These seizures may present in several ways depending on the parts of the brain involved and the persons age. Seizures
The most common type (60%) of seizures are convulsive which involve involuntary muscle contractions. Of these, one-third begin as generalized seizures from the start, affecting both hemispheres of the brain and impairing consciousness. Two-thirds begin as focal seizures (which affect one hemisphere of the brain) which may progress to generalized seizures. The remaining 40% of seizures are non-convulsive. An example of this type is the absence seizure, which presents as a decreased level of consciousness and usually lasts about 10 seconds.Certain experiences, known as auras often precede focal seizures. The seizures can include sensory (visual, hearing, or smell), psychic, autonomic, and motor phenomena depending on which part of the brain is involved. Muscle jerks may start in a specific muscle group and spread to surrounding muscle groups in which case it is known as a Jacksonian march. Automatisms may occur, which are non-consciously generated activities and mostly simple repetitive movements like smacking the lips or more complex activities such as attempts to pick up something.There are six main types of generalized seizures: tonic-clonic, tonic, clonic, myoclonic, absence, and atonic seizures. They all involve loss of consciousness and typically happen without warning. Tonic-clonic seizures occur with a contraction of the limbs followed by their extension and arching of the back which lasts 10–30 seconds (the tonic phase).
Despite this, treatment is often continued once effective, because the risk of untreated epilepsy is believed to be greater than the risk of the medications. Among the antiepileptic medications, levetiracetam and lamotrigine seem to carry the lowest risk of causing birth defects.Slowly stopping medications may be reasonable in some people who do not have a seizure for two to four years; however, around a third of people have a recurrence, most often during the first six months. Stopping is possible in about 70% of children and 60% of adults. Measuring medication levels is not generally needed in those whose seizures are well controlled. Surgery
Epilepsy surgery may be an option for people with focal seizures that remain a problem despite other treatments. These other treatments include at least a trial of two or three medications. The goal of surgery is total control of seizures and this may be achieved in 60–70% of cases. Common procedures include cutting out the hippocampus via an anterior temporal lobe resection, removal of tumors, and removing parts of the neocortex. Some procedures such as a corpus callosotomy are attempted in an effort to decrease the number of seizures rather than cure the condition. Following surgery, medications may be slowly withdrawn in many cases. Neurostimulation
Neurostimulation via neuro-cybernetic prosthesis implantation, may be another option in those who are not candidates for surgery, providing chronic, pulsatile electrical stimulation of specific nerve or brain regions, alongside standard care.