Tests For Hearing
A young man presents with an accident leading to loss of hearing in right ear. On otoscopic examination, the tympanic membrane was intact pure tone audiometry that shows an air-bone gap of 55 dB in the right with normal cochlear reserve. Which of the following will be the like ympanometry finding: (LQ)
|A||As type tympanogram|
|B||Ad type tympanogram|
|C||B type tympanogram|
|D||C type tympanogram|
This is also a very interesting question:
• The question says. Pure tone audiometry shows an air bone gap of 55 dB in the right ear with normal cochlear reserve.
• The air-bone gap in pure tone audiometry is a measure of total conductive deafness.
• Hence - it means there is a conductive deafness of 55 dB in the right ear.
• Next the question says - Patient has intact tympanic membrane so we have to look for a cause ofthis 55 dB conductive deafness.
Average hearing loss seen in different lesions of conductive apparatus Ref. Dhinqra 5th/ed p 34
1. Complete obstruction of ear canal
2. Perfo!ation of tympanic membrane
3. Ossicular interruption with intact drum
4. Ossicular interruption with perforation
5. Closure of oval window
As is clear from above table - with tympanic membrane intact and a hearing loss of 55 dB is seen if ossicular chain is disrupteD.
Hence- it is a case of ossicular discontinuity.
Tympanogram seen in ossicular discontinuity is a high compliance tympanogram . Ad tympanogram.