https://newatlas.com/medical-tech/sound-spice-tone-motion-sickness/
[snip]
Motion sickness occurs when the movement that we see with our eyes and/or sense with our muscles and joints doesn't match up with the movement sensed by our inner ear.
This disconnect affects our sense of balance, resulting in unpleasant reactions such as dizziness, nausea and fatigue. And while preemptively taking certain medications can help stop this from happening, they don't always work that well. That's where the tone comes in.
Previous studies already suggested that using sound to stimulate the inner ear's fluid-filled utricle cavity may assist in maintaining a sense of balance. Takumi Kagawa, Masashi Kato and colleagues at Japan's Nagoya University set about exploring that theory further, by observing how tones of different frequencies and loudnesses activated the vestibular (balance-maintaining) function of extracted mouse utricles.
The tone that worked best had a frequency of 100 hertz and a loudness of 65.9 dBa (A-weighted decibels). It has been trademarked as "sound spice."
[snip]
Human test subjects showed a similar response after just one minute of listening to the tone, before being subjected to prolonged movement in a swing, a driving simulator, and an actual car traveling on the road. Electrocardiography and posturography analysis showed that an untreated control group of volunteers didn't fare nearly as well.
"Our study demonstrated that short-term stimulation using a unique sound called 'sound spice' alleviates symptoms of motion sickness, such as nausea and dizziness," says Kagawa. "The effective sound level falls within the range of everyday environmental noise exposure, suggesting that the sound technology is both effective and safe."