Tabes dorsalis: electrodiagnostic features.

Electrodiagnostic data have not been previously reported in tabes dorsalis. A patient with tabes dorsalis is described whose nerve conduction studies and median nerve somatosensory evoked responses (SEPs) were normal. H-reflexes were absent. SEPs of the tibial nerve suggested posterior column dysfunction. These electrodiagnostic findings correlate precisely with the known pathology of tabes dorsalis.