Objectives: To assess the prevalence of residual trans-lesion connectivity in persons with chronic clinically complete spinal cord injury (discompleteness) by neurophysiological methods.
Participants: A total of 23 adults with chronic sensorimotor complete spinal cord injury, identified through regional registries the regional spinal cord registry of Östergötland, Sweden.
Methods: Diagnosis of clinically complete spinal cord injury was verified by standardized neurological examination. Then, a neurophysiological examination was performed, comprising electroneurography, electromyography, sympathetic skin response and evoked potentials (sensory, laser and motor). Based on this assessment, a composite outcome measure, indicating either strong, possible or no evidence of discomplete spinal cord injury, was formed.
Results: Strong neurophysiological evidence of discomplete spinal cord injury was found in 17% (4/23) of participants. If also accepting "possible evidence", the discomplete group comprised 39% (9/23). The remaining 61% showed no neurophysiological evidence of discompleteness. However, if also counting reports of subjective sensation elicited during neurophysiological testing in the absence of objective findings, 52% (12/23) showed indication of discomplete spinal cord injury.
Conclusion: Evidence of discomplete spinal cord injury can be demonstrated using standard neurophysiological techniques in a substantial subset of individuals with clinically complete spinal cord injury. This study adds to the evidence base indicating the potential of various modes of cross-lesional sensorimotor functional restoration in some cases of chronic clinically complete spinal cord injury.
Keywords: complete; discomplete; electromyography; laser evoked potentials; motor evoked potentials; somatosensory evoked potentials; spinal cord injury; sympathetic skin response.