Sense of hearing is one of the most important gifts given by god to human beings. We have no sharp eyes like the eagle or the acute sense of smell provided to dogs. All of us prefer to live with normal hearing though we can get along with mild or total hearing loss. Man s hearing system is a bundle of complex physical system. A defect in any part of the system causes some hearing loss, conductive and sensory. The former is caused by the loss of easy conduction of sound waves from outside to the inner ear. The causes may be a simple obstruction like ear wax, infection, a stiffening of ossicles that should vibrate with sound, scarring tumors and the perforation of the ear drum. Hearing can be restored if the cause is diagnosed. But sensor neural hearing loss cannot be cured and restored.
Deafness of the Nerve
It is damage to the auditory nerve or to the hair cells of the inner ear that causes sensor neural or sensory hearing loss. The inner ear or the nerve running from the inner ear to the brain, or the brain itself is damaged in sensory hearing loss. Ageing is also a cause of this “nerve deafness”. Other causes for sensor neural hearing loss include tumors, frequent exposure to blaring noise, specific toxic medication, heredity or infection. Sensory hearing loss is irreversible unlike conductive hearing loss. It leaves hope for future treatment. Genetically causes for sensory hearing loss are related to guilty genes and they can be treated by genetic therapy in future.
Sensor neural hearing loss falls into two divisions, namely, sensory and neural types. Strictly speaking, damage to cochlea is called sensory hearing loss, the causes bring loud noise, infection, toxic medication or Meniere s disease. Neural loss is the effect of damage to the auditory nerve or the eighth cranial nerve. Tumors or neurological disorders are responsible for this type of damage. Critical, life threatening problems are caused by tumors on the eighth cranial nerve though they can be treated and cured. Hence any hearing disorder should get immediate attention of the doctor. Mostly, it is cochlear damage that is seen in sensory hearing loss and not the neural loss. It is rarely that hearing is due to damage to the auditory centre of the brain. Here, sound hearing may be at normal level though the sound is poor making the speech hard to understand.
[tags]Sensory Hearing Loss, Cranial Nerve[/tags]