In looking at the nsrr/shhs1 and shhs2 datasets, I see that there are variables such as ndes2ph that gives you the count of desat events in each record at different % decreases. Am I correct in assuming that 1) those are what was used to calculate ODI, and that 2) there is no annotation of where all those events occurred in each record? The xml annotations include "SpO2 desaturation" events but now I'm understanding that those are just SpO2 levels associated with hypopnea and/or arousal events, and not pure desat events independent of airflow. Thanks for the help!