Marc's Public Blog - OSA, Obstructive Sleep Apnea and MMA Surgery

Now, because I need to wear a retainer every night anyway after I got my teeth moved, I figured I might as well get a sleep appliance again (think of a retainer with hardware that forces your bottom jaw forward) and improve my airway and room for my tongue when I sleep, just in case that helps further.

I was due for a sleep study at Standford, so we did a split night, first half withe sleep appliance and second half without it. While it's true that my sleep is not the same at the begining of the night vs the end, my sleep is usually deeper at the beginning of the night.

Apnea results

Long story short, my sleep was clearly worse with the sleep appliance than without. My AHI/RDI was 15.5 along with SPO2 drops with the appliance (That counts as apnea), while it went down to an almost normal 9 without SPO2 drops without the appliance.

So, there are 3 possibilities:

So let's have a look at the stanford graph, knowing that I removed the appliance around 03:00 but took almost 30mn to sleep again after that (and got up once to drink around 03:20):

Stanford vs Zeo

I brought my Zeo sleep monitor and the tech allowed me to wear it on top of their sensors to record the night on my phone while they were recording it themselves.
Let's compare the two (note that the Zeo monitor which consolidates stages 1 and 2 as light sleep, and 3 and 4 as deep sleep):

Having a quick look the Zeo does a reasonable job, even if not perfect:

Zeo has a quick explanation on their consolidated stages of sleep, and what each means and more articles on sleep stages.

Verdict for Zeo? I'd say it wasn't bad considering, especially since it is designed to smooth and average data, while Stanford is meant to show raw data.

Stanford vs Bluetooth Pulse Oximeter CMS50EW

This brings us to my SPO2 saturation. I used a CMS50EW finger clamp SPO2 monitor which actually worked a bit more reliably than the stanford sensor which dropped signal a couple of times during the study.

The drop around 03:20 is because I god unhooked, but the drops at 03:00 (to 60%?) and later around 06:00, look like monitoring issues. It seems that the tech who did the report did reject them as such.

Here are the dumps from my own monitor for that night:

My graph, first part of the night, with sleep appliance

Stanford graph

My graph, second part of the night, without sleep appliance

Comparing the results, my monitor did show the drops at 23:35, 00:55, but it missed 01:25 and 03:00. I'm not sure who's right there, you'd think Stanford obviously has more sensitive equipment, but I also think it might be too sensitive. I think their sensor might show big drops when it'd bumped wrong, or the analog plug is touched.
At 03:20, I was unplugged so that drop is expected. After that, the big drops around 06:00 seem to be bad data which my own monitor did not record.
Because my own recorder was built in and did not rely on wires that would be messed with when I move, I actually think I got better SPO2 readings than they did. Too bad it's soo uncomfortable to wear and requires a good amount of tape to make sure I don't have it drop off my finger, or move enough to affect its readings.

Verdict?

what a mess :)

This is why I've been working on my own recording at home so that I can get as much data as I can over several nights and average that out.

Now, because I need to wear a retainer every night anyway after I got my teeth moved, I figured I might as well get a sleep appliance again (think of a retainer with hardware that forces your bottom jaw forward) and improve my airway and room for my tongue when I sleep, just in case that helps further.

I was due for a sleep study at Standford, so we did a split night, first half withe sleep appliance and second half without it. While it's true that my sleep is not the same at the begining of the night vs the end, my sleep is usually deeper at the beginning of the night.

Apnea results

Long story short, my sleep was clearly worse with the sleep appliance than without. My AHI/RDI was 15.5 along with SPO2 drops with the appliance (That counts as apnea), while it went down to an almost normal 9 without SPO2 drops without the appliance.

So, there are 3 possibilities:

So let's have a look at the stanford graph, knowing that I removed the appliance around 03:00 but took almost 30mn to sleep again after that (and got up once to drink around 03:20):

Stanford vs Zeo

I brought my Zeo sleep monitor and the tech allowed me to wear it on top of their sensors to record the night on my phone while they were recording it themselves.
Let's compare the two (note that the Zeo monitor which consolidates stages 1 and 2 as light sleep, and 3 and 4 as deep sleep):

Having a quick look the Zeo does a reasonable job, even if not perfect:

Zeo has a quick explanation on their consolidated stages of sleep, and what each means and more articles on sleep stages.

Verdict for Zeo? I'd say it wasn't bad considering, especially since it is designed to smooth and average data, while Stanford is meant to show raw data.

Stanford vs Bluetooth Pulse Oximeter CMS50EW

This brings us to my SPO2 saturation. I used a CMS50EW finger clamp SPO2 monitor which actually worked a bit more reliably than the stanford sensor which dropped signal a couple of times during the study.

The drop around 03:20 is because I god unhooked, but the drops at 03:00 (to 60%?) and later around 06:00, look like monitoring issues. It seems that the tech who did the report did reject them as such.

Here are the dumps from my own monitor for that night:

My graph, first part of the night, with sleep appliance

Stanford graph

My graph, second part of the night, without sleep appliance

Comparing the results, my monitor did show the drops at 23:35, 00:55, but it missed 01:25 and 03:00. I'm not sure who's right there, you'd think Stanford obviously has more sensitive equipment, but I also think it might be too sensitive. I think their sensor might show big drops when it'd bumped wrong, or the analog plug is touched.
At 03:20, I was unplugged so that drop is expected. After that, the big drops around 06:00 seem to be bad data which my own monitor did not record.
Because my own recorder was built in and did not rely on wires that would be messed with when I move, I actually think I got better SPO2 readings than they did. Too bad it's soo uncomfortable to wear and requires a good amount of tape to make sure I don't have it drop off my finger, or move enough to affect its readings.

Verdict?

what a mess :)

This is why I've been working on my own recording at home so that I can get as much data as I can over several nights and average that out.

Since I had been working on arduino, I happened to have one of those 3.3V FTDI USB-serial converters, and was able to make a cable that connects my bedside Zeo to my server closer via a custom cable going through my existing Cat-5 wiring.

The example code they gave is however, while very fancy, not that simple to borrow from for a more simple application that simply needs to keep track of the sleep stage.

So, after finