Brachial plexus and radicular neurography in relation to cortical evoked responses.

An application of somatosensory potential recording suitable for clinical neurodiagnostics is described. Evoked responses were recorded with surface electrodes at four levels between wrist and scalp: Erb's point, seventh cervical spine, inion, and the somatosensory area of the scalp. The normal latency and latency difference values based on 16 healthy subjects are presented as well as those of four examples of pathological cases with lesions at various levels in the nervous system. The method presented offers novel possibilities for solving problems of differential diagnosis, especially at the level of the brachial plexus.