Preserved spinal dorsal horn potentials in a brain-dead patient with Lazarus' sign. Case report

The case of a brain-dead patient with complex movements of the extremities (Lazarus' sign) is reported. This is the first description in the literature of short-latency somatosensory evoked potentials (SSEP's) following median-nerve stimulation by a noncephalic reference method. The scalp P14 wave (a far-field positivity with a peak latency around 14 msec that originates from the cervicomedullary junction) disappeared, and the spinal N13 wave (a near-field negativity with a 13-msec peak recorded on the posterior neck and generated by the cervical dorsal horn) was preserved. Respiratory-like movement was also seen in this case. The SSEP. findings support the hypothesis that both Lazarus' sign and respiratory-like movement have a spinal origin.