Utility of Trial-to-Trial Latency Variability of Somatosensory Evoked Potentials for Diagnosis of Spinal Cord Demyelination

Abstract

Traditional measurement of somatosensory evoked potentials (SEPs) depends on averaging of many recordings, which introduces loss of dynamic variability. Single trial extraction provides a new measurement of SEP latency variability for evaluation of the neurodynamic status of the somatosensory pathway. The aim of this study was to apply a single trial SEP to diagnose the severity of demyelination in a chronical spinal cord injury model. The severity of demyelination was measured by myelin area and staining intensity at the ventral column (VC), lateral column (LC), and dorsal column (DC) by histological examination with Luxol fast blue staining. Results showed that there was a strong negative correlation of the latency variability of trial-to-trial SEP with the myelin area in three columns (DC: r=-0.90, p<0.05; VC: r=-0.91, p<0.05; LC: r=-0.89, p<0.05), and the staining intensity in three columns (DC: r=-0.95, p<0.05; VC: r=-0.94, p<0.05; LC: r=-0.93, p<0.05). These data suggest that single trial SEP can provide a dynamic indicator of spinal cord demyelination.