Ear, Nose and Throat Specialist, Paarl
There are 2 types of hearing loss in children: Conductive hearing loss due to abnormal conduction of sound to the inner ear or Sensory-Neural Hearing Loss due to decreased function of the inner ear itself. Although conductive deafness is the most common cause of hearing loss (4% of school children), sensory-neural hearing loss (0.3%) is the most severe and more permanent cause.
Temporary hearing loss due to Eustachian tube dysfunction (fluid in the middle ear) or middle ear infections is common and is treated with medication or ventilation tubes. Permanent hearing loss is often present at birth but in about 10-20% of cases, the hearing loss occurs after birth. The risk factors for sensory-neural hearing loss include: family history of deafness, certain infections during pregnancy (rubella, mumps, meningitis), certain medications that may affect the ear, certain syndromes associated with hearing loss, complications during / after birth, prematurity, low APGAR score, severe jaundice, and head injuries. If babies have any of these risk factors, hearing tests should be requested. However, in 20-30% of cases, the cause is unknown.
The presentation of hearing loss depends on the age of presentation and degree of hearing loss. Severe hearing loss is usually diagnosed at 6-9 months of age. Mild hearing loss usually presents with speech and language impairment, behavioural problems or poor school performance. If a child is specifically struggling with speech impairment, hearing tests should be done in the first instance.
The faster the hearing loss, especially severe sensory-neural hearing loss, is diagnosed, the quicker treatment can be started and the better the outcome for the child. In most First World countries this is realized, and universal hearing screening is done in all newborn babies. In South Africa this is not the case, but the equipment is widely available, and audiologists can do this test just after birth. This is known as an OAE test and lasts only a few minutes. Brain stem reflex tests can also be done if an OAE screening test fails. The diagnosis of hearing loss must be made early, before 6 months, so that treatment such as hearing aids or possible cochlear implants can be given. Children with deafness also need special education, and schools for hearing impaired children are there to perform these functions.
