Wideband energy reflectance measurements: normative study and effects of negative and compensated middle ear pressures
Shaver, Mark D.
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Conventional clinical procedures for middle ear assessment have been used for several decades but have shown limitations. Application of a new technology, wideband energy reflectance (ER), has shown great potential. The ER measurement determines the proportion of acoustic energy reflected by the middle ear, across a broad frequency range. Negative middle ear pressure (MEP) is a highly prevalent, and mostly transient, form of middle ear dysfunction which effects ER measurement. Goals of the present study were to examine various factors relating to the ER test: (1) test-retest reliability, (2) the effects of pressure manipulations, (3) the effects of negative MEP, and (4) the effectiveness of a corresponding compensation procedure. Data were collected in 48 adults and analyzed across the frequency range from 0.223 to 8 kHz. Measurements were conducted using both ambient and dynamic pressure methods, under three conditions: normal MEP, negative MEP, and compensated negative MEP. Correlation between immediately repeated tests were strong for all frequencies. The sweeping pressure procedure caused ER reduction for a few frequencies but differences were small. Thirty-five subjects were able to produce a negative MEP ranging from -40 to -220 daPa. Negative MEP increased ER at low- and mid-frequencies while decreasing ER at high-frequencies. Magnitude of changes and frequency at which maximum change occurred increased when MEP became more negative. Compensated negative MEP reduced ER at low- and mid-frequencies but increased ER at high- frequencies. The present study demonstrated that negative MEP altered ER in a frequency-specific pattern. The compensation procedure eliminated the effects of negative MEP. Immediate test-retest reliability of the ambient ER test was excellent. Both probe reinsertion and manipulation of the ear canal and middle ear pressure produced minimal effects.
Thesis (Ph.D.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders