P06. Prognostic value of multimodal neurophysiological testing in spinal cord injury

Abstract

The disability secondary to traumatic spinal cord injury (SCI) is known to be highly variable among patients due to the vast variety of lesion levels and varying severity, resulting in a mixture of central and peripheral neural lesion burden. In this context prognostication of outcome becomes a challenge, yet is paramount in planning rehabilitation and clinical trials. Next to clinical assessment by International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) neurophysiological techniques have been used for diagnosing lesion severity and prognostication as they are objective and early available. Evoked potentials (EPs) have been suggested as diagnostic and prognostic tools in SCI, although their importance and prognostic value has not been completely established. Prognostic significance of multimodal EPs was assessed in a cohort of 633 SCI cases from the European Multicenter Study about Spinal Cord Injury database (EMSCI, www.emsci.org ). SCI patients underwent complete neurophysiological evaluation (NPE) prospectively, including nerve conduction studies, somatosensory and motor EPs within 4 weeks after spinal injury. Functional recovery after SCI as the endpoint was assessed at 3, 6 and 12 months during and after rehabilitation by standardized and validated testing using the international Spinal Cord Independence Measure (SCIM). EPs abnormalities were quantified through an index of global EPs alteration (EP score). The relationship between EP score and disability in SCIM was analyzed by Spearman ρ correlation coefficient. Receiver operated characteristic (ROC) curves were used to determine best EP score cut off values to predict SCIM endpoints within sub-score categories such as mobility and hand function. Significant correlations could be shown between EP score (motor and somatosensory EPs) and SCIM score at the time of NPE and at 3, 6 and 12 months of follow-up. Goodness of fit increased over time indicating true predictive value of early EP assessment for late functional outcome. For each functional sub-score endpoint, significant sensitivity, specificity, positive and negative predictive values were obtained. Multimodal EPs are valuable objective procedures to predict disability in traumatic SCI patients. This prediction can be achieved independent of clinical assessment (ISNCSCI) and without knowledge of lesion level.