(11-23-2013, 12:10 PM)rgmichel Wrote:Curiosity: Why do you think the snore graph tells you how many times you snore? Or are you just counting the number of times the snore graph has peaks in it?(11-18-2013, 12:07 AM)archangle Wrote: I've never heard any meaningful definition of the "snore" scale other than "higher is more."I think whether or not you experience a snore at all or how many times a night is useful. The graphs show you when you snore and how many times. Correlate that with the scale and that might be useful. (emphasis added)
Snoring data is not well understood because neither Resmed nor PR has openly published much about what their snoring data means---other than "you're snoring."
The scale in ResScan indicates that on the Resmed S9s, the higher the snore graph is, the louder the machine thinks you are snoring. But there are no "units" on this snore graph, and hence the numerical values in SH really carry no meaning that we users have been able to clearly ascertain---beyond "higher is louder."
The snoring data on PR System One machines is extremely confusing---regardless of whether you look at it in Encore or SleepyHead. When JediMark was writing the SH code that displays the snoring data for PR System One machines, he discovered there were two kinds of snoring data being recorded by a PR System One that is run in Auto mode. He called them VS and VS2 for lack of any better names.
The VS snores are recorded only when the System One is run in Auto mode, and these are the snores that trigger pressure increases. The VS snores have time stamps on them, but otherwise there is no number attached to them in the SH events list in the daily data. On a System One machine, the SH VSI is calculated as:
- SH VSI = (number of VS scored)/(total run time)
The VS2 snores are recorded regardless of whether the System One is running in fixed pressure mode or Auto mode. There are numbers attached to the VS2 snores, and it is these numbers that SH uses to draw the snore graph for System One machines. Whether those numbers actually mean "louder snoring" or "longer snoring" is not at all clear. The assumption that a lot of people make about the SH snore graph is that the higher the graph, the louder the snoring. That may or may not be correct, and looking at the snoring data for a System One machine in Encore (the official software for the PR machines) does not clarify things very much.
In Encore, the VS2s show up in the event table as VS tick marks, but they do not show up in the Encore wave form data. The VS snores show up as tick marks in the Encore wave form data, but do not seem to show up in the tick marks for the VS line in the event table. The Encore VSI is NOT equal to the number of VS2 snores divided by the run time; typically it is much larger than the number of VS2 snores divided by the run time. Reviewing my own data it becomes clear that the Encore VSI is also NOT equal to the total number of VS and VS2 snores divided by the run time. What I've found out in staring at my snore data for a very long time is this data based conjecture:
- Encore VSI = (Sum of the VS2 snore numbers)/(total run time)
Why the Encore VSI is defined this way remains a mystery to me. It is possible, however, that those parenthetical numbers just might be counting the time the snoring continued measured in (seconds? or breaths?). In which case the VSI would equal an "average amount of time per hour spent snoring" where the "time spent snoring" is measured in whatever the units for the VS2's actually are. But calling this number an "index" seems misleading in that case since all the other indices in the Encore reports are clearly defined as
- Event Index = (number of events of given type)/(total run time)
Moreover the Periodic Breathing data (PB) is reported as a percentage (%) of the night in Encore, which clearly indicates that it is the length (in seconds) of the PB that is being recorded by the machine. And that length in seconds value is the parenthetical number that shows up in SH by each PB event.
Hence: It's a real mystery on how the PR System One machines score a snore, how they tell whether it is a VS or a VS2, and what the numerical meanings are for the individual VS2 numbers; the SH VSI; and the Encore VSI.