Optical coherence tomography (OCT) has been applied to the study of hearing mechanics, not only as an imaging technique, but also an interferometer to measure the vibration of structures in the middle and inner ear.  In this talk, we will present the OCT techniques and their applications in hearing mechanics, especially a recent developed dual-mode OCT system.

To date, the reported OCT systems for vibrometry were developed based on the technique of either time-domain optical coherence tomography (TD-OCT) or spectral-domain optical coherence tomography (SD-OCT). Phase-sensitive optical coherence tomography, which enables noninvasive vibrometry at the subnanometric scale with optical sectioning capability, has proved to be an excellent vibrometer in hearing research. However, performing such vibrometry at high frequencies (e.g., > 50 kHz) is limited by the line-scan rate of the SD-OCT setup. A TD-OCT system is able to measure the vibration at higher frequencies. Such vibrometry, however, is challenged by the low imaging speed and the intrinsic unstable vibration output. We present a newly developed PS-OCT system involving both the SD-OCT and TD-OCT modes. The SD-OCT is responsible for the depth-resolved imaging, while the TD-OCT works as low-coherence vibrometry. We demonstrate the capability of the developed system in both high-frequency vibrometry and image-guided localization of the PoI by measuring the sound-induced vibration in the middle-ear samples ex vivo.  

Fangyi Chen is currently an associate professor in Southern University of Science & Technology. He received his PhD degree from Boston University and did postdoc training in Oregon Health & Science University. His research interests include: development of OCT systems for imaging and vibration measurement the hearing organ; functional evaluation of the auditory and vestibular system of modal animals; as well as discovery of drugs or genes related to hearing loss and protection.