Our Sense of hearing facilitates communication with other people thereby promoting relationships and fostering social interactions which is necessary for the survival of the normal human being. Hearing enables us to participate in daily activities, protects us by making us alert to danger and above all helps us experience life events.
Hearing impairment (loss) is the most frequent sensory impairment in humans (comparing to other senses of the body) with significant social and psychological implications.
The effects of a hearing loss will vary from one individual to another due to factors such as severity, age of onset, treatment and management options. Hearing loss present at birth (either it developed in utero or acquired during the process of delivery) tends to affect the child strongly. The greatest impact of hearing loss on a child is on the acquisition of language and development of communication leading to poor literacy skills and altered long-term employment opportunities and social interactions.
The World Health Organisation (WHO) estimates 320 million people (5% of world's population) living with disabling hearing loss, of which about 32 million (close to 10%) are children.
It is also noted that majority of people with debilitating hearing loss are in the world's low and middle income countries possibly due to the high level of disease occurrence and weaker maternal and child health services as compared to the high income countries.
WHO estimates that 60% of childhood hearing loss is preventable, however when the hearing loss is unavoidable, appropriate intervention measures can and will ensure that the child reaches full potential through habilitation, education and empowerment.
At the Hearing Assessment Centre of the Korle Bu Teaching, a total of 923 children were referred (new referrals) for assessment in 2015. The table below gives an elaboration of children assessed.
The total number of 923 gives an average of 76.9 children per month. Per the outcomes of assessment about 85 to 90% are diagnosed with varying degrees of hearing loss.
Infants under one year are referred for assessment by paediatricians due to complications during birth or other congenital anomalies that may suggest possible hearing loss.
Occasionally, a parent has been smart and noted the child does not respond to sound at that early age.
The figure for 1- 4 years is greatest and this can be narrowed down to 2-3years because at this stage the child is expected to begin talking but compared to his peers, he is not or has a few words- 'Delayed Speech' is the commonest complaint. From 5-14 years- the child may be talking but missing some speech sounds, not responding to soft speech or has poor school performance.
Our concern is that most often than not, the children are brought in too late (by 2 years the infant has acquired all the language syllables ready to be spoken) - It has duly been established that early identification of hearing loss and intervention gives the child the greater opportunity for learning spoken language, significantly reducing increased education costs associated with hearing loss and later in life improving earning capacity.
What are the causes of childhood hearing loss?
Hearing loss in children may be congenital (present at birth or soon after) or acquired as the child ages. Causative factors include:
Genetics: this may be responsible for close to 40% of childhood hearing loss. The impact of genetics is higher in areas with consanguineous marriages (couples who may be related). Aside some systemic congenital issues causing hearing loss, malformations of the ear and auditory nerve maybe due to genetics or environmental factors and may cause hearing loss.
Congenital Rubella Syndrome can cause hearing loss, eye and heart defects, sometimes thyroid dysfunction, autism and diabetes mellitus.
Conditions at the time of birth (accounts for about 17%): conditions including prematurity, low birth weight, birth asphyxia (lack of oxygen to the newborn) and neonatal jaundice may cause hearing loss.
Infections (accounts for about 31%): should the mother acquire any infection such as rubella or cytomegalovirus, there is a high possibility of the child getting hearing loss. Childhood infections such as mumps, measles, and meningitis can cause hearing loss. Ear infections if poorly treated or left untreated can lead to hearing impairments.
Medicines: use of ototoxic medicines in expectant mothers and for treatment of neonatal infections, malaria, tuberculosis and cancers may lead to permanent hearing loss. There is an unregulated use of ototoxic antibiotics across many parts of the world.
Noise: exposure to loud sounds, including personal audio devices played at loud volumes for prolonged periods, exposure to short high intensity sounds like fireworks may cause hearing loss. The noisy machinery in a neonatal intensive care unit can have impact on a babies' hearing.
Importance of early identification
Evidence-based practice has established that early identification and intervention with appropriate measures can minimize developmental delays, improve communication, education and social development.
There are researches to show children who are born deaf or acquire hearing loss soon after birth, once interventions are carried out by six months of age are likely to be at par with their hearing colleagues by five years of age.
Newborn hearing screening programmes established in various places across the world are aimed at identifying babies born with congenital hearing losses a few days after birth. Ghana is yet to establish such a programme.
Strategies for prevention and care
The WHO implores health agencies, organizations and governments to carry out the following measures
A : Strengthen
i-Immunization programmes- infections leading to hearing loss like congenital rubella, meningitis, mumps and measles be included in immunization programmes and improve coverage.
ii- Improve maternal and neonatal care- proper nutrition, promotion of hygienic practices and safe birth, prevention of undue delayed labour, prompt management of neonatal infection and jaundice.
iii- Support for people with hearing loss and their families
iv- Awareness programmes for promoting ear and hearing care in the community
i- Newborn hearing screening programmes for early identification
ii-Availability of hearing rehabilitation measures such as hearing aids and cochlear implants. Government intervention to make hearing devices affordable
iii-Speech therapy and other communication options
iv-School hearing programmes for continuous monitoring of hearing status and management of common ear diseases.
I- primary ear care training programmes be enhanced to widen the management of ear and hearing problems
ii- professional training programmes in Audiology and Otology to develop the human resources in the field of hearing health
D. Regulate and monitor
I- use of ototoxic drugs to minimize the dangers, restrict sale of such medicines
ii. regular audiological monitoring for patients on ototoxic medicines
iii. control of environmental noise (industrial or leisure), standards for use of personal audio devices