Hello, I have a question concerning ODI calculation. In a previous discussion it has been mentioned that the series of ndes*ph variables can include desaturations that occurred in wake time and that it would be possible to calculate ODI if the desaturation events were scrubbed from wake time. Would it be correct to calculate ODI from ndes*ph variables using the ndes*ph/slptime? Thank you!
Thanks for checking out the site. I think you are referencing this old forum thread: https://sleepdata.org/forum/o2-desat-events-for-odi-calculation/
ndes*ph/slptime would be the correct way to calculate ODI, however the numerator may inadvertently include desaturations in wake time that shouldn't be included in the calculation. A better way to calculate may be to use the XML annotation files and then identifying SpO2 Desaturations that occurred strictly in sleep epochs.
The SHHS polysomnography scoring annotation files are located here: https://sleepdata.org/datasets/shhs/files/polysomnography/annotations-events-profusion