Epilepsy and the frontal lobes.

Although the frontal lobes contain a large proportion of the total cerebral cortex in human brain, the epilepsies arising in this region are less studied and less well characterised than epilepsies arising in the mesial temporal lobe. Detailed studies of seizure semiology have identified a number of patterns of frontal lobe seizure, but with inconsistency across studies, and with limited evidence that specific patterns arise in specific discrete frontal lobe regions. In contrast to mesial temporal lobe epilepsy, there is no consistent pattern of cognitive impairment seen in patients with frontal lobe epilepsy, although some evidence exists to support the notion that cognitive function may be impaired. Given the rich interconnectivity between frontal lobes and many other brain regions, it is not surprising to find functional deficits in the frontal lobes in patients with epilepsy arising in other sites; this is best studied in patients with temporal lobe epilepsy. Current concepts in epilepsy suggest that epilepsies hitherto regarded as idiopathic generalised (rather than focal) may in fact have a focal origin of seizure activity; this may be supported by increasing evidence for focal structural and functional frontal lobe abnormalities in idiopathic generalised epilepsies.