Definition:
A hearing impairment means that one or more part of ear is damage or not working properly.
OR
A hearing impairment is a hearing loss that prevents a person from totally receiving sounds through the ear.
OR
OR
Hearing impairment refer to a condition in which individuals are fully or partially unable to detect or perceive at least some frequency of sound which can typically be heard by member of their species.
The general terms used for hearing loss are:
Deafness:
Deafness means a hearing impairment that is so severe that the child is impaired in processing linguistic information through hearing, with or without amplification, that adversely affects a child’s educational performance.
The children labelled as deaf are unable to make use of their hearing to understand speech even if they are equipped with one or other type of hearing aids. Even if they have perception of some sounds through residual hearing, they are unable to make its use for their learning and communication.
Hard of hearing:
Any one with a lesser hearing loss is identified as hard of hearing. And it does not adversely affect on child’s educational performance.
How we hear:
The ear has 3 parts. Each with its own task.
Outer ear collects sounds and sends it to middle ear. In the middle ear sounds change into vibrations. These vibrations travel into the inner ear. In inner ear where tiny hair cells (cilia) and hearing nerves turn the vibrations into nerve impulse (signals). These signals are sent to the brain. The brain then figures out which ear the sound is coming from. With hearing loss either a temporary blockage or permanent problem within the ear or brain keeps sounds from being heard or understood.
Classification of hearing impairment
According to defects in structure or function there are four types of hearing impairment
Ø Conductive hearing loss
Ø Sensorineural hearing loss
Ø Mixed hearing loss
Ø Central hearing loss
1. Conductive hearing loss:
It is common in children. It can affect one or both ears. For someone to hear, sounds signals must travel from outside the ear through the ear canal and ear drum into the inner ear. Conductive hearing loss results when sound become partially or fully blocked in outer or middle ear. Some causes of conductive hearing loss are:
Ø Wax buildup in ear canal
Ø Fluid buildup behind the ear drum(by infection)
Ø Abnormal formation of ear bones
Ø Object stuck in ear canal such as food or toy parts
It is often temporary and may be improved with medical or surgical procedure.
Sensorineural hearing loss:
Hearing loss can affect one or both ear. It is due to problem with inner ear or damage to hair cells or nerves inside the inner ear. To hear properly these hair cells and nerves must process and carry sounds to brain. The brain then sense what we hear. With sensor neural hearing loss, the hair cells or nerves are damage and do not send the signals to brain, needed for hearing. Some causes include:
1 .explore to loud sound
2. Infection of mother during pregnancy
3. Medication that is toxic to ear
4. Family history of permanent hearing loss.
Sensory hearing loss is usually permanent. So treatments involve devices that help the child to hear as well as possible.
Mixed hearing loss:
It is combination of conductive and sensor neural hearing loss. And it means that a problem occur in both the outer or middle and the inner ear. As a result children suffering from such mix loses exhibit the impairment and disabilities related to both the above two categories
Central hearing loss:
Central hearing loss result from damage or impairment to the nerve of nuclei of central nervous system, either in pathway to brain or in the brain itself. It results into a quite severe hearing impairment and hearing disabilities among affected children.
TYPES OF HEARING LOSS ON BASIS OF HEARING LEVEL
From this angle, therefore it is practicable to classify the hearing loses as slight, mild, moderate, severe or profound; depending upon how well adperson can hear the intensities (loudness) of the sound, measured in unites called decibels (db) or frequency (pitch) of sound, measured in units called hertz. (Hz) generally only children whose hearing los is sever or profound, greater than 90 Db are considered deaf and the remaining once to suffer from slight mild or moderate hearing loses are termed as hard of hearing.
