Clonic seizures consist of rhythmic jerking movements of the arms and legs, sometimes on both sides of the body.
If the clonic seizure has a focal onset (starts in one part of the brain) the person may be aware during the seizure.
If the clonic seizure has a generalized onset (affecting the whole brain) , the person is not aware during the seizure.
If a person is standing when a clonic seizure occurs, they may fall. An important first aid step when assisting someone having a clonic seizure is to protect the person from injury when the jerking occurs, if there is a fall or loss of consciousness. Do not try to restrain the person's movements.