title: The path of a click stimulus from ear canal to umbo.
abstract: The tympanic membrane (TM) has a key role in transmitting sounds to the inner ear, but a concise description of how the TM performs this function remains elusive. This paper probes TM operation by applying a free field click stimulus to the gerbil ear and exploring the consequent motions of the TM and umbo. Motions of the TM were measured both on radial tracks starting close to the umbo and on a grid distal and adjacent to the umbo. The experimental results confirmed the high fidelity of sound transmission from the ear canal to the umbo. A delay of 5-15 μs was seen in the onset of TM motion between points just adjacent to the umbo and mid-radial points. The TM responded with a ringing motion, with different locations possessing different primary ringing frequencies. A simple analytic model from the literature, treating the TM as a string, was used to explore the experimental results. The click-based experiments and analysis led to the following description of TM operation: A transient sound pressure on the TM causes a transient initial TM motion that is maximal ∼ at the TM's radial midpoints. Mechanical forces generated by this initial prominent TM distortion then pull the umbo inward, leading to a delayed umbo response. The initial TM deformation also gives rise to prolonged mechanical ringing on the TM that does not result in significant umbo motion, likely due to destructive interference from the range of ringing frequencies. Thus, the umbo's response is a high-fidelity representation of the transient stimulus. Because any sound can be considered as a consecutive series of clicks, this description is applicable to any sound stimulus.
authors.affiliation: The BioRobotics Institute, Scuola Superiore Sant' Anna, Viale R. Piaggio 34, 56025 Pontedera, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Milazzo
authors.affiliation: Department of Otolaryngology & Head and Neck Surgery, Department of Biomedical Engineering, Columbia University, 630 West 168th Street, P&S 11-452, New York, NY 10032, USA.
authors.forename: Elika
authors.initials: E
authors.lastname: Fallah
authors.affiliation: Department of Otolaryngology & Head and Neck Surgery, Department of Biomedical Engineering, Columbia University, 630 West 168th Street, P&S 11-452, New York, NY 10032, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Carapezza
authors.affiliation: Department of Otolaryngology & Head and Neck Surgery, Department of Biomedical Engineering, Columbia University, 630 West 168th Street, P&S 11-452, New York, NY 10032, USA.
authors.forename: Nina S
authors.initials: NS
authors.lastname: Kumar
authors.affiliation: Department of Otolaryngology & Head and Neck Surgery, Department of Biomedical Engineering, Columbia University, 630 West 168th Street, P&S 11-452, New York, NY 10032, USA.
authors.forename: Jason H
authors.initials: JH
authors.lastname: Lei
authors.affiliation: Department of Otolaryngology & Head and Neck Surgery, Department of Biomedical Engineering, Columbia University, 630 West 168th Street, P&S 11-452, New York, NY 10032, USA. Electronic address: eao2004@columbia.edu.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Olson
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001696:Biomechanical Phenomena; D004424:Ear Canal / Q000502:physiology*; D005849:Gerbillinae; D008954:Models, Biological; D009038:Motion; D011312:Pressure; D014432:Tympanic Membrane / Q000502:physiology*