RESUMEN
OBJECTIVE: Multifrequency tympanometry (MFT) analyzes tympanograms obtained using different probe tones between 226 and 2000 Hz. An important parameter of MFT is resonance frequency (RF). Studies have recently demonstrated that the RF value can vary depending on many factors. To provide new data regarding MFT, middle ear RF values were investigated with regard to body mass index (BMI). MATERIALS AND METHODS: This study included 78 volunteers (i.e., 156 ears) aged 18-40 years who did not have hearing loss and whose otoscopic examinations were normal. Hearing thresholds were measured using pure tone audiometry, and RF values were recorded with immitansmetric measurements. The participants were divided into the following three groups according to their BMI: <18.5 kg/m2, Group 1; 18.5-24.9 kg/m2, Group 2; and >25 kg/m2, Group 3. The RF values were also analyzed. RESULTS: Although there was no significant difference between Groups 1 and 2 in terms of RF values, a significant difference was observed between Groups 1 and 3 and between Groups 2 and 3. CONCLUSION: In the light of these data, BMI values should be considered when middle ear RF values are assessed.
Asunto(s)
Pruebas de Impedancia Acústica/instrumentación , Índice de Masa Corporal , Oído Medio/fisiología , Análisis de Frecuencia de Resonancia/métodos , Adulto , Audiometría de Tonos Puros/métodos , Umbral Auditivo/fisiología , Femenino , Audición/fisiología , Humanos , MasculinoRESUMEN
Cochlear input impedance was measured in 6 temporal bones taken from 3 dogs by use of a newly developed ceramic device. The device was composed of two ceramic bimorph elements, one for activation of the stapes and the other to pick-up vibration of the former element in the form of an electric output, which varies in accordance with the magnitude of cochlear impedance. Average impedance in the dogs was 2.3 Mohm at 2 kHz, 6.3 Mohm at 4 kHz and 17.8 Mohm at 6 kHz. Effect of closure of the round window was also investigated by placing dental cement on the window. In 3 ears, the impedance increased mainly below 4 kHz, while in the remaining 3 ears no such change occurred. This was probably because the closure was complete in the former but not in the latter.