Mismatch Negativity according to the Changes of Auditory Stimuli

Kim, Lee Suk; Kim, Bo Young; Kim, Chang Gun; Lee, Seung Hwan; Jung, Sung Wook; Kim, Jae Ryong

Abstract

BACKGROUND AND OBJECTIVES
Infrequent sounds (deviant stimuli) occurring in a sequence of repetitive sounds (standard stimuli) elicit an event-related potential response called the mismatch negativity (MMN) even in the absence of attention to these sounds. The purposes of these studies are to record the MMNs elicited by the changes of auditory stimuli in stimulation rate, duration and probability in healthy adults and to record the MMNs in healthy children.
SUBJECTS AND METHOD
Three studies were performed. The subjects were 15 adults in study 1, 20 adults in study 2, and 22 children in study 3. The standard stimulus was 50 msec, 750 Hz, 80 dB SPL tone burst. In study 1, the deviant stimulus was 750 Hz, 80 dB SPL tone burst, in which duration of the deviant stimulus was varied (25, 75, 100, 125, 150 msec) and stimulation rate was varied (0.9/sec, 2/sec). In study 2, the deviant stimulus was 125 msec, 750 Hz, 80 dB SPL tone burst and the probabilities of the deviant stimulus were varied (40, 35, 30, 25, 20, 15, 10, 5%). In study 3, the deviant stimulus was 125 msec, 750 Hz, 80 dB SPL tone burst and the probability of the deviant stimulus was 20%.
RESULTS
We obtained stable MMNs in adults and children. The amplitude of MMN was largest when duration of the deviant stimulus, stimulation rate and probability of the deviant stimulus were 125 msec, 0.9/sec and 5% respectively.
CONCLUSION
The MMNs can be obtained from healthy adults and cooperative children. The MMN could be used as an objective measure for central auditory processing and individual discrimination ability.