Wideband Power Reflectance and the Minimum Audible Pressure Curve

Abstract

The peripheral hearing mechanism, which involves structures and mechanisms that exist between the pinna (part of the ear I can see) and the brainstem, consists of the outer, middle and inner ears. The purpose of this study was to examine the natural resonances of our outer and middle ears and what role they play in determining an individual’s hearing thresholds. This was done through middle ear reflectance and Békésy audiometry. Middle ear reflectance permits the opportunity to see how the outer and middle ears affect the acoustic signal across frequency (200-6000 Hz). Minimum audible pressure thresholds differ as a clinical tool in that they are a behavioral response that reflects the participant’s perception of the acoustic signal across frequency. Threshold refers to the softest sound that a person can hear at any given frequency. Minimum audible pressure thresholds can be determined at static octave intervals (250, 500, 100, 2000, 4000, and 6000 Hz) or through Békésy Audiometry, which involves a sweeping of frequencies from 125 Hz to 8000 Hz at much smaller frequency. This process results in a minimum audible pressure (MAP) curve made up of more discrete frequency intervals. I hypothesize that the MAP curve will correlate strongly with the middle ear reflectance curve, suggesting that the natural resonances of the outer and middle ears account for our varying sensitivity across frequency. To my knowledge, these correlations have not yet been examined.