There are many different types of seizures. They are usually classified as being either partial seizures (also called focal seizures) or generalized seizures.

Partial seizures involve abnormal activity in specific parts of the brain. These types of seizures can occur at any age, although they occur slightly more frequently in adults than in children. Approximately 60 percent of patients with epilepsy experience partial seizures, according to the National Institute of Neurological Disorders and Stroke (NINDS).

Types of partial seizures include:

• Simple partial seizure. During a simple partial seizure, there is no alteration or loss of consciousness. People who have simple partial seizures can experience abnormal sensations such as inexplicable feelings of joy, anger or sadness. They may also see, hear, smell or taste things that are not really there.
  
  
• Complex partial seizure. During a complex partial seizure, an individual will experience a pronounced change or loss of consciousness. They may appear to be “out of it” or in a dreamlike state. They may also make repetitive movements that appear to be conscious, such as lipsmacking, picking at clothing, or repetitive motions with the hands.

Certain effects associated with partial seizures (e.g., abnormal sensations such as a flash of lights or unpleasant odors) can occur prior to the onset of a more severe seizure. When these effects act as a warning sign, they are known as an aura.

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

• Absence seizures (petit mal seizures). This kind of seizure involves a momentary change in a person’s state of consciousness. This short-term “absence” of conscious activity can be so mild it may not noticed by others. People who experience this type of seizure may suddenly have a blank look on their faces, 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 can suggest the possibility of absence seizures as the underlying cause.
  
  
• Tonic-clonic seizures (grand mal seizures). The most powerful type of seizure, it is also known as a convulsion. A person who experiences this type of seizure can fall to the floor and become unconscious as muscles tense up, eyes roll back in the head and saliva production increases. Seconds after falling, the person’s entire body can begin to shake violently and rhythmically. Labored breathing and loss of bladder or bowel control may follow. 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. This is the type of episode most people associate with the term seizure.
  
  
• Atonic seizures. Atonic seizures are sometimes called drop attacks because they involve a sudden loss of muscle function. During brief atonic seizures, the person may only experience a quick drop of the head. Longer seizures may result in the person collapsing and falling to the floor. This type of seizure can be particularly dangerous because of the risk of the head injury or broken bones from the fall.
  
  
• Myoclonic seizures. A myoclonic seizure is one in which the muscles of a part of the body or the entire body suddenly and briefly contract and partially release, much like the jerking sensation some people experience as they are falling asleep. This type of seizure often occurs at the same time as other generalized seizures.