Procedures to assure confidentiality will be strictly observed. All certification and research data transmitted to the PRC will have identification numbers (PID) and no personal identifiers. The morning after the sleep study, the PSG will be backed up to CD/DVD. This backup CD/DVD should be labeled with the PID, date of the sleep study, and date the archive was created. PSG will be de-identified, i.e. transformed so as to remove any personal or identifying information and the appropriate PID assigned before transmitting and files to the PRC. Clinical studies must have all personal information removed.