Dim light melatonin onset (DLMO)
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The time of onset of melatonin secretion in light condition (< 50 lx), in the evening, called the dim light melatonin onset (DLMO) phase is assessed for each patient. Patients wear glasses composed of acrylic lenses and a UV-530 filter (Bio Optik, Lux Therapie, Strasbourg, France), filtering the blue component of light, 1 h before the beginning of the first sampling. Patients are prompted to give 5 to 6 saliva samples of 2 ml every 30 min using Salivettes (Sarstedt, Newton, NC) 4 h before their average bedtime. The participants tip the cotton swab from the Salivette into their mouths and roll the cotton swab in their mouths for up to 5 min until saturated, before spitting it back into the Salivette. Toothpaste or mouthwash are not allowed during the phase assessments. Small snacks and fluids are permitted, except in the 20 min before each sample, and participants are required to rinse and brush their teeth with water while remaining seated 10 min before each sample if they had consumed food or drink. Participants are not permitted to consume any alcohol or caffeine at least 24 h before each phase assessment.After collection, saliva samples are frozen at -20 °C, then at -80 °C until analysis. Salivary melatonin is determined by a Direct Saliva Melatonin ELISA kit from NovoLytiX GmbH society (Witterswill, Switzerland). Saliva specimens from a given subject are run with the same assay kit [