Hearing loss takes place with growing age and starts basically after the early 50s. It is broadly categories into three types;
Conductive- it affects outer or middle ear.
Sensorinerual- takes place at inner ear.
Mixed – involves outer, middle and inner ear.
It does not take place suddenly. It is in itself a gradual process that is accompanied by several signs and symptoms. Some of the major ones are listed below.
Muffling of sounds
Not hearing the sound clearly
Raising the volume of Tv or radio above the normal level.
Difficulty in distinguishing the sounds properly
Problem in understanding the words majorly against background noise
If you come across any of the above symptoms, contact your doctor as soon as possible.
Yes, hearing loss takes place as you get older but apart from that there are other reasons as well;
Harm to the inner ear
Loud noise damage the hairs on nerve cells present in cochleathat transmit the sound signals to the brain. If these hairs are damaged electrical signals are not transferred properly that further becomes a reason for hearing-loss.
Gradual building of earwax is another major cause of hearing loss. Earwax blocks the ear canal and prohibits the conduction of sound waves. Removal of earwax restores hearing.
Ear infections and other abnormalities like bone-growth and tumors cause hearing loss. Basically, such abnormalities occur in the outer or middle ear.
A cochlear implant is an electronic medical device that replaces the function of the damaged inner ear. Unlike hearing aids, which make sounds louder, cochlear implants do the work of damaged parts of the inner ear (cochlea) to send sound signals to the brain.
Most important thing is early diagnosis. Management of deaf and mute child should be started as early as possible. Success of cochlear implant is more if it is done by the age of 3years. Success rate decreases with advancement of age of child.
How we hear?
The eardrum vibrations caused by sound waves move the chain of tiny bones (the ossicles – malleus, incus and stapes) in the middle ear transferring the sound vibrations into the cochlea of the inner ear. This is where the streams of nerve impulses are converted into meaningful sound.
Parts of ear:
Outer Ear :
Middle Ear: Converts sound waves in to vibrations.
Inner Ear (Cochlea): converts vibrations into electrical impulse. Theses electrical impulse travel to brain via nerve of hearing (Cochlear nerve)
What is cause of Hearing Loss in children?
As the cases of children being unable to hear pile up in Gwalior, it is necessary to know what causes the loss of hearing at such an early age. In children hearing loss can be congenital (from birth) or acquired (after birth). Acquired can be due to various infections or trauma, etc.
Hearing loss can also be classified as per language development as follows
Pre-lingual –hearing loss developed before child could start speaking, it can be either congenital (from birth) or acquired (after birth).
Post-lingual – hearing loss developed after child started speaking. It means it is acquired.
Cause of hearing loss is any defect in the transmission of sound through the ear. It can be
Conductive – Caused by defect in middle or external part of ear. It can usually be treated by some medications. Less frequently a surgery is required to correct this type of hearing loss
Sensory-neural – Caused by defect in nerve of hearing or cochlea. Mild to moderate hearing loss can be treated by hearing aid whereas severe to profound hearing loss requires Cochlear Implant surgery
Burden of Hearing loss?
In US Significant bilateral hearing loss is present in ~1 to 3 per 1000 newborn infants in the well-baby nursery population, and in ~2 to 4 per 100 infants in the intensive care unit population.
In India, 63 million people (6.3%) suffer from significant auditory loss. Four in every 1000 children suffer from severe to profound hearing loss. The estimated prevalence of childhood onset deafness to be 2%
How to assess Hearing loss in a new born?
Detection of infant hearing loss requires universal screening of all infants. Screening by high-risk registry alone (eg, family history of deafness) can only identify ~50% of newborns with significant congenital hearing loss. Reliance on physician observation and/or parental recognition has not been successful in the past in detecting significant hearing loss especially in the first year of life.
Tests for screening include otoacoustic emissions (OAE) and auditory brainstem response (ABR / BERA). Both test are noninvasive, quick, and easy to perform, although each assesses hearing differently. Aim is to initiate necessary intervention by 6 months of age.