In an interview with Howard Stern, Foo Fighters frontman Dave Grohl revealed he has noise-induced hearing loss (NIHL), and that he has "had to read lips for like the last 20 years." Prior to playing guitar for the Foo Fighters, Grohl played drums for the Seattle grunge band Nirvana.
Grohl admitted that his hearing had not been tested by a doctor in many years -- mainly because, he said, "I know what they're going to say: 'You have hearing damage, tinnitus in your left ear, more so than your right ear.'"
Grohl maintains that he can still hear certain frequencies well, so that when he is mixing an album in the studio, he can still hear if something is slightly out of tune, or "if a cymbal's not bright enough ... within the mix I can ... hear the minutiae of everything we have done with that song."
However, voices, especially in crowds, restaurants, or even at a dinner table, are more difficult for Grohl: "Even if you were sitting right next to me, I wouldn't hear a [single] word you said to me the whole time." Mask-wearing during the pandemic has made things worse for him, he said, since he's no longer able to read lips.
Despite his hearing loss, Grohl refuses to wear earpieces when he performs on stage; he says they distort his spatial experience of the music. He has used the same sound mixer for over 31 years, and he knows what everything is sounding like. Lastly, he claims that he has "small ear holes," and the earpieces frequently pop out of his ears. In addition, he doesn't like that wearing over-the-ear protection would make him look "like a praying mantis ... I want to go out there and go nuts," he said.
NIHL
NIHL is caused by exposure to excessively loud sounds. This can be a one-time exposure from a very loud sound, blast, or impulse, or can occur when loud sounds are experienced over a long period of time. The hearing loss can be immediate, or it can take a long time to be noticeable. It can be temporary or permanent, and can affect one ear or both ears.
According to CDC estimates, some 10 million to perhaps as many as 40 million adults under age 70 in the United States have hearing test findings that suggest NIHL. In addition, an estimated 17% of young people ages 12-19 may be experiencing NIHL in one ear or both ears.
Exposures that increase the risk of NIHL can be occupational and/or recreational. The National Institute for Occupational Safety and Health (NIOSH) surveils industries where there is a higher risk for NIHL and makes recommendations to decrease the risk for those workers, including the following:
- Farming
- Construction
- Manufacturing
- Mining
- Aircrews
- Musicians
- Yard workers
Recreational activities that increase the risk of NIHL include target shooting and hunting, snowmobile riding, listening to MP3 players at high volume through earbuds or headphones, playing in a band, and attending loud concerts. Woodworking tools can also be a source of loud sounds.
Sound and Hearing 101
Sound
Sound is measured in decibels (dBs) and is a measure of sound intensity. It can be measured in two ways:
- By frequency, the number of sound waves per second. This corresponds to the pitch of a sound as we perceive it. High frequency is high pitched, such as a child's voice; and low frequency is low pitched, like a growl
- By amplitude, the amount of pressure a sound wave produces. This is perceived as the volume of a sound
It is important to note that decibels increase logarithmically or exponentially. Therefore, an increase from 10 to 20 dB is actually 100 times louder!
According to data from the National Institute on Deafness and Other Communication Disorders (NIDCD), the following are some common sounds and their average decibel range:
- Normal conversation: 60-70 dB
- Movie theater sounds: 74-104 dB
- Motorcycles/dirt bikes: 80-110 dB
- Music through headphones at maximum volume: 94-110 dB
- Sporting events and concerts: 94-110 dB
- Sirens: 110-120 dB
- Fireworks show: 140-160 dB
Sounds at or below 70 A-weighted decibels (dBA), even after long exposure, are unlikely to cause hearing loss. However, long or repeated exposure to sounds at or above 85 dBA can cause hearing loss. The louder the sound, the shorter the amount of time it takes for NIHL to occur.
Hearing
Sound waves entering the ear canal cause the tympanic membrane to vibrate. The vibrations are transmitted to the three small bones of the middle ear (malleus, incus, and stapes), which amplify the vibrations and transmit them to the adjacent cochlea.
