Laughter threatens Kay Underwood's health

Kay Underwood, 20, of Barrow Upon Soar, Leicestershire, has cataplexy, which means her muscles weaken when she laughs, causing her to fall over.

The University of Lincoln architecture student has in the past collapsed 40 times in a single day.

She said many people think that she is joking when her condition does make her fall over.

Emotion cause

Ms Underwood was diagnosed as having cataplexy a year ago, but believes she has had it for about four or five years.

She said: "I think a lot of people, if I've told them about it and they've not seen it, would quite like to see me do it (collapse), so they try to make me laugh.

"Quite a few people have thought I'm still strange and 'Is she making it up?'

"And if I collapse a lot of people have thought I'm just putting it on."

Cataplexy

An abrupt temporary loss of voluntary muscular function and tone, sometimes evoked by an emotional stimulus such as laughter, pleasure, anger or excitement. The attacks can last just a few seconds or many minutes. They may end in the resumption of normal behaviour or be followed by sleep for half an hour.

Epidemiology:

• Cataplexy is often associated with narcolepsy and can affect 60% to 90% of patients with narcolepsy
• Isolated cataplexy is rare
• Are triggered by emotions such as anger, surprise, laughter and exhilaration.

Presentation:

• Attacks vary considerably in severity from a barely susceptible slackening of the facial muscles, dropping of the jaw or the entire head, weakness at the knees or collapse on to the floor
• Speech is slurred and eyesight impaired with blurring or double vision. Hearing and awareness remain unaffected.