This work aims at investigating the somatosensory evoked potential topographical distribution by applying the Magnitude Squared Coherence (MSC), an Objective Response Detection technique in the frequency domain. The EEG was collected from eight volunteers at derivations according to the 10–20 International System during stimulation of the right posterior tibial nerve. The stimuli were applied at the rate of 5 Hz and with intensity slightly above the motor threshold. Detection was identified based on the null hypothesis of response absence rejection (significance level α = 0.05 and M = 500). The best percentages of detection were achieved in the parietal and central regions ipsilateral to the stimulation limb. C4, P4, Cz and Pz were considered the best derivations for SEP monitoring when monopolar derivations are used.
- Somatosensory evoked potential
- Topographic distribution
- Magnitude Squared Coherence