The purpose of this study is to learn how well an instrument called an Actiwatch-2 can determine whether a child is asleep or awake. The Actiwatch-2 (manufactured by Minimitter/Respironics of Bend, Oregon) is the brand name for an actigraphy monitor; that is, a motion sensor that is typically worn on the wrist and looks like a wrist watch. It measures and records the amount of movement a person makes each minute. After being worn overnight, data are transferred from the Actiwatch to a computer, and a program estimates whether a person is awake or asleep by analyzing the recorded movement data. The enrollment target is 80 participants. Although other actigraphy equipment has been used to monitor sleep in children, the Actiwatch-2 has not been validated in the pediatric population.

Inclusion Criteria:

• Children (ages 6 months to 18 years) who are undergoing a medically necessary sleep study [polysomnography (PSG)] in the OHSU Sleep Disorders Laboratory
• ASA classification I and II (children in good health)

Exclusion Criteria:

• ASA classification III, IV (children with a chronic or severe disease).
• Children with developmental delay.
• Children born extremely prematurely (before 32 weeks gestation), as these children and their parents may react differently to experimental procedures
• Children who do not speak English or whose parents do not speak English.

pediatric patients receiving sleep study as part of their standard medical care