Somatosensory evoked potentials for the diagnosis of proximal sensory median neuropathy with preserved distal sensory action potential.

A 33 year-old-man with paresthesia in first three fingers of the right hand after minor trauma of the arm was examined electrophysiologically. The proximal sensory median neuropathy was isolated which it is unusual in traumatic lesion. Motor and distal sensory conduction studies were normal but sensory evoked potentials (SEPs) were abnormal by right median nerve stimulation at the wrist level with decrease in amplitude of peripheral potential at the Erb's point, the cervical and contralateral parietal levels.