Developmental changes in cerebral lateralization during speech processing measured by near infrared spectroscopy

Yutaka Sato, Koichi Mori, Izumi Furuya, Ryoko Hayashi, Yasuyo Minagawa-Kawai, Toshizo Koizumi

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Infant's developmental changes in cerebral lateralization in response to speech stimuli were assessed using a multi-channel near infrared spectroscopic measurement system. Analysis-synthesized Japanese word stimuli were used as phoneme (/itta/ and /itte/) and pitch (/itta/ and /itta?/) contrasts. The baseline blocks contained only/itta/, whereas /itta/ and its phoneme or pitch counterpart were presented randomly with equal probability during the contrast blocks in each session. To analyze cerebral lateralization, we calculated laterality indices using maximal total-Hb changes during the contrast blocks in the left and right auditory areas. Significant differences were found in the laterality indices between phoneme and pitch sessions for the infant groups of 11-12 months and older, as well as for 2- to 5-year-old infants and adults. The results imply that cerebral dominance for processing speech is formed just before one year after birth in normal infants. The method used in this study can be used clinically as an objective test of language development for infants with increased risk in language development.

Original languageEnglish
Pages (from-to)165-171
Number of pages7
JournalJapan Journal of Logopedics and Phoniatrics
Issue number3
Publication statusPublished - 2003
Externally publishedYes


  • Auditory area
  • Cerebral dominance
  • Developmental test
  • Language processing
  • NIRS (near infrared spectroscopy)

ASJC Scopus subject areas

  • LPN and LVN
  • Speech and Hearing


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