What is it?
Cataplexy is the term given to sudden muscular weakness triggered by strong emotions such as laughter, anger and surprise. The loss of muscle tone that occurs may range from a just-perceptible weakening of the facial muscles through weakness at the knees, to total collapse on the floor. Speech may be slurred, and eyesight impaired (double vision, inability to focus) but hearing and awareness remain undisturbed.
How long does it last?
Cataplexy attacks generally last less than two minutes, and they may only last a few seconds, though some people have repeated attacks of cataplexy which persist for up to 30 minutes. During both mild and severe attacks, the person stays fully conscious.
Does everyone with narcolepsy have cataplexy?
It is thought that about 75% of patients with narcolepsy experience cataplexy. Typically, cataplexy does not develop for months or even years after the first signs of excessive daytime sleepiness, but in rare cases it is the first observed symptom of narcolepsy. Cataplexy may be most severe when the person with narcolepsy is tired rather than fully alert, and can lead to considerable anxiety.
When cataplexy is present, it is extremely rare for it to be an isolated symptom – the vast majority of those with typical cataplexy will also have symptoms of narcolepsy. Whilst there are a few neurodevelopmental conditions in which a form of cataplexy may be seen, those conditions are exceedingly rare, and so the occurrence of cataplexy generally makes diagnosis of narcolepsy much more certain.