- Children are admitted to the NIH Clinical Center for 2-3 nights for bright light treatment. They remain in their rooms for alternating periods of exposure to standard dim room light and bright light, using a light box placed within 3 to 5 feet of the child. An electroencephalogram (EEG) with additional electrodes to track eye movements is used to monitor the child s attention. Between 8AM and 6PM serial blood samples are collected to measure melatonin levels. A parent rates the child s mood and behavior during the 2-day test period.