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December 1986

Effect of Middle Ear Modification on Umbo Vibration: Human Temporal Bone Experiments With a New Vibration Measuring System

Author Affiliations

From the Department of Otolaryngology, Ehime (Japan) University School of Medicine (Dr Gyo); the Division of Otolaryngology, Stanford (Calif) Medical Center (Dr Goode); and the Otolaryngology Section, Palo Alto (Calif) Veterans Medical Center (Drs Goode and Miller).

Arch Otolaryngol Head Neck Surg. 1986;112(12):1262-1268. doi:10.1001/archotol.1986.03780120026004

• 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 noncontacting video measuring system. This system, combined with stroboscopic illumination, allowed measurement of umbo vibration down to 0.3 μm 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.

(Arch Otolaryngol Head Neck Surg 1986:112:1262-1268)