Generalized seizures involve both sides of the brain simultaneously and are often more severe than partial seizures. Types of generalized seizures include:

• Tonic-clonic seizures (grand mal seizures or convulsions). The most powerful type of seizure, tonic-clonic seizures are a combination of two types of seizures that often occur together: tonic seizures (in which muscles contract) and clonic seizures (spasms in which muscles periodically contract then partially relax). A person who experiences a tonic-clonic seizure may fall to the floor and become unconscious as muscles tense up (a tonic seizure), eyes roll back in the head and saliva production increases. Seconds after falling, the person’s entire body may begin to shake violently and rhythmically (a clonic seizure). Labored breathing and loss of bladder or bowel control may follow.
  
  Typically, tonic-clonic seizures are not dangerous. However, people who witness this kind of seizure should seek medical care if the person’s seizure lasts for more than 5 minutes or if seizures follow in succession without the person waking. Tonic-clonic seizures are the type of seizure most people associate with the term seizure. They are also the most common type of single-episode seizure.
  
  
• Absence seizures (petit mal seizures). This kind of generalized seizure involves a momentary change in a person’s state of consciousness. This short-term “absence” of conscious activity may be so mild it is not noticed by others. People who experience this type of seizure may suddenly have a blank look on their face, appear to be staring off into space or drop something they were holding. Eyelids may droop or blink and muscles may twitch. Each episode lasts for just a few moments, making this type of seizure difficult to recognize and diagnose. Absence seizures most often occur during childhood and often resolve themselves as the child enters adolescence. Unexplained difficulties in school may indicate the occurrence of these types of seizures.
  
  
• Atonic seizures. This type of generalized seizure is sometimes called a drop attack because it involves a sudden loss of muscle function. During brief atonic seizures, a person may only experience a quick drop of the head. Longer atonic seizures may result in a person collapsing and falling to the floor. Atonic seizures can be particularly dangerous because of the risk of head injury during a fall.
  
  
• Myoclonic seizures. This involves the sudden and brief contraction and partial release of muscles of the body. It can affect muscles in just one part of the body or in the entire body. The movement experienced is similar to the jerking that can occur as people fall asleep. Myoclonic seizures tend to occur at the same time as other types of generalized seizures.