[Comparison of orthodromic and antidromic sensory nerve conduction. 2. Patients with polyneuropathies and polyradiculitis (author's transl)].

The results of the orthodromically and the antidromically recorded nerve action potentials from a median nerve in 30 patients with clinically slight or beginning polyneuropathies have been compared. Antidromic conduction velocity was slowed in 8 cases, in 8 patients it was normal and in 14 patients no definite antidromic nerve action potential could be recorded. This last finding is not considered as being definitely abnormal. In all but one patient orthodromic nerve action potentials could be elicited. In 28 out of 30 patients the orthodromic method gave pathological findings. Duration of the nerve action potentials and the number of their potential component were the most sensitive single parameters, which were abnormal in more cases than conduction velocity of the fastest fibres. For the detection of slight or beginning polyneuropathies the diagnostic yield of the orthodromic method turned out to be much greater than the antidromic. In contrast, in a group of 19 young patients, which previously had suffered from a polyradiculitis, no significant difference between the two methods was found.