New applications of EEG/MEG in epilepsy evaluation.

Newly developed digital EEG and MEG recording techniques have provided the ability to ask and at least partially answer questions that were previously beyond our capability. These include the location and character of cerebral sources for epileptiform spike and seizure rhythms and the prediction of anti-epileptic drug efficacy by electrophysiologic means. The techniques of EEG voltage topography and equivalent dipole modeling have now given clinicians a 2-D and 3-D view, respectively, of epilepsy-related brain activity. Quantitative EEG spike morphology measurements have, in addition, shown changes that correlate with and even predict anti-convulsant drug usefulness in a given individual. MEG devices can now measure brain magnetic fields from the entire head and provide localization of epileptic spike sources that are probably more accurate than that achieved by EEG.