A 3 stage stratified sampling procedure is conducted on pre-adolescent Tucson school children between the ages of 6 and 12 years of age. Stratification is performed on the following factors:age, ethnicity, gender and snoring status. In the initial phase, 2500 (625 each year) pre-adolescent Tucson school children between the ages of 6 and 12 years of age are surveyed using a questionnaire designed to elicit symptoms of sleep disordered breathing (SDB) including obstructive sleep apnea (OSA). From these data, a subset of 90 snoring and 30 non-snoring children (500 total) will be recruited each year to have home polysomnography, basic anthropometric measurements and a battery of neurocognitive tests performed in order to identify a group of children with SDB including OSA and a group without this condition. In the third phase of the study, 20 children with SDB and 20 without will be recruited each year (80 total) to undergo more intensive anatomic and physiologic testing including cephalometry, measurement of upper airway geometry and resistance using acoustic reflection and oscillation techniques and control of ventilation studies.