Tests For Hearing
A 38-year-old male presented with a suspected diagnosis of suppurate labyrinthitis. A positive inne's test and positive fistula test was recorded on initial examination. The patient refused treatment, and returned to the emergency department after 2 weeks complaining of deafness in the affected ear. On examination, fistula test was observed be negative. What is the likely expected finding on repeating the Rinne test. (LQ)
|A||True positive Rinne's test|
|B||False positive Rinne's test|
|C||True negative Rinne's test|
|D||False negative Rinne's test|
In the above question: Patient was suffering from suppurative labyrinthitis which was not treated and led to total loss of hearing. severe SNHL.
In severe SNHL: Rinne's test is false negative and because labyrinth is deaD. fistula test is negative.
False negative Rinne test as explained earlier 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.
The 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 vertigo. Normally the test is negative because the pressure changes in the EAC cannot be transmitted to the labyrinth,
Positive HstulaTest 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