- Case study: differences in human Per2 gene expression, body temperature, cortisol, and melatonin parameters in remission and hypersomnia in a patient with recurrent hypersomnia. Tomoda, A., Joudoi, T., Kawatani, J., Ohmura, T., Hamada, A., Tonooka, S., Miike, T. Chronobiol. Int. (2003)