Epilepsy is a neurological disorder marked by sudden recurrent episodes of sensory disturbance, loss of consciousness, or convulsions, associated with abnormal electrical activity in the brain. There are many forms of epileptic seizures and the ones outlined in this book are just a sample of many types of seizures that exist.
Seizures can be both visible and invisible. You may know of someone who has seizures or you may have seen someone having a seizure. However there are many other seizure types which are less well known.