“The human brain, per se, is sensitive to light”

This hypothesis was the starting point of Valkee science and research, in joint cooperation with researcher groups of University of Oulu, Finland, in 2007.

Bright light is a generally accepted and effective treatment for a variety of mood swings and especially for winter depression. However, the mechanisms of the effects of light are not entirely known.

The Valkee studies, all placebo-controlled since mid-2012, focus on the responses and applications of transcranial bright light (TBL).

The Valkee researchers have discovered the following:

  • Human brain responds to light when it’s administered directly through the ear canal.
  • Valkee alleviates the symptoms of seasonal affective disorder (SAD).
  • Valkee improves cognitive performance.
  • Valkee improves motor reaction time.
  • Valkee reduces acutely anxiety symptoms.

Download the Valkee research summary and the list of peer-reviewed and published articles.

Valkee Science Overview and Publications

Science fact 1 / biology: The human brain is inherently sensitive to light

The research localized the enchephalopsin (OPN3), a photosensitive receptor in the human and mouse brain in the all areas studied. These brain areas include the core areas of serotonin and dopamine production and storage, and play key roles in mood regulation.

The light sensitive retinal melanopsin (OPN4) has been shown to contribute to the circadian pace making effects of light. The study conducted with human cadavers showed that OPN4 is also expressed in the human brain, which suggests that the brain can itself respond to light exposure.

Science fact 2 / imaging (fMRI): Earlight activates neural networks of the human brain
(Valkee placebo controlled study)

Bright light via the ear canal causes a biological response in the human brain neural networks as seen in the placebo controlled, single blind, functional magnetic resonance imaging study – suggesting that the brain tissue is inherently light-sensitive. In the study by the University of Oulu researchers, the human brain’s visual and sensomotor cortexes showed significantly increased functional connectivity in the light group compared to the placebo group.

Science fact 3 / clinical: Earlight alleviates depressive and anxiety symptoms of SAD

Valkee clinical pilot study with 13 SAD patients

In the four weeks pilot study (N=13) 92.3% of study participants suffering from SAD reached at least 50% reduction of symptoms with a daily 8-12 minute dose of Valkee. Winter depression symptoms were measured with the HAMD-17 psychiatrist rating scale, the BDI-21 patient self-rating scale.

Valkee clinical, double-blinded study with 89 SAD patients

In the four weeks study 89 subjects suffering from SAD were randomized to receive a 12-min daily doses of photic energy of three different intensities (1 lumen, 4 lumens or 9 lumens) at home. The response rates (at least 50% reduction) varied between 74-79% for depression (BDI) and 47-62% for anxiety (HAMA) symptoms. There were no intensity based (1 lumen, 4 lumens or 9 lumens) dose response relationships in the improvement of anxiety and depressive symptoms or cognitive performance between treatment groups receiving different intensity of bright light via ear canals.

Science fact 4 / clinical: Earlight alleviates acutely anxiety symptoms
(Valkee double-blind, placebo controlled study)

 Twenty-eight participants with anxiety symptoms were randomly assigned to either 12 minutes of acute transcranial bright light (TBL) or placebo exposure (double-blind) under laboratory conditions. Anxiety symptoms (STAI-Y1) were measured 5 minutes prior and 10 minutes after the exposure. Mean anxiety symptoms decreased significantly only in the TBL group. There was a statistically significant difference in decrease of symptoms between the TBL and placebo groups, favoring the TBL group.

Science fact 5 / clinical: Earlight improves cognitive performance

Valkee randomly controlled clinical study with university students

Forty one university students were randomly divided into transcranial bright light (TBL) and control groups. TBL group received a daily 12-minute dose of Valkee for three weeks. The control group received no treatment. Attention performance (Cognispeed) was measured at the start and end of the study. There was a statistically significant difference found in number of subjects whose attention performance improved between the TBL and control group, favoring the TBL group.

Valkee placebo controlled clinical study with top athletes

Psychomotor speed tests with visual warning signals were administered to a Finnish National Ice Hockey League team before and after 24 days of transcranial bright light (TBL) or placebo treatment. A daily 12-min dose of bright light or placebo (n = 11 for both) treatment was given every morning between 8–12 am at home with a transcranial bright light device. Motor time with a visual warning signal decreased in the bright light treatment group but did not change significantly in the placebo group. There was a statistically significant difference between the groups in decrease of motor time.

Science fact 6 / clinical: The effects of earlight are not mediated via melatonin
(Valkee placebo controlled, randomized clinical study)

Eight healthy young adults participated into placebo controlled crossover trial. The subjects were exposed in random order to 24 minutes of transcranial bright light (TBL) or placebo exposure via ear canals at 01:10 h. The saliva and urine samples for melatonin and cortisol measurements were collected hourly between 21 h–03 h and 06 h–09 h, at 12 h and 18 h. There were no significant differences in the melatonin or cortisol concentrations between the exposures at any sampling points. The curves of melatonin and cortisol secretion concerning the circadian surges and acrophases paralleled those profiles seen under control conditions. The present results indicate that TBL via ear canals does not suppress nocturnal melatonin secretion.

Contact the Valkee Science and Research Team firstname.lastname@valkee.com:

Juuso Nissila, CSO – Heidi Jurvelin, Research Manager – Melanie Rueger, PhD, Research and Science Liaison Manager – Jari Karhu, Professor, Medical Advisor

Visit the Valkee #shine blog for the many interesting blog posts by the Valkee Team.