Illustrations of the five cochlear features investigated in this study and expressed as continuous variables.

<p>The external cochlear length (ECL, in mm), number of turns (TUR, expressed as the sum of full circle rotations and the angle between lines “AB”—center to apex—and “AC”—center to base), and relative length (RECL = ECL/TUR, in mm), the curvature gradient (CUR, expressed as a dimensionless ratio between the radii of the larger first—noted “R2”—and the smaller last spiral turns—noted “R1”), and the oval window area (OWA in mm²).