 This is a randomized clinical trial with 2 groups blue enriched withe bright light versus nothing including 20 patients.The treatment will take 8 weeks with 30 minutes exposition at awakening to withe blue enriched bright light Luminette, Belgium. The investigators willl estimate the fatigue severity scale score , the quality of life the score SF12, the sleepiness Epworth score, and the Psychomotor Vigilance Task PVT The investigators will included patient with severe BI more than six months after the BI. 