Children's brain responses to sound changes in pseudo words in a multifeature paradigm.

OBJECTIVE: The multifeature mismatch negativity (MMN) paradigm has previously been used to study MMN responses to changes in tones or isolated syllables. We tested 4-12 year old children's MMNs to changes in a naturally produced pseudo word context. METHODS: We studied preschoolers' (under the age of 7 years, N = 15, mean age 5 years 4 months) and school childrens' (over the age of 7 years, N = 15, mean age 9 years 3 months) MMNs to five types of changes (vowel duration, fundamental frequency, gap, intensity, vowel identity) in the middle syllable of a pseudo word [tɑtɑtɑ] using a multifeature paradigm. RESULTS: Vowel duration and gap changes elicited larger frontocentral MMN responses than other change types and the vowel identity change also produced an early positive p-MMR. The presence of the MMN was also determined at the individual level, and it was found that vowel duration and gap deviants produced MMNs in most of the participants. CONCLUSIONS: The current study shows that children's neural speech sound discrimination can be assessed in a word context in a short recording time (30 min) by using the multifeature paradigm. SIGNIFICANCE: A paradigm which can be used to investigate the discrimination of several change types of speech-sounds in a natural context can be useful for investigating speech development and deficits.

Cortical processing of musical sounds in children with Cochlear Implants.

OBJECTIVE: We studied the neurocognitive mechanisms of musical instrument sound perception in children with Cochlear Implants (CIs) and in children with normal hearing (NH). METHODS: ERPs were recorded in a new multi-feature change-detection paradigm. Three magnitudes of change in fundamental frequency, musical instrument, duration, intensity increments and decrements, and presence of a temporal gap were presented amongst repeating 295 Hz piano tones. Independent Component Analysis was utilized to remove artifacts caused by the Cochlear Implants. RESULTS: The ERPs were similar in the two groups across all perceptual dimensions except for intensity increment deviants. CI children had smaller and earlier P1 responses compared to controls, and their MMN responses showed less accurate neural detection of changes of musical instrument, sound duration, and temporal structure. P3a responses suggested that poor neural detection of musical instruments affected their involuntary attention shift. CONCLUSIONS: The similarities of neurocognitive processing are surprising in the light of the limited auditory input provided by the CI, suggesting that many types of changes are adequately processed by the CI children. SIGNIFICANCE: Our results indicate that CI children's auditory cortical functioning may be enhanced, and difficulties in auditory perception and in attention switching towards sound events alleviated, by multisensory musical activities.