A cure for seasickness or other forms of motion sickness could be as simple as a quick zap to the brain, researchers in Britain suggest.
A mild electrical current applied to the scalp can regulate responses in an area of the brain responsible for processing motion signals, they say.
Although the cause of motion sickness is not well understood, many scientists believe it may stem from confusion in the brain involving such signals arriving from both the eyes and the ears, which are involved in balance, as we are moving.
Electrical stimulation can reduce the impact of those confusing inputs that may cause the symptoms of motion sickness, the researchers at Imperial College London report in the journal Neurology.
Motion sickness is a common affliction, as anyone who's ridden a roller coaster or sailed on rough seas knows, but for around three people in 10 the symptoms – including dizziness, nausea and cold sweats – can be extreme.
The researchers said that people whose inner ear was damaged, interfering with its balance duties, sometimes no longer had motion sickness.
That inspired them to employ "transcranial direct current stimulation" to manipulate the part of the brain that normally interprets messages coming from those balance mechanisms in the ear, "specifically unipolarcathodal stimulation over the left parietal cortex."
For their study, the researchers put volunteers in a device known as a "chunder chair," which simulates the disorienting motions of a fairground ride.
After all the participants spent some time in the chair – and experienced motions sickness as a result – half the group were given another session after having tiny electrical currents applied to their scalps to manipulate brain activity.
For that group, in their second session in the chair, it took an average of three additional minutes for motion sickness to start.
A device for personal use could be available in the next 5 or 10 years, suggests study leader Qadeer Arshad.
"It may be something like a TENS machine that is used for back pain," he says.
TENS stands for Transcutaneous Electrical Nerve Stimulation, available in devices meant to treat nerve-related pain conditions.
The technique might even be incorporated into a smartphone, he says.
"We hope it might even integrate with a mobile phone, which would be able to deliver the small amount of electricity required via the headphone jack," he explains. "In either case, you would temporarily attach small electrodes to your scalp before traveling – on a cross-channel ferry, for example."