MAGNETIC CORTICAL STIMULATION IN ACUTE SPINAL-CORD INJURY

We studied 25 patients within 6 hours of acute spinal cord injury usin g magnetically evoked cortical motor evoked potentials (MEPs). The sub jects included 16 quadriplegics with cervical spine injuries and eight paraplegics. MEPs were recorded from abductor digiti minimi (ADM), bi ceps, flexor hallucis brevis, and tibialis anterior muscles on each si de using appropriate directions of coil current. MEPs were not obtaine d, either at rest or during attempted voluntary contraction, in patien ts without preceding clinical evidence of voluntary activation. This w as the case even for muscles that later had motor recovery after an in itial paralysis. In comparison with normal controls, MEP thresholds at rest in ADM and biceps were elevated even for muscles innervated abov e the level of injury (p < 0.001). On repeat testing, 6 weeks postinju ry, there was a return toward normal, but a significant threshold elev ation remained for ADM (p < 0.05). We conclude that in acutely injured spinal cord patients, magnetically evoked MEPs do not provide useful information regarding the likelihood of motor recovery.