What is High Frequency Sensorineural Hearing Loss?
The way that we hear and the system that process the sounds that come to our ear are complex. Our hearing system is comprised of 4 distinct areas and 4 distinct modes to help transmit the signal in order for us to process the sound. Those areas are as follows: 1) Outer Ear 2) Middle Ear 3) Inner Ear and 4) The Brain. The outer ear is comprised of what you see on the outside, also called the pinna, and the ear canal. The middle ear has 3 small bones called the malleus, incus, and stapes. The inner ear is comprised of the cochlea (snail shell shaped organ) and the nerve that transmits the signals to our brain. When a sound signal like an alarm or speech is happening, it moves the air molecules from the source of the sound to our ear. It then travels through the ear canal which vibrates the ear drum and pushes on the 3 bones in the middle ear, which in turn pushes on the cochlea. The cochlea is fluid filled and the movement of that fluid vibrate hair cells that are lining the cochlea. Those vibrations of hair cells sends an electrical signal to the brain to be processed.
A sensorineural hearing loss is a hearing loss that is a result from damage to the cochlea hair cells and/or the nerve that runs those signals to the brain, generally this type of hearing loss is a permanent condition. The hair cells that line the cochlea are what we call tonotopic, meaning the high frequencies (pitches) line the outside of the snail shell shaped organ, middle frequencies are lining the middle area of the organ, and low pitches are lining the very center of the organ. It is most common for the high frequencies to be damaged first due the placement of the hair cells on the outside turns of the organ and the middle and low frequencies are more protected from the shape of the organ wrapping around itself.
The most common complaint for people with high frequency sensorineural hearing loss is that they can hear but they cannot understand. The reason for this complaint is that low pitches give people a sense of volume, while the high frequencies give people a sense of clarity. Also, vowels generally are a low or middle frequency signal while a lot of consonants are high frequency signal. People with this type of hearing loss are receiving part of the signal or they are misinterpreting the type of consonant that is being spoken.
People with hearing loss of this nature tend to start to feel isolated from family and friends as they are having a difficult time understanding the full message that is being spoken. If you or a family member is suspected to have a hearing loss, contact our office in order to have a full audiological evaluation from a licensed audiologist. If you or the patient is a candidate for hearing aids, you can try our flex trial hearing aids at no cost to you for two weeks.
I hope this article answers your questions about how we hear and about hearing loss. If you have any questions please do not hesitate to speak with an audiologist.