Understanding Seizure Types
Tonic Seizures
Tonic seizures cause muscle stiffening. They may happen while awake or asleep and can cause falls.
About this information
ESCO reviews this information regularly. It supports learning and does not replace professional medical advice, diagnosis or treatment. Discuss your own care with your healthcare provider.
What might you notice?
The trunk or limbs may stiffen suddenly. During sleep, brief stiffening may occur alongside eye opening or a sound.
Understanding the difference
Tonic means stiffening; atonic means reduced muscle tone. Both can cause falls. Tonic-clonic seizures include stiffening followed by rhythmic jerking.
Assessment and planning
Tonic stiffening can occur in focal or generalized seizures. Report repeated nighttime episodes, falls and injuries to the healthcare team.
Protect without forcing movement.
Time the event and remove hazards. Never force stiff limbs to bend, restrain the person or place anything in their mouth.
Call 911 for breathing problems, serious injury, a seizure in water, a first known seizure, an event exceeding five minutes or repeated seizures without recovery.