The Middle Latency Response: A Review of Findings in Various Central Nervous System Lesions

Abstract

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.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.A systematic review and synthesis of the literature focusing on the MLR and lesions of the central auditory system.Studies and individual cases were reviewed and analyzed that evidenced documented lesions of the central auditory nervous system.The authors searched and reviewed the literature (journal articles, book chapters, and books) pertaining to central auditory system lesion effects on the MLR.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.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.

Longitudinal Auditory Pathophysiology Following Mild Blast Induced Trauma

“…Here, P1 corresponds to subcortical activity, largely encompassing the ABR. N1 corresponds to thalamocortical transmission, while P2 and N2 are thought to correspond to primarily cortical activity (Deiber et al, 1988; Liégeois-Chauvel et al, 1994; Tichko and Skoe, 2017; Musiek and Nagle, 2018).…”

Do tone duration changes that elicit the mismatch negativity also affect the preceding middle latency responses?

“…Most researchers agree that the auditory MLR is generated from anatomical sites between the inferior colliculus and the auditory cortex, although some disagreement exists in regard to the specific sites (Musiek & Nagle, ). Kuriki, Nogai, & Hirata, ( and Yvert, Crouzeix, Bertrand, Seither‐Preisler, & Pantev, ( narrowed the location of the MLR down to Heschl's gyrus (Musiek & Nagle, ). As with the MLR, a major MMN source is located in the auditory cortex (Alho, ; Giard et al, ).…”

“…Giard et al, ( suggested that generators of the MMNs elicited by deviating sounds with either frequency, intensity or duration change differ from each other. Liegeois‐Chauvel, Musolino, Badier, Marquis, & Chauvel, ( reported that the distribution of the generators of each component of the MLR was different (Musiek & Nagle, ). These differences may have caused the difference in the response of each component; that is, location‐deviation sounds enhance the Na component, while frequency‐deviation sounds enhance the Nb component and duration‐deviation sounds do not enhance any components.…”

Auditory Evoked Potentials in Communication Disorders: An Overview of Past, Present, and Future

“…1B), with generators in the thalamocortical pathways. [5][6][7] Around this time, there was also interest in the late AEPs which led to the discovery of P1-N1-P2-N2 waves of the LLR (see Fig. 1C), with generators predominantly in the cortex.…”