A child who is unable to hear those sounds, which lie within the normal audible range, is said to have hearing loss. Such a child finds it difficult to hear a sound that a child with normal hearing can hear clearly.
The normal hearing thresholds limit is of 25dB or better in both ears, anything less than this can be considered as hearing loss. This problem occurs when any part of an ear or both the ears is not working in a usual way. Hearing loss may be mild, moderate, severe or profound. Children with more than normal hearing loss, ranging from mild to severe are usually referred as hard of hearing. Such children can communicate effectively through spoken language and can benefit from devices, such as hearing aids and assistive devices.
[Read: Ear Wax Build-up in Kids]
Children with more significant hearing losses may benefit from cochlear implants and with profound hearing loss, which implies very little or, no hearing, are categorized as deaf. Such children use sign language for communication. Latest WHO fact sheets say that currently there are 32 million children with disability with hearing loss. Loss of hearing in children up to 14 years of age refers to the condition where the loss is greater than 30 dB than the better hearing ear.
Despite the large number of children getting affected by hearing loss, almost half of all cases are avoidable through primary prevention. Captioning, sign language training, educational and social support also help a child overcome the hearing problem. Since hearing loss has a huge negative impact on learning and development of a child, it is very important to diagnose and treat it as early as possible. Unattended hearing loss, otherwise, can have an impact on your child’s employment, education, and general well-being in future.
Hearing loss can affect the ability to learn and develop communication, language, and social skills. There can be several causes of hearing loss ranging from wax in ear to low weight at birth. However, the causes are categorized into two types:
1. Congenital Causes:
It means that the hearing loss is present since birth. Such hearing loss can be caused by hereditary and non-hereditary genetic factors or by certain complications during pregnancy and childbirth, like maternal rubella, syphilis or certain other infections. Problems like underweight during birth and lack of oxygen, also called birth asphyxia, are also among the major congenital causes of hearing loss.
Severe jaundice in the neonatal period, can also damage the hearing nerve in a newborn. Out of every 1000 children who are under 18 years, are found to be affected by hearing loss, where congenital cases are in majority, amounting to one in every 650 babies. The presence of hearing loss increases in babies with other health problems. Apart from these causes, inappropriate use of ototoxic drugs (such as aminoglycosides, cytotoxic drugs, antimalarial drugs and diuretics) during pregnancy also increases risk of hearing loss in children.
It is one of the most common congenital problems in babies, where around 5 percent to 10 percent of all children with severe or profound hearing loss are born to parents with severe and profound hearing problem. While, non genetic factors can account for about 25% of congenital hearing loss in children, heredity is believed to cause more than 50% of all such hearing loss. A genetic hearing loss can be described as autosomal recessive or autosomal dominant.
In autosomal recessive hearing loss, both parents carry the recessive gene and pass it along to the child. In this case, the parents might not be suffering from hearing loss themselves and therefore can be surprised to discover their child has a hearing loss. However, an autosomal dominant hearing loss occurs, when an abnormal gene from one parent is able to cause hearing loss in the child even though the matching gene from the other parent is normal. The parent carrying the dominant gene may also be hard of hearing.
[Read: Kids and Ear Infections]
2. Acquired Causes
Acquired causes lead to hearing loss that appears after birth. It can occur at any time in one's life and is caused by non-genetic causes. Chronic ear infection is one of the most common acquired causes that can lead to hearing loss in children. Infectious diseases, such as meningitis, measles and mumps also lead to hearing loss in children. Use of ototoxic drugs, wax or foreign bodies blocking the ear canal, excessive noise, and exposure to loud music or other loud noises, are other acquired causes that can harm a child’s hearing.
Among children, chronic ear infection also called otitis media is the leading cause of hearing loss. The passage between the middle ear and the back of the throat is smaller and more horizontal in children than in adults, leading to frequent ear infections. Ear infections happen when the middle ear, a small space behind the eardrum, becomes inflamed. Such infection can happen in one or both the ears. This allows it to be more easily blocked by infections in the ear.
[Read: Dealing With Hearing Loss]
While some children have no change in their hearing, however, chronic ear infection can cause permanent damage. Hearing loss due to otitis media can be prevented by practicing healthy ear and hearing care. Early detection and intervention is the most important factor in minimizing the impact of hearing loss on a child’s development. Early identification and management through infant hearing screening programmes can improve the linguistic and educational outcomes for the child.
Read more articles on Hearing Loss.