Childhood Hearing Loss

Preschool development of language and other skills is large dependent on the child having normal hearing. Conductive hearing loss and sensori- neural deafness are the two types of hearing loss that can occur in children.

"Nerve deafness" also known as sensori-neural deafness is caused by the inner ear not processing the sound stimuli it receives properly. Children with this type of sensori-neural hearing impairment often have to wear a hearing aid to improve their hearing. This type of hearing injury does not occur very often.

The other type of deafness ie conductive hearing loss is much more common. It is different from sensori-neural hearing injury in that there is no problem with the functioning of the inner ear but the construction of sound from the environment to the inner ear is impaired due to the presence of fluid in the middle ear. This condition is also known as "glue ear". Ideally, the middle ear should be air-filled for sound construction. The presence of fluid impairs the functioning of the middle ear causing an intermittent hearing impirement which is often seasonal in nature.

Conductive deafness is often inconsistent. Sometimes the child with this condition hears well and sometimes the build-up of fluid eg. when the child has an ear infection causing the hearing threshold to be significantly reduced. This type of hearing impairment is also seasonal as children are more likely to have colds and upper respiratory tract infections in the winter months.

It is worth pointing out that fluid can also occur in the middle ear, causing conductive deafness, in the absence of an accompaniment ear infection. Sometimes there may be a build-up of middle ear fluid in the absence of an accompaniment ear infection.

The position of the eustachian tube in the preschool child is a significant factor in the development of aductive hearing impairment. This tube connects the ear with the throat to allow an equilibrium of air pressure in the ear and to allow any fluid present to drain away easily. However, it does not work very well in youngger children because it is nearly horizontal. As the child grows, the eustachian tube has a more vertical position between the ear and the throat, resulting in better drain of middle ear fluid in the older child than in a pre-schooler.

Conductive deafness is common in preschoolers because of the position of the eustachian tube in this age group.

There is a surgical procedure to correct conductive hearing loss if it is chronic in the young child. "Grommets" can be inserted surgically via the eardrum allowing drainage of middle ear fluid but most children with conductive hearing impairment do not need this procedure. Conductive hearing loss often resolves by itself in children who present with it and the simple surgical procedure of grommet insertion or myringotomy as it is known is an option for those children in whom the deafness is not resolving itself.