|
5. CAUSES OF HEARING IMPAIRMENTS A hearing impairment may be present at birth or may develop at time during life. A person with a hearing impairment could have prelingual loss, this occurs prior to the age of 2, or before speech development or postlingual loss that occurs at any age following speech acquisition. The age of the onset of the hearing impairment is a very critical variable in determining the type and extent of intervention, especially in speech and langure development. Hearing impairment can develop due to congenital factors whereas the hearing loss can be hereditary or due to a prenatal disease. Later in life hearing impairment can be acquired due to a postnatal disease or environmental factors. Most typical causes of hearing impairment are: - Otitis media (ear infection that affects the middle ear) - Genetic disorders (affecting correct development of the ear) - Ear and head injuries (fractures, contusions, bleeding) - Problems connected with pregnancy or birth. (infection of mother during pregnancy, premature birth) - Repeated infections or illnesses. (ear infections, mumps, measles, chickenpox, brain tumours) - Medications (specific types of antibiotics and chemotherapy) - Loud noises (both sudden and long ter exposure to extremely loud or high pitch noises) Hearing loss can be difficult to diagnose in infants and babies because they haven't yet developed communication skills. Often babies are screened before they leave the hospital to see if they have hearing loss. Sometimes parents may begin to notice that the baby doesn't respond to loud noises or to the sound of voices. |