Age-related amplitude variations of the posterior tibial nerve spinal SEP P21 component

The effects of aging on the amplitude of the surface-recorded tibial nerve spinal somatosensory-evoked potential P21 component (L5-T12 electrode derivation) were studied in 79 subjects. The results of this investigation indicate that a significant moderately negative correlation (r = -0.46) exists between subject age and the amplitude of component P21. These findings suggest that the absence of a P21 potential in an elderly patient does not necessarily represent evidence of neural pathology.