Cortical somatosensory evoked potentials to posterior tibial nerve stimulation in newborn infants

Successful cortical recordings of somatosensory-evoked potentials (SEPs) to posterior tibial nerve (PTN) stimulation were obtained in 21 (87.5%) for P1 and 22 (91.7%) for N1 of 24 infants who were followed up for at least 3 years and had a normal outcome. There were linear decreases with increasing post menstrual age in both P1 and N1 peak latency. Of the four cases with diplegia later, three showed definite abnormalities, no responses and delayed latency in PTN SEPs respectively, however, the other case showed normal responses. Of the three cases with mental retardation, two showed relatively long latency and borderline responses respectively, and the other case showed normal responses. As the pathway of PTN SEPs traverses the periventricular area of the brain likely to be affected by ischemic lesions in premature infants, abnormalities in the responses might indicate a later motor disorder.