SEPs to median nerve stimulation: normative data for paediatrics.

Somatosensory evoked potentials (SEPs) provide neurologists with an assessment of the neuraxis from peripheral nerve to sensory cortex. Their value is particularly relevant in paediatric neurology as sensory clinical examination can be difficult in young infants and children. The clinical utility of SEPs, however, requires knowledge of the alterations in wave form which occur with growth and development. This study presents normative SEP data from 4 months-35 years. Different non-linear maturational months-35 years. Different non-linear maturational patterns were seen in spinal and central segments of the nervous system. The cervical components (N12, N13) changed little in latency until 2-3 years, the N20 decreased in latency until 2-3 years and P22 decreased in latency until 6-8 years, after which latencies increased until adulthood. The greatest latency changes occurred in N12 and N13, the least in N20. Wave form morphology and interpeak latencies also changed with age. Adult morphology was achieved early (from 1 year), but central conduction time (N13-N20) reached adult values only at 6-8 years. This study provides normative values of SEPs during maturation and a functional assessment of pathways known to myelinate and mature at varying rates.