Abstract
Background:
The middle latency response (MLR) first came to light as an auditory evoked potential
in 1958. Since then, it has aroused substantial interest and investigation by clinicians
and researchers alike. In recent history, its use and popularity have dwindled in
tandem with various other auditory evoked potentials in audiology. One area for which
MLR research and application has been overlooked is its potential value in measuring
the neural integrity of the auditory thalamocortical pathway. In a broader sense,
the MLR, when combined with the auditory brain stem response, can provide information
concerning the status of much of the central auditory system pathways. This review
is intended to provide information concerning the MLR as a measure of central auditory
function for the reader to consider.
Purpose:
To review and synthesize the scientific literature regarding the potential value of
the MLR in assessing the integrity of the central auditory system and to provide the
reader an informed perspective on the value of the MLR in this regard. Information
is also provided on the MLR generator sites and fundamental characteristics of this
evoked potential essential to its clinical and or research application.
Research Design:
A systematic review and synthesis of the literature focusing on the MLR and lesions
of the central auditory system.
Study Sample:
Studies and individual cases were reviewed and analyzed that evidenced documented
lesions of the central auditory nervous system.
Data Collection and Analysis:
The authors searched and reviewed the literature (journal articles, book chapters,
and books) pertaining to central auditory system lesion effects on the MLR.
Results:
Although findings varied from study to study, overall, the MLR was reasonably sensitive
and specific to neurological compromise of the central auditory system. This finding
is consistent with the generator sites of this evoked potential.
Conclusions:
The MLR is a valuable tool for assessing the integrity of the central auditory system.
It should be of interest to the clinician or researcher who focuses their attention
on the function and dysfunction of the higher auditory system.
Key Words
auditory evoked potentials - central auditory nervous system - lesion - middle latency
response
