Effect of bone-conduction harmonic distortions on hearing thresholds.

This study compares bone conduction (BC) thresholds obtained with two bone vibrators (BV): The Radioear B71 and an advanced BV, the Radioear B81. B81 has less distortion and is capable of higher output levels. Two tests with 20 normal hearing subjects were conducted to determine if the low distortion of B81 offers any advantages for audiometry. Hearing threshold differences between B71 and B81 are only significant at 250 Hz for levels between 20 dB hearing level (HL) and 30 dB HL. At other frequencies and higher levels, where B81 also performs with less distortion than B71, tactile responses interfere before B81 can be advantageous.