The snail-shaped cochlea (or inner ear) contains a group of interconnected, fluid-filled chambers. An elastic partition, the basilar membrane, runs throughout the cochlea and begins to ripple as its fluid vibrates.
The basilar membrane is covered with sensory cells, called hair cells, named for the stereocilia that cover them and protrude into the cochlear fluid. Bending of the stereocilia causes pore-like channels, which are at the tips, to open. When that happens, chemicals rush into the cell, creating an electrical signal that is transmitted to the auditory nerve.
Most NIHL is caused by the damage and eventual death of hair cells. Unlike bird and amphibian hair cells, human hair cells are unable to grow back. The damage is permanent.
What Are the Effects and Signs of NIHL?
Exposure to loud noise over an extended period can cause a gradual loss of hearing. As the changes are slow, however, they often go unnoticed or ignored until they become pronounced. Sounds may become muffled or distorted and it may be difficult to understand speech, especially in crowded or noisy rooms. Often, relatives complain that someone with NIHL has turned the volume on their TV or radio way up.
Loud noise exposure can also cause tinnitus -- a ringing, buzzing, or roaring in the ears or head. Tinnitus may subside over time but can become continuous or intermittent throughout a person's life. Hearing loss and tinnitus can occur in one or both ears.
Exposure to impulse or continuous loud noise can cause temporary hearing loss that resolves within 16 to 48 hours. Recent research suggests, however, that although the loss of hearing seems to disappear, there may be residual long-term hearing damage.
Preventing NIHD
According to the CDC and NIDCD, hearing loss caused by exposure to loud sound is preventable. To reduce the risk of NIHL, they recommend adults and children do the following:
- Understand that NIHL can lead to communication and learning difficulties, pain or ringing in the ears, distorted or muffled hearing, and an inability to hear some environmental sounds and warning signals
- Identify sources of loud sounds (such as gas-powered lawnmowers, snowmobiles, power tools, gunfire, or music) that can contribute to hearing loss and try to reduce exposure
- Seek hearing evaluation by a licensed audiologist or other qualified professional, especially if there is concern about potential hearing loss
- Adopt behaviors to protect hearing: (1) Turn down the volume of music systems; (2) Move away from the source of loud sounds when possible; and (3) Use hearing-protection devices when it is not feasible to avoid exposure to loud sounds or reduce them to a safe level
NIHL in Musicians
Overexposure to sound, both in intensity and duration, is common among musicians. This includes not only performers but also orchestra players, music teachers, conductors, deejays, and sound engineers.
NIOSH has received several requests for assistance in measuring and mitigating exposures from many of the above groups. For example, the agency prepared a Health Hazard Evaluation report for elementary and high school music classes, as well as a Workplace Solutions document: "Reducing the Risk of Hearing Disorders among Musicians."
NIOSH recommends that employers, music venue operators, schools, and colleges consider the following actions to reduce potential hearing damage for musicians, music teachers and students, and other exposed workers:
- Encourage participation in educational and awareness campaigns on music-induced hearing loss
- Conduct regular sound level assessments to identify whether levels exceed 85 dB
- If sound levels are above 85 dB, implement a hearing loss prevention program that includes annual hearing testing and training
- Identify hearing protection solutions that work best for the individual musicians or affected workers. Consider altering the workspace, such as adding sound-absorbing materials to walls or using rooms with higher ceilings for brass or percussion instruments
Musicians should consider taking the following actions:
- Monitor the level and duration of exposure to musical sounds. If professional sound measurement equipment is not available, some smartphone apps can provide useful and accurate information about sound levels
- Play music at lower levels during individual and group rehearsals, whenever possible
- Get a yearly hearing evaluation by a licensed audiologist
- Give the ears some rest; take advantage of breaks in quiet areas when possible
- Wear hearing protection when appropriate; some hearing protectors are manufactured and targeted specifically for musicians
Michele R. Berman, MD, is a pediatrician-turned-medical journalist. She trained at Johns Hopkins, Washington University in St. Louis, and St. Louis Children's Hospital. Her mission is both journalistic and educational: to report on common diseases affecting uncommon people and summarize the evidence-based medicine behind the headlines.