Assessment of sensory function in neonatal sheep with somatosensory evoked potentials: methodology and normative data

Fetal sheep are increasingly used as animal models for fetal surgical interventions such as repair of myelomeningocele. Since behavioral observations cannot provide objective information about preservation of sensory function, we have developed a technique for reliably recording somatosensory evoked potentials in neonatal sheep. We determined anatomic criteria for placement of recording electrodes over the somatosensory cortex using external landmarks, and recorded normative data for both ulnar and posterior tibial nerve stimulation in a series of normal neonatal sheep. The methodology and normative data are presented in this report; a companion paper demonstrates the utilization of this technique in a variety of experimental fetal interventions.