Summertime means time spent on the water – whether on a cruise or sailboat, on the lake, at the waterpark or swimming in the pool or ocean. But do you ever have the sensation that you’re still rocking or swaying back and forth after you get out of the water and on to dry land? Baylor College of Medicine sensorimotor physiologist and occupational therapist Dr. Helen Cohen explains the sensation, formally called mal de debarquement.
Translated literally, mal de debarquement (MdD) means sickness of disembarking. It is the sensation that people feel after they get off a boat or after they have flown in turbulence, not the nausea and other symptoms that they have during the event.
“If you’ve ever had a slight rocking sensation when you go to sleep at night after being out on a boat, that’s an example of mild MdD,” said Cohen, professor of otolaryngology and associate director of the Center for Balance Disorders at Baylor. “We don’t know why some people get it and not others, but we do know that, while men do experience it, it has generally been more common in women.”
Cohen explains that MdD usually occurs after an intense motion experience, which typically includes rolling, or the side-to-side tilt, of the head. Most of the time it fades away quickly, after a few minutes or a few hours.
“The underlying cause of MdD is a bit complicated,” Cohen said. “The vestibular labyrinth, a sensory system essential to movement and equilibrium, collects information about acceleration of the head. It then converts those signals to velocity. Within the brain pathways that receive and process information from the vestibular labyrinth, there is a mathematical mechanism that converts the velocity signal to a positional signal while also storing the velocity signal momentarily for use in spatial orientation. That mechanism is supposed to dump out its memory store as soon as the contents are no longer needed. One theory about MdD is that it represents a failure of the velocity storage integrator to dump out those signals, or to forget about them, so the signals reverberate.”
Those who have MdD can have symptoms lasting anywhere from five minutes to years. If it does not fade away within a week or two, the individual should seek medical care, Cohen said.
If you experience a rolling or rocking sensation that does not subside within a few days, Cohen says there are certain things you should avoid: