Lumbar spinal cord and early cortical evoked potentials after tibial nerve stimulation: effects of stature on normative data.

Short-latency somatosensory evoked responses to tibial nerve stimulation were recorded simultaneously over the spinous processes of the lumbar vertebrae and scalp in normal young subjects. This non-invasive test revealed values which are highly reproducible and could be closely correlated with subject-related variables such as height and leg length. A nomogram describing the close relationship between absolute latency of various response components and stature was derived and shown to be an important variable in the establishment of normative data nad interpretation of SSEP in relation to disorders affecting the peripheral and central nervous system. In contrast, central conduction times of interpeak intervals (N22-P37 and N22-N45) were unrelated to variations in the subjects, stature providing a reliable clinical measure in the assessment of the central somatosensory pathway.