title: Effect of middle ear modification on umbo vibration. Human temporal bone experiments with a new vibration measuring system.
abstract: The effects of aditus blockage, decrease of tympanic cavity volume, and resection of the tensor tympani muscle on umbo displacement were studied in human temporal bones using a new non-contacting video measuring system. This system, combined with stroboscopic illumination, allowed measurement of umbo vibration down to 0.3 micron in the 0.1- to 4.5-kHz frequency range for a constant 124-dB sound pressure level at the tympanic membrane. Aditus blockage caused a mean increase of 5.4 dB with a peak at 2.8 kHz and a mean decrease of 3.4 dB below 1.6 kHz. Decrease of the tympanic cavity volume by 30% to 42% showed an improvement of 2.2 dB in the 1.4- to 3-kHz range and a similar loss below 1 kHz. Resection of the tensor tympani muscle produced a slight improvement of 1.7 dB at 1.8 kHz.
mesh_terms: D001844:Bone Conduction; D004432:Ear, Middle / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D008416:Mastoid / Q000601:surgery; D013701:Temporal Bone / Q000502:physiology*; D013719:Tensor Tympani / Q000601:surgery; D014732:Vibration; D014743:Videotape Recording