All seizures are caused by abnormal electrical disturbances in the brain. Partial (focal) seizures occur when this electrical activity remains in a limited area of the brain. The seizures can sometimes turn into generalized seizures, which affect the whole brain. This is called secondary generalization.
Partial seizures can be divided into:
Simple -- not affecting awareness or memory
Complex -- affecting awareness or memory of events before, during, and immediately after the seizure, and affecting behavior
Joseph V. Campellone, M.D., Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.