More than 48 million Americans suffer from some degree of hearing loss. The number has doubled within the last 30 years. Hearing loss is the third most common physical condition in the United States, behind only arthritis and heart disease. The most common causes of hearing loss are noise exposure and aging (presbycusis), although there are a variety of other causes.
The ear is divided into three parts: the outer, middle and inner ear. A sound wave is captured by the outer ear and funneled down the ear canal where it hits the eardrum and causes a vibration. That vibration is then passed through the three bones within the middle ear: the malleus, incus and stapes. The stapes, the last bone in the series, pushes against the oval window causing the fluid within the cochlea to move. The cochlea, which is within the inner ear, is lined with tiny hairs. The movement of fluid causes the hairs to move which in turn prompts them to send out an electronic signal. That signal travels through the auditory nerve to the brain, where it is processed as sound.
There are three types of hearing loss: conductive, sensorineural and mixed. They are categorized by which part of the auditory system is affected.
Conductive hearing loss occurs when the sound wave is unable to pass from the outer or middle ear to the inner ear. This can be caused by impacted earwax, fluid in the middle ear, an infection or a perforated eardrum. This type of hearing loss is usually temporary and can be corrected through medical or surgical means.
Sensorineural hearing loss occurs when there is damage to the inner ear or the nerve that connects the ear to the brain. This type of hearing loss is caused by exposure to loud noise, aging, head trauma and illness. While this kind of hearing loss is permanent, most find the use of a hearing aid beneficial.
Mixed hearing loss is a combination of both conductive and sensorineural hearing loss. This means the patient has a problem with their outer or middle ear and inner ear. This type of hearing loss is treated in stages. First, the cause of the conductive hearing loss is identified and corrected. After that the sensorineural hearing loss is treated, usually with the use of a hearing aid.
In addition to determining the type of hearing loss you are suffering from, your audiologist must also determine the degree. The degree of hearing loss can range from mild to profound. It is important to note that different frequencies can have different levels of hearing loss, so a patient can have mild low-frequency hearing loss as well as moderate high-frequency loss. . Hearing loss is measured in decibels, such as:
- Normal hearing is -10 to 20 dB
- Mild hearing loss is 20 to 40 dB
- Moderate hearing loss is 40 to 70 dB
- Severe hearing loss is 70 to 90 dB
- Profound hearing loss is over 91 dB
In order to determine the appropriate treatment plan for your hearing loss, your audiologist will need to complete a series of tests to determine the type and degree. Don’t wait to seek help; contact our office at 337-266-9820 to schedule a hearing screening.