Hearing Evaluation

Sound plays a very important part in our every day life. Is enables us to communicate and enjoy the sounds of nature and listen to music, sound may also warn us of different dangers. All sounds originate from movement when e.g. the wind blows it causes the leaves on trees to move. The leaves push the molecule in the air making them viberate, these vibrations are called sound waves.. Slow vibrations (low frequencies) are heard as the deep tones while fast vibrations (high frequencies) are heard as high tones.

The Human Ear

The ear is a sophisticated, sensitive and a complex organ, which consists of there main parts:

The External Ear

The external ear is made up of external cartilaginous part of the ear and the ear canal. Ear drum is located at the end of ear canal and forms the boundary of the middle ear. The external ear picks up sound waves and conducts them to the ear drum causing it to vibrate

The Middle Ear

The middle is an air filled space that connects the external ear canal to the inner ear. It starts from the tympanic membrane (ear drum). It also contains the bones of the middle ear and ends with the oval window of the cochlea. The middle ear bones are the smallest bone in the human body and are very delicate. The first bone is called malleous the second bone is called incus and the last bone is called stapes. The sound vibrations causes the stapes to move back and forth. This motion is then transferred to the inner ear.

The Inner ear

The inner ear, or cochlea is shaped like a snail shell and filled with fluid. The balance organ is attached to the cochlea and is made up of three fluid filled semicircular canals. The oval window connects the middle ear and the inner ear. The foot plate of the stapes is attached to the oval window and functions as a piston moving the fluid of the inner ear. This movement of the fluid activates the hair cells in the inner ear (there are about 20 thousand these sensory cells). When the hair cells activate, they send impulses via the acoustic nerves to the brain which perceives these impulses as sound. The slightest problem in this complex system can impair the hearing ability.

Hearing Impairment

Millions of people world wide are facing the problems of hearing loss or tinitus (ringing or other sounds in the ear) but only in minority of these people use hearing aids. Hearing loss is mainly an age related problem but effects the people of all ages.

Sensorineural Hearing Loss

Sensorineural Hearing loss is due to the problem in the inner ear or cochlea. The inner ear does not change sounds into tiny electrical impulses which the auditory nerve need. The nerve cannot send sound information to the brain. A problem in the inner ear can cause sensorineural hearing loss. This can be mild, moderate, severe to profound and even total hearing loss. Sensorineural Hearing losses are usually permanent. There is no surgical procedure to cure the problem in this part of the ear, depending on the cause, medication may be helpful in some cases. Conventional hearing aids usually help in mild to severe degree hearing losses. Cochlear implants can be a very effective option for those people with severe, profound or total hearing loss, who have not been able to get enough speech information with most powerful hearing aids.

Neural Hearing Loss

Neural Hearing Loss is due to a problem in the nerve pathway. The auditory nerve being damaged or missing so the signal cannot passe to the brain. In very rare cases hearing loss may be caused by the absence or damage to the auditory nerve resulting in neural hearing loss. Conventional hearing aids will give little benefit because the nerve is not able to pass on enough information to the brain. A cochlear implant will not help unless there is some residual auditory nerve.

Conductive Hearing Loss

Conductive Hearing Loss is due to a problem in the outer or middle ear, ear drum and bones cannot vibrate. Any problem in the outer and the middle ear can block sounds to the ear and causes a Conductive Hearing Loss. Conductive Hearing Loss is usually mild or moderate and is generally temporary. Large number of such cases can be treated with medicine or surgery.