光照耳道可以预防患冬日抑郁？

　　Ear's an idea: The effects of seasonal affective disorder could be combated by channeling light to the brain down the ear duct

　　As the nights get longer, those who suffer from the winter blues will be planning ways to escape to the sunshine.

　　But there may be a much simpler way of cheering yourself up... simply shining a bright light into your ear canal.

　　Up to one in four Britons suffer from seasonal affective disorder, with seven percent of the population having full-blownSAD.

　　It is caused by the brain not receiving enough daylight which is needed to trigger serotonin, a hormone that regulates mood. Symptoms range from mild lethargyto depression and insomnia, but a cure might be in sight.

　　Two clinical trials, run by Valkee - who make a device that can shine light into your ear - and the University of Oulu in Finland, have found that carefully targeted light can help prevent the condition.

　　Juuso Nissil , Valkee's co-founder and chief scientist said: 'We presented earlier that the human brain is sensitive to light.

　　'These two clinical trials demonstrate that channeling bright light via ear canal into brain's photosensitiveareas effectively prevents and treats seasonal affective disorder.'

　　The University of Oulu reported that in their first study, 92 percent of the patients with seasonal affective disorder achieved full remissionafter a month of daily eight-to-12 minute doses of light from the Valkee.

　　Timo Takala, chief physician at the Oulu Deaconess Institute said: 'These two trials show that bright light channeled into the brain via ear canal is an important future method to treat seasonal affective disorder.'

　　Valkee launched its bright-light headset in August 2010. It is classed as a medical device under EU regulations.

　　The device channels bright light direct to the brain via the ear canal to prevent and cure depression, mood swings and even circadian-rhythmdisorders such as jetlag.

　　It costs ￡185 and looks like an iPod - only the earphones emit light rather than sound.