Hearing Impairment
Hearing ability is quite essential in human beings since it determines their speech and oral skills. Hearing helps people socialize and connects people to the outside world. Hearing also helps one recognize potential danger, and therefore it helps in people’s safety. Just like any other part of the body, ears at times may not function as expected due to various reasons leading to hearing impairments.
Hearing impairment occurs when there is damage to one or more parts of the ear. Hearing impairments arise in various forms and can be categorized into conductive hearing disorders, sensorineural impairments, mixed hearing loss and central hearing disorders (Paludetti et al., 2012). Conductive hearing loss occurs when there is structural damage or blockage to the outer and inner ear. Destruction of the eardrum and ear canal and ossicles also leads to conductive hearing impairment. Conductive hearing impairment affects how sounds are transmitted through the ear and make the sound appear faint or more of a whisper. Sensorineural hearing loss occurs as a result of damage of the cochlea, the inner ear or the auditory nerve. Sensorineural hearing loss is also brought about by the impaired functioning of the hair cells, and the affected person may have challenges in interpreting speech and hearing. A person may be affected by both conductive hearing loss and sensorineural hearing impairment; a condition referred to as mixed hearing loss. Central hearing loss is as a hearing impairment whereby the inner ear is working, but some parts of the brain are not working well. Hearing impairments present at birth are called congenital hearing disorders while those acquired later in life are known as acquired hearing disorders.
In children, congenital disorders are caused by numerous factors. The factors are either genetic or non-hereditary. Premature births lead to hearing impairments. The hearing system of children born prematurely is not fully developed and is very sensitive. Prematurely born children may be put in some medications which may adversely affect their hearing. The health of the mother is paramount in the development of babies. If the mother has infections like cytomegalovirus, the child is likely to acquire some hearing defects (Goderis et al., 2014). Cytomegalovirus is transmitted to the through breast milk, saliva or during birth. The virus affects the hearing system, and hearing loss is one of its symptoms. Use of drugs and substances while pregnant inhibits the proper growth of the fetus. Under the influence of alcohol and drugs, development of the hearing system of the fetus is disrupted, leading to hearing impairments. Some medications like ototoxic medication used by the mother while pregnant may cause potential damage to the auditory nerves. Children born with brain and nervous system disorders are also likely to suffer congenital hearing disorders.
Majority of the hearing problems in children are caused by genetic factors (Korver et al., 2011). Genetic mutations can lead to hearing loss. Inner ear hair cells play a critical role in the hearing process. Mutations of these sensory hair cells prevent them from functioning as required therefore leading to problems in hearing and at times total hearing loss. Otosclerosis is also an inherited condition that causes hearing loss. Otosclerosis is a condition where there is an abnormal growth of the bone in the middle ear. The deformed structure of the bone prevents the normal functioning of the affected parts of the ear leading to hearing loss. Parents who are suffering from Usher’s syndrome, genetic mutations of the inner ear are likely to pass the faulty genes to their children leading to hearing loss in children. Parents who do not have hearing loss but are carriers of a recessive gene are likely to pass over the defective gene to their offspring. Some of the hearing impairments are acquired later. Acquired hearing impairments are caused by exposure to loud noise leading to noise-induced hearing impairment, severe brain injury, being exposed to smoke, and a tear in the tympanic membrane that is a ruptured eardrum.
Hearing loss can be detected, and when detected earlier it can be prevented. Physicians may conduct a physical examination. Physician looks out for the cause of hearing loss by checking any inflammation in the ear or ear wax blocking the ear. Structural causes of hearing loss are also assessed to pinpoint the exact cause of hearing loss to give the proper treatment. The doctor may also conduct general tests by whispering and telling the patient to cover one ear to determine the affected ear. The patient is also tested using various levels of sound to determine whether he or she can hear from a distance. Audiometer tests are also carried out. Audiometer tests are carried out by an audiologist where sounds are directed to each ear in different tones to determine the lowest sound one can hear. Children at risk of hearing loss are subjected to neuro-imaging whereby a scan is carried out to assess the anatomy of the outer, middle and inner ear. The scan can detect malformations; hence it is useful in providing a prognosis, and necessary measures are put in place. Hearing impairments can also be identified in the womb. Expectant mothers undergo counselling and samples from the fetus who are at risk of being born with hearing impairments are extracted for further diagnosis (Yin et al., 2014). Testing of the fetus helps in making parents aware of the likelihood of their children being born with the disorder, and therefore necessary precautions are put in place to manage the situation.
Hearing impairments are caused by various factors and can be detected early. Some of the factors are genetic while others are modifiable. Diagnosis of hearing impairment should, therefore, be conducted soon enough to mitigate the effects and prevent deafness since hearing is a critical sense of the human body.
References
Goderis, J., Leenheer, E. D., Smets, K., Hoecke, H. V., Keymeulen, A., & Dhooge, I. (2014). Hearing Loss and Congenital CMV Infection: A Systematic Review. Pediatrics, 134(5), 972–982. https://doi.org/10.1542/peds.2014-1173
Korver, A. M. H., Admiraal, R. J. C., Kant, S. G., Dekker, F. W., Wever, C. C., Kunst, H. P. M., … Oudesluys ‐Murphy, A. M. (2011). Causes of permanent childhood hearing impairment. The Laryngoscope, 121(2), 409–416. https://doi.org/10.1002/lary.21377
Paludetti, G., Conti, G., Di Nardo, W., De Corso, E., Rolesi, R., Picciotti, P. M., & Fetoni, A. R. (2012). Infant hearing loss: from diagnosis to therapy Official Report of XXI Conference of Italian Society of Pediatric Otorhinolaryngology. Acta Otorhinolaryngologica Italica, 32(6), 347.
Yin, A., Liu, C., Zhang, Y., Wu, J., Mai, M., Ding, H., … Zhang, X. (2014). Genetic counselling and prenatal diagnosis for hereditary hearing loss in high-risk families. International Journal of Pediatric Otorhinolaryngology, 78(8), 1356–1359. https://doi.org/10.1016/j.ijporl.2014.05.030