<prompt> In Bing test, on alternately compressing and releasing the external acoustic meatus, the sound increases and decreases. This indicatesOtosclerosisSensorineural deafnessAdhesive otitis mediaChronic suppurative otitis media  <response>: Tests for bone conduction TestPrincipleMethodImpressionBing test Examines the effect of occlusion of ear canal on hearing Tuning fork placed on mastoid while examiner alternatively closes opens the ear canal by pressing on the tragus inwards Patient hears louder when the ear canal is occluded softer when the ear canal is open - Normal persons or sensorineural deafness Bing ve No change in ear canal opening or occlusion - conductive deafness Bing - ve Gelles test Examines the effect of increased air pressure in ear canal on hearing Placing a vibrating fork on mastoid while changes in air pressure in the ear canal are brought about by Siegel;s speculum Positive - normal persons or sensorineural deafnessNegative - ossicular chain fixed or disconnectedRefer: PL Dhingra, Textbook of Ear, Nose, Throat, 6thedition, pg no: 21,22,23 