Do Valkee bright light headsets reduce SAD symptoms?

Question

This is old news in Finland by now, but I don't know if these products are well known elsewhere yet.

The idea of Valkee headsets is bright light therapy with a twist—the light is channeled through the ear canal, directly to the brain. It should come as no surprise that the products have been greeted with great skepticism.

What is a bit surprising is that a nontrivial amount of scientific evidence is given to support the headsets' efficacy. The major claims made are as follows:

Valkee’s scientific program has discovered the following:

• Human brain is sensitive to light, not just our eyes
• Valkee is effective for seasonal affective disorder ("winter blues")
• Valkee affects body’s circadian rhythm, and therefore can be an effective tool for sleep problems and circadian rhythm disturbances such as jetlag

I'm specifically targeting the second claim in this question. The evidence for the photosensitivity of the brain doesn't imply that pointing LEDs in your ear canal is beneficial in any way. And it seems the evidence for the benefits is significantly thinner.

Is the evidence Valkee produce good enough, or is the methodology and the connections between the industry and the researchers problematic? Have the results been verified independently?

Answer 1

The evidence given at that link is not strong, for any of the claims you mention, but especially for SAD treatment. Refs 1 to 6 are about other forms of light therapy, not shining through the ears. Refs 7, 8 & 10 are posters, not from peer-reviewed journals. Refs 11 through 18 are about chemical (not light) treatments for Generalized Anxiety Disorder (not SAD).

This leaves ref 9. It seems to be from a peer-reviewed journal (no idea how much weight experts assign to articles in Front Syst Neurosci, but it does seem to have a nonstandard review process described here, making me suspicious) but it doesn't say what the citation would have you believe "....suggesting that the brain tissue is inherently light-sensitive [9]." It's actually an article about analysis techniques for fMRI scans.

Regarding the posters:

• ref 7 is about ear-light and SAD, but: part 1 has no control group and only 13 patients, so the effect could be completely placebo; part 2 splits the patients into 3 groups getting 3 different doses of light (varying 10-fold), but sees no difference in efficacy between the doses, suggesting again placebo effects (there is no zero-dose control);
• ref 8 shows the distribution of a particular protein in the brain, which is a long way from showing that the brain is light-sensitive, let alone that this sensitivity is useful for treating SAD;
• ref 10 claims only to show that there is a observable (via fMRI) effect on the brain from the light administration, not that this has any effect (positive or negative) on SAD. I don't know anything about fMRI or their analysis methods to know how convincing this data is.

Not mentioned on the Valkee page: The same authors have another recent article in the journal Medical Hypotheses. It seems to be based on the same study as ref 7 part 1, with the same criticisms. Also note that Medical Hypotheses has a very colourful history, although Elsevier claims this has changed in the last couple of years.

Timonen and Nissilä are shareholder/CEO of Valkee, and are authors of refs 7 through 10, and various of their co-authors have financial ties to Valkee.