NSRR staff
Boston, MA
0000-0002-0506-8368
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The 30-second epoch sleep staging is separate from the respiratory event scoring. The ScoredEvent sections of the XML files give timestamps and durations of respiratory events (e.g., apnea, hypopnea).
There are many AHI variables available, e.g., https://sleepdata.org/datasets/shhs/variables?search=ahi
Date of death and other MrOS outcomes data are only available on MrOS Online (https://mrosonline.ucsf.edu/). You may also need to contact the adminsitrators there to obtain an ID linking key between the data repositories.
Thanks for using the site!
SHHS variables can be browsed here: https://sleepdata.org/datasets/shhs/variables
Some medications-related data are available at both the SHHS1 and SHHS2 visits, e.g., https://sleepdata.org/datasets/shhs/variables?folder=Medical+History%2FMedications
You can browse SHHS variables here: https://sleepdata.org/datasets/shhs/variables
Unfortunately, I don't see any results for diet: https://sleepdata.org/datasets/shhs/variables?search=diet
Yes, that sort of information exists in the dataset. You can browse variables here: https://sleepdata.org/datasets/shhs/variables
E.g., for position: https://sleepdata.org/datasets/shhs/variables?search=supine
What "Study" (dataset) are you referring to? Thanks!
I've heard of pyEDFlib for working with EDFs in Python - https://pypi.org/project/pyEDFlib/
I presume there are other Python tools to read in XML files, though it will probably be up to you to write code to specifically process/combine/analyze the NSRR files.
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/).