Maturation of speech discrimination in 4- to 7-yr-old children as indexed by event-related potential mismatch responses.
OBJECTIVE
This study examined maturation of mismatch responses (MMRs) to an English vowel contrast (/I/ versus /ε/) in 4- to 7-yr-old children.


METHODS
Event-related potentials were recorded to a standard [ε] and deviant [I] vowel presented in trains of 10 stimuli at a rate of 1/650 msecs and with an intertrain interval of 1.5 secs. Each train contained two deviant vowels. Averaged responses were calculated for the infrequent (deviant) and the frequent (standard) trials for each child and compared across age groups.


RESULTS
Significantly greater negativity, consistent with the adult mismatch negativity (MMN), was observed to the deviants between 300 and 400 msecs for both younger (4- and 5-yr-old) and older (6- and 7-yr-old) children. This MMN-like negativity shifted earlier in latency by 25 msecs/yr with increasing age. Most of the children younger than 5.5 yrs and some of the older children also showed a positive MMR (p-MMR) peaking between 100 and 300 msecs. The p-MMR diminished in amplitude with increasing age.


CONCLUSIONS
Maturation of speech discrimination, as indexed by MMN, occurs more rapidly between 4 and 7 yrs of age for vowels than for tones. A p-MMR preceding the MMN also reflects discrimination in younger children and declines in amplitude with age.
Shafer
Valerie L
VL
The Graduate School and University Center, The City University of New York, New York, New York 10016, USA. vshafer@gc.cuny.edu
Yu
Yan H
YH
Datta
Hia
H
D000161:Acoustic Stimulation / Q000379:methods; D000367:Age Factors; D002648:Child; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010700:Phonetics; D011930:Reaction Time / Q000502:physiology; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*