By Layal Liverpool
Leonard Lab/UCSF/Jhia Louise Nicole Jackson
An in-ear device that stimulates a major nerve leading to the brain can help people learn unfamiliar sounds in a new language.
Vagus nerve stimulation has been used for more than 20 years to treat conditions like epilepsy but it usually involves surgery to implant electrodes so they are directly in contact with the nerve in the neck. Matthew Leonard at the University of California, San Francisco and his colleagues developed an earbud-like electrode that can stimulate part of the vagus nerve that extends into the ear without the need for an implant.
Leonard and his team tested their in-ear device in a group of 36 English-speaking volunteers, stimulating their nerves at various time points while they performed a task that required them to identify sounds in Mandarin Chinese – a language they were totally unfamiliar with. Because the nerve stimulation is imperceptible, the volunteers didn’t know whether or when they received stimulation. Twelve of the volunteers didn’t receive any nerve stimulation at all.
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The researchers found that they could enhance learning by synchronising the nerve stimulation with the presentation of Mandarin speech sounds. “I was quite shocked that just a small amount of stimulation over a very short time period gave us a relatively large bump in learning,” says Leonard.
The participants who received nerve stimulation were 13 per cent better, on average, at classifying tones in Mandarin and achieved peak performance twice as quickly as those who wore the device but didn’t receive stimulation.
“We think that vagus nerve stimulation may enhance learning by helping individuals pay attention to the right things during the learning process,” says Leonard. Although it was only tested with tones from Mandarin in this study, Leonard says that in principle this could be applied to any language.
“As the world becomes more interconnected, I think it’s important that everyone has the opportunity to learn about other languages and cultures,” says Leonard. “Technology like non-invasive vagus nerve stimulation – which is simple, cheap and safe – may help level the playing field.”
“We’re also extending this work to see whether we can enhance the ability to learn to produce, not just perceive, non-native speech sounds,” says Leonard.
Journal reference: npj Science of Learning, DOI: 10.1038/s41539-020-0070-0
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