Tests For Hearing
Rinne's test is negative if minimum deafness is:
As discussed in the text in Rinnies test-air conduction of the ear is compared with its bone conduction.
Principle and Result
• In normal individuals → AC > BC . Rinne test is positive
• In case of conductive deafness ~ air conduction is decreaseD. Hence BC> AC . Rinne test negative
• In U/L SNHL → air conduction is normal whereas BC is further decreaseD. Hence AC > BC. Rinne test positive
• But in case of severe U/L SNHL - patients do not perceive any sound of tuning fork by air conduction but respond to bone conduction testing which is in reality due to transcranial transmission of sound from the normal ear.
Hence there is false negative Rinne test (BC > AC).
Air conduction> Bone conduction
Bone conduction> Air conduction
• Normal individuals
• Conductive deafness
• Severe SNHL
A negative Rinne test indicates a minimum air bone gap of 15-20 dB (Ans 7)
Now lets see Os 5 and 6
0.5 says Rinne's test is negative in -
We know negative Rinne test is seen in case of conductive deafness. Amongst the options given, only tympanosclerosis is a cause for conductive deafness.
Again in 0.6 - only CSOM causes conductive deafness.