Also known as: Startle disease


Hyperekplexia is an inherited genetic condition that mainly affects children and babies. An affected person will startle easily at a sudden sound, unexpected touch or bump, become stiff and may fall and be injured, because they cannot put out their arms to save themselves. When a baby startles, there may be a tendency for severe non-epileptic convulsions with increased stiffness and fast quivering. Even daily activities, such as bathing, may bring this on. These convulsions are potentially dangerous because they induce a severe syncope (loss of consciousness) owing to a lack of oxygen reaching the brain; these episodes can be recurrent and are also known as ‘breathing attacks’ or ‘apnoea attacks’. Hyperekplexia responds well to treatment with benzodiazepines, and the condition usually improves as the individual gets older. Most individuals with hyperekplexia are of normal intelligence and may live as fulfilling and productive lives as other people, though some may show a delay in reaching developmental milestones, such as delayed speech or walking.


Medical text approved March 2014 by Dr Jenny Fisken (retired), formerly Associate Specialist in Community Paediatrics, North Yorkshire and York PCT.

Is there support?

There is no support group for Hyperekplexia in the UK. Families can use Contact’s freephone helpline for advice, information and, where possible, links to other families. To meet other families with disabled children, join Contact’s closed (private) Facebook group.

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