[Trigeminal evoked potentials. Normal values]

The author describes the examination technique of trigeminal evoked potential (TEP) by electric stimulation with paired skin electrodes separately for each side of the maxillary and mandibular branch of the trigeminal nerve. The obtained evoked response contains two negative and two positive deflections N11, P19, N27, P39, whereby wave P39 could not be evaluated in 47.8%; therefore it was not processed by statistical method. The other latency values are stable against a major variability of amplitudes. Evaluation by linear regression displayed only a minor correlation of latencies of the trigeminal evoked potential with advancing age. The author present normal latency and amplitude values for every side of maxillary and mandibular part of the Vth nerve as well as maximal lateral differences. With regard to the hypothetical possibility to influence results of the trigeminal potential by afferentiations of the VIIth nerve in patients with idiopathic paresis of the fascial nerve, this method in not a suitable model for testing the selectivity of examinations of TEP. The submitted method of trigeminal evoked potential is reliable and simple and can be used as a diagnostic aid in examinations of the functional state of the pathway of the Vth nerve, e.g. in multiple sclerosis, neuralgia of the Vth nerve, tumours of the Vth nerve and in conditions after operation of the Vth nerve.