OSCAR Support for DSPD (Time/Session Issue

[greenwsj]

Hi,

OSCAR is great! I've used it for about a week now with my Resmed Airsense 10. But I have noticed a strange thing.

I have delayed sleep phase disorder and typically fall asleep (start using my machine) after midnight, and wake up after noon. So an actual "session" for me might last from 6am to 2pm on the same calendar day.

The problem is that OSCAR appears to start "sessions" at noon. Which causes a problem.

Suppose I sleep on July 29 from 6am to 2pm.This means that if i choose July 29 to examine with OSCAR, I see a "session" composed of July 29 from noon to 2pm, and July 30 from 6am to noon. Which gives a misleading account of my actual sleep "session". It actually shows the last part of my prior sleep period, and the first part of my next sleep period! The reverse of what I would want!

Does my explanation make sense? Have I missed an option somewhere? For me, selecting midnight (instead of noon) for a session would make a lot more sense.

[Crimson Nape]

A Resmed day is from noon to noon. Since your sleep session occurs during a change of days, your best option is to set the Resmed's clock back about 6 hours. This should allow your session to be encompassed in one day. The sleep times don't mean as much as keeping the data together.

[pholynyk]

It is the ResMed machine which sets the day running from noon to noon. The easiest solution I can think of is to change the time on the machine to be six hours slow, so that machine noon is at 6:00 pm. I recommend setting it to standard time, not Daylight Saving Time, and not bothering about the time changes.

As far as I can tell, the AirSense 11's come set to GMT, and all you can select is your time zone - and you can't change it without erasing all the memory. I trust (not) that they have built in time synchronisation, or at least a better crystal than my AS-10.

[greenwsj]

A Resmed day is from noon to noon.  Since your sleep session occurs during a change of days, your best option is to set the Resmed's clock back about 6 hours. This should allow your session to be encompassed in one day. The sleep times don't mean as much as keeping the data together.

Thank you for the suggestion, but I have two problems with it.

1) You can't change the time back on a Resmed Airsense 10. I presume they don't allow this due to problems with data overwrites/race conditions. This is also a problem when I switch time zones traveling.

2) I don't want to mess with the source data. That could lead to all sorts of problems. It strikes me as a lot better to make a slight change to the OSCAR software that allows an advanced user to specify the start of "day" or something like that. For example, start the day at 12 midnight, instead of 12 noon.

[GuyScharf]

You can change the time back, but it's tricky and you have to be careful about when you do it.

Splitting the day at a different point in OSCAR is not a "slight" change. Consider sleeping from 11 am to 1 pm. ResMed splits that sleep block into two sessions, one from 11 am to 12:00 and another from 12:00 to 1:00. If you could set the day boundary in OSCAR to some other time, OSCAR would have to split a session that crossed the boundary into two different sessions, each in a different day. That would be more than a slight change, with ramifications throughout OSCAR. Also, OSCAR data with a date boundary other than at ResMed's noon could never be compared with ResScan reports or with MyAir. The former would lead to questions about the accuracy of OSCAR and difficult explanations. So would the latter (interesting to see that "MyAir" rhymes with "who cares?").

[cathyf]

You just need to take a variation on the "it's 5 o'clock somewhere" theme.

Set your clock forward 12 hours and that will swap AM & PM -- and it will have the added benefit of the "name" of the day being the date that you slept rather than the day before.

When I hosed my ResMed clock by trying to correct the time over the midnight boundary I slept two nights with the clock that way, and then I went back and fixed the times in my data files in a text editor.

But seriously, just think of it as choosing another time zone twelve hours after your time. Pick out a fun destination in that time zone and put up pictures of it. Have some fun!

(I usually go to sleep after midnight, but do get up well before noon, so I leave my ResMed clock as it is. When I pay attention I will roll my eyes at the fact that "the night's date" is not the day I slept!)

[greenwsj]

Very good advice. Thank you!

I will check with my sleep disorder physician to get his approval on this; I don't want to mess around with basic source data without the approval of an expert.

I still find it totally astonishing that such a basic thing as a "sleep session" does not get handled properly (even with a basic thing like a sliding window of variable duration for time under investigation instead of a "day" that doesn't start in accordance with common definitions in any culture on Earth). You go to sleep; you wake up: a session. Not that complicated a concept.

I did contact Resmed on this; they dismissed me in a rather offhand and trite manner; I suspect they have heard this before and thought me stupid or something.

(In case anyone wonders: I have a Ph.D. in computer science, have a lot of experience in software design, understand the basic issues, and wonder why such callousness exists towards people with delayed sleep phases! We can't possibly have that much rarity among sleep disorder specialists! Not to mention shift workers!)

[fakename1845]

I have free-running non24 and the session time graph is hard for me to use as well.