Sensory Impairments: Hearing

Educators need to take a child’s hearing loss very seriously, as it is the fastest growing disability in the world and hearing impairments can have such a detrimental effect on speech and language development.

Definitions:


Decibels

The intensity of sound or loudness is measured in decibels (dB), with 0 dB being the faintest sound that people with normal hearing are able to detect.

Degrees of Hearing Loss

Hearing Impairment broadly covers any hearing loss ranging from mild (loss range is 25-40dB) to completely deaf (loss range is 91dB+).

Deaf Persons

With or without a hearing aid, these people are unable to hear and process language effectively.

Hard-of-Hearing persons:

With the use of a hearing aid, these people are generally able to hear enough language in order to process it successfully.

Prevalence:

About 10% of those living in North America have some form of hearing loss; this rate rises to 50% for seniors. Hearing loss is not a common disability at birth: about 1 in 1000 babies are born deaf or is deaf by age three. 5% of school-aged kids have some degree of hearing loss, ranging from mild to profound. About 10 – 20% of these kids require some kind of special education. These percentages are estimates only, as accurate prevalence figures are difficult to obtain for many reasons, including inconsistent data and other research problems.

Etiology:

Outer Ear

Problems such as external otitis (swimmer’s ear), wax build-up, auditory atresia (missing/undeveloped auditory canals), Microtia (misshapen or tiny pinna), foreign objects stuck in the ear, and perforation of the eardrum are all possible causes for outer ear impairment which may cause hearing loss.

Middle Ear

Otitis Media (middle ear infection), is very common in infancy, and early childhood; and, 20-30% of elementary school kids suffer from this type of infection at least once. In addition, Otosclerosis (a hereditary condition, which is rare in childhood), congenital defects, and head trauma can all result in hearing losses. Most of these losses are conductive (sound is reduced or blocked before it gets to inner ear) and do not exceed 65 dB.

Inner Ear

Impairments involving the inner ear are sensorineural problems (sound may get to the inner ear, but cannot properly be received or transmitted) and can cause profound hearing loss. Meningitis, maternal Rubella and hereditary factors can result in these kinds of hearing disabilities in childhood. In addition, prolonged exposure to loud, intense noises can destroy the tiny hair cells in the inner ear, which can cause permanent hearing loss. Many other causes for inner ear problems are not yet known. Premature and low birth weight babies carry and increased risk for hearing impairments, and some birth complications can cause deafness. Apnea at birth can cause hearing problems as well.

Syndrome

Hearing loss may also be associated with various syndromes, including Treacher-Collins syndrome, Waardenburg’s syndrome and Down syndrome.






Bennett, S., Dworet, D., & Weber, K. (2008). Special Education in Ontario Schools (6th ed.). St.
     Davids, Canada: Highland Press, pp. 191-193.

Winzer, M. (2008). Children With Exceptionalities in Canadian Classrooms (8th ed.). Toronto,
     Canada: Pearson Prentice Hall, pp. 321-333.