Seizures are classified under two major categories: focal and generalized, according to MedicineNet. Not every seizure can be diagnosed as either focal or generalized. At times, a person can experience focal and generalized seizures almost simultaneously.
Focal seizures originate from only one part of the brain. There are two types of focal seizures: simple and complex. Sudden mood swings, nausea and loss of consciousness are symptoms associated with focal seizures, according to MedicineNet.
Generalized seizures are caused by abnormal neuronal activity on both sides of the brain, states MedicineNet. Loss of muscle tone and extreme muscle spasms are major symptoms of generalized seizures. Generalized seizures are classified as clonic, tonic, myoclonic, atonic or tonic-clonic.