Tonic Seizure Summary 1

TONIC SEIZURE SUMMARY

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Tonic seizures can often be confused with nightmares or bad dreams.1,2

LENGTH

Tonic seizures normally last less than 20 seconds.1

MUSCLE STIFFNESS

The individual's arm, leg, or other muscles suddenly tense/stiffen, and their hands may clench into fists or spread open.1

BACK ARCHING

The individual's neck stiffens, and their back may arch dramatically.1,2

DURING SLEEP

The individual will often be sleeping when they experience this type of seizure, but it can also happen when they're awake.1

AFTER THE SEIZURE (POSTICTAL)

The individual quickly returns to normal but may look confused or tired.1

REFERENCES

1. Kiriakopoulos E, Shafer PO. Epilepsy Foundation. Updated March 27, 2017. Accessed October 28, 2025. https://www.epilepsy.com/what-is-epilepsy/seizure-types/tonic-seizures 2. Duncan AH, Peric I, Boston R, Seneviratne U. J Neurol. 2022;269(4):2172​-2178.