Selected neurophysiologic studies can supplement clinical examination in assessing residual motor function after spinal cord or head injury. The ability of polyelectromyographic recording to detect subclinical suprasegmental control is illustrated in paraplegic patients after spinal cord injury. Excitatory or inhibitory modulation of segmental motor activity in a subpopulation of patients with clinically complete motor paralysis suggests residual connection across the lesion. This observation is consistent with the pathologic finding that complete transection of the spinal cord is rare after spinal cord injury. A preliminary study of motor-evoked potentials also indicates their potential value as an objective measure of the functional status of descending pathways. Neurophysiological assessment of subclinical residual motor function may be useful in understanding the role of suprasegmental input in the manifestation of spasticity, in objectively documenting recovery of function after injury, and may aid in the development of more specific restorative measures. Our limited experience in head-injured patients also suggests the potential usefulness of these tools in supplementing clinical evaluation.
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