mrueschman

Thanks for inquiring and sorry for the confusion. I looked up that CCSHS subject in our source data and found a variable called rdi0p (not shared on the site), which has a value of 2.2. That matches the 18 event total you found and computed from the XML annotation file.

Is there any additional filtering of the XML events required to get closer to the true AHI?

Yes, this is exactly it. The XML annotation files in the studies you referenced do not give you information (per event) about linked oxygen desaturations and/or arousals. Most of the main AHI variables require hypopneas to be linked to an oxygen desaturation (e.g., >= 3% or >= 4%) or an arousal, however the scoring rules in many of these studies allowed for hypopneas to be scored without an associated desaturation/arousal. Hence, the XML event count ends up being "inflated" since many of those hypopnea events ultimately will not be counted in the numerators of the main AHI variables.

Regrettably, the Compumedics Profusion software did not output these additional details (e.g., linked to X% desat; linked to arousal) in the EDF/XML conversion process. We have recognized this limitation before. It would be up to users to try and link the respiratory events to the desaturation/arousal events if they wanted to pinpoint exactly what events in the XML were included in different AHI metrics.

Thanks for checking out the site. Regrettably, Epworth was not collected at follow-up in the HeartBEAT study.

Thanks for using the site. From what I understand, it's likely the data were preprocessed at the Nonin module (i.e., not at the time of EDF export), but I don't have any more details other than what Nonin puts on their website (e.g., https://www.nonin.com/products/oem3/).

Correct, a days to AF since baseline variable does not exist in SHHS.

Thanks for using the NSRR!

For your first question, these variables are where I would start:

• https://sleepdata.org/datasets/shhs/variables/stdatep (days between the home sleep tests specifically)
• https://sleepdata.org/datasets/shhs/variables/formdate_sh (days between the Visit 1 home sleep test and filling out a Sleep Habits form for Visit 2)

The Interim Follow-up was a distinct visit. No home sleep test; the visit consisted of a couple sleep-related forms, weight/BP measurements (if there was an in-clinic portion), and questions about cardiovascular events since Visit 1.

Hey Snowman,

I heard back from WSC today - they have log files that provide information about lights out/on for each of the naps. I think these will provide the "precise indices" you need to segment the data as you discussed.

The WSC team offered to prepare these log files for the MSLTs posted on the site, however it will take them some time (at least a few months) to fit it into their schedule. I will post here again when I have further updates.

Thanks for using the site. I pinged the WSC team for more information.

I have not checked every SHHS file myself to know whether your conclsuion is sound. I still think it would be advisable to run some systematic check across all the XML files to make sure the position codes are in the same order.

Thanks for your thoughtful question!

The WSC team let me know that they do not have plans to share medication lists for each WSC subject. They did highlight that the Manual of Procedures (https://sleepdata.org/datasets/wsc/files/documentation/WSCS_Manual_of_Operations.pdf - pages 41-46) specifies the drug groupings that went into variables such as sedative_med.

Thanks for using the site. The position values may differ between SHHS subjects, so you should reference the individual Profusion XML files.

If you open a Profusion XML file, you'll find the Position Input definitions near the top, e.g.

The labels here correspond to the order of the position signal values, so

0 - Right

1 - Left

2 - Back

3 - Front