Could you shed more light on how many subjects you have found that are affected with the misalignment issue? Did you do a test across all 1,800+ subjects with overlapping PSG/actigraphy, or did you identify the problematic subjects above in a more piecemeal fashion? Originally you said you were "noticing many subjects with temporal misalignment".
Thanks again. This is still on our radar - I am trying to see if someone else on our team can take a closer look to gain a better understanding of the issue.
Thanks! How about these IDs? These subjects all used the same actigraphy device and the studies below occurred in chronological order, with some other subjects in between who did not have accompanying PSG data. Between Groups 1 and 2 I believe the actigraphy device may have gone to the manufacturer for maintenance/repairs. Between Groups 2 and 3 there was a daylight saving time shift. I am curious to see if there is a point in time where the watch shifts from being aligned to misaligned, so to speak.
Could you check for this issue and post your plots for MESA ID 5303? This subject used the same actigraphy device as your 6318 example. 5303 was completed a week before 6318.
We will take a look at the examples you provided in more detail and report back.
Thanks for diving into the MESA PSG and actigraphy data and posting this question. PSG and actigraphy were scored independent of one another, so some incongruity may be expected when overlapping the two data sources. The PSG and actigraphy devices were meant to be initialized and setup on the same computer such that the internal timekeeping would match.
Everything I see about subject 4892 looks "OK" from my end. I double-checked with the PSG scorer that the time for sleep onset (9:17 p.m.) is set correctly. The device was set to record between 9:00 p.m. and 7:00 a.m. The subject is very still (based on the activity counts) for some time before 9:17 - maybe they were lying in bed before actually trying to fall asleep. We see this a lot, which adds some guesswork to determining where sleep actually begins when reviewing the actigraphy data.
Please let me know if you find any other questionable disagreements when using the overlap file.
You need to have an approved data request to access most datasets.
Click "Request data access" next to the dataset(s) of interest to start the data request process. Thanks!
The meanings are as follows for studies scored in Compumedics:
I have never seen anything like that in SHHS. The parent cohorts (Framingham, ARIC, CHS) undoubtedly have this sort of knowledge about occupation, but it would be a lot of work for a user to go to each cohort and obtain the supplemental data.
There was an Occupation questionnaire, from which the current/longest variables were derived. The most granular level of categories are as follows:
Subjects don't appear to ever have been asked to record their occupation (say, in "raw" free text). If you think having the additional categories like the above would be helpful then please let me know here. I could slot those variables to be added in a future release.