An Animal Model Of Superior Canal Dehiscence

Superior canal dehiscence (SCD) syndrome is a non-middle-ear source of conductive hearing loss [3, 5]. The purpose of this study is to develop a better understanding of the physiology and mechanics behind SCD-induced changes in auditory sensitivity to both air-conducted (AC) and bone-conducted (BC) stimuli. To achieve this goal we surgically introduced a hole (dehiscence) into the chinchilla superior canal (SC) and then monitored cochlear potential (CP) in response to both BC and AC stimuli. As a result of SCD, low frequency sensitivity to BC stimuli increased and in response to AC stimuli it decreased, producing an air-bone gap of 12dB. Our results support the hypothesized 'third window' mechanism, which suggests that the SCD introduces a pathological shunt pathway that alters inner-ear fluid motion and results in an air-bone gap.