Testing

18. Loudness Balance ( Real-Ear Attenuation Above Threshold ) Earplug Fit Testing

19. Test Sequence Part 1: Both ears unoccluded This sets the baseline level for each ear, and measures any asymmetry. Part 2: Right ear occluded Attenuation for the right ear is measured. Part 3: Both ears occluded Attenuation for the left ear is measured. Result ~ Personal Attenuation Rating (PAR)

23. 1.Measures real-world attenuation of any earplug 2.Fulfills requirement to ‘ensure proper fitting’ of earplugs and evaluate their attenuation 3.On-screen training videos 4.Administered anywhere, quiet room not required 5.Protected exposure level and safe exposure level calculated

24. OSHA Alliance: Best Practice Bulletin www.hearingconservation.org Additional Information www.hearforever.org Hearing Conservation Metrics

25. From Kevin Michael, PhD and Cindy Bloyer “Hearing Protector Attenuation Measurement on the End-User” 192 users of a flanged reusable earplug ~ 27 NRR Retraining and refitting resulted in an average 14 dB improvement for this group Real user attenuation <0 to 38 dB 30 20 10 0 -10 Attenuation in dB 40 50 NRR = 27 Multiple-Use Earplug Real-World Attenuation ≠ NRR Noise Reduction RatingHearing Conservation Metrics

26. Published NRR Hearing Conservation Metrics

27. Personal Factors Gender Age Years in Noise Ear Canal Size Familiarity Model of Earplug Program Factors # Group Trainings # Personal Trainings Hearing Conservation Metrics

28. Published NRR Trying a second earplug often improves attenuation REDUCING COSTS / CLAIMSHearing Conservation Metrics

29. “How well can users predict their attenuation after a short fit-testing training session?" Reducing Costs of Hearing LossHearing Conservation Metrics

30. Fitting Tips Ability to Predict Noise Reduction Reducing Costs of Hearing LossHearing Conservation Metrics

34. "I know how to better fit my earplugs now." "I was amazed with the results after being shown the proper way to use earplugs. "Learned A LOT about best earplugs for me" "I found a more comfortable fit. It was very beneficial." "Very glad I did the fitting test. Now I know the correct way to fit my ear plugs.” "Recently had threshold shift" "Found better earplugs" Field Verification – Fit-Testing "Feel like am protected now!" "I had no idea I was not using my earplugs correctly." Reducing Costs of Hearing LossHearing Conservation Metrics

35. Earplug fit-testing as a Problem Solver Training tool for noise-exposed workers Train-the-trainer tool Follow-up on significant threshold shifts in hearing Documentation of HPD adequacy Assessment of overall HCP effectiveness Match HPD to worker’s specific noise level Selection of appropriate HPDs for new hires Benefits per Best Practices Bulletin (OSHA Alliance) Hearing Conservation Metrics

36. In-ear dosimetry measures/records worker’s actual noise dose, with and without protection Provides real-time monitoring and alerts when worker approaches/exceeds safe limits Only metric with direct potential to measure and prevent further progression of occupational hearing loss

37. Reducing Costs of Hearing LossContinuous Monitoring / In-ear-dosimetry

38. Mean Hearing Threshold (2k, 3k, 4kHz): 2000 – 2007 (N = 46) Employees using continuous in-ear dosimetry starting in 2005 Reducing Costs of Hearing LossHearing Conservation MetricsContinuous Monitoring / In-ear-dosimetry

39. In-ear dosimetry as a Problem Solver Employees with Documented Noise-Induced Hearing Loss or Standard Threshold Shift [STS] Employees At-Risk for NIHL Employee Training + Sampling Dual-Protection/Extreme Noise Exposure Engineering Controls Reducing Costs of Hearing Loss In-ear monitoring as a Problem Solver Hearing Conservation Metrics

40. Preventive Action After NIHL In practice, an OSHA-recordable STS is not a preventive action It is documentation of a hearing loss after the fact. How soon will an employee suffering NIHL be re-fit / re-trained ? “Best case scenario” per Hearing Conservation Amendment 0 246810121416 Months Audiometric test Retest Notification In-ear dosimetry “worst case” scenario … 1 Day Hearing Conservation Metrics

41. PROS Estimate Measure NRR obsolete Fulfills OSHA compliance Eliminates need for de-ratings Medico-legal cases Delineates non-occupational Eliminates double protection Provides employee feedback (HPD Inventory control) CONS Cost Time Investment Not standardized Reducing Costs of Hearing Loss Tools for HCP Prevention Metrics Hearing Conservation Metrics

42. Training + Motivation

43. Common Objections to Wearing HPDs “Hearing protectors are uncomfortable to wear.” “I don’t need them! I am used to the noise.” “I already lost some of my hearing, so why should I wear them?” “I can’t hear my co-workers if I wear them.” “I can always get fit with a hearing aid.” “Can I hurt my eardrums if I insert an earplug to deeply.” “My machine sounds different.” “Won’t I get an ear infection?” Training + Motivation

44. Show, Don’t Tell Provide copy of annual audiogram to worker Use personal examples to demonstrate consequences of hearing loss Ask questions: What is your favorite sound? What sound would you miss the most if you couldn’t hear? What sounds connect you to people and your environment? Training + Motivation Personalize Hearing Loss

45. Training + Motivation Training Materials www.hearforever.org www.hearingconservation.org atl.grc.nasa.gov/HearingConserv ation/Resources/index.htmlatl.grc.nasa.gov/HearingConserv ation/Resources/index.html www.cdc.gov/niosh/topics/noise www.dangerousdecibels.org Demonstrate Future Risk www.hearforever.org/honaaohn

46. Training + Motivation Send Clear Message On + Off Job HC Part of Everyday Life Include recreational hearing conservation in annual training Provide extra HPDs for home use Promote Hearing Conservation at company/family events

47. Training + Motivation Remove Barriers to HPD Use Make HPDs Available Highlight “where to find HPDs” in annual training Make sure HPDs are well- stocked and accessible Include group of workers in selection process for increased acceptance Offer wide variety to match comfort, job requirements

48. Make Hearing Conservation Part of Your Everyday Life www.hearforever.org/honaaohn