<prompt> All are true about Rinnes test except ?Positive in normal earPositive in sensorineural hearing lossMinimum 15-20 dB air bone gap is required in conductive deafnessBone conduction is better in sensorineural hearing loss  <response>: Ans. isd i.e., Bone conduction is better in sensorineural hearing loss Rinnes Test The Rinne test is a tuning fork test that compares hearing by air conduction and bone conduction. The Rinne test is based on the idea that hearing mechanism is normally more efficient by air conduction AC than it is by bone conduction BC, i.e., AC BC in normal persons. For this reason, a tuning fork will sound louder and longer by air conduction than by bone conduction. However, this air conduction advantage is lost when there is a conductive hearing loss in which case the tuning fork sounds louder by bone conduction than by air-conduction. Method Administering the Rinne test involves asking the patient to indicate whether a vibrating tuning fork sounds louder when its base is held against mastoid process bone conduction or when its prongs are held near the pinna, facing the opening of ear canal air conduction. After striking the fork, the clinician alternates it between these two positions so that the patient can make a judgement about which one is louder. Interpretation of Rinnes test The outcome of the Rinne test is traditionally called positive if the fork is louder by air conduction and this finding implies that the ear is normal or has sensorineural hearing loss. The results are called negative if the bone-conduction is louder than air-conduction, which is interpreted as revealing the presence of conductive deafness i.e., lesions of either external ear, tympanic membrane, middle ear or ear ossicles.. In conductive deafness Rinnes test will be negative if the conductive hearing loss is greater than 15-20 dB minimum air bone gap 15-20 dB. That means, at least 15-20 dB of conductive hear loss is required to show bone conduction better than air conduction, i.e., Negative Rinnes test. A negative Rinne test for 256, 512 and 1024 Hz indicates a minimum air-bone gap ABG of 15, 30, 45 dB respectively. Therefore, AB gap can be made if tuning forks of 256, 512 and 1024 Hz are used : - A Rinne test equal or negative for 256 Hz but positive for 512 Hz indicates air-bone gap of 20-30 dB. A Rinne test negative for 256 and 512 Hz but positive for 1024 Hz indicates air-bone gap of 30-45 dB. A Rinne negative for all the three tuning forks of 256, 512, and 1024 Hz, indicates air-bone gap of 4560 dB. Rationale of positive test Positive test AC BC is seen in :? 1. Normal person It has already been explained that air conduction is better than bone conduction, thus Rinne test is positive in normal person. 2. Sensori-neural hearing In sensorineural hearing loss, the defect is in cochlea or VIII nerve or its central connection. There is no defect in conductive apparatus of ear air conduction or in mastoid bone bone conduction. As air conduction is better than bone conduction, Rinne test will be positive because both air conductive apparatus and bone conductive apparatus are normal and the pathology is distal to them. Negative test BC AC is seen in : ? 1. Conductive deafness As the conductive apparatus is defective, bone conduction becomes better than air conduction BC AC. 2. Severe unilateral sensorineural hearing loss Here the Rinne test is false negative not true negative as it is interpreted by the patient that BC AC, but actually it is not. In reality this response is from the opposite ear because of transcranial transmission of sound during bone conduction testing. This can be prevented by masking the non-test ear with Baranys box while testing the bone conduction. Weber test will help for such situation. 