Polysomnography - Science topic

No, typical PSG does not measure the diaphragm directly. However, D-EMG has been done by Luo (2008 and 2009*), and which determined many apneas thought to be central were in fact obstructive. MAIN POINT: Diaphragm spasm could represent a novel form of apnea, a peripheral one. Also, it could mimic obstructive apneas on PSG.

*Luo YM, Tang J, Jolley C, Steier J, Zhong NS, Moxham J, Polkey MI. Distinguishing obstructive from central sleep apnea events: diaphragm electromyogram and esophageal pressure compared. Chest. 2009 May;135(5):1133-1141. doi: 10.1378/chest.08-1695. Epub 2008 Dec 31. PMID: 19118271.

Lukas Krondorf the paper ( http://downloads.hindawi.com/journals/wcmc/2019/2786837.pdf) of my friend José R. Torres Neto presents an architecture that uses Publish-subscribe paradigm. The validation process is done with applications on the recognition of emotions.

I doubt that changes in sleep due to COVID-19 infection would be novel enough to have a high enough sensitivity and specificity for diagnosis. It’s conceivable that COVID would worsen oxygen saturations during sleep in some patients, increasing the number of EEG arousals. But this would be the same for any other lung disease that compromises the respiratory system.

Thank you so much, Franklin Lue , much has changed since we last spoke. Check out this new research which compares a non-contact sleep monitor to polysomnography:

Even though, you have been sceptical towards even the validity of PSG, would you think that measuring sleep without interrupting the subject would yield better results?

I would not recommend using Empatica E4 to calculate HRV. We have compared PPG (as used in E4) versus ECG and it overly sensitive to any motion for the data to be usable.

As I understand your question, there are two problems, a. to extract the digital information from graphical output, and b. to perform the integration and other operations on this digital output.

a. There are quite a few digitizer apps on the net, these can turn the paper based graph (or better its scan) into something like .csv (comma separated values) or .xls(x) format file containing the digitised chart. You can find an overview of (some of) the available digitisers here http://connectedresearchers.com/graph-digitizer-comparison-16-ways-to-digitize-your-data/ and one I've used a few times https://www.digitizeit.de/ (a moderately priced pro solution with 21d period to try for free). If none of these satisfies your needs, you might wish to continue Googling along the keywords you find in the above links.

b. Once you have the digital data, most any statistical SW or a dedicated Matlab/R add-on might help you to evaluate the requested parameters. Alternatively, you may wish to create a spreadsheet in Excel, OfficeLibre, whatever table think, or to write (have written for you) a simple app in whatever programming language you (or your friends) feel proficient in. Even the good old Basic would do.

I don't know if this will help, but when arterial blood gases are drawn during a cardiopulmonary exercise test, the results of the blood in the syringe are 15 - 20 seconds behind what the heart and lungs are pumping out.

Hello Matteo,

Here is the study that might be helpful:

Ng AS, Wong TK, Gohel MD, Yu WW, Chung JW, Fan KL. Using pulse oximetry level to indicate the occurrence of sleep apnoea events. Stud Health Technol Inform. 2006;122:672-5.

In brief, this research on ten people ( all men, mean age 45 /SD 8.9, body mass index 27/SD 3.3, apnea/hypopnea index 47/SD 15) attempted to select pulse oximetry (SpO2) level as an alternative parameter to indicate the occurrence of sleep apnoea. Time differences were compared between the "onset of nasal airflow cessation" and the "onset of three percent oxygen desaturation from the baseline" during sleep apnoea events. The results of this study showed there was around a twenty second delay after the onset of the cessation of nasal airflow. The paper provides results for each individual patient: the lowest time, in second (mean/SD) is 19.5/5.8, and the highest is 27.3/7.74.

These researchers concluded that the SpO2 level is not immediately sensitive to the occurrence of sleep apnea, where the time delay may be caused by: i) time utilized by the devise to process the signal, ii) time needed to carry deoxygenated blood to the finger, or iii) the desaturating of SpO2 level, which is affected by the last sleep apnea event and during the occurrence of repetitive events.

Hope this helps. Best wishes with your study,

Tatyana

Thank you Sir.

We intend to use WatchPAT to generate the ground truth for WAKE, LIGHT, DEEP and REM stages of sleep in normal healthy subjects. As sleep monitoring in the natural environments are required a validation against conventional PSG is not possible.

According to the Pittsburgh Sleep Quality Index, sleep efficiency is considered normal 85% or more.

See many BrainMaster YouTube videos such as: https://www.youtube.com/user/brainmastereeg/featured

i don't have any information about sleep analysis, but MATLAB signal processing toolbox includes hundreds of useful functions for analyzing any kind of 1-D signals  including biophysical signals.  Also, EEGLAB provides useful tools to analyze EEG signals.

How many channels of data is contained in your polysomnography data? Why do you think you need to "figure out how to filter the data"? 

Why submental?  Refer to the Bibliography in the R&K Manual:

Berger, R. J. (1961). Tonus of Extrinsic Laryngeal Muscles during Sleep and Dreaming. Science (New York, N.Y.), 134(3482), 840. http://doi.org/10.1126/science.134.3482.840

The tonus of extrinsic laryngeal muscles was studied in sleeping humans by means of electromyograms. A striking decrease in the muscle tonus was observed at the onset of each phase of electroencephalographic light sleep, rapid eye movements, and dreaming.

Jacobson, A., Kales, A., Lehmann, D., & S, F. (1964). Muscle tone in human subjects during sleep and dreaming. Experimental Neurology, 10(5), 418–424. http://doi.org/10.1016/0014-4886(64)90033-0

It has been shown that dreams occur during EEG sleep stage I-rapid eye movement periods, and that simultaneously the tonus of some neck muscles decreases. To determine the activity of other somatic muscle groups, the tonic electrical activity of 29 muscle areas was recorded from cutaneous bipolar electrodes on sleeping human Ss. The EEG and the eye movements were recorded simultaneously. Indeed, tonus of most head and neck muscles studied decreased with the onset of EEG stage I-rapid eye movement sleep. Yet, trunk and limb muscles exhibited stable levels of tonic activity throughout the night with no change of level associated with rapid eye movement periods.

We have used this paste (Abralyt 2000: http://easycap.brainproducts.com/e/products/products.htm) and it worked very well. Additionally, we've used a one-way swimming cap to prevent that the participants sleep on pillow covered with this paste. A nice side-effect was that due this swimming cap the paste did not dry out overnight.

     http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2869.2010.00831.x/full

Achilleas,

              The above URL may be relevant to your  request. Additionally, I have appended  a copy of information from my files.

Regards,

  Ed

----------------------------------------------------------------------------------------------------                             The Ever Present  Past                                                                                                                          

Dr. Paul MacLean's triune brain theory describes a three- layered process of encephalization ... A neocortical (neomammalian layer), which covers an older limbic (paleomammalian) system, and which in turn is layered above even more ancient diencephalic (reptilian) structures. Originally each of the underlying layers controlled its own type of somatic behavior and supporting autonomic system, but as each new layer was evolving it gradually suppressed or inhibited full expression of the one beneath it. Nevertheless, according to the theory, the human condition still continues to reflect the persisting influences of its ancestral origins. In that regard, added Maclean, we put so much emphasis on ourselves as unique creatures possessing spoken and written languages that , like rich men denying their poor relatives , we are loath to acknowledge our animal ancestors.

Accordingly, while recalling that Dr. Nathaniel Kleitman observed that the trick was not to explain sleep but to explain consciousness, by applying MacLean's triune brain theory in terms of Kleitman's observation, it becomes possible to move human consciousness up the evolutionary ladder to its present-day neocortical-neomammalian position on the top rung. In other words, what we call 'sleep' must actually be comprised in what can only be described as being older and more primitive states of ancestral consciousness.

Additionally, we know that sleep reflects two distinct phases, namely NREM sleep and REM sleep, and that the latter can be further divided into tonic REM and phasic REM (dreaming sleep). Therefore, the question becomes one of inquiring as to their order in ascending the evolutionary ladder of human consciousness.

To address the question it may be observed that : (1) the closest phase of sleep to complete neocortical consciousness is phasic REM (dreaming) sleep, which (2) means that tonic REM and NREM were older predecessor/ancestral consciousness stages, and (3) since tonic REM is absent thermoregulation, and as Parmegianni observed 'contradicts the paradigm of homeostasis' while NREM enhances homeostasis with only a slight decrease in thermo-sensitivity, we may conclude  that the oldest state of suppressed ancestral consciousness is now reflected by tonic REM, next oldest is NREM,  then phasic/dreaming REM ( MacLean’s paleomammalian / limbic consciousness), and finally where we are to day , namely neocortical consciousness.

In other words, speaking evolutionary-wise , the oldest , and what we call tonic REM sleep, can be considered as being the predecessor of NREM sleep, and NREM sleep then likewise as being the predecessor of phasic (dreaming) REM sleep; and accordingly all three as being reflective of former ancestral evolutionary stages in the development of human consciousness .

The original method that produced opposite tracings for left and right EOG channels in sleep recordings (e.g., Rechtschaffen & Kales, 1968) was based upon the placement of the EOG electrodes next to the outer canthi with a reference electrode, between them, just above the nasion.  This placement of the reference electrode causes the two EOG channels to have opposite polarities when the eyes move (but not for delta waves).  Your tracing suggests that the reference being used for the EOG channels is not located between the EOG electrodes.  instead, it is a lateral reference and the signals have the same polarity with regard to that lateral reference.

Solms M. Dreaming and REM sleep are controlled by

different brain mechanisms. Behav Brain Sci.

2000;23(6):843-850; discussion 904-1121.

I work on the National Sleep Research Resource (NSRR -- https://sleepdata.org/). We have published many large, de-identified sleep databases (EDFs and covariates).

None of our current databases match the specifications laid out above (i.e. missing actigraphy), though we hope to soon post data collected as part of the Multi-Ethnic Study of Atherosclerosis Sleep ancillary study (MESA Sleep -- http://www.mesa-nhlbi.org/). As part of that project, participants (2,000+) wore an actigraphy device for 7 days and went through a single night of full PSG. Most subjects have a single night of concurrent PSG and actigraphy. Combining data from different devices may pose new challenges, but it might be fruitful.

Here's a recent publication that describes the MESA Sleep project: https://www.researchgate.net/publication/268791362_RacialEthnic_Differences_in_Sleep_Disturbances_The_Multi-Ethnic_Study_of_Atherosclerosis_(MESA)

In our study we used the Nellcor 595 with its reflectance foehead sensor.  I have attached a unpublished report that explains what we did.  In Figure 1 you scan see there will not be a baseline shift under ideal conditions (i.e., subject was slightly inclined).  With a loose strap and when the patient shifts to a lateral position (when baseline shift is most impacted) I have seen >5% error.  The oximeter continues to respond to desaturation events so the changes are accurately detected but measures like the % of time below 90% can be impacted.  

There has been research related to improved reflectance accuracy using multiple LEDs.

Dra. Maria:

Are you using EMG recordings of the mentalis or masseter muscles? If so, you might see a discrete RERA (respiratory effort-related arousal) preceding the bruxism.  It's thought that the RERA triggers the clench i.e. increased masseteric muscle activity?  Hope that helps -

Brainstorm is a free, open-source application that can read almost any EEG file and now, synchronized videos as well. It can do the screen capture you need, including the vertical bar moving over the EEG traces. For more info and full documentation (incl. tutorial data) see link. Cheers!

See this recent paper:

Sleep Spindles Predict Stress-Related Increases in Sleep Disturbances Thien Thanh Dang-Vu et al. Front Hum Neurosci. 2015; 9: 68.

There is an free app for that...

Really there is a sleep app for your iphone, developed by some sleep researchers I think from UBC that is pretty good. They have all the validation studies but you will have to bug them for it. Its called "sleep time" by Azumio.

Hello!

it depends on the content of the tool that you have selected. Basically the tool is made considering the target population. If the illiterate population has to be included, a picture based tool could be useful. The numbers of hours of sleep one had had could be marked in the specified box or space denoting the 

The conditions you have mentioned are influent in the result of PSG in two ways: Central apnea and variation of respiratory control ( see respiratory frive, loop gain ). The influence isn't about the difficult in breathing but in the control of ventilatory drive

I used a Biosemi Active Two system (with active electrodes) and I generally liked it. Now I am using Brain Vision which is also fine. Biosemi seems to be a bit more "user friendly" (it was easier & quicker to prepare the electrodes, compared to Brain Vision) but the data quality is a bit higher right now (with Brain Vision). But that may reflect the fact that I now spend more time on impedances, whereas I spent much less time on getting impedances down with Biosemi. Bottom line: both systems are quite nice. If you go for one of those, it should be a good investment. 

hello:

here are 62 references some of them electro myo and some are physiological  .hope you like them

professor galil

Hi 

Now a days many available devices have this option of portabililty/wifi /linked/pc based/laptop based features. However, they vary in their cost and add on features .

SOMNOscreen™ plus - SOMNOmedics

The Alice PDx portable diagnostic:Phi;ips

ResMed’s ApneaLink™ Plus: for portable 

Embletta X 100

Either convert your hypnogram to EDF format or make an EDF hypnogram using our software Polyman at http://www.edfplus.info/downloads/software/polyman.zip. The same program then nicely displays the hypnogram.

Forgive me my late response. I just joined researchgate.

In sleep medicine, sleep onset is usually defined as the first 30s epoch of sleep including the lightest sleep stage N1 (drowsiness). However, the definition of drowsiness relies heavily on slow eye movements and alpha rhythm, features that strongly vary between persons. Also, drowsiness is not a sudden phenomenon such as "falling asleep" is. Drowsiness can fluctuate for dozens of minutes.

Therefore, some researchers including myself prefer a definition based on spindles in the EEG. These mark the rather sudden blocking (by the thalamus) of sensory input. The 'sudden' aspect is illustrated by Figure 6 of my 2010 publication "Measurement of sleep". This blocking makes sure that NonREM sleep is no longer disturbed and can slowly grow deeper. This is illustrated by the same figure.

A very good method to detect the spindle process is the Neuroloop analyzer at www.edfplus.info/downloads. This is better that detecting isolated spindles because it also feels the activity in between clear spindles.

Thanks, Diego Alvarez-Estevez, for informing me about these questions of Christian and Antoinette.

1. Christian, have you seen the list of standard texts at http://www.edfplus.info/specs/edftexts.html? What kind of extra standardization would you suggest?

2. Christian, in my sleep lab, the PSG file contains the recorded signals and only the on-line annotations, either on-line typed by the technician or coming from a marker button. We do not allow any change to that file, so it is never rewritten. Any annotations made off-line after the recording session (possibly made by a different technician), such as sleep scores but also corrections of the on-line annotations, are put in a separate file. If a third technician would also score the PSG, she produces her own annotations file.

We typically record PSGs with 13 EXG signals sampled at 256Hz, 11 polygraphic signals (resp, SaO2, sound, light, body position etc) sampled at different frequencies of 4 - 256Hz. The file has datablocks that are each about 10kByte in size and 2 seconds in duration. The annotations have 120 samples, that is 240 bytes, reserved in each datablock. Not ever in a history of many thousands of EDF+ recordings did we need more than 240 bytes in 2 seconds. No technician types that fast. Rewriting the big PSG files (typically 500MByte) is never necessary.

The off-line file contains only annotations including the sleep scores, respiratory events, leg movement events and so on. These files are typically 50kByte till 100kByte, so rewriting those is no problem. In fact they are rewritten as a backup several times during the scoring procedure without the technician noticing that.

Your suggestion to also save the on-line annotations separate from the PSG signals is interesting. It makes life for the programmers more easy, at the rather small cost of having to organize the coupling between those two files. We did not choose this option because we wanted to disable changing the on-line obtained annotations. Having the on-line annotations in a separate file (just like the off-line annotations) would make it more easy to change those unless the on-line file is protected in another way.

3. Antoinette, can you provide info about the AANEM standards? The standardization of EEG terms has until now mainly been limited to electrode names and polarization rules. The EDF+ article explicitly notes the possibility to add other standard texts.