Research interest(s)/area of expertise
The human ear is a delicate organ – it contains the smallest bones and the fastest motor cells in our body – allowing detection of air particles’ vibration at a magnitude less than the width of an atom and a rate more than ten thousand times per second. The exquisite structures in the ear are extremely vulnerable to diseases, noise, and aging.
My research aims to better understand the structure-function relationship of the ear under normal and pathological conditions, with the long-term goal of developing diagnostics and devices to treat hearing loss and other hearing disorders.
I am particularly interested in exploiting novel technologies, such as fiberoptic sensors and non-invasive imaging, to measure the sound transmission and the motion of the inner-ear at tissue and cellular level to understand how the biomechanics of the inner ear is traumatized by pathologies.
In addition, I worked with collaborators on an implantable microphone prototype for fully implantable hearing devices. I plan to devise a new generation of the component to improve the bandwidth and the signal-to-noise ratio.
X. Guan, Y.S. Cheng, D.J. Galaiya, J.J. Rosowski, D.J. Lee, H.H. Nakajima. Bone-conduction hyperacusis induced by superior canal dehiscence in human: the underlying mechanism. Scientific Reports 2020; https://doi.org/10.1038/s41598-020-73565-4
Y.S. Cheng, S. Raufer, X. Guan, C.H. Halpin, D.J. Lee, H.H. Nakajima. Superior canal dehiscence similarly affects cochlear pressures in temporal bones and audiograms in patients. Ear and Hearing 2019; DOI: 10.1097/AUD.0000000000000799.
C. Stieger*, X. Guan*, R.B. Farahmand, B.F. Page, J.P. Merchant, D. Abur, and H.H. Nakajima. Intracochlear sound pressure measurements in normal human temporal bones during bone conduction stimulation. Journal of the Association of Research in Otolaryngology 2018; 19:523-539. * co-first author
S. Park, X. Guan, Y. Kim, F. Creighton, E. Wei, I. Kymissis, H.H. Nakajima, E.S. Olson. PVDF-based piezoelectric microphone for sound detection inside cochlea: towards totally implantable cochlear implants. Trends in Hearing 2018; 22:1-11.
D. Frear, X. Guan, C. Stieger, J.J. Rosowski, H.H. Nakajima. Impedances of the inner and middle ear estimated from intracochlear sound pressures in normal human temporal bones. Hearing Research 2018; 367:17-31.
X. Guan, R.Z. Gan. Factors affecting sound energy absorbance in acute otitis media model of chinchilla. Hearing Research 2017; 350:22-31.
F. Creighton, X. Guan, S. Park, I. Kymissis, E. Olson, H. Nakajima. An intracochlear pressure sensor as a microphone for a fully implantable cochlear implant. Otology and Neurotology 2016; 37:1596-1600.