Anti-phasic oscillatory development for speech and noise processing in cochlear implanted toddlers

Abstract

Human brain demonstrates amazing readiness for speech and language learning at birth, but the auditory development preceding such readiness remains unknown. Cochlear implanted (CI) children with prelingual deafness provide a unique opportunity to study this developmental stage. Using functional near-infrared spectroscopy, we revealed that the brain of CI children was nearly irresponsive to sounds at CI hearing onset. With increasing CI experiences up to 32 months, the brain demonstrated function, region and hemisphere specific development. Most strikingly, the left anterior temporal lobe showed an oscillatory trajectory, changing in opposite phases for speech and noise. In addition, speech responses increased linearly in left sylvian parieto-temporal area and right inferior frontal gyrus, and noise responses changed in U shape in right supramarginal gyrus. Such cortical development predicted behavioral improvement. The study provides the first longitudinal brain imaging evidence for early auditory development preceding speech acquisition in the human brain. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/483211v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@d84974org.highwire.dtl.DTLVardef@1be9ba0org.highwire.dtl.DTLVardef@db5fb7org.highwire.dtl.DTLVardef@68f420_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIThe brain of cochlear implanted toddlers is functionally inferior to neonates C_LIO_LIHearing experiences drive functional development in auditory related cortical areas C_LIO_LISpeech and noise processing develop in anti-phasic oscillatory trajectories C_LIO_LIAuditory cortical development predicts post-implantation behavioral improvement C_LI