Data collection for PSG was standardized among various manufactured instruments by use of standardized collection and display montages. Each unit used for collection was certified before use to maximize signal quality integrity throughout the EDF conversion and import into Compumedics Profusion software used for scoring.
Raw polysomnography data are available for 2,907 subjects at MrOS Sleep Visit 1 and 1,026 subjects at MrOS Sleep Visit 2. Each recording has a signal file (.EDF) and two versions of the event scoring and epoch staging annotations (.XML).
NSRR XML files can be overlaid onto EDF signal files using the EDF Viewer tool. For more information about the XML translation (mapping) process, review the files available on the EDF Editor and Translator Releases page.
Hypopnea events are represented by two different tags in the XML annotation files. Events with the
Hypopnea tag are hypopneas with a reduction in airflow between 30% and 50% from baseline levels. Events with the
Unsure tag are hypopneas with a reduction in airflow greater than 50% from baseline levels.
If interested in all hypopneas that have a 30% or more reduction in airflow, both event types should be included. If interested in events with greater reduction in airflow (>50%), use those that were labeled with the
Unsure tag does not represent uncertainty about the event, but rather was the only custom tag available in the original polysomnography scoring program.
Additional criteria can be applied to limit events based on associated desaturation and/or arousal.