Otosclerosis is a common cause of hearing impairment and is hereditary. Someone in earlier generations of your family had the condition and passed it down to you. Similarly, your descendants may inherit this tendency from you, although the hearing impairment may not manifest itself for a generation or two. Being hereditary, diseases such as scarlet fever, ear infection, measles and influenza have no relationship to the development of otosclerosis. The external ear collects sound, the middle ear mechanism transforms the sound and the inner ear receives and transmits the sound.
Sound vibrations enter the ear canal and cause the eardrum to vibrate.
Movements of the eardrum are transmitted across the middle ear to the inner ear fluids by three small ear bones. The fluid waves stimulate delicate nerve endings in the hearing canals. Electrical impulses are transmitted on the nerve to the brain where they are interpreted as understandable sound. If there is some difficulty in the external or middle ear, a conductive hearing impairment occurs. If the trouble lies in the inner ear, a sensorineural or nerve hearing impairment is the result.