Understanding seizure types
Atonic (Drop) Seizures
A sudden loss of muscle tone can cause a head drop, a dropped object, or an unexpected fall. These seizures may be very brief, but preventing injury is important.
About this information
This webpage is subject to continuous review by Epilepsy Ontario to help keep the information current. This material is for informational purposes only and should not be used for self-diagnosis or as a substitute for professional medical advice, diagnosis, or treatment. Consult your healthcare provider about your own health and care.
What is an atonic seizure?
“Atonic” refers to a loss or reduction of muscle tone. During an atonic seizure, muscles suddenly become less able to support the affected part of the body.
The change may involve the head, trunk, or limbs. Atonic seizures are usually very brief.
A smaller movement
The head may nod forward, the shoulders may slump, or something held in the hand may fall.
A sudden fall
The knees may give way or the person may collapse without enough warning to protect themselves.
“Drop attack” describes what happens, not the diagnosis. Tonic, myoclonic, and other seizures can also cause falls. Fainting and other medical conditions may look similar. Assessment is needed to identify the cause.
Diagnosis and treatment
Atonic seizures may occur with other seizure types, including in epilepsy syndromes such as Lennox-Gastaut syndrome. The healthcare team considers the person’s history, witnessed events, and test findings when making a diagnosis.
Treatment may include anti-seizure medication or other specialist treatments. The plan depends on the epilepsy syndrome, seizure frequency, injuries, and the person’s overall needs.
Safety and support
Help prevent injury.
During and after a fall
Stay calm, protect the person from nearby hazards, and check for injury. Do not pull them upright before they have recovered.
Follow their seizure action plan and record what happened, including any injury.
Plan for everyday safety
Discuss repeated falls with the healthcare team. They may recommend changes to the environment, activity precautions, or properly selected protective headgear.
A helmet can reduce some injury risks but cannot prevent every injury.
When to get emergency help
Call 911 for a serious injury, breathing difficulty, a seizure in water, a first known seizure, or repeated seizures without recovery. Follow the person’s emergency plan.
A brief seizure still needs urgent attention if the fall causes a significant injury.
What to share with the healthcare team
- Which part of the body lost support.
- Whether there was stiffening or a jerk before the fall.
- How long the episode lasted and how recovery looked.
- How often episodes happen and whether injuries are occurring.
