Hearing Loss and Conservation in Industrial Settings

NICHOLAS PARMER, AuD Audiologist Munson Medical Center Central Michigan University B.S. in Communication Disorders 2010 Doctor of Audiology 2014

Interests Traditional Amplification First time amplification users Counseling Hearing conservation

IS MY WORK ENVIRONMENT TOO NOISY?

Indications of a problem When noise levels are above 80 decibels (db), people have to speak very loudly When noise levels are between 85 and 90dB, people have to shout When noise levels are greater than 95dB, people have to move close together to hear each other at all

The Action Level Noise levels at or above an eight hour timeweighted average (TWA) of 85dBA

The TWA 85dBA 8hr TWA = 50% dose >100% dose (90dBA) = damage to hearing For every 5dBA increase, the dose is doubled (or the allowable duration of exposure is halved)

Noise level (8hr TWA) Allowable exposure 85 dba 16 hours 50% dose 90 dba 8 hours 100% dose 95 dba 4 hours 100 dba 2 hours 105 dba 1 hour 110 dba.5 hour 115 dba 0

Dosimetry Testing What kind of environment is being tested? Area sampling Representative personal sampling Needs to be repeated when noise levels change Employees at or above action level of noise must be notified Employees or employee reps are able to observe the noise monitoring procedures

Noise Control Engineering Impractical Expensive Not done very often

AN EFFECTIVE HEARING CONSERVATION PROGRAM

An effective hearing conservation program can prevent hearing loss, improve employee morale and a general feeling of well-being, increase quality of production, and reduce the incidence of stress-related disease. - OSHA

Monitoring program Audiometric testing program Hearing Protection Devices (HPDs) Employee training and education Record keeping

Monitoring Program Monitoring method is chosen to best suit each individual environment and situation Contraindications for area monitoring include high worker mobility, significant variations in sound level and significant impulse noise Personal monitoring method may produce more accurate and representative results Must measure all noise from 80 to 130 dba Repeat when there is change in equipment, process, production or controls Repeat when additional employees become exposed at or above the action level

Monitoring Program Employer MUST notify all at risk employees of the results of the monitoring Employer MUST provide all at risk employees with opportunity to observe monitoring procedures

Audiometric testing program Baseline and Annual Audiograms Standard Threshold Shift (STS) Evaluation of Audiogram Revised Baseline Follow-up Procedures Testing and Equipment

Audiograms Employee must have baseline audiogram within six months to one year of first exposure to noise at or above action level Employee must have annual audiograms after baseline

The STS Standard Threshold Shift A 3 frequency (2, 3, 4kHz) average drop of 10dB or more Employee must have PTA of 25dB or greater to be a recordable STS Software applies aging (presbycusis) correction factors In the event of an STS, the employee must be notified within 21 days of test Employer can chose to have employee retested

OSHA Decision Tree

Beware of Impacted cerumen, otitis media, acute colds or sinus issues, temporary threshold shifts (TTS) Lapses in employment Lifestyle determining work relatedness of shift will depend on taking a history Not possible to determine specific cause of NIHL

Recordable STS

Referral audiogram

NIHL & Presbycusis

Evaluation of audiogram Comparisons of audiogram to baseline can be performed by a technician Problem audiograms must be reviewed by an audiologist, otolaryngologist, or physician Revised baseline If STS is persistent If hearing improves significantly from previous year

Follow up procedures Employees who STS must be fit with HPD, trained in their use and required to use them If already using HPD, they must be refit, retrained and provided with HPD that offers greater attenuation Employee must be referred for further audiological or medical examination as necessary

Testing and equipment Necessary equipment Otoscope Audiometer or microprocessor audiometer Quiet room or sound attenuating booth A technician performing audiograms is responsible to an audiologist, otolaryngologist, or physician. A technician may operate automated audiometers independently

Hearing Protection Devices (HPD) Employees must be able to choose between variety of HPDs, generally plugs and muffs Employer must provide proper training on care and use of HPDs Employer must supervise initial proper fitting and correct use

Estimating attenuation TWA NRR = Exposure Subtract 7 from NRR for using dba measurements 100 (29-7) = 78

Employee training and education Training program must be provided and repeated annually for any employee in HCP The effects of noise on hearing The purpose of hearing protectors, the advantages, disadvantages, and attenuation of various types, and instructions on selection, fitting, use, and care The purpose of audiometric testing and an explanation of test procedures Provide access to information and training materials

Record keeping A record of all employees who STS is sent to MIOSHA Employers fill out a Log 300 suspected work injury report for a persistent STS We send records to employers where they must be kept for duration of employment

Adverse effects of high noise levels On job performance Difficulty understanding speech Annoyance Difficulty concentrating Reduced efficiency Low morale Adverse social behavior

Adverse effects of high noise levels On health High blood pressure Abnormal secretion of hormones Muscle tension Ulcers Loss of sleep Fatigue Stress reactions

HEARING LOSS

What can cause hearing loss Occupational or recreational noise exposure Trauma (physical or acoustic) Ototoxic medicines Heart disease, stroke, HBP, diabetes Tumors and growths Childhood illness Aging (presbycusis)

Signs of Hearing Loss What? Leaning into the conversation Unusual amount of visual focus on your face Looks of confusion and concentration Complaints of others mumbling or speaking too fast Reports from family members What are their hobbies? Occupation?

-Ask Questions- Do you have difficulty communicating in noisy places? Do you have difficulty communicating on the phone? Do you like the television louder than others would like it? Do you have to ask for repetition? Not if they speak up and stop mumbling

The Importance of Early Treatment and consequences of untreated hearing loss

Early intervention prevents Strain on relationships Social withdrawal and isolation Decline in emotional health Decline in physical health

Neural Reorganization Acoustical Society of America (ASA). How does the brain respond to hearing loss? ScienceDaily. ScienceDaily, 19 May 2015. Credit: Anu Sharma Adults with early-stage age-related hearing loss (right) show decreased activation of the hearing portion of the brain compared with normal hearing age-matched adults (left).

Neural Reorganization Adults with mild age-related hearing loss (right) show brain reorganization in hearing portions of brain, which are recruited for processing visual patterns. This is not seen in age-matched adults with normal hearing (left). Credit: Anu Sharma

Untreated Hearing Loss and Dementia Hearing loss affects performance on tests for dementia People with untreated hearing loss have a greater risk of developing dementia Participants with hearing loss have a 40% greater chance of cognitive decline compared with those who had normal hearing at the beginning of the study Johns Hopkins Medical Center, 2011

Untreated Hearing Loss and Dementia Fitting hearing aids to patients diagnosed with Alzheimer s dementia was effective in helping with their communication skills and significantly decreased patient behavioral problems and caregiver stress Palmer CV, Adams SW, Bourgeois M et al. (1999)

The Role of the Physician Leave the patient with positive feelings about the hearing evaluation Give hearing aids your endorsement

Amplification What kinds? What for? Cochlear Implants Osseo-integrated hearing devices CROS & BiCROS systems Traditional hearing aids

Cochlear Implants

Traditional CI

Hybrid CI

Osseo-integrated Hearing Device

Single Sided Deafness (SSD)

Conductive or Mixed Hearing Loss Conductive Mixed

CROS & BiCROS Systems CROS BiCROS SSD or unaidable ear with normal hearing on contralateral side SSD or unaidable ear with hearing loss on contralateral side *The patient is being fit with the same devices either way

Traditional Amplification (Hearing Aids)

Recent Advancements Bluetooth Cell phone connectivity with and without intermediary device Rechargeability Lithium ion battery

Resources MiOSHA Consultation, Education & Training Division (517) 284-7720 Nick Parmer, AuD 231-935-6643 nparmer@mhc.net