First complete anatomical analysis of the entire cochlea at a sub-millimeter resolution using synchrotron-radiation phase-contrast imaging

Abstract

The cochlea is the spiral-shaped end organ of hearing within the inner ear which contains sensory hair cells responsible for transducing mechanical sound vibrations to the electrical impulses we perceive as sound.  When the sensory hair cells in the cochlea are not functioning, known as sensorineural hearing, cochlear implants can be used to restore hearing. Cochlear implants are surgically implanted neural-prosthetic devices which directly stimulate auditory nerve fibers, bypassing the hair cells, to restore sound perception in cases of sensorineural hearing loss. However, current cochlear implant electrodes are short and do not stimulate the entire cochlea due to the lack of anatomical knowledge on fine intracochlear structures. The current work scans nineteen human cadaveric cochleae using synchrotron-radiation phase-contrast imaging (SR-PCI) and presents anatomical measurements of the entire cochlea, including the largest inscribed circle and the cross-sectional area at various degrees in the cochlea. These preliminary measurements will extend current anatomical cochlear knowledge to inform safe implantation of longer electrode arrays to restore low-frequency ranges.