EPILEPSY Epilepsy is a condition characterised by the continued recurrence of seizures. A seizure is the manifestation of an intense, uncontrolled, transient electrical discharge across the surface of the cerebral cortex. It is analogous to a ﬁerce electrical storm moving across the surface of the earth. The discharge may be constrained to one region of the cortex (i.e. focal) or arise in a discrete cortical region and spread to involve a greater area on one or both sides of the brain (i.e. diffuse). The cause of a seizure may be either a biochemical imbalance (e.g. electrolytes, glucose, pH) or a structural abnormality (e.g. tumour, injury, disease).