Tonic seizures cause stiffness in the body, while atonic seizures cause muscles to go limp. Learning the signs of both can make you better prepared to help the people experiencing them.

Seizures can generally be categorized as either tonic or atonic.

A tonic seizure is what most people associate with seizures: The body stiffens and experiences muscle spasms or jerks. The person falls to the ground and possibly even loses consciousness.

By contrast, atonic seizures cause muscles in the body to completely go limp — though falling is still a possibility.

In both cases, the event is typically brief.

Knowing which type of seizure a person experiences can help to determine the right treatment method to prevent future epileptic episodes.

Tonic seizures can affect either part or both sides of the brain, and they’re more likely to occur when a person is sleeping. Typically, this type of seizure affects both sides of the body and can be triggered without warning. If it affects only one part of the body, it’s known as a focal tonic seizure. If it affects the whole body, it’s a generalized tonic seizure.

While the root cause of atonic seizures isn’t fully understood, we do know that they can either start in one part of the brain or affect both sides of the brain. If only one part of the brain is affected, this is known as a focal motor atonic seizure. If both parts are affected, this is known as a generalized onset atonic seizure.

Atonic seizures are more likely to begin in childhood and are often associated with syndromes such as Lennox-Gastaut syndrome and Dravet syndrome.

A person experiencing either tonic or atonic seizures may not get a lot of advance warning that one is coming. Often, the biggest concern is that the person will fall and hurt their head while seizing.

Physical cues will be the biggest sign that someone is experiencing a seizure.

With tonic seizures, a person might suddenly become stiff and then experience forceful movements. Immediately after the seizure ends, that person might be exhausted and confused. If the person is awake shortly after and is uninjured, no immediate first aid is needed for them.

However, if this is the first time someone has ever experienced a seizure, they should seek medical evaluation, even if they feel OK afterward.

For atonic seizures, symptoms will be slightly different. With these events, a person might go limp. Other signs include:

  • eyelid drooping
  • head falling forward
  • might drop items

After an atonic seizure, the person may be fully lucid, or they may be confused. Additionally, they may be able to resume normal activities within a few minutes, though some people may require rest.

With both seizures, the biggest concern is that they may fall and hit their head. In both cases, seizures are usually short, lasting no longer than 15 to 20 seconds.

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There are a variety of treatment methods for both tonic and atonic seizures.

That said, people who experience atonic seizures may require more specialized medications that target the specific underlying conditions that contribute to them such as Lennox-Gastaut syndrome.

People with atonic seizures may also experience better relief through certain diets. Well-known options include the ketogenic diet, a modified Atkins diet, and a low glycemic diet, which have all been linked to managing seizure frequency.

Diet changes may not work for everyone, so it’s important to check in with your doctor before making any changes to your eating habits.

Additionally, since many people with epilepsy often experience poor sleep — a known trigger for episodes — treating this issue can also help reduce seizure frequency.

In some cases, someone who experiences atonic seizures may require vagus nerve stimulation from a neural implant device or even a surgery known as a callosotomy to treat their condition.

Surgical treatment is usually reserved for people who have tried multiple medications to manage seizures with little or no success.

Ultimately, the right treatment plan will depend on whether someone is experiencing seizures in both sides or one area of the brain, as well as any underlying conditions that might contribute to it.

Learn more about the difference between epilepsy and seizures here.

Both tonic and atonic seizures can occur with little to no warning, with tonic seizures being more common while a person sleeps.

While both seizures can result in falling because of a loss of muscle control, atonic seizures are typified by a lack of muscle tone while tonic seizures are categorized as extreme muscle rigidity.

Both forms may require a nuanced treatment plan that takes into account underlying medical conditions as well as potentially making dietary and lifestyle adjustments to reduce the frequency of future seizures.