Somatosensory evoked potentials in neonates and infants: developmental and normative data

Fifty-two sets of cortical somatosensory evoked potentials (SEPs) were recorded from 23 normal children between the ages of 1 day and 13 weeks with median nerve stimulation. Two bandpass settings 5-1500 Hz and 30-3000 Hz were used; rate of stimulation was 1.1 Hz and sweep-time was 200 msec. The state of wakefulness was documented, but SEPs were obtained and evaluated independently of the child being awake or asleep during the recording. SEPs were present in every recording. The bandpass 30-3000 Hz best differentiated positive and negative early potentials. The bandpass 5-1500 Hz was helpful in some cases, as late slow waves were recorded with this setting. Normative data were established. Mean values were calculated for 3 age groups: 0-2 weeks, 2-6 weeks and 7-13 weeks. P15 and N20 were the first components seen in the newborn, with the P22 becoming the major component by 2-3 weeks of age. The study indicates that maturation of the somatosensory system is fastest during the first 3 weeks of life.