Obstructive Apnea Hypopnea Index at 4% oxygen desaturation. Ratio of the count of all obstructive apneas plus the count of hypopneas associated with at least a 4% oxygen desaturation to the total sleep time expressed in hours. {[(Total number of obstructive apneas) + (Total number of hypopneas associated with >= 4% oxygen desaturation)] / (hours of sleep)}

Obstructive Apnea Index at all oxygen desaturations [(Total number of obstructive apneas associated with all oxygen desaturations) / (hours of sleep)]

RDI at all oxygen desaturations [(Total number of apneas and hypopneas) / (hours of sleep)]

Supine RDI at all oxygen desaturations [(Total number of apneas and hypopneas in supine body position) / (hours of sleep)]

Non-REM RDI at all oxygen desaturations [(Total number of apneas and hypopneas in non-REM sleep) / (hours of NREM sleep)]