Subdural EEG in Frontal Lobe Epilepsy

This chapter is concerned with the use of subdural EEG for location of the epileptogenic zone and for functional mapping in frontal lobe epilepsy (FLE), tasks that are both necessary before epilepsy surgery in various subtypes of FLE. It reviews clinical features of subtypes of FLE, individualized electrode arrays, and the recording and analysis of epileptiform abnormalities of ictal and interictal states. It then reviews the principles of functional mapping by cortical stimulation and by other methods, e.g. intrinsic EEG activity. Intrinsic EEG activity consists of Bereitschaftspotentials or readiness potentials, judgment-related potentials from pre-supplementary motor area (SMA), somatosensory evoked potentials from SMA proper and pre-SMA, and language-related potentials. It also reviews new methods such as event-related synchronization, event-related desynchronization, coherence analysis for functional mapping, wide-band EEG analysis of slow (DC) shifts and high-frequency oscillations, and three-dimensional EEG source analysis for epileptogenic mapping.