Seizures are the only visible symptom of
epilepsy. There are different kinds of seizures, and
symptoms of each type can affect people differently. Seizures typically last
from a few seconds to a few minutes. You may be alert during the seizure or
lose consciousness. You may not remember what happened during the seizure or
may not even realize you had a seizure.
Seizures that make you
fall to the ground or make the muscles stiffen or jerk out of control are easy
to recognize. But many seizures do not involve these reactions and may be
harder to notice. Some seizures make you stare into space for a few seconds.
Others may consist only of a few muscle twitches, a turn of the head, or a
strange smell or visual disturbance that only you sense.
Seizures occur in girls and boys at an equal rate and are more common before the age of 15 and after age 65. Inherited seizures are more likely to occur in girls. Seizures occurring after head trauma are more likely in boys. For now, there is no way to screen for a seizure disorder before it develops. However, avoiding head injuries -- such as by wearing a helmet while riding a bicycle -- can reduce the risk of acquiring a seizure disorder.
Epileptic seizures often happen without warning,
although some people may have an
aura at the start of a seizure. A seizure ends
when the abnormal electrical activity in the brain stops and brain activity
begins to return to normal. Seizures may be either partial or
begin in a specific area or location of the brain. The most common types of
partial seizures are:
Complex partial seizures.Complex partial seizures do affect level of consciousness. You may become
unresponsive or may lose consciousness completely.
Partial seizures with secondary generalization. Partial seizures with secondary generalization begin as
simple or complex
partial seizures but then spread (generalize) to the
rest of the brain and look like
generalized tonic-clonic seizures. These two types can
easily be confused, but they are treated differently. Most tonic-clonic
seizures in adults begin as partial seizures and are caused by partial
epilepsy. Generalized tonic-clonic seizures are more common in children.
Seizures that begin over the
entire surface of the brain are called
generalized seizures. The main types of generalized
Generalized tonic-clonic seizures
(grand mal seizures), during which the person falls to the ground, the entire
body stiffens, and the person's muscles begin to jerk or spasm
Absence seizures (petit mal seizures),
which make a person stare into space for a few seconds and then "wake up"
without knowing that anything has happened.
Atonic seizures, in which a sudden loss of muscle tone makes the person fall
down without warning.
Tonic seizures, in which the muscles
suddenly contract and stiffen, often causing the person to fall down.
People may refer to seizures as convulsions, fits, or
spells. But seizure is the correct term. Convulsions, during which the muscles
twitch or jerk, are just one characteristic of seizures. Some seizures cause
convulsions, but many do not.