Summary of: Voss, S. E., Merchant, G. R., & Horton, N. J. (2012). Effects of middle-ear disorders on power reflectance measured in cadaveric ear canals. Ear and hearing, 33(2), 195–208. https://doi.org/10.1097/AUD.0b013e31823235b5
The paper systematically characterises how absorbance is altered by five specific middle ear disorders. (1) positive and negative static pressure, (2) middle ear fluid, (3) fixation of the stapes footplate, (4) disarticulation of the incudostapedial joint, and (5) tympanic membrane perforations. Absorbance measures were performed on 8 cadaver ears which were manipulated to be representative of conditions 1-4. Retrospective absorbance calculations were made on 11 separate cadaver ears for condition 5. These measurements were then compared to a middle ear model which was modified to represent the five middle ear disorders outlined above. The results showed that the general trends for a given condition were similar between the cadaver measurements and the model middle ear. A detailed discussion of how the measured absorbance for each modified condition differs from the normal state is provided and examples are shown (Adapted versions of these examples can however be found within the Titan software). From reading this paper it becomes clear that different middle ear conditions affect absorbance at different frequencies and the degree of how these frequencies are affected is determined by the extent of the disorder.