SEEG in Frontal Lobe Epilepsy

Frontal lobe epilepsy (FLE) constitutes a challenge for presurgical evaluation because of specific anatomical and physiological factors. Semiological expression of frontal lobe seizures is notably varied and complex but nevertheless certain distinct patterns can be characterized, associated with different sublobar epilepsy localizations. These electro-clinical patterns have been largely demonstrated by stereo-electroencephalographic (SEEG) studies. An electro-clinical spectrum of semiological expression has been shown, with the most anterior prefrontal regions being associated with complex motor behaviour, distal stereotypies, and an integrated or naturalistic appearance; posterior prefrontal regions associated with proximal stereotypies sometimes associated with tonic posture; and motor/premotor regions associated with elementary motor signs. This rostrocaudal gradient is in keeping with current theories of frontal lobe functional organization. This chapter discusses issues specific to SEEG exploration of FLE, reviews historical investigations of frontal semiology, and highlights different patterns of semiological expression in both focal and widespread frontal seizures, as elucidated by SEEG.