Drug induced double peak waveforms in the N20-component of somatosensory evoked potentials.

The double peak waveform of the N20 component of the early somatosensory evoked potentials is a rare finding. In the present paper we investigated 9 patients (mean age +/- SD: 31.3 +/- 11.3 years; range 18-52 years) with the phenomenon of the two subcomponents of the primary cortical complex, after stimulation of the median nerve in a retrospective analysis. The results of the heterogenous patient group showed that the generation of the second subcomponent is not pathognomonic for patients with severe head injury, that it could be reversible and that pharmacological induced effects are presumably responsible for this phenomenon.