Eligible patients will be approached for enrollment after their first night in the hospital (i.e.: not on day of admission). Patient/parent will be asked to complete a brief questionnaire describing the child's general sleep habits prior to admission. The parent and/or child will then be asked to complete a questionnaire describing sleep while in the hospital; this in-hospital sleep questionnaire will be obtained for 3 consecutive nights after enrollment, or until discharge, whichever is soonest. A subgroup of patients (between the ages of 5 and 18) will be invited to participate in an additional aspect of the study, where they wear an actigraph (a small device that looks like a watch) for up to 72 hours. This device reliably measures sleep by monitoring the child's motion. This will be used to relate sleep perception to more objective measures of sleep as provided by actigraphy.

Pre-hospital sleep questionnaire completed (Brief Infant Sleep Questionnaire (BISQ)7 in children 0-3 years old; Children's Sleep Habits Questionnaire (CSHQ)8 in children 4 years and older). Subsequent Day(s):

In-hospital sleep questionnaire completed between one and three times per subject (Sleep at MSK questionnaire (SAM), adapted from Sleep in a Children's Hospital (SinCH)9 by Dr. Lisa Meltzer). (Patients will be observed for up to 3 consecutive nights in total).

(using the Sleep at MSK questionnaire)