Auditory and visual novelty processing in normally-developing Kenyan children.
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.


CONCLUSIONS
ERPs may be used to assess children's cognitive development in rural areas of Africa.
Kihara
Michael
M
The Centre of Geographical Medicine Research (Coast), Kenya Medical Research Institute (KEMRI), P.O. Box 428, Kilifi, Kenya. mkihara@kilifi.kemri-wellcome.org
Hogan
Alexandra M
AM
Newton
Charles R
CR
Garrashi
Harrun H
HH
Neville
Brian R
BR
de Haan
Michelle
M
D000161:Acoustic Stimulation / Q000379:methods; D000367:Age Factors; D001931:Brain Mapping; D002648:Child; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D004569:Electroencephalography / Q000379:methods; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D007630:Kenya / Q000208:ethnology; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology