Bing test is ?

Ans. is 'c' i.e., Bone conduction test Bing test It is a bone conduction test and is done to examine the effect of occlusion of ear canal on hearing. The base of vibrating tuning fork is placed on the mastoid and the examiner alternately closes and opens the ear canal by pressing the tragus inward. Interpretatons are as follows : - Normal person or person with sensorineural deafness hears louder when ear canal is occluded and softer when the canal is open (Bing positive). This occurs because occlusion of ear canal prevents ambient noise (opposing background noise) to enter through air conduction route. A patient with conductive hearing loss will appreciate no change (Bing negative). In patient with conductive deafness ambient noise does not interfere because it cannot enter through air conduction route as the conductive apparatus is defective. So patient hears sound with same loudness with ear canal open and with ear canal occluded.