The Anatomy of Hearing Loss

We all know that protecting our ears around extreme noise helps prevent hearing loss. What most of us never talk about is why loud noise physically damages our hearing? One out of every ten Americans has hearing loss that makes it difficult to understand normal speech. Exposure to high levels of noise is the number one cause of hearing loss. The National Institute of Health found that about fifteen percent of all Americans age 20-69 have high frequency hearing loss related to work or leisure activities. The problem is serious, but also highly preventable. Hopefully by diving into the actual physical reaction to extreme noise, we can better understand how to protect ourselves. So, let’s talk about the anatomy of hearing loss.

Types of Hearing Loss

There are three primary types of hearing loss. Sensorineural Hearing Loss, Conductive Hearing Loss, and Central Hearing Loss. This article is going to dive into the anatomy of hearing loss characterized as Sensorineural Hearing Loss which is caused by exposure to noise. To fully understand how noise affects your hearing, we have to first look at the anatomy of the human ear.

Anatomy of the Human Ear

The human ear consists of three primary areas. The outer ear, the middle ear, and the inner ear. The outer ear consists of the auricle, the external auditory canal, and the lateral surface of the tympanic membrane. The middle ear contains the medial surface of the tympanic membrane, the ossicular chain, the eustachian tube, and the tympanic segment of the facial nerve. Finally, the inner ear consists of the auditory-vestibular nerve, the cochlea, and the vestibular system.

How Does Noise Affect Your Ears?

When the ears are exposed to noise that is too loud, the sound wave actually begins killing cells within the inner ear. The longer the exposure time to high noise levels, the more hair cells are killed. The more hair cells killed, the more your hearing is damaged and the damage is permanent.

How Loud is Too Loud?

According to OSHA standards, regular exposure to noise levels above 85 dB causes progressive hearing loss in most people. Noise levels even higher will increase the damage significantly. Without hearing protection, the acceptable time of exposure goes down by half for every 5 dB increase in the actual noise level. For example, exposure needs to be limited to 8 hours per day at 90 dB, 4 hours per day at 95 dB, and 2 hours per day at 100dB. The unprotected ear should never be exposed to 115 dB for more than 15 minutes per day.

What Can Be Done?

If excessive noise is unavoidable, make sure to wear hearing protection especially if you’re working around machinery, using power tools, running loud yard equipment, or operating firearms. Hearing protection lowers the intensity of the sound waves that reach the inner ear.

Earplugs can be inserted into the outer ear canal and they will greatly reduce the intensity of loud noise. To work properly, earplugs must fully block the ear canal with a good seal. A seal can be weakened by using old, damaged, or dirty earplugs. We recommend that you use washable silicone molded earplugs rather than foam earplugs in order to ensure a good seal.

We hope that this article about the anatomy of hearing loss has increased your knowledge of how high noise levels actually damage your hearing and what can be done about it. We plan to produce more articles like this in the future, so make sure to keep checking back.

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