Abstract
Background Tinnitus, hyperacusis, and difficulties listening in background noise may be associated
with the loss of auditory nerve fibers known as the condition of cochlear synaptopathy.
Multiple research-based tests of auditory function have been developed to identify
the potential for synaptopathy in animals and humans, including assessment of the
middle-ear muscle reflex (MEMR). Despite these research-based tests, there is no verified
method for measuring or identifying the potential for cochlear synaptopathy using
standard audiologic equipment.
Purpose The goal of this study was to determine if commonly used audiometric equipment could
be configured in a way that approximated the test methods used in the research environment,
making it a viable tool in the assessment of patients who present with symptoms consistent
with cochlear synaptopathy (tinnitus, hyperacusis, speech-in-noise difficulties).
Methods Laboratory-based and clinically based measures of MEMR strength—as estimated from
changes in probe pressure/admittance in response to contralateral noise—were compared
for 20 subjects. MEMR strength estimated from laboratory equipment increased with
increasing intensity of the contralateral noise elicitor.
Results and Conclusions A moderate positive correlation was found between laboratory- and clinically based
measures of MEMR strength. This correlation supports the hypothesis that commonly
used clinical equipment can be employed to assess the potential for cochlear synaptopathy
in patients who present with the associated symptoms.
Keywords
acoustic reflex - synaptopathy - cochlear nerve degeneration - middle-ear muscles
- hidden hearing loss
