Once you’ve had your hearing test, your hearing healthcare professional will explain the results of the audiogram to you. Your hearing loss will fall into several different categories: type, degree, and shape, and I will cover each of these. The reason it is important for you to understand your hearing loss is that it matters when it comes to having realistic expectations, as well as selecting the right hearing aid for you and your hearing needs.
Types of hearing loss are broken down into three general categories: sensorineural, conductive, and mixed. All hearing losses and types of hearing losses will fall into one of these three categories, and the categories can be subdivided into more specific types (like sudden hearing loss, noise induced hearing loss, etc), but that is another blog entirely.
- Sensorineural hearing loss (SNHL) occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain. Most of the time, SNHL cannot be medically or surgically corrected. This is the most common type of permanent hearing loss. SNHL reduces the ability to hear faint sounds. Even when speech is loud enough, it may not be clear enough. (www.asha.org)
- Conductive hearing loss occurs when the sound is not conducted efficiently through the outer ear canal to the eardrum and the bones of the middle ear. Conductive hearing loss usually involves a reduction in sound level or the ability to hear faint sounds. This type of hearing loss can often be corrected medically or surgically. (www.asha.org)
- Mixed hearing loss occurs when a person’s audio-gram shows both SNHL and conductive components. That means there can be damage present both in the outer and middle ear portion as well as the inner ear.
Degrees of hearing loss are variable, as well. Not all hearing losses are created equal. Hearing loss is categorized as mild, moderate, moderately-severe, severe, and profound, and is based on your response to sounds at each frequency. The louder a sound has to be before you detect it, the more severe your hearing loss. The degree of hearing loss is the same for everyone; the range doesn’t change based on your age or life experience. Click this link (http://www.asha.org/public/hearing/Degree-of-Hearing-Loss/) to see where you fall.
The third identifying factor to your audiogram is the shape of your hearing loss. Many clinicians will use a term in their report to your physician about the overall shape.
- Flat loss: A flat hearing loss is one that is approximately the same at all frequencies and is essentially a straight line across the audiogram.
- Ski slope loss: A ski slope loss is the most common type of loss we see. In a ski slope loss, there is little or no loss in the low frequencies but a considerable loss in the higher frequencies, making the audiogram look like a ski slope or hill.
- Reverse slope loss: A reverse slope loss is the opposite of a ski slope loss. The person has significant loss in the low pitches, sloping upwards towards normal as we get into the higher frequencies.
- Cookie bite loss: A cookie bite loss looks like someone took a bite out of the top end of the audiogram. A person will have normal or close to normal hearing in the low frequencies and the high frequencies, but a more significant hearing loss in the middle frequencies.
- Reverse cookie bite loss: A reverse cookie bite loss is the opposite of the cookie bite. Patient’s will have normal hearing in the middle frequencies, sloping off to considerable losses in the low frequencies and the high frequencies.
It is important to know what type, degree, and shape of hearing loss you have so that you can make an informed decision when it comes time to purchase the best instrument for your needs.
Until next time,