Development of holographic methods to characterize form and function of the Tympanic Membrane
Morteza Khaleghi (WPI), Cosme Furlong (Worcester Polytechnic Institute), Jeffrey Cheng (Massachusetts Eye and Ear infirmary), John Rosowski (Massachusetts Eye and Ear Infirmary)
Experimental Nanobiomechanics
Mon 4:20 - 5:40
Barus-Holley 163
Hearing processes involve series of physical events where acoustic wavefronts are transduced into mechanical motions, chemo-electrical reactions, and into electrical signals that are interpreted by the brain. This research focuses on the mechanics of the middle-ear, where acoustic wavefronts are coupled into mechanical motions by first interacting with the Tympanic Membrane (TM), which undergoes nanoscale amplitude motions during normal hearing conditions. Therefore, characterization of the shape and 3D displacements of the TM becomes critical to gain a detailed understanding of the complicated mechanics of sound reception by the ear. We are developing full-field-of-view holographic methods to enable the simultaneous measurements of the shape as well as the complete 3D motion of the TM with submillimeter and nanometer resolutions, respectively. This represents capabilities, of a single holographic system, to measure with at least five dimensional orders of magnitude. Our methods are based on dual-wavelength lensless digital holography techniques that we have implemented into metrology systems currently deployed at a hospital for medical research purposes. To validate our measurements and to overcome the technical challenges imposed by the dimensions, i.e., millimeter, of the structures that compose the middle-ear, multi-physics finite element methods together with miniaturization engineering are applied in our developments. Representative results demonstrating our current measuring capabilities are shown.