What should be the loss of hearing at least for Weber's test to lateralise?

Ans. a (5 db). (Ref. Diseases of ENT by PL Dhingra, 2nd ed., 26; 3rd ed., 30)# Lateralization of sound in Weber test, a tunning fork of 512 Hz implies a conductive loss of 15-25 dB in ipsilateral ear or a sensorineural in contralateral ear.# However as less as 5 db hearing loss can cause lateralization of Weber's test.# A negative Rinne's test indicates a minimum air-bone gap of 15-20 db. TestNormalConductive deafnessSensorineural deafness1Rinne's testAC > BC (Rinne +)BC > AC (Rinne -)AC > BC2Weber's testNot lateralisedLaterlized to poor earLateralized to better ear3ABCSame as examinersSame as examinersReduced4Schwabach's testEqualLengthenedShortened