Volume 52 (2011) Issue 4 Pages 307-312
Auditory evoked potentials are useful for evaluation of auditory cognition required for language acquisition. Peaks of recorded waves represent synchronized spikes in clusters of neurons at each component along peripheral and central auditory pathways. Auditory brainstem response (ABR), which is available the most easily, is applied even for newborns, and latencies of peaks get shortened as myelination progresses. Comparison between responses of multiple stimuli is a basic strategy to observe the process of auditory cognition of language in event related potential (ERP). Mismatch negativity is an example of such a method, and it has proved that infants acquire abilities to discriminate fundamental properties of their mother tongue, such as specific duration of each phoneme and various kinds of prosody. Negative deflection around 400 milliseconds (N400) has revealed that 18-month-old children discriminate meanings of acoustically presented words. Detection of syntactic violation and understanding of sentences in 3-year-olds have been demonstrated on ERPs at 400-800 ms latency.