Various pathologies directly impede the conduction of sound through the human middle ear, and thereby produce a ‘conductive’ hearing loss which is the second most prevalent health issue globally. According to Hearing Health Foundation more than 360 million people suffer from hearing disorders worldwide. Hearing depends on a series of events that change sound waves in the air into electrical signals. Sounds that travel down the ear canal set the surface of the flexible eardrum or tympanic membrane (TM) into rapid pico- to nanometer scale vibrations. These motions are coupled to the inner ear by the ossicular chain (the malleus, incus, and stapes). Since the TM and ossicular chain are the primary portal through which acoustic stimuli reach the inner ear, pathological changes in the TM or ossicular chain result in conductive hearing losses. Accurate diagnosis of middle-ear diseases is critical to effective and timely treatments of hearing loss. No currently available clinical technique is capable of simultaneously visualizing and quantifying the structure and sound-induced vibration of the middle ear in vivo. Recently, Chang et al. demonstrated a new functional imaging technique based on optical coherence tomography (OCT) and the principle of vibrography for middle ear imaging at a low frequency range (<3 kHz). In this method, termed OCT-vibrography, a speaker is used to excite acoustic vibration in the tissue, and the resulting tissue displacement (minimum peak to peak amplitude of 1 nm) is captured by OCT. In addition to 3D morphological imaging, this method captures sound-induced vibrations on the tissue. Even though they could only examine ex vivo specimens, this technique has a huge potential to be translated into clinics with significant improvements. The main goal of this project is to make for a miniaturized OCT-vibrography probe for middle ear imaging. The miniaturized probe will be designed through integrated optics which will enable high-speed imaging. The system will operate in two modes: static imaging mode for examining biofilms and ear infections behind the ear drum; dynamic imaging mode for capturing high frequency (up to 20 kHz) oscillations in the middle ear structures.
