[Analysis of the Resonant Frequency of the Middle Ear in Otosclerosis]

Multifrequency tympanometry scans pressures and frequencies from 226 to 2000 Hz to analyze the resonant frequency of the middle ear, which determines the balance between stiffness and mass. We studied 143 patients (a total of 200 ears) diagnosed as otosclerosis at the E.N.T. Service of Santiago de Compostela University Hospital Complex, and 136 control subjects. The mean age of patients was 47.7 years; women were predominant (female/male ratio 2.25:1). The mean duration of the disease was 10.4 years. Using the Virtual model 310 tympanometer, we calculated the resonant frequency through the susceptance tympanogram, corresponding to the minimal frequency at which the central notch of the tympanograrn was equal to or less than the negative tail. The mean resonant frequency was 1230 Hz, the tympanometric amplitude was 88.32 daPa, and the admittance of the middle ear was 0.63 cc. We confirmed an increase in the resonant frequency in patients with otosclerosis compared with normal subjects (1132.33 Hz), and a decrease in the admittance of the middle ear. The relation between the two values was significant.