Polysomnographic Reference Curves 
for the First and Second Year of Life

Summary Objective To derive reference curves of polysomnographic parameters for clinically healthy infants and children in the first and second year of life. Study design From January 1989 to December 1999 a total of 13 373 polygraphic sleep recordings were carried out at the sleep laboratory of the Vestische Kinderklinik Datteln, a tertiary referral centre for sleep‐related respiratory problems in infants and children. In order to create a data base for reference curves, 681 recordings were retrospectively selected from the total pool, if the following criteria were fulfilled: first polygraphic sleep recording of the proband, clinically healthy term infants without symptoms of upper respiratory infection at the time of sleep study. Premature birth (