Hearing as Reflected by Middle and Long Latency Event-Related Potentials

Abstract

One of the few ways of obtaining neural information in humans is with evoked responses. Research in auditory evoked responses has gone through an evolution over the past 30 years. Initially, there was intense interest in the development of long latency responses (i.e. evoked responses with latencies exceeding 50 ms) as a method for 'objectively' assessing auditory system sensitivity. With the advent of more efficient computers, attention was focused on shorter latency responses beginning with the 'fast' responses (now referred to as middle latency responses) and then with the auditory brainstem response. The discovery of the auditory brainstem response brought forth an explosion of investigations that demonstrated the usefulness of this response for assessment of auditory system sensitivity and the transmission capabilities of the pontine auditory pathways. The bulk of these investigations occurred between 1975 and 1985. Beginning in the early 1980s and continuing today there has been renewed interest in both the middle and long latency auditory evoked responses and the nonmodality-specific endogenous responses. Interest in these electrical events with longer latencies is rooted in the knowledge that they originate from more rostral structures (midbrain, thalamus, cortex), and thus, provide us with information about auditory processing at a higher level than can be assessed with the auditory brainstem response. That is, these longer 1 Portions of this chapter were modified from references 34, 137, 244 and 245.

Auditory P300 event-related potential in tobacco smokers

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“…For example, the auditory brainstem response (ABR) occurs in the first 20 ms after the stimulus, the middle latency response (MLR) from 20 to 70 ms, and the slow vertex response (SVR) up to 500 ms after stimulation. The midlatency auditory evoked potential (MLAEP) is generated as the auditory signals pass through the primary auditory cortex, perhaps with some additional contribution from the mesencephalic structures such as the medial geniculate (Jacobson et al, 1997;Deiber et al, 1988). In the review by Pockett (1999), the empirical work was reviewed which correlated the presence or absence of various parts of the auditory evoked potential with the disappearance and reemergence of auditory sensation during induction of and recovery from anesthesia.…”

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