As per The Rights of Persons with Disabilities Act, 2016, the following definitions regarding hearing impairment are stipulated:
- "deaf" is reserved for persons having 70 DB hearing loss in speech frequenciesin both ears;
- "hard of hearing" is defined as a person having 60 DB to 70 DB hearing loss in speech frequencies in both ears;
Normal hearing is considered to be within thresholds of 25 dB or better in both ears.
There are four types of hearing loss:
- Sensorineural Hearing Loss: Hearing loss that occurs when there is a problem in the way the inner ear or hearing nerve works.
- Conductive Hearing Loss: Hearing loss caused by a physical barrier that prevents sounds from getting through the outer or middle ear. This type of hearing loss can often be treated with medicine or surgery.
- Mixed Hearing Loss: Hearing loss that includes both a conductive and a sensorineural hearing loss.
- Auditory Neuropathy Spectrum Disorder: Hearing loss that occurs when sound enters the ear normally, but because of damage to the inner ear or the hearing nerve, sound isn’t organized in a way that the brain can understand.
The causes of hearing loss and deafness can be congenital or acquired.
Congenital causes may lead to hearing loss being present at or acquired soon after birth. Hearing loss can be caused by hereditary and non-hereditary genetic factors or by certain complications during pregnancyand childbirth, including:
- maternal rubella, syphilis or certain other infections during pregnancy;
- low birth weight;
- birth asphyxia (a lack of oxygen at the time of birth);
- inappropriate use of particular drugs during pregnancy, such as aminoglycosides, cytotoxic drugs, antimalarial drugs, and diuretics;
- severe jaundice in the neonatal period, which can damage the hearing nerve in a new borninfant
Acquired causes may lead to hearing loss at any age, such as:
- infectious diseases includingmeningitis, measles and mumps;
- chronic ear infections;
- collection of fluid in the ear (otitis media);
- use of certain medicines, such as those used in the treatment of neonatal infections, malaria, drug-resistant tuberculosis, and cancers;
- injury to the head or ear;
- excessive noise, including occupational noise such as that from machinery and explosions;
- recreational exposure to loud sounds such as that from use of personal audio devices at high volumes and for prolonged periods of time and regular attendance at concerts, nightclubs, bars and sporting events;
- ageing, in particular due to degeneration of sensory cells; and
- wax or foreign bodies blocking the ear canal.
Among children, chronic otitis media is a common cause of hearing loss.
Sensorineural Hearing Loss
There is no medical or surgical method of repairing the tiny hair-like cells of the inner ear or the auditory nerve if they are damaged. However, sensorineural hearing loss can be treated with hearing aids or cochlear implants, depending on the severity of the loss. Assistive listening devices, like alerting devices, vibrating alarm clocks and captioned phones help provide a complete hearing solution. For people with severe-to-profound hearing loss, power hearing aids can help.
Conductive Hearing Loss
There are sometimes medical or surgical treatments that can improve the hearing ability for those with conductive hearing loss. For example, conductive losses caused by wax impaction, foreign objects, abnormal growths or ear infections can often be corrected with medical treatments, like extraction of earwax, antibiotics or surgical procedures. These causes usually result in temporary hearing losses. The treating physician and hearing healthcare professional will monitor hearing ability and work with the patient to determine when and if a hearing solution is needed.
Conductive hearing losses caused by other abnormalities, like stenosis of the ear canal, exostoses, otosclerosis and ossicular chain discontinuity are more difficult to treat medically and may be considered a permanent hearing loss. These conductive losses may be treated with either standard hearing aids or bone-anchored implantable device
LossTreatment options for mixed hearing loss will depend on whether the loss is more sensorineural or conductive in nature. If a greater portion of the loss is caused by a conductive component, surgical procedures and other medical treatments might be more effective in correcting the hearing concerns. If a greater portion of the loss is sensorineural, hearing aids or implantable devices may be the best option.
Auditory Neuropathy Spectrum
DisorderResearchers are still seeking effective treatments for people with auditory neuropathy. Meanwhile, professionals in the hearing field differ in their opinions about the potential benefits of hearing aids, cochlear implants, and other technologies for people with auditory neuropathy. Some professionals report that hearing aids and personal listening devices such as frequency modulation (FM) systems are helpful for some children and adults with auditory neuropathy. Cochlear implants (electronic devices that compensate for damaged or nonworking parts of the inner ear) may also help some people with auditory neuropathy. No tests are currently available, however, to determine whether an individual with auditory neuropathy might benefit from a hearing aid or cochlear implant
Statistics in India
There are about 18 million deaf people in India. An estimated 63 million people suffer from significant hearing loss in India.
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