Tympanometric measures in normal and otosclerotic ears
ค่าชี้วัดจาก Tympanometry ในหูปกติและหูที่เป็น Otosclerosis
Satit Chayarpham, Asst. Prof., D. of Otolaryngology, F. of Medicine, PSU.
E-mail : chsatit@ratree.psu.ac.th
Presented : Annual Meeting of Thai Speech and Hearing Association, 22 - 24 November 2000 Prince Palace Hotel Bangkok, Thailand
Key words : multifrequency tympanometry
Objective : The primary goal of this study was to evaluate alternative tympanometric para-meters for distinguishing normal middle ears from ears with otosclerosis. A secondary goal was to provide normative data for interpretating multifrequency tympanometry obtained using the Virtual
310 immittance system.
Design: Five tympanometric measures were examined in 61 normal ears and 20 ears with surgically confirmed otosclerosis. No subjects in either group had a history of head trauma or oto-
scopic evidence of eardrum abnormalities. Three parameters, static admittance (SA), tympanometric width (TW), and resonant frequency-automated screening mode (RF screening) were derived from standard low-frequency tympanometry and three parameters, resonant frequency-optimal estimation procedure (RF estimation) and frequency corresponding to admittance phase angle of 45 degree (F45 degree), were derived from multifrequency tympanometry.
Results : Differences between normal and otosclerotic ears were statistically significant only
for RF estimation and F45 degree.
Conclusion : The findings confirm the advantage of multifrequency tympanometry over standard low-frequency tympanometry in differentiating otosclerotic and normal ears. Recommendations for interpretating RF estimation and F45 degree measures obtained using the Virtual Immittance system are also provided.
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