Types and causes of hearing loss in children
There are several types of hearing losses and many reasons why a child could suffer from a hearing loss. Additionally, a hearing loss could be one that is temporary or permanent, range from slight to profound loss, and may be in one or both ears.
The ear is divided into three main parts — outer ear, middle ear, and inner ear. The ability to hear is an extremely complex process beginning with the outer ear picking up sound that then travels to the middle ear. Vibrations from the eardrum and bones of the middle ear then sends the sound into the inner ear, along the auditory nerve and then to the brain where the sound is finally deciphered into meaningful speech and environmental sounds that we are able to understand. This process of hearing is critical to our ability to understand the world around us and damage to any one part of the ear will result in a child not only having difficulties hearing but may also result in speech, language, and other learning and social delays.
A hearing loss that occurs when the child is born is known as a congenital hearing loss. Congenital hearing losses are usually caused by genetic disorders but can also be caused by other factors. If the hearing loss occurs after the child is born it is called an acquired hearing loss. An acquired hearing loss results from any number of factors and may occur at any time during childhood. An acquired hearing loss may get progressively worse as the child grows. Congenital and acquired hearing losses usually fall into one of three major categories of hearing loss — sensorineural hearing loss, conductive hearing loss, or mixed hearing loss.
Sensorineural hearing loss
This is the most common type of hearing loss and is usually a permanent one, affecting the inner ear. It occurs when there is damage to either the tiny hairlike cells of the inner ear or to the auditory nerve. When damage occurs, it prevents or weakens the transfer of the auditory signals to the brain resulting in hearing loss.
- Infections like rubella (German measles), cytomegalovirus, or herpes, passed from mother to child during or at birth;
- Premature birth;
- Infections such as meningitis, mumps, scarlet fever and measles;
- Traumatic head injuries;
- Acoustic neuroma or other cancerous growths in the inner ear;
- Side effect from certain ototoxic medicines that damage hearing;
- Family history of hearing loss;
- Malformations of the inner ear;
- Exposure to loud noise and/or music.
There is no medical or surgical way to repair the damage to the inner ear hair cells or auditory nerve from this kind of hearing loss. However, depending on the severity of the hearing loss, successful treatment using hearing aids and/or cochlear implants is very possible. Additionally, there are other types of assistive listening devices that work independently or along with hearing aids and cochlear implants to improve sound transfer in difficult listening environments, like the classroom. To avoid further damage to your child’s auditory system, always ensure the fitting of any type of hearing aid or amplification device is done by a certified audiologist.
Conductive hearing loss
This type of hearing loss occurs when an obstruction, damage, or deformity occurs in the outer or middle ear that prevents sound from travelling to the inner ear. In most cases, a conductive hearing loss is temporary and is one that can be corrected through medical treatment or surgical intervention. A conductive hearing loss is extremely common in children suffering from middle ear infections. Children who continue to have repeated bouts of otitis media may eventually sustain ear damage that results in a permanent, sensorineural hearing loss.
- Fluid in the middle ear from colds;
- Middle ear infection;
- Poor Eustachian tube function
- Perforated eardrum
- Benign tumors
- Impacted wax
- Infection in the ear canal
- Swimmer’s ear
- Foreign body in the ear
- Deformity of the outer ear, ear canal, or middle ear
A conductive hearing loss can usually be treated with medicine, surgery, or a combination of both. In some cases, when even after treatment a hearing loss remains, a traditional hearing aid, or a bone anchored hearing aid that is surgically implanted, may be selected to improve the hearing as much as possible.
Mixed hearing loss
This type of hearing loss is a combination of both the sensorineural hearing loss and the conductive hearing loss. It occurs when there is damage to the outer ear and/or middle ear as well as to the inner ear or auditory nerve. A portion of this hearing loss may be temporary while a portion is permanent. The causes of mixed hearing loss will be some combination of those listed for the other two types of hearing loss above.
Treatment options for mixed hearing loss depends on which type of loss is greater. If the conductive component is greater, surgical procedures and other medical treatments may be used. If the sensorineural component is greater, hearing aids or an implantable device may be the better option. There is help for children struggling with hearing loss.
- For further information on any hearing-related disorders, please contact Dr. Deborah Nubirth, doctor of audiology, in New Providence at Comprehensive Family Medical Clinic, Poinciana Drive at 356-2276 or 677-6627 or 351-7902 in Grand Bahama; or email [email protected].