Atonic and tonic seizures are characterized by a sudden change in muscle tone.

In atonic seizures, there is a loss of muscle tone in part or all of the body. For example, the head may fall forward, as in a 'head nod'. The muscles in the trunk may give way causing the person to slump forward or there may be a loss of tone in the whole body so a person falls to the ground 'like a rag doll'. These are usually brief lasting less than 15 seconds. Afterwards, the person usually can resume their prior activity. Another name for this type of seizure is "akinetic" (a-kin-ET-ik), which means "without movement."

With a tonic seizure, the muscles become rigid or stiff and may extend or reach out. If standing, the person may fall over 'like a tree' and hit the ground hard. These also are very brief, and occur without any warning.

Since both these types of seizures occur suddenly without warning and cause people to fall, injuries can easily occur.

• Atonic Seizures
• Tonic Seizures

Continue to Complex Partial Seizures

Topic Editor: Steven C. Schachter, MD and Patricia O. Shafer, RN, MN.
Last Reviewed:5/25/07