Maturation of the neonatal somatosensory evoked response in preterm infants.

A group of 102 neurologically normal neonates with gestations between 26 and 40 weeks, without abnormality on cranial ultrasound, underwent evoked response testing. Satisfactory results were obtained for 90 per cent of the infants. Normal ranges with 95 per cent tolerance limits for the short-latency N1 component of the response were obtained at postmenstrual ages between 29 weeks and term. Somatosensory evoked responses are a practical tool for evaluating sensorimotor pathways in the newborn infant's brain.