Neurophysiological evaluation of the corticospinal tract by D-wave recordings in young children

Abstract

Objective. The objective was to neurophysiologically evaluate corticospinal tract (CT) maturation in children younger than 36 months by recording D-waves.

Methods. In 19 children, D-wave recordings were attempted during resection of intramedullary spinal cord tumors (imSCTs). D-waves were elicited by transcranial electrical stimulation (TES; single pulse, anodal stimulation) and recorded from a catheter-electrode inserted into the epidural space caudal to the imSCTs. The presence of the D-wave was analyzed in respect of the patients' age.

Results. A D-wave was present in 7 children (21–36 months) and absent in the remaining 12 children (8–31 months). In the youngest child (21 months) the D-wave was recorded from the lower thoracic spinal cord.

Conclusion. These D-wave recordings indicate that in the immature CT a synchronized descending volley via fast conducting fibers is evoked by TES and can be recorded as a D-wave from the lower thoracic spinal cord at 21 months. As all D-waves have been recorded caudal to the imSCTs, it is difficult to distinguish the contributing factor affecting the D-wave recordings in children older than 21 months: the prolonged CT maturation for the lower extremities, the individual variability of CT maturation or the influence of the imSCT.