Auditory and visual novelty processing in normally-developing Kenyan children.
Kihara M., Hogan AM., Newton CR., Garrashi HH., Neville BR., de Haan M.
OBJECTIVE: The aim of this study was to describe the normative development of the electrophysiological response to auditory and visual novelty in children living in rural Kenya. METHODS: We examined event-related potentials (ERPs) elicited by novel auditory and visual stimuli in 178 normally-developing children aged 4-12 years (86 boys, mean 6.7 years, SD 1.8 years and 92 girls, mean 6.6 years, SD 1.5 years) who were living in rural Kenya. RESULTS: The latency of early components (auditory P1 and visual N170) decreased with age and their amplitudes also tended to decrease with age. The changes in longer-latency components (Auditory N2, P3a and visual Nc, P3a) were more modality-specific; the N2 amplitude to novel stimuli decreased with age and the auditory P3a increased in both latency and amplitude with age. The Nc amplitude decreased with age while visual P3a amplitude tended to increase, though not linearly. CONCLUSIONS: The changes in the timing and magnitude of early-latency ERPs likely reflect brain maturational processes. The age-related changes to auditory stimuli generally occurred later than those to visual stimuli suggesting that visual processing matures faster than auditory processing. SIGNIFICANCE: ERPs may be used to assess children's cognitive development in rural areas of Africa.