Hearing loss can be complicated. There are many components in our hearing system that can cause hearing issues if they malfunction. Some diseases, conditions, and medications can target specific areas of the ear, causing different types of hearing loss. The topic for this blog post is how noise-related hearing loss looks on a hearing test.
Usually, excess noise will affect the part of your inner ear known as the cochlea. The cochlea is a spiral shaped boney shell, also known as the organ of hearing. Inside the cochlea are tiny sensors, called outer hair cells, that move when they come in contact with sound waves. Regular cochleae have thousands of outer hair cells, which are responsible for sensing different pitches of sound. The hair cells closest to the entrance of the cochlea are responsible for sensing high pitch sounds, and the hair cells deep in the cochlea are responsible for sensing low pitch sounds. Want to learn more about how the hearing system works? Click here!
When noise levels are high, hair cells can actually get damaged. Over time, excessive noise can permanently damage hair cells, affecting their ability to send sound information to the brain.
Usually, the first sign of noise-induced hearing loss is a drop in hearing at 4kHz (also called a noise notch). Why 4kHz? Well, the hair cells responsible for sensing 4kHz sounds are right in the 'pummel-zone' for all incoming sound waves. When sound waves enter the cochlea, sounds will need to hit the 4kHz section before it gets to where it needs to be. This constant action causes the hair cells to damage over time.
After the 4kHz drop in hearing, higher pitches (6&8kHz) drop in hearing. This has to do with the amount of hair cells located in each region of hearing. There are fewer hair cells in the high pitch range of hearing relative to the amount of hair cells in the low pitch range of hearing. So, loosing hair cells in the low pitch range will not have as big of an effect on hearing as loosing hair cells in the high pitch range.
The focus for this blog post is on the hearing test results, but noise-related hearing loss goes far beyond this. People often experience difficulty in noise, tinnitus, and issues understanding sound too.
If you were exposed to a noisy workplace and are suffering from hearing loss, get your hearing tested! There are several programs available to you that can provide you with hearing aids and hearing assistive devices. We can help, book an appointment with our licensed audiologist today.