Startle epilepsy

29th January 2019

Startle epilepsy (or startle-induced seizures) is a type of reflex epilepsy whereby a seizure is caused by a sudden and unexpected stimulus. This could be a wide variety of things, and it often varies from person to person. Some people with epilepsy may be particularly sensitive to one type of stimulus. Startle epilepsy is very uncommon and it can affect both males and females equally.

What kinds of stimulus cause startle-induced seizures?

As previously mentioned, this can vary from person to person. A sudden and unexpected stimulus can take on many different forms, including:

  • Sudden loud noises
  • Somatosensory
    • Pressure
    • Pain
    • Touch
    • Taste
    • Changes in temperature
    • Movement
    • Vibration
  • Visual (less common)

A person with startle epilepsy may be susceptible to one or all of these stimulus. As you may expect, the sudden and unexpected nature of the trigger may make every day life quite anxious for people who have been diagnosed with startle epilepsy.

It’s important to note that it’s the unexpected nature of the stimulus that characterises startle epilepsy. For example, loud noises at a firework display are expected, and as such would not cause a seizure. However, a car backfiring or a fire alarm, for example, are rarely anticipated and therefore could cause a seizure in someone who is sensitive to loud noises.


An MRI scan is often required to make a diagnosis of startle epilepsy. Brain abnormalities will predominate in the lateral sensory-motor complex, making it necessary for the scan to make an accurate diagnosis. There may also be other tests and scans used to confirm the diagnosis.


Startle epilepsy can be managed with anti-epileptic drugs (AEDs). Carbamazepine, clonazepam, clobazam and lamotrigine are all commonly prescribed. Surgery might help to control startle seizures that are associated with infantile hemiplegia. However, startle epilepsy is typically intractable, meaning at best incomplete or temporary seizure control can be achieved.

National Epilepsy Training can help

For more information on startle epilepsy or to enquire about any of our services, please call us on 01706 373075 or email