Noise-Induced Hearing Loss (NIHL)

What is the incidence aged 20-69 have hearing loss?

17% or 26 million

What is the incidence aged 18 and over report trouble hearing?

15% or 37.5 million

According to WHO, globally, what is the incidence of teenagers at risk due to unsafe audio device use or loud entertainment venues?

1.1 billion

According to the NIH, in the U.S., what is the incidence aged 6-19 that has permanent damage?

12.5% or 5.2 million

What is the incidence in 8th graders in the last 10 years?

quadrupled

What is the incidence of 1st to 3rd graders show high-frequency loss?

3%

What is the incidence of high-school aged student that rises from 3% of 1st-3rd graders with high-frequency hearing loss to a static that rises to ___?

22%

What are the causes of NIHL?

Industrial and occupational noise: flight lines and factory machinery

Recreational activities: rock concerts, sporting events, and nightclubs

Personal audio devices: prolonged use of earbuds and smartphones at high volumes

Common loud sounds: lawnmowers, fireworks, firearms, and power tools

Noisy toys: toy firearms, arcade games, and model airplanes

Medical environments: noise levels in infant ICUs from life support and monitoring equipment

What is the purpose of the Walsh-Healey Act? 

was the first regulation to set allowable levels and duration for exposure to excessive noise

When did the Walsh-Healey Act enacted and later becoming what?

• 1969, later becoming the Occupational Safety Health Act (OSHA)

What are the aspects of Walsh-Healey Act?

in 1974, OSHA added requirements for hearing conservation programs which include monitoring noise exposure, mandatory audiometric testing, record keeping, and employee education

OSHA Permissible Time/Intensity Scale

8 hours: 90 dBA

4 hours: 95 dBA

2 hours: 100 dBA

1 hour: 105 dBA

30 minutes: 110 dBA

8 hours

90 dBA

4 hours

95 dBA

2 hours

100 dBA

1 hour

105 dBA

3O minutes

110 dBA

Describe the theory for hidden hearing loss.

Challenging the "classic view" that hair cells are the primary target, researcher M. Charles Liberman found that noise can cause the permanent loss of over 50% of synaptic connections between hair cells and the auditory nerve, even without hair cell loss

Describe the findings for hidden hearing loss.

This is "hidden" because it does not affect threshold detection in quiet environments, which is what standard audiograms measure. However, the loss of these high-threshold fibers makes hearing and speech recognition critically difficult in noisy environments

What is acoustic trauma?

the result of a single exposure or very few exposures to extremely high sound levels, such as an explosion or a gunshot near the ear. It can cause ruptured eardrums and damaged ossicles and is essentially permanent

What is the a Temporary Threshold Shift (TTS)?

a short-term elevation in hearing threshold that gradually recovers after the noise exposure ends

What is a Permanent Threshold Shift (PTS)?

Hearing changes that persist throughout life with no possibility of recovery. It is more common than acoustic trauma and results from repeated, cumulative exposure over years.

What are some ways we can prevent NIHL?

• Ear Protection: Wear earplugs (reducing sound by 20–30 dB) or earmuffs during yard work, concerts, or shooting

• 60/60 Rule: Listen to personal audio devices at no more than 60% volume for 60 minutes a day

• Headphone Choice: Opt for over-the-ear headphones instead of earbuds, which sit dangerously close to the eardrum

• Technology: Use smartphone apps to monitor volume and set volume cap

• Recovery: Give your ears breaks during loud events and allow 18 hours of quiet for recovery after a night in a loud environment

What is a Noise Reduction Rating NRR?

indicates how effectively a hearing protector blocks sound

What is the highest rating for earplugs in NRR?

33 dB

How much noise does properly fitted plugs or muffs typically reduce noise?

20-30 dB

What frequency is earplugs generally better?

low frequency noise

What frequency is ear muffs generally better?

high frequency noise

Describe findings of the noise measurements of toys.

• Measurements show many toys produce dangerous sound levels.

• A producer study of 30 average toys found that 24 produced sounds over 110 dB, and 2 exceeded 140 dBA

• 2021 list shows toys like squeeze toys and drum sets reaching levels between 80 dB and nearly 110 dB at the child's ear

Describe hearing conservation programs such as "Crank It Down”

A program created by the National Hearing Conservation Association to educate school-aged children on the dangers of loud noise early in life to prevent permanent loss

Describe hearing conservation programs such as “Dangerous Decibels.”

A public health campaign aimed at reducing the prevalence of NIHL and tinnitus by changing the knowledge, attitudes, and behaviors of children regarding sound exposure