Maintaining a good sense of smell has knock-on benefits, including on our sense of taste
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Beaming powerful radio waves directly into a person’s head seems to improve their sense of smell – at least temporarily.
Ageing, trauma and some neurological conditions can all affect the olfactory nerve, which enables smell, reducing or even eliminating the sense entirely. Many people also report a diminished sense of smell with covid-19. This has a knock-on effect on a person’s sense of taste and can be detrimental to safety, for instance, if they fail to detect a gas leak.
“In current clinical practice, severe olfactory dysfunction may be treated with surgery, while more common cases rely on chemical-based therapies, such as repeated aroma exposure at home,” says Yongwoo Jang at Hanyang University in Seoul. “Unlike other medical fields where therapeutic devices have advanced rapidly, treatment in this area has remained relatively traditional. Recognising this gap, we introduced the concept of electroceuticals, using bioelectronic stimulation as therapy.”
Jang and his colleagues wanted to directly stimulate the olfactory system, but because it lies deep inside the human head, they were unable to use electrical stimulation, so they instead turned to radio waves.
The scientists first recruited 28 people with no smell issues. For 5 minutes, these participants were exposed to 15 watts of power, emitted from a 5-centimetre square antenna attached to a mount located 10 cm from their head. “The stimulation itself is not directly perceived by the patient,” says Jang. “However, if the stimulation continues for some time, some individuals may experience a mild warming sensation at the site of stimulation.”
Sense of smell was assessed via the commonly used Sniffin’ Sticks smell-threshold test. This involved the participants trying to detect the presence of the alcohol n-butanol, produced in the fermentation of sugars, at varying dilutions.
The researchers found that the participants scored significantly better after the radio-wave treatment than they did before, with this improvement lasting for around a week. People with smell issues may need recurring treatments, says Jang.
The team is now preparing studies to test the approach on people with olfactory problems. The device has also been upgraded to deliver more focused stimulation, which may bring about even greater improvements, says Jang.
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