If you're prone to sadness during the dark months of the year, getting some sunshine is known to help. If you can't get enough sunlight, a light therapy box (which shines in your general direction while you eat breakfast) is the second best option. But there's another gadget that some people rely on very much – earbuds, which act as tiny flashlights that shine light into your ear canal. Are they legitimate?
A **care TikToker @emmahoareau1 posted a short review of LED headphones for people like me with seasonal affective disorder and concluded that they were "absolutely life-changing." In the follow-up, commenters began to debate whether it was possible for light to reach your brain efficiently through the device.
The most obvious question is: does light really reach your brain?If so, does the brain know it's there?Surprisingly, the answer to these questions is: yes, and probably.
For decades, scientists have been studying the first question – whether light can pass through brain tissue. In a 1963 study, a light detector (somewhat like a miniature solar panel) was mounted on the end of a needle, which then got stuck into the brains of sheep, dogs, rabbits, or mice – dead in some cases and alive but anesthetized in others. The researchers illuminated different parts of each animal's head with bright light. They did some testing indoors and in the sun, and covered different parts of the head with aluminum foil to find out where the light was entering. They conclude that light does reach the brain easily, especially through the temples, where the bones are particularly thin.
We also know that photodetection proteins are found in various parts of the body, including the brain. For example, they may help birds know what season it is, but so far, there is no clear explanation as to why humans have these proteins or whether they play plays a role in seasonal affective disorder.
In 2016, another group of researchers found evidence that light in the ear canal has something that the brain can detect, but it's unclear whether this is good or bad, or whether it accomplishes anything meaningful.
The researchers photographed a ** of a cadaveric skull with a Valkee device in its ear (similar to the one in TikTok). The light is bright enough to pass through the bones and into the brain. But this is not to say that the device is effective: "Whether the chronic intense light transmission through the ear canal has a clinically applicable benefit is beyond the scope of research." The study. ”
There's a huge leap between "light can reach the brain" to "this will ** your seasonal affective disorder," and that's where this product gets stuck.
The light therapy headphones used in TikTok (which are the only major brands of them as far as I know) are manufactured by Valkee. Their current product is called the Humancharger and retails for $200.
The company commissioned several studies on its products, and in the early years of marketing, they seemed to rely heavily on these studies. Based in Finland, Valkee reviewed a 2012 TV show that confronted the company over its marketing claims and pointed out to viewers that their research didn't hold water. Many do not have enough placebos, all have conflicts of interest (company founders and board members as authors), and most are not published in peer-reviewed journals. At the time, their only peer-review** was published in Medical Hypotheses, a journal dedicated to exploring "radical hypotheses rejected by most traditional journals." ”
At the time, the company's **mentioned that its product could**migraine and jet lag;It's worth noting that the current HumanCharger ** avoids any such claims. A piece of marketing** shows a woman entering a hotel room with a suitcase scrolling behind her, with a caption next to it saying the device "gives you energy." In another**, it says that the device fights "blues".
Since then, research has ceased to be promising. A 2014 study (whose authors included Valkee employees and shareholders) claimed that the device lowered people's scores on depression surveys. But there was no control group;The researchers were simply looking for evidence that people who received the highest dose of light performed better than those who received the lowest dose of light. They don't.
A group of unrelated researchers, experts in chronobiology, tested people using the Valky device. They found no difference between those who used the device and those who did not glow in the "fake" version. (As you might expect, visible light produces a strong reaction.) Their ** caption: "Extraocular light through the ear canal does not seriously affect the physiological performance of circadian rhythms, alertness, and psychomotor vigilance in humans." ”
Other studies on circadian rhythms have not found any conclusive evidence that our biological clock can be affected by light from the ears, behind the knees, or anywhere other than the eyes. Interestingly, our eyes' ability to perceive daylight seems to be separate from our vision. Many blind people find that their circadian rhythms are out of sync with daylight, but some have their light detection systems intact even if they don't have vision.
Therefore, there is no strong evidence that light-emitting earbuds do anything;And there is plenty of evidence that they may be nonsense. I am happy for everyone who buys this device and feels that their lives have changed for the better because of it (God knows I have my own placebo for emotional support), but I advise you, dear reader, to save some money.