Obstructive Apnea Index at 4% oxygen desaturation [(Total number of obstructive apneas associated with >= 4% oxygen desaturation) / (hours of sleep)]

Respiratory Disturbance Index at 4% oxygen desaturation. Ratio of the count of all apneas (central and obstructive) and hypopneas associated with at least a 4% oxygen desaturation to the total sleep time expressed in hours. [(Total number of apneas and hypopneas associated with >= 4% oxygen desaturation) / (hours of sleep)]

Non-Supine RDI at 4% oxygen desaturation [(Total number of apneas and hypopneas in non-supine body position associated with >= 4% oxygen desaturation) / (hours of sleep)]

Non-REM RDI at 4% oxygen desaturation [(Total number of apneas and hypopneas in non-REM sleep associated with >= 4% oxygen desaturation) / (hours of NREM sleep)]