[The effect of tramadol on the EEG and the electronystagmogram (author's transl)].

1-(m-Methoxyphenyl)-2-(dimethylaminomethyl)-cyclohexan-1-ol (tramadol; Tramal) in oral doses of 150 mg/kg caused no essential changes in the EEG pattern in man. Only the alpha-rhythm of the occipital leads was more synchronized and the amplitude somewhat higher. beta-Waves increased slightly, but the delta-waves were not significantly changed. Tramadol induced no measurable alterations in the electronystagmographic recordings of quick voluntary eye movements or follow-up to-and-fro eye movements. In the optokinetic and postrotatory nystagmus, however, there was a moderate decrease in the total amplitude and maximal angular velocity of the slow nystagmic stage. The results of EEG and electronystagmographic investigations indicate that tramadol has a moderate relaxant (central depressant) effect.