Measurement and interpretation of cochlear reflectance

Reflectance is the transfer function between forward and reflected waves. Cochlear reflectance (CR) contributes to measured ear-canal reflectance (ECR) and contains useful information about hearing status. Comparisons between measurements and models should lead to improved clinical interpretation of CR measurements. Our ECR model consists of (1) a uniform tube representing the ear canal, (2) a lumped-element representation of the middle ear and (3) a non-uniform transmission-line representing the cochlea. The model simulation results were compared with measurements of both ECR and CR in both the time domain and frequency domain. Substantial agreement between measurements and model supports the view that CR originates mainly as linear coherent reflection due to random impedance perturbations along the cochlear partition.