Wideband energy reflectance measurements: normative study and effects of negative and compensated middle ear pressures
Abstract
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.
Description
Thesis (Ph.D.)--Wichita State University, College of Health Professions, Dept. of Communication Sciences and Disorders