Hearing Loss

Hearing Loss:

a- Etiology of hearing loss:

1- Conductive hearing loss:

-          It's the loss of hearing due to interruption of the conductive pathway from the auricles towards the cochlea.

-          Causes include: impacted ceuremen, middle ear congestion/effusion, otosclerosis, ossicles disruption  , rupture of tympanic membrane

2- Sensorineural hearing loss:

-          Loss of hearing due to interruption or damage in the pathway between cochlea and vestibule-cochlear nerve.

 -          Etiology include: presbycusis, congenital deafness, 8th nerve injury and ototoxixity.

       b- How to diagnose the type of hearing loss:

THE FIRST THING TO DO IS TO PERFORM WEBER TEST, USING 512 MHz fork to detect the presence of Lateralization.

WEBER test is performed via placing the oscillating fork on the temple:

If sound is heard in the midline, i.e. no lateralization, therefore, no hearing loss.

If lateralization is present,

Conductive hearing loss: sound is heard well in the affected ear.

Sensorineural hearing loss: sound is heard well in the normal ear.

To differentiate perform Rinne test , by placing the tuning fork on mastoid bone to test for air conduction AC then when the sound fades away place the tuning fork to test for bone conduction BC.

In conductive hearing loss BC is better than AC

In sensorineural hearing loss AC is better than BC