High resolution spatio-temporal EEG-MEG analysis of rolandic spikes

Using high resolution EEG and MEG and a realistic volume conductor model, the authors investigated spatio-temporal aspects of the sources of spikes in children with benign rolandic epilepsy. A 64-channel EEG and simultaneous 151-channel MEG of interictal spike activity in five children all having general and/or focal seizures were recorded. A spatio-temporal multiple signal classification (MUSIC) analysis was performed on the spike data. Sources having a complex spatio-temporal configuration as well as single stationary sources were found. Results for the EEG and MEG were different. In this group of five patients, both high resolution EEG and MEG revealed that in some cases sources well separated in space and time exist, whereas in other cases only single source activity can be resolved. For multiple sources, differences for EEG and MEG in timing and localization of activity suggest that sources are spatio-temporally distributed. Sources can propagate from initial activity in the finger/hand area around the central sulcus down to the mouth/tongue area.