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Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
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Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
This post shows limited progress toward use of OSCAR's Somnopose import "tool" to display a general purpose accelerometer's data from a CSV file. An accelerometer along with an Autoset and a Vauto and the help received here at AB squelched my OSA, a huge help from all.

The key words in my Thread Subject are dealt with below. They reflect matters grappled with to get to the point where I hope to help some other OSA apneic who may be searching as I did for a way to determine and portray what positions were best for sleep, what moves are made in sleep, and what are the results of corrective measures. To many apneics, especially the tech types, all of this very long post is (and may be) much adieu about nothing. Thinking-about


Yes, there is the video alternative which may now have a fast and OSCAR-synchronous way to (somewhat definitively and numerically) review and document such positional and movement habits in sleep. My earliest searches, probably faulty, found little available before finding the website of fellow apneic, "basementdwellingeek", and his posts of accelerometer work. I bought the general purpose device (manufacturer Gulf Data Concepts) he studied, a device neither jailed inside proprietary software nor wrist worn. I was happy then and now to find and benefit from the X-2-2 (Li ion) and cheaper X16 (alkaline) models. 


But it has been tedious though rewarding work to present those Xs' data graphically and synchronously integrated with OSCAR's graphics. The OSCAR graphic had to be pasted into an Excel spreadsheet where the X's data had been charted/graphed (see graphic "3" below). Then, to synchronize all data, the time scales had to be adjusted to match as well as the start times--those finicky tasks to be done with a shaky hand on a mouse. 


Now, as shown below, I am more than half way to direct and accurate OSCAR importation, integration and display of position and motion intensity data along with OSCAR's graphed sleep data. I simply paste the X's data table (from X's output CSV file) into a spreadsheet that converts it for Somnopose. Presently, I copy and paste that converted data into a CSV blank spreadsheet and then have OSCAR import that CSV file data and display the graphic. The converter has provision to enter and remove clock differences (Vauto vs X).

Many thanks to AB members pholynyk and sawinglogz who gave me a boost in my earlier Software Support forum thread by suggesting that I might emulate the OSCAR-compatible Somnopose software for the Somnopose motion sensing device (which I am doing). I have the adaptation of the Somnopose feature, Orientation (the left-right angular rotation from supine), worked out, but am asking for suggestions how to better utilize the other Somnopose feature, Inclination. (The latter displays the angle of the body's head-to-toes axis to the vertical: not an interesting angle for most persons who sleep at 90 degrees, but could easily be used for sleepers who must elevate their head). The Somnopose manufacturer's data table structure and a sample of my adaptation are shown in that earlier thread and post asking for help (which the two members gave me). 

Explanation and discussion of the graphics

The graphs overall:
Graphs 1-1, 1-2 and 2 display X2-2 accelerometer data as converted by an Excel spreadsheet that has been imported from a CSV spreadsheet directly into OSCAR with its Somnopose data import feature. Graph 1-1, of Orientation data, mirrors the blue colored trace of graph 3 as was generated by and in Excel from the same data.

Graphs 1-2 and 2: These are attempts to display bodily acceleration data in a manner similar to how that "suddenness-of-motion" information is conveyed in the green trace of Excel graph 3. (Note that the green trace has obscured all parts of the red and blue traces in graph 3 that the green trace overlies.)

Graph 1-2: The acceleration data may be too fine vs more granular data accepted by the Somnopose software for Inclination. It is structured to hold values from 0 to plus and minus 180 degrees. My body-part accelerations relative to 1 g ( gravitational acceleration 32 ft/per sec per sec) typically have a range >0.90 to <1.10--about 20lb difference either way--both of which graphic 1-2 seems to indicate Somnopose rounds down to 0.0 or to 1.0 as is shown by the small purple rectangles where acceleration has varied more (see that in 3, the green trace  from Excel).

Graph 2: This is one of several different attempts to more closely approximate the acceleration display of the green colored trace in 3. In this case acceleration was added to 10.00 and the result squared. It is a bit more reflective of the green in 3. Adding acceleration to some number from 1.0 upward and raising the result to various powers helped get more pleasing but hard to interpret dispersion or zoom effect. At least small moves not obvious in the Somnopose Orientation window become noticeable that way.

For now, showing z-coordinate data plotted in the Somnopose Inclination window has more value to me than the inferior Somnopose indications of accelerations no matter how magnified they may be shown at this time. 

(A deep in the weeds rambling explanation is offered here: In my on-side-only sleep, greater movement is often observed more in the z-coordinate than in the x-coordinate which yields the Somnopose Orientation and my Excel (L-R rotation) angles. Not understanding at first I could not see how an axis passing straight through me, through spinal column and navel, both at my navel height (in a standing position), could contribute as much to total acceleration as it often does--my thinking was the x-coordinate "says" all there is to say about significant angular rotations in the x-y plane. But not so. It is a matter of there being two parallel axes: one, the most important and analytically tractable one, of rotation around a body-central axis, that axis that passes from between ankles, through the "tween" and neck axis, and out the apex of the skull; the other being one half body width away and along the line of body length, shoulder to hip, which is in a  fixed, non-translating, but hinging contact with the mattress while lying on one side. Another way of looking at it is to remember a little math, that the rate of change of sine curve amplitude to the rate of change of angle is slowest at the maximum of the accelerometer's sine curve (when I am at 90 degrees from supine) and that the simultaneously measured rate is fastest at 90 degrees farther away, either way (at 180 or 270 degrees, as applies to the z-axis when I am turned 90 degrees from supine.

So rocking back and forth on my side, but not actually rotating around my central body axis can be very significant motion, associated or not, with leg or other body-part movements. I wonder, but am guessing that few commercial sleep-motion detecting devices measure such movements. Somnopose data is for only the two angles: one from standing through lying down to standing on hands inverted; the other from rotation about the central body axis when lying down. Possibly the other special motion sensing and reporting devices do measure overall spatial accelerations along x, y and z axes, which I still hope to have Somnopose present, given the overall view it gives of all gathered information. 


Graph 3: First, it omits only the y-coordinate data display which could be used by a sleeper who was concerned about sleeping with head elevated (whole body tilted) or one who is concerned about accelerations of the head along all three x, y, and z axes. Typically, for my side sleep at 90 degrees to the vertical with accelerometer against my lower back, the y- values only slightly reinforce motions reflected in x and z coordinates and they are always included in computing accelerations shown by the green trace.

Explanation of the boxed A through E parts of the graphs that mark the most noiticeable distinctives for May 13

A. There is Zero disturbance indicated there vs. motion shown in all other traces. 

B. Both Somnopose Orientation and Excel's blue trace portrayal of the same angular rotation understate the greater significance of the z-acceleration that shows in the green trace: this is due to acceleration picking up (primarily) the z-component of motion along with whatever contribution the y-component made.

C. The motions were not picked up in the "1-2" and "2" graphs and only slightly in the "1" graph. Comment at B applies here too, though the blue Excel trace irregularity is slightly more noticeable than the same-area portrayed by Somnopose in "1-1"(they are scaled alike).

D. and E. It seems clear in all of B, C, D, and E the comments at B and C apply. The Orientation graphic in Somnopose and the nearly identical blue trace of Excel capture most all of the gross motion and position data, but tend to be silent about suddenness of the more accelerated motions that the z-axis captures.

   

Seeing an overall acceleration stand-in in the z-axis motion component
Until some advance can be worked out--suggested I hope by others or possibly by suitably adding a figure to acceleration and raising that value to some exponential power--it seems worthwhile to use the Somnopose Inclination window for portrayal of the z-axis' contribution to acceleration from the "hinge" like rocking action. That will suggest the understatements of moves in the Somnopose and Excel rotation graphics.

Other matters that have come up in others' threads or in my work with accelerometers
 
Where to wear accelerometer
Two accelerometers, which can be affixed at most any point of interest (restless legs or PLM?) are better than one. One mounted on the more mobile and active head and another at the small of my back show a lot more and different motions to ponder. When my second one came with the rechargeable Li ion battery I wore both a couple of nights to see if it seemed worthwhile. No, not for me.

Somnopose time shift, if any
One member was concerned about a time shift by Somnopose. The answer lies in whether the intent is for Somnopose or Oscar or the users's data conversion spreadsheet (Excel or One Office in my case) is to handle the local vs GMT time difference, including the effect of the Daylight Time changes. The OSCAR-Somnopose team work fine for me in the -8 hr GMT zone which is now on Daylight time. My spreadsheet deducts 3600 seconds (1 hour) from the local time in my X2 to compensate for PDT. Regarding time: Masked up, auto-start on and ready to lie down, I start the Vauto, the X2 and my CMS50i oximeter all within one second and adjust later as necessary to have all agree with Vauto time wherever it drifts. Otherwise, synchronization is a hassle.


(No, my OCD has not reached the point of trying to determine the individual devices' time lags at their start ups. The problem is being an analytical type and fascinated  with OSA, pulmonological, cardio and blood matters. I see so many struggle with difficult, less treatable health matters than mine and I want to help where I might by sharing what has helped me a great lot.)

CSV files and spreadsheets
For those unfamiliar as I was with a quirk of comma delimited data as handled by Excel and CSV files it can drive you mad. Somonopose, I do believe, demands that all data elements other than date and indications of local clock time must be presented to the Somonopose program (inhabiting, for us, the OSCAR and SleepyHead programs) to two decimal places. Fine. But little did I know or take the right approach to find out that CSV files used by Excel will not show leading or trailing zeroes when opened up after a Save that did show the (my case) trailing zeroes when saved. 

For example, values of 60.00 and 5.10--complying with Somonopose's 2-decimal form when I Saved would come back to me as 60 and 5.1 no matter what I did to avoid that. Unknown to me, in most if not in all cases, the saved CSV file would still carry the two decimal form I saved when it was imported by Somnopose into OSCAR. Hours and hours were wasted! With the aid of a text editor I finally came to understand the CSV quirk. 

Accuracy of data and its presentation
The data is very useful but there are questions (minor ones I believe) that arise from anisotropic measures of forces. For example, the positive x-axis may have a limit of 6554 (the gravitational constant value for the low speed and sensitivity setting of the X2-2) and the negative axis a limit of -6400; the differences are within the instrument itself (and might have been caused by a careless drop of the instrument on a tile floor). The result is that the zero neutral axis is shifted parallel to but away from or toward the central horizontal axis of the graphs at the 0-degree supine position. Similarly the charted 1.0 central acceleration base (the horizontal green trace above) typically shows equal small offsets away from the intended central axis at 1.0. there is a jog in the horizontal trace when one rolls over to his opposite side. All said, absolute values have some error, but relative values that are presented are entirely adequate for my use.


Closing comment and request for constructive comment and corrections
Please help me correct errors above and suggest any ways you might see to show the acceleration values in the approximate range 0.9 to 1.1 g. Those do not show how much body mass is moving at the indicated acceleration from a 1.0 baseline. But some sense of what mass is moving can be gained when one considers where and how well the accelerometer is affixed to a body part.

I don't duplicate the sample X2-2 data and analysis of it that is in another Software Support Forum post I made. That post shows a starting analysis/data-conversion spreadsheet in a red colored font. There is a typo. The first column of time data in red colored font is in hours not seconds. Anyone who might wish to see the converter spreadsheet as it is now with fully converted data should PM me. Another post in that same thread has a Somnopose data structure table that is a "must read and comply" item.

Sleep well,

2SB
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  

Of my 3 once-needed, helpful, and adjunctive devices I have listed, only the accelerometer remains operative (but now idle). My second CMS50I died, too, of old age and the so-so Dreem 2 needs head-positioning band repair--if, indeed, Dreem even supports use of it now.



 
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#2
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
This post updates my earlier post to show better and more appropriate use in OSCAR of the Inclination feature of Somnopose.

Overlaid on an OSCAR graphic there is a blue-colored trace with cross hatches which shows that an Excel spreadsheet chart and the Somnopose Inclination display are alike. They both differ from the Orientation display omission of movements (differences are marked in yellow). The Excel display shows the formula underlying the plotted Inclination data.

Graphs of x, y, and z coordinates in a plot show significant rocking-on-my-side motions (for this side-sleep only person) that may barely show, if at all, in the Orientation display of x-axis data alone--though x-data alone is relied on to show all (my) rotation around my body-central, head-to-toes y-axis [while omitting rotation (no, "rocking") on a parallel line ( another axis) where my side is in contact with the mattress]. When attempting to evaluate the extent of sleep disturbances, getting more information to show in some way all significant motions of a selected body part is or can be important. Accordingly, all this fuss with the Inclination feature that was only intended to indicate angles from standing on feet, to lying down, to standing on hands.


The Orientation graphic has been expanded only to show how OSCAR's display flexibility can be used to zoom vertically the orientation graph and bring out body rotation detail.

The red grid lines are there only to make simultaneity of fluctuations in the sleep metrics more visible.


   
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  

Of my 3 once-needed, helpful, and adjunctive devices I have listed, only the accelerometer remains operative (but now idle). My second CMS50I died, too, of old age and the so-so Dreem 2 needs head-positioning band repair--if, indeed, Dreem even supports use of it now.



 
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#3
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
2SleepBetta, this is a really cool idea. I'm trying to understand and measure my periodic leg movement (plm) and have acquired a 9-axis accelerometer (Wit-Motion WT901BLE) which measures acceleration, angular motion and magnetic flux in 3 dimensions each and reports via low energy bluetooth. I have it reporting at 5Hz (i.e every 0.2 seconds) and it will last more than 12 hours on a single battery charge. I wear this on the inside of my right ankle with positive y axis pointing up my leg, x is down and z is left when lying on my back:
   

I've used a similar approach by using Inclination to indicate movement but calculations are a little different.

Orientation measures rotation, but I've used 0-360 for lying positions (ay <= 0.7g) and -360-0 when upright (ay > 0.7g):
        orient = 180 + atan2(-az, -ax) / pi * 180
        orient = -orient if (ay > 0.7)
The result is spine/supine is around 180 degrees, ~270 for right side, ~90 for left side and ~0/~360 for prone (with some variation due to leg rotation relative to torso).

Instead of using acceleration for movement I've used the rotational measures wx and wz (wy on my first unit is unreliable, waiting for replacement). These measure in degree/sec and are generally stable at near 0 when stationary. I've used a modified log calculation to be able to see the relatively small twitches that have (while reducing the noise of pure log calculation close to zero):
         inclination = 100* log(1+abs(wx)+abs(wz))

In order to synchronize the graphs from with the PAP data I do some deep inhales/exhales simultaneous to raising and lowering my leg and adjust the movement data to match times:
   

Here's an example showing my breathing changes associated with leg movement:
   
The OA's here are misclassified CA's and there appears to be some hyperventilation associated with the leg movements...
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#4
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
idk how I overlooked this thread for all this time. really interesting and (potentially?) useful stuff! but before I embark down this road I have to ask: aside from confirming the flow rate pattern as plm (as in kappa's screenshot and which is useful in itself), how are you using this info? how do you expect it could be applied in the future? does it bear on how you are approaching your own treatment for apnea and plm?
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#5
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
Hi Sheepless,

I'm sure I've referenced this thread from others you've contributed too...

I think it's important to determine if your leg movements are a response to a breathing issue or vice versa. In my case I'm pretty sure leg movements are at the start of most of the CA type events reported by the CPAP.

I'm using the movement monitor every night and experimenting with different treatments. I've some code to walk through the data and classify movements based on the AASM PLM guidelines (e.g. between 0.5-10s long, min 5s apart, plm is at least 4 movements each starting < 90s from the last one starting). Given that those measures are based on EMG electrical activity and I am measuring movement I have chosen a threshold of 3.5 degrees/sec (=150 on my graphs). I'm hoping to calibrate this when I have a proper PSG study soon (once Covid restrictions here allow).

For me I tend to have much more leg movements when on CPAP, which aligns with the results of most patients (80-90%) in this study. Given my objective is to avoid arousals as a potential cause of AF progression I need to find a balance between reducing moderate OSA and reducing PLMs. This paper suggests that 'Frequent periodic leg movement during sleep is an unrecognized risk factor for progression of atrial fibrillation'. Of course other papers talk about The Interplay between Obstructive Sleep Apnea and Atrial Fibrillation and Association Between Atrial Fibrillation and Central Sleep Apnea.

Here's a graph of my (modified) PLMI over the last month or so:
   
I've graphed total movements (0.5-10s long only), PLMs (>= 4 such movements spaced <90s apart) and CPAP hours used. I see a correlation between CPAP use and increased PLM, some reduction in movement, potentially due to improved Iron/Ferritin levels with oral supplements, no significant change to PLM with the Clonazepam the Neurologist put me on, and potentially some other interactions I'm looking in to.
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#6
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
it's encouraging that you & others are chasing this down; discouraging that you find plm is worse with pap & that it's associated with increased risk of afib.

I haven't looked into afib yet. my mother had it (she snored & probably had apnea) & lately I've had a very subtle heart flutter that takes my breath away & makes me cough. seems minor but noticeable & present enough to make me wonder.

in my case I haven't observed any relationship between pap & plm so your observations are intriguing.
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#7
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
(09-21-2020, 08:57 PM)sheepless Wrote: . . . . I have to ask: aside from confirming the flow rate pattern as plm (as in kappa's screenshot and which is useful in itself), how are you using this info?  how do you expect it could be applied in the future? does it bear on how you are approaching your own treatment for apnea and plm?

An apt question, more polite than these: Why bother to get an accelerometer and what can I  do with its data?

Situation: My 50-60 AHI (primarily OSA Sep. 2015) has been dramatically reduced below the eventual 5.0 "SA Treated" level to a present 6-month AHI of 0.2. My sleep is vastly improved but with many remaining Flow Limits (FL) and Flow Rate (FR) spikes.   Those remainders are after supine sleep and chin tucking have been stopped, largely with credit due AB and my accelerometer's help.

At first my primary goal was to use an accelerometer device to determine sleep position and make any necessary change I could tolerate. I knew the worst of my remaining OSA was in my preferred supine position. For a time I tried to discipline myself to sleep laterally, on my side, that is. But I'd awaken supine or near it, even when wearing a reversed, large, solid-stuffed fanny pack. I finally adopted a wearable chock (nested cardboard boxes, about 4 x 10 x 16  in., stuffed inside the knapsack of an old but well made surveyor's vest). It keeps me at least 45 degrees away from supine. That chock and a change to a VAuto reduced FL dramatically from my AutoSet's levels . 

My recent receipt and far far tardy review of a Dec. 2015 sleep study showed significant "spontaneous arousals", 11 events in the dubious 128 minute sleep part of a 6 hour session of mask fiddling and leaks. Those arousals probably account for many of my remaining (reduced numbers of?) FR spikes. It seems to me that sub-flaggable (low level) FL and FR spikes might be reduced more by changes in one of, or combinations of, a dozen or more life style changes, nutritional intake, or (last-choice?) medications. But which to try changing? How much time or patience or persistence can I, would I, muster without getting some shorter feedback after trials? Accordingly, I'm working on solving the feedback I want get after starting trials of dropping remaining pleasures and debatable habits.  

My secondary goal, at the outset, was to assess, somehow, how large and significant were short bursts of bodily movements in my sleep. Further, and later, could there be any way to tease out of the accelerometer's data the moves made to gain comfort versus those caused by airflow irregularities (sleep disrupting respiratory arousals). I did, as most of us do, eventually learn that a sleep lab's electroencephalography (by EEG) and electromyography (by EMG) are uniquely suited and needed to determine sleep, sleep stages, respiratory arousals and muscular activity. But can we achieve and synchronize useful (that is, sufficiently accurate and precise) measurements of movement with OSCAR curve presentations to score trials we run to reduce our FR curve and FL indications of sleep disorder? I believe member kappa and I are both working on that and seeing progress and gaining more insight into an area where many sleep clinics are, for practical purposes, inaccessible or poorly versed as staffed.

I am coming to believe my accelerometer's data, imported into and synchronized and integrated with usual OSCAR sleep presentations, promise or do--even now--shine some light on arousals. Some are pre-announced by unflagged "micro" FR-curve and motion disturbances that precede brief, multi-wave, FR-doubling surges.  Not into mysticism, but I do find, as I continue working on this, that my sleep FR does have a kind of language, a grammar and a kind of musical set of patterns or variations (with an off beat FL "drummer"). But the challenge, assuming the following distinction is or can be a valid or a useful marker of significant arousals, is to decide which came first: a motion or its "coinciding" disruption of the FR curve--just as I acknowledged earliest on. The tech bugaboo I struggle with is the fact that the VAuto and accelerometer have separate real time clocks and different start-up lag times. I'm quite sure that (like kappa notes twice above) sharp inhales at and at a few subsequent 1-minute intervals can pin down combined startup lag and achieve accuracy, maybe even precision, near or just slightly below 0.5 second. That may be sufficient for "which came first" calls wider than 0.5 second. That's where I am: like an old dog continuing to chew on a bone.  


And kappa, thank you. Regrettably, I did not acknowledge your first post above, which was encouraging to see and to gain understanding from it along with your posts in sheepless' enlightening thread about plm. I will organize a parallel history presentation like you developed, use and have posted. Very helpful, and just one of the many benefits gained here at AB from so many efforts, progress, trials and, even, content rich failure reports. 

2SB
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  

Of my 3 once-needed, helpful, and adjunctive devices I have listed, only the accelerometer remains operative (but now idle). My second CMS50I died, too, of old age and the so-so Dreem 2 needs head-positioning band repair--if, indeed, Dreem even supports use of it now.



 
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#8
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
I find all this to be very interesting, if largely beyond me, so I'm very happy that you folks are fleshing it out. meanwhile, my non-scientific brain delights in 2SB's poetic:

"...my sleep FR does have a kind of language, a grammar and a kind of musical set of patterns or variations (with an off beat FL "drummer")."

so theoretically, a conclusion that disorded breathing precedes motion would suggest cpap might be an apropriate treatment & vice versa if motion precedes disordered breathing(?).

I suspect that which comes first varies in individuals and it would be practical to have the ability to differentiate.

for what little it's worth, based on my admittedly weak, mostly subjective experience of my own case (supported by my wife's reports & a couple audio recordings), I would be quite surprised to discover that my plm doesn't precede, and indeed, trigger breathing anomolies.

but that's just one case & of course I may be wrong. maybe I'll find out when you-all complete your work on methodology!
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#9
RE: Re words: positional motion accelerometer Somnopose Excel spreadsheet CSV GMT emulate
(09-23-2020, 11:24 AM)sheepless Wrote: ....so theoretically, a conclusion that disorded breathing precedes motion would suggest cpap might be an apropriate treatment & vice versa if motion precedes disordered breathing(?).

2SB: Short reply to the question: Yes, for the first part as limited, no for the second part because motion, say, is so often a mere comfort seeking effort and will cause irregular (disordered?) breathing--as is usually, if not always, reflected in a brief increase in the flow rate (FR), but that would not ordinarily be an arousal.


I suspect that which comes first varies in individuals and it would be practical to have the ability to differentiate.

2SB: The timing distinction may not always apply, though my guess is that it does. 

Further, I believe the key overall function of sleep tests is to help patients attain more restful, less interrupted sleep. To accomplish that, the lab's EEG, EMG, and Pes and/or nasal pressure transducers and sleeper-monitoring technician detect, score and take note of medically accepted evidences of apneas flow limits (FL), etc., and of wakefulness, such as motions. All the usual indications of disturbances of restful sleep are noted and summarized.

But we "hose heads" lack labs' necessary (MD and insurance satisfying) diagnostic tools to positively identify respiratory arousals. We must make do, best we can, with an accelerometer or other tool, things more easily obtained and used to gather such evidence as we can to add to any arousal-suggesting pattern of sudden brief enlargements in the FR curve curves' local envelope.

If we are concerned about FR irregularities and questions about unrested sleep, then, for me at my state of limited knowledge, the accelerometer is my best bet, as far as I know, as a kind of analytical type.


...my own case (supported by my wife's reports & a couple audio recordings), I would be quite surprised to discover that my plm doesn't precede, and indeed, trigger breathing anomolies.

2SB: Knowing nothing about parasomnias like, plm, my guess again, is that you are correct. That guess is reinforced by having seen your 2-minute OSCAR views of and our exchanges of posts about your plm.  What little I know explaining our breathing is limited to airway causes of irregular or disordered breathing, but it is possible, I suppose, that our central nervous system can be airway involved sometimes (e.g., CMT, Charcot Marie Tooth disease as an extreme). 

Central apnea (with loop gain, I have experienced, and EER involvments) and plm are in peripheral vision as focus is on trying to understand FL, RERA, UARS, spontaneous arousals--all those related items lying mostly below the insured treatment horizon, though long time research topics. ResMed, at least, filed a 2018 patent application that would extend the width and depth of its earlier flow limit detection patents. I'd not be surprised to learn its 2013 patent was soon reflected in the new AutoSet or another device and am expecting next generation of their machines will be enhanced dramatically to assess FL.
I have no particular qualifications or expertise with respect to the apnea/cpap/sleep related content of my posts beyond my own user experiences and what I've learned from others on this site. Each of us bears the burden of evaluating the validity and applicability of what we read here before acting on it.  

Of my 3 once-needed, helpful, and adjunctive devices I have listed, only the accelerometer remains operative (but now idle). My second CMS50I died, too, of old age and the so-so Dreem 2 needs head-positioning band repair--if, indeed, Dreem even supports use of it now.



 
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  Can you provide example data file(s) for Viatom/Wellue, Somnopose or CMS0-50D? HeyBigGuy 4 820 10-25-2022, 10:54 PM
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  MyAir - download .cs . to creat spreadsheet. Expat31 11 2,058 02-13-2022, 01:10 PM
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  Call for Excel VBA help: to support effort to clarify/understand FL 2SleepBetta 44 5,765 10-24-2021, 04:54 AM
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  Torena, sleep position monitor for Android (similar to SomnoPose) NelsonM 13 2,724 08-06-2021, 10:02 AM
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  Help with Excel Correlation please SevereApnea 5 938 03-29-2021, 09:26 AM
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  SomnoPose does not save data in OSCAR A KLERK 2 963 01-29-2021, 03:30 PM
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