Maturation of near-field and far-field somatosensory evoked potentials after median nerve stimulation in children under 4 years of age

Objectives: The maturation of subcortical SEPs in young children. Methods: Median nerve SEPs were recorded during sleep in 42 subjects aged 0–48 months. Active electrodes were at the ipsilateral Erbʹs point, the lower and upper dorsal neck, and the frontal and contralateral centroparietal scalp; reference electrodes were at the contralateral Erbʹs point, the ipsilateral earlobe and the frontal scalp; bandpass was 10–3000 Hz. The peaks were labelled by their latencies in adults. Results: The peak latencies of N9 (brachial plexus potential) decreased exponentially with age during the first year, but increased with height thereafter. The interpeak latencies (IPLs) N9–N11, which measure conduction between brachial plexus and dorsal column, decreased with age (linear regression). The IPLs N11–P13 and N11–N13b, which measure conduction between the dorsal column and approximately the cervico-medullary junction, did not change across this age range. The IPLs N13a–N20, N13b–N20 and P13–N20, which measure central conduction, showed negative exponential regressions with rapidly decreasing latencies during the first year of life and slowly decreasing latencies thereafter. Conclusions: Maturation of the peripheral segments of the somatosensory pathway progresses more rapidly than that of the central segments. The maturation of central conduction is not completed within the first 4 years of age. Our maturational data may serve as a reference source for subsequent developmental and clinical studies.