Deafness And Hearing Aids Explained
“Hearing aids may be analog which only increases the sound or digital, which cuts out background noises and helps the patient hear speech clearly”
Deafness can be mild, moderate, severe. profound or total. It can be unilateral or bilateral. If it is mild or moderate, it often goes unnoticed as the deaf patient can hear normal sounds and speech but may sometimes miss a soft whisper. This kind of deafness becomes apparent if the patient goes in for a pre employment hearing test (audiogram). Also, if the loss is severe and unilateral. it may again go unnoticed especially in children.
Causes Of Deafness
Deafness can be congenital (at birth) or acquired. It can be caused by lesions in the external ear like congenital atresia, stenosis, polyps, granuloma which can cause a conductive hearing loss and can be treated medically or surgically. Lesions in the inner ear cause nerve deafness known as sensorineural loss and this can be treated with hearing aids. If hearing loss is mixed, namely conductive and sensorineural, surgery may not provide 100per cent improvement and in that case, a hearing aid is a must.
What Is A Hearing Aid?
It Is a device worn on or In the ear which amplifies external sound, to bring it to a hearing level. Hearing aids may be analog which only increases the sound or digital, which cuts out background noises and helps the patient hear speech clearly.
Types Of Hearing Aids
- Behind the ear (BTE)
- In the ear (ITE) which is of three types:
- In the concha (ITC)
- In the canal (ITC)
- Completely in the canal (CIC)
The Hearing aid is fitted on the patient after a hearing aid trial to check which aid suits the loss best. The BTE or ITE aid can be chosen by the patient but in the canal it will not suit profound hearing loss as it is not powerful enough.
Hearing Aids As Per Hearing Loss
Hearing aids are also implanted surgically in the middle ear but only for severe losses. (Example, Vibrant Sound Bridge). If the patient has a conductive loss (congenital atresia) where surgery may not be successful, he/she can have a bone anchored hearing aid (BAHA) implanted behind the ear.
Additionally, if a child or an adult has profound or total hearing loss not benefitted with hearing aids, he/she can get a cochlear implant which is implanted surgically in the inner ear to bypass the damaged cochlear hair cells and stimulate the spiral ganglia directly.
Also, a speech processor has to be worn along with the implanted device, which houses a microphone and a battery. And, pre-lingually deaf children have to undergo a rehabilitation programme for at least six weeks after which they can perceive sounds and speech.