Gill Archer, a British nurse, stepped off a turbulent long-haul flight to Florida in the US in 2006, feeling nauseous, off balance and dizzy.
And six years on, the 47-year-old’s symptoms still haven’t disappeared.
Archer says it feels like she is constantly “being pulled to one side, like I’m bobbing about all over the place”.
The mother-of-three says she suffers from attacks that last for months at a time.
“The episodes come and go every few months, and they get worse every time they come back.
“When my episodes get really bad, I struggle even to walk in a straight line,” she says.
Archer was diagnosed with Mal de Debarquement Syndrome (MdDS), which distorts a person’s motion perception.
Archer says: “Everyday life can be really difficult. Supermarket shopping is horrendous, as all the bright colours and long aisles aggravate my symptoms.
“I can’t even go out to the cinema with my partner, and the movements on the screen are too much for me to cope with.
It makes doing my job very difficult. The lights in the long hospital corridors are a nightmare, I have to try very hard to walk around without looking like I’m drunk.”
Dr Yoon-Hee Cha, a professor at the University of California and one of the few medics who has researched the disorder.
He says: “Patients usually describe the sensation as a rocking, bobbing, or swaying as if they were still on the boat or other vessel that caused the symptoms.
“A hallmark feature is the temporary symptomatic improvement of the rocking sensation when the patient is passively moved again, notably when they are driving.
“The worst situations are usually when they are standing still or coming to a stop after either passively or actively moving.”
He added: “It is an abnormality in the function of the brain. There is no known cure.”