Movement-related cortical evoked potentials using four-limb imagery.

We compared the electroencephalographic changes during actual and imaginary movements with four limbs and classified optimally the responses during four-limb imagery. Evoked potentials in imagery exhibited lower and delayed peaks compared to actual-movement responses, but activations in the primary and the supplementary motor area were similar. Source-modeling analysis revealed that the motor and the parietal cortex were activated similarly, but several dipole sources were active in the frontal cortex for imagery. We compared thirteen classification methods and a combination of template matching and time-frequency methods showed the highest average of 70% classification rate for all limbs.