Clinical features

The main features of otosclerosis include:

• onset usually 20 - 40 years
• family history in two thirds of cases
• two thirds of patients are female, with the condition precipitated or promoted by pregnancy
• commonly bilateral and symmetrical; may be unilateral
• patient may hear better in noisy surroundings
• tinnitus may be present

On examination:

• absent stapedial reflex
• normal tympanic membranes
• Rinne's test negative; Weber's test - hearing best in the deafer ear
• audiometry - air conduction is impaired

A normal ear drum, in the presence of conductive hearing loss suggests otosclerosis.

If the cochlea is affected, there may be signs of sensori-neural deafness - Rinne's positive; Weber's - sound heard loudest in the normal ear.