About Hearing Loss
Understanding Hearing Loss
How we hear:
Sound waves enter your outer ear and travel through the ear canal to your eardrum.
Your eardrum vibrates with the incoming sound and sends the vibrations to three tiny bones in your middle ear. The bones in your middle ear amplify the sound vibrations and send them to your inner ear, or cochlea. The sound vibrations activate tiny hair cells in the inner ear, which in turn release neurochemical messengers. Your auditory nerve carries this electrical, signal to the brain, which translates it into a sound you can understand.
Hearing loss can be experienced in varying degrees, such as mild, moderate, moderately-severe, severe or profound. Additionally, this loss can also vary depending on pitches or frequencies. A series of hearing tests can determine the amount of loss you experience.
Conductive hearing loss
Caused by any condition or disease that blocks or impedes the transmission of sound through the middle ear resulting in a reduction in the sound level (loudness) that reaches the cochlea. Symptoms for conductive hearing loss are similar to other types of hearing loss; however, individuals may complain of sounds being muffled or far too quiet.
Some causes of conductive hearing loss can include:
- Outer or middle ear infections
- Complete earwax blockage
- Deterioration of the middle ear bones (ossicles)
- Otosclerosis, the fixation of the ossicles
- Perforated tympanic membrane or a hole in the eardrum
- Absence of the outer ear or middle ear structures
Conductive hearing loss may be temporary or permanent, depending on the source of the problem. Medical management can correct some cases of conductive hearing loss, while hearing instruments may be a recommended treatment option in long-standing or permanent cases.
Sensorineural Hearing Loss
A loss or distortion of sound transmission resulting from damage to the inner ear hair cells or to any of the pathway from the inner ear hair cells to the auditory cortex of the brain. This type of hearing loss is usually permanent and irreversible. The treatment for sensorineural hearing loss is amplification through hearing aids.
Individuals with sensorineural hearing loss may hear muffled speech, suffer from tinnitus (or ringing in the ears), have difficulty hearing in background noise or clarity of speech problems.
There are a number of causes of sensorineural hearing loss, including:
- Presbycusis: Age-related hearing loss
- Congenital: These hair cells have been abnormal since birth, which is considered a congenital condition.
- Damage to hair cells: A deficit in hearing also occurs when the cells are damaged as a result of genetics, infection, drugs, trauma or over-exposure to noise (late-onset or acquired).
Sensorineural hearing losses are generally permanent and may remain stable or worsen over time. Routine hearing tests are needed to monitor the hearing loss. Hearing aids are the most common and successful treatment, allowing hearing professionals to adjust settings as needs change.
Mixed hearing loss
Mixed hearing loss occurs when a person has a sensorineural hearing loss in combination with a conductive hearing loss. This means there is a problem in the inner ear as well as in the outer and/or middle ear.