Understanding atonic seizures or ‘drop attacks’

  • October 26, 2022
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Do you care for someone who experiences atonic seizures? This is when they suddenly lose muscle tone and go ‘limp’. 

Atonic seizures can be challenging to predict. There are various treatment options available, as well as simple adjustments you can make so they’re easier to live with. 

Let’s learn more about atonic seizure causes, diagnosis and treatment.

What is an atonic seizure?

When we are moving about, standing up, or sitting down, the muscles in our bodies use tension to hold us in position. This is called muscle tone

For people who have atonic seizures, their muscle tone may suddenly disappear. This means their muscles go ‘limp’ and cannot hold them up.

Atonic seizures may be the only type of seizure a person has. But the seizures may come with certain kinds of epilepsy such as Lennox Gastaut syndrome and Dravet syndrome. If so, they will often have other kinds of seizures too.

Atonic seizure symptoms

Atonic seizures typically last just one or two seconds, and rarely longer than around 15 seconds. The exact symptoms the person has depends on where in the brain the seizure happens.

If the seizures happen in just one area of the brain, this is called a focal atonic seizure. Focal atonic seizures often mean only part of the person’s body (such as one side or one arm) goes ‘limp’. People with focal atonic seizures often remain conscious.

If the person’s epileptic seizures happen all over the brain at the same time, this is called a generalized atonic seizure. Most of their muscles will go limp, and they will usually fall over (or slump forward if sitting down). They will lose awareness during the seizure. Generalized atonic seizures appear to be more common than focal atonic seizures.

Diagnosing atonic seizures

If someone you care for appears to be having atonic seizures, then it is important to visit your doctor as soon as possible. To diagnose atonic seizures, doctors will:

  • Ask for a description of the seizures (providing a video is especially helpful)
  • Use an electroencephalogram (EEG) which can monitor electrical activity in the brain. Certain types of brainwave patterns are associated with atonic seizures and can therefore help with diagnosis
  • It may be helpful to visit an epilepsy monitoring unit where their brains and behavior can be monitored for a longer time

Treating atonic seizures

Atonic seizures are often treated using anti-seizure medication. These include valproic acid, topiramate, lamotrigine, clonazepam, and lorazepam, among others. Unfortunately, medication is not always effective for treating atonic seizures.

If anti-epilepsy drugs do not work, other therapies include vagus nerve stimulation, following certain kinds of diet, and brain surgery.

You may be able to modify your home to make it safer for someone with atonic seizures by, for instance, putting cushioning over hard edges. Outside of the home, people who have atonic seizures might wear helmets and other protective equipment.

Are atonic seizures dangerous?

Yes, they can be. Atonic seizures often happen with no warning, which means you may fall over whilst walking around outdoors, at school, or at home. Unfortunately, this means that people with atonic seizures may injure themselves by falling against hard surfaces.

Carers: Taking care of yourself when looking after a person with epilepsy

Outlook for people with atonic seizures

Atonic seizures usually begin in childhood, and people often grow out of them. For some people they may continue for many years and into adulthood. So, it's really important to work closely with your medical treatment team to update your seizure management plan as you get older, and record whenever you have seizures in your seizure diary.

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