Hearing loss can be caused by a number of different factors. To understand what causes the loss of hearing you will first need to understand how you hear. The ear is broken down into three parts: the outer, the middle and the inner ear.
The outer ear consists of the cartilage and soft tissue visible on the outside (the pinna), the ear canal and the outer portion of the eardrum. The middle ear is made up of the eardrum and the ossicles, three small bones called the malleus, incus, and stapes. The inner ear consists of the cochlea, the semicircular canals and the auditory nerve.
A sound wave is captured by the pinna, funneled into the ear and down the ear canal where it hits the eardrum. This creates a vibration, which is passed through the ossicles into the inner ear. The vibration then causes the fluid within the semicircular canals and the cochlea to move. Movement within the semicircular canals provides your brain with information on body position and balance. The movement of fluid within the cochlea causes the tiny hairs that line the cochlea to move as well. This movement creates an electrical signal which is carried by the auditory nerve to the brain. The brain then interprets this signal as sound.
As you can see, hearing is a complicated process. A problem with any part of this process can lead to a loss of hearing.
There are three main types of hearing loss:conductive, sensorineural and mixed.
Conductive hearing loss occurs when there is a problem that prevents sound waves from traveling from the outer to the middle ear. Fluid in the middle ear, an ear infection, a malformation of a structure of the ear, impacted earwax or a perforated eardrum are the most common causes. This type of loss can usually be reversed and successfully treated through medical or surgical means.
Sensorineural hearing loss is caused by a problem with the inner ear or the auditory nerve. This type of loss is usually caused by exposure to loud noises, head trauma, a virus, disease or normal aging. Unfortunately, damage that results in this type of hearing loss is permanent. Fortunately, hearing aids are able to be used as treatment. This is the most common type of loss.
Mixed hearing loss is exactly what it sounds like; those with this type of loss experience a problem with their outer or middle ear and their inner ear. To treat this type of loss of hearing the cause of the conductive hearing loss is addressed first. Once this has been treated, the sensorineural hearing loss can be addressed.
Not only can the type of hearing loss you have vary, the degree of your loss can range as well—from mild, moderate, severe to profound. Mild hearing loss is often easily overlooked. Those with this degree of loss will miss words from conversations only in noisy environments. Moderate hearing loss makes it harder for individuals to keep up with one-on-one conversations. Severe hearing loss makes it nearly impossible to follow a conversation without the use of a hearing aid. Those that suffer from profound hearing loss may not be able to utilize a hearing aid, often relying on sign language to communicate.