Noise-Induced Hearing Loss Study Questions

What is the incidence of hearing loss in adults in the US?

Approximately 17% or 26 millions between the ages of 20 and 69 have hearing loss. Nearly 15% or 37.5 million aged 18 and older report some trouble hearing.

What is the incidence of hearing loss in teenagers in the US?

Globally, the Word Health Organization (WHO) estimates 1.1 billion are at risk of hearing loss due to unsafe audio devices use or loud events. In the U.S., the incidence for those of high school age is 22%, a statistic that has soared in recent years

What is the incidence of hearing loss in children in the US?

Approximately 12.5% or 5.2 million of Americans aged 6 to 19 have permanently damaged their hearing from noise. Specifically, 3% of 1st–3rd graders and a quadrupled number of 8th graders in the last decade demonstrate high-frequency hearing loss.

What are some of 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 and aspects of the Walsh-Healey Act?

was the first regulation to establish rules regarding allowable levels and length of exposure to excessive noise. It later became part of the Occupational Safety and Health Act (OSHA), which in 1974 added requirements for hearing conservation programs, including noise monitoring, audiometric testing, employee education, and record-keeping.

Be familiar with the OSHA time/intensity scale.

The permissible noise levels established by OSHA are as follows:

• 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

30 minutes

110 dBA

Describe the theory for hidden hearing loss.

Traditional views suggest hair cell damage is the primary cause of hearing loss. However, Liberman’s research shows that primary neural degeneration (synaptopathy) can occur before hair cells are lost or thresholds elevated.

Describe the findings for hidden hearing loss.

Noise exposure can cause a permanent loss of over 50% of synaptic connections between hair cells and the auditory nerve even when hair cells survive. This is "hidden" because it often affects high-threshold fibers critical for hearing in noisy environments but doesn't show up on a standard audiogram in quiet settings.

What is acoustic trauma?

defined as the effect of a single or very few exposures to extremely high sound levels, such as an explosion or a gunshot near the head. It often results in permanent damage and may include ruptured eardrums or damaged ossicles.

What is the difference between a TTS and PTS?

• Temporary Threshold Shift (TTS): A short-term elevation in the hearing threshold that recovers gradually after noise exposure.

• Permanent Threshold Shift (PTS): Hearing changes that persist throughout life with no possibility of recovery. It typically results from repeated daily exposure over several years.

What is Temporary Threshold Shift (TTS)?

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

What is Permanent Threshold Shift(PTS)?

Hearing changes that persist throughout life with no possibility of recovery. It typically results from repeated daily exposure over several years.

What are some ways we can prevent NIHL?

• Wear earplugs: Use them at concerts, sporting events, or while using noisy machinery.

• Follow the 60/60 rule: Listen to music at no more than 60% volume for no more than 60 minutes a day.

• Choose over-the-ear headphones: They are safer than earbuds, which sit closer to the eardrum.

• Use smartphone apps: Monitor and cap volume levels using built-in features or apps.

• Give ears time to recover: Ears need roughly 18 hours of quiet to recover after a night at a loud venue.

• Use noise-cancelling features: This reduces the need to turn up music to block out background noise.

What is an Noise Reduction Rating (NRR)?

a measure of how effectively an earplug or earmuff reduces noise. The highest NRR currently offered is around 33 decibels. Properly fitted plugs or muffs typically reduce noise by 29–30 dB.

Describe findings of the noise measurements of toys.

Measurements have found that many toys produce sounds capable of causing acoustic injury. A 20/20 producer found that 24 out of 30 average toys produced sounds over 110 dB, and two exceeded 140 dB

Describe hearing conservation programs such as "Crank It Down”

A program developed by the National Hearing Conservation Association to inform school-aged children about the dangers of early noise exposure to prevent permanent loss.

Describe hearing conservation programs such as“Dangerous Decibels.”

A public health campaign designed to reduce NIHL and tinnitus by changing the knowledge, attitudes, and behaviors of children through education.