A 100 Hz sound developed by Nagoya University researchers safely reduces motion sickness by stimulating the inner ear and improving balance.
A research team led by Takumi Kagawa and Masashi Kato at Nagoya University Graduate School of Medicine has found that “a unique sound stimulation technology,” a device that targets the inner ear with a specific sound wavelength, can reduce motion sickness. Just one minute of stimulation significantly decreased the dizziness and discomfort experienced by people reading in a moving vehicle. The findings, published in Environmental Health and Preventive Medicine, point to a simple and effective method for treating this widespread condition.
“Our study demonstrated that short-term stimulation using a unique sound called ‘sound spice’ alleviates symptoms of motion sickness, such as nausea and dizziness,” Kagawa said. “The effective sound level falls within the range of everyday environmental noise exposure, suggesting that the sound technology is both effective and safe.”
The discovery is an important expansion of recent findings about sound and its effect on the inner ear. Increasing evidence has suggested that stimulating the part of the inner ear associated with balance using a unique sound can potentially improve balance. Using a mouse model and humans, the researchers identified a unique sound at 100 Hz as being the optimal frequency.
How the Sound Stimulates the Inner Ear
“Vibrations at the unique sound stimulate the otolithic organs in the inner ear, which detect linear acceleration and gravity,” Kato explained. “This suggests that a unique sound stimulation can broadly activate the vestibular system, which is responsible for maintaining balance and spatial orientation.”
To test the effectiveness of the devices, they recruited voluntary participants who were exposed to the unique sound. Following the stimulation, motion sickness was induced by a swing, a driving simulator, or riding in a car. The researchers used postural control, ECG readings, and Motion Sickness Assessment Questionnaire results to assess the effectiveness of the stimulation.
Exposure to the unique sound before being exposed to the driving simulator enhanced sympathetic nerve activation. The researchers found symptoms such as “lightheadedness” and “nausea,” which are often seen with motion sickness, were alleviated.
“These results suggest that activation of sympathetic nerves, which are often dysregulated in motion sickness, was objectively improved by the unique sound exposure,” Kato said.
“The health risk of short-term exposure to our unique sound is minimal,” Kagawa said. “Given that the stimulus level is well below workplace noise safety standards, this stimulation is expected to be safe when used properly.”
Their results suggest a safe and effective way to improve motion sickness, potentially offering help to millions of sufferers. The researchers plan to further develop the technology with the aim of practical application for a variety of travel situations including air and sea travel.
Reference: “Just 1-min exposure to a pure tone at 100 Hz with daily exposable sound pressure levels may improve motion sickness” by Yishuo Gu, Nobutaka Ohgami, Tingchao He, Takumi Kagawa, Fitri Kurniasari, Keming Tong, Xiang Li, Akira Tazaki, Kodai Takeda, Masahiro Mouri and Masashi Kato, 25 March 2025, Environmental Health and Preventive Medicine.
DOI: 10.1265/ehpm.24-00247
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