The Magnetic Acoustic Change Complex and Mismatch Field: A Comparison of Neurophysiological Measures of Auditory Discrimination

Shu Hui Yau,Fabrice Bardy,Jon Brock,Paul F Sowman

doi:10.3934/neuroscience.2017.1.14

Abstract

The Acoustic Change Complex (ACC), a P1-N1-P2-like event-related response to changes in a continuous sound, has been suggested as a reliable, objective, and efficient test of auditory discrimination. We used magnetoencephalography to compare the magnetic ACC (mACC) to the more widely used mismatch field (MMF). Brain responses of 14 adults were recorded during mACC and MMF paradigms involving the same pitch and vowel changes in a synthetic vowel sound. Analyses of peak amplitudes revealed a significant interaction between stimulus and paradigm: for the MMF, the response was greater for vowel changes than for pitch changes, whereas, for the mACC, the pattern was reversed. A similar interaction was observed for the signal to noise ratio and single-trial analysis of individual participants’ responses showed that the MMF to Pitch changes was elicited less consistently than the other three responses. Results support the view that the ACC/mACC is a robust and efficient measure of simple auditory discrimination, particularly when researchers or clinicians are interested in the responses of individual listeners. However, the differential sensitivity of the two paradigms to the same acoustic changes indicates that the mACC and MMF are indices of different aspects of auditory processing and should, therefore, be seen as complementary rather than competing neurophysiological measures.

Highlights

The ability to discriminate between different sounds is a basic prerequisite for spoken language perception [1]
Analyses of peak amplitudes revealed a significant interaction between stimulus and paradigm: for the mismatch field (MMF), the response was greater for vowel changes than for pitch changes, whereas, for the magnetic ACC (mACC), the pattern was reversed
Results support the view that the Acoustic Change Complex (ACC)/mACC is a robust and efficient measure of simple auditory discrimination, when researchers or clinicians are interested in the responses of individual listeners

Summary

Introduction

The ability to discriminate between different sounds is a basic prerequisite for spoken language perception [1]. This is especially true in populations such as young children, or individuals with neurodevelopmental or degenerative conditions, for whom poor attention or task understanding might impact adversely upon performance For this reason, researchers have increasingly made use of electroencephalography (EEG) and magnetoencephalography (MEG) to passively measure event-related cortical responses to changes in auditory stimuli, taking the presence and magnitude of the elicited brain response as an index of perceptual discrimination. Researchers have increasingly made use of electroencephalography (EEG) and magnetoencephalography (MEG) to passively measure event-related cortical responses to changes in auditory stimuli, taking the presence and magnitude of the elicited brain response as an index of perceptual discrimination The majority of these studies have employed an oddball paradigm, in which participants hear a sequence of discrete sounds composed of frequent “standards” and rare “deviants” that differ along a single stimulus dimension. Like the MMN, the ACC is correlated with behavioural measures of intensity and frequency change [13,16,17] and has good test-retest reliability [15,16]

Methods

Results

Conclusion