The representation of voice onset time in the cortical auditory evoked potentials of young children.
OBJECTIVE
The aim of this study was to determine whether, in young children, a cortical neurophysiologic representation of the voicing status of a stop consonant could be found in the absence of the N1 component in the cortical auditory evoked potential (CAEP). In adults, a 'double-on' N1 response is often considered a cortical marker of VOT representation.


METHODS
Scalp-recorded CAEPs were measured from six electrode sites in 10 children aged 4-8 years in response to a /da/-/ta/ continuum in which voice onset times (VOTs) varied from 0 to 60ms. CAEPs were also recorded from C(z) in a group of eight children aged 2-3 years in response to stimuli with VOTs of 0 and 60ms.


RESULTS
Cortical evoked responses elicited by stimuli with VOT values ranging from 0 to 60ms (i.e., by stimuli perceived as /da/ and /ta/) were similar in morphology. There was no evidence of a 'double-on' morphology for stimuli with long VOTs. However, latency changes in the P1 and N2 components were observed as a function of VOT changes.


CONCLUSIONS
Our results demonstrate that a representation of VOT, as recorded by scalp electrodes, exists in the developing cortical evoked response, but that representation is different than that in the adult response. The results describe the developmental changes in cortical representation of VOT in children ages 2-8 years.


CONCLUSIONS
The child's CAEP reflects physiologic processes, which are involved in the cortical encoding of VOT. Overall, cortical representation of VOT in children ages 2-8 is different than in adults.
King
Katrina Agung
KA
Callier Advanced Hearing Research Center, Department of Brain and Behavioral Sciences, University of Texas at Dallas, TX, USA.
Campbell
Julia
J
Sharma
Anu
A
Martin
Kathryn
K
Dorman
Michael
M
Langran
Justin
J
D000367:Age Factors; D000704:Analysis of Variance; D001303:Auditory Cortex / Q000502:physiology*; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D002755:Choice Behavior / Q000502:physiology; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology*; D013061:Speech Acoustics; D013997:Time Factors; D014831:Voice