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Abstract:
Several electrophysiological studies suggest that mismatch
negativity (MMN) recorded to speech CV syllables are of similar
latency in children and adults (e.g., Kraus et al., 1993). However,
a number of studies using tonal stimuli found MMN peaked at longer
latencies for children than for adults (Kurtzberg et al, 1995). The
current study investigated whether MMN to steady state vowels would
demonstrate spatiotemporal differences with maturation.
Event-related potentials were recorded in school-age children and
adults from 32 electrode sites in response to short duration vowels
(/I/ as in "bid" vs. /e/ as in "bed"). Stimuli were presented in an
oddball paradigm with a standard stimulus occasionally replaced by
one of three different deviant stimuli: one deviant vowel fell
within category boundary as the standard; two different deviant
vowels fell across category boundary. The subject's ability to
behaviorally identify and discriminate the different vowels was
also evaluated. Differences in both topography and timing of MMN
were found between the children and adults. The amplitude of MMN
was larger and more posterior in the left hemisphere of the
children. MMN also occurred at longer latencies in the children.
These data demonstrate maturational changes in the spatiotemporal
characteristics of MMN to vowel phonemes. 51A
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