Tonic Seizures

By: Aliana Gordon

What are Tonic Seizures?

Tonic seizures are categorized by the short-lived stiffening of the muscles in the body in the arms, legs, or trunk with the loss of consciousness. Muscle tension is increased while the seizure occurs. If the person is standing, it could lead them to fall, but is also common for it to occur while the person is asleep. During sleeping tonic seizures, most of the brain is affected, resulting in both sides of the body to stiffen. The seizures typically occur for 20 seconds before regaining control of their body. Some symptoms that may occur following the seizure are a lack of memory of the occurrence, feeling drowsy, and can be agitated.

Tonic seizures could be generalized or partial (focal), depending on the abnormal electrical activity the brain is affected by. Generalized seizures occur throughout both hemispheres of the brain, whereas partial can start in one region of the brain. Partial, or focal, seizures could become generalized as the seizure proceeds.

These seizures can be experienced by anyone but are most prevalent in people with Lennox-Gastaut syndrome.


The symptoms of tonic seizures include the stiffening of the body, can also be described as being tense while gradually stiffening or experiencing strong jerking movements. As mentioned, if the person is standing it could cause them to fall at seizure onset. This is due to the brain sending nerve signals to muscles and ligaments to contract. It can also be triggered by stress which signals the brain to increased pressure in blood vessels, in turn decreasing blood flow to the muscles. With the restricted blood flow, the face and lips may turn blue, and it may seem as if the person has stopped breathing. In reality, the person is aware of their surroundings but may still face slight confusion following the seizure with slight memory loss. The phase of the tonic seizure may be followed by a clonic seizure, characterized by rhythmic jerking back and forth.

Types of Tonic Seizures

There are a few types of tonic seizures. Axial tonic seizures begin with the contraction of the neck muscles, also called neck spasms, and can be painful. These seizures cause the head to fall into the vertical position with a clenched jaw, mouth open, and eyes wide open. A high-pitched cry could also be expelled as the respiratory and abdominal muscles contract.

Tonic axorhizomelic seizuresare similar to axial tonic seizures in the way they begin but differ as the contractions also extend to the upper limbs. The shoulder become stiff, limiting the range of motions, and the arms are raised.

Global tonic seizuresbegin with contractions in the neck then spread to the ends of the limbs. The arms will be in a semi-extended position while the fists are clenched. The clenching also expending the lower extremities resulting in the person falling if they are standing.

Asymmetric tonic seizuresaffect one side of the body. This seizure could include an array of symptoms. A common symptom is the contraction of all muscles on one side of the body, leading to the rotation of the head to the side affected.


The treatment involved in tonic seizures differs from each individual with consideration if there are other seizures present or influenced by syndromes. To determine the type of seizures that are occurring, an MRI and EEG are used to diagnose and monitor the electrical activity in the brain. Treatments for adults can include the prescription of anti-seizure medication such as lamotrigine, levetiracetam, or topiramate. Another common treatment is the use of vagus nerve stimulation (VNS). VNS is placed on the vagus nerve and will regularly send electrical impulses to the brain to regulate electricity. Using the ketogenic diet as a form of therapy has also shown to be beneficial. Recent studies have shown that it can significantly decrease the occurrence of seizures by nearly half within a few months. Surgery could be a possible treatment if seizures are persistent after trying other therapies. Surgery might be a possibility for children with Lennox-Gastaut syndrome to correct congenital deformities and lessen future seizures. It is always best to consult with the neurologist about possible treatments.

What can you do?

If you know someone with epilepsy or Lennox-Gastaut syndrome, they are most likely to experience tonic seizures along with others. It is important to talk to them first about how they would like to be helped. If they mention that they are experiencing an aura, an indicator of a seizure, be aware that they might fall. It might be helpful to guide them to sit down to prevent injury.

Otherwise, it is important to remain calm and to avoid restraining them in any way. A cluster of seizures can occur, so it is prevalent to prevent further injury by cultivating a safe environment. When they regain mobility and consciousness, be compassionate and supportive as they might become tired or confused. If a seizure lasts for 5 minutes, call 911.


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Coppola, Giangennaro, et al. “Anticonvulsant Drugs for Generalized Tonic-Clonic Epilepsy.” Expert Opinion on Pharmacotherapy, vol. 18, no. 9, 19 May 2017, pp. 925–936,, 10.1080/14656566.2017.1328499. Accessed 28 Feb. 2021.

“How Does Vagus Nerve Stimulation Work?”, 2021, Accessed 28 Feb. 2021.

Ciattei, Jennifer. “Ketogenic Diet Therapy for Epilepsy | the Johns Hopkins Epilepsy Center.”, 9 Feb. 2021, Accessed 28 Feb. 2021.

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