In severe SNHL: Rinne's test is false negative and because labyrinth is dead. Fistula test is negative.False negative Rinne test occurs in case of severe SNHL because patient does not perceive any sound of tuning fork by air conduction but responds to bone conduction due to intracranial transmission of sound from opposite healthy ear.Fistula TestThe basis of this test is to induce nystagmus by producing pressure changes in the external canal which are then transmitted to the labyrinth. Stimulation of the labyrinth results in nystagmus and veigo. Normally the test is negative because the pressure changes in the EAC cannot be transmitted to the labyrinth.Positive Fistula Test is seen in:Erosion of horizontal semicircular canal (Cholesteatoma or fenestration operation)Abnormal opening in oval window (post stapedectomy fistula) or round window (rupture of round window).A positive fistula test also implies that the labyrinth is still functioning.False-negative fistula test: Dead labyrinth, cholesteatoma covering site of fistula.False-positive fistula test (Positive fistula test without Fistula): Congenital syphilis, 25% cases of Meniere's disease (Hennebe's sign.)OAE is considered as best screening test as it is less time consuming, easy to perform, child does not need to be sedated and results are available immediatelyAbsent OAE indicates cochlear lesion.If OAE are absent child is taken up for BERA which is confirmatory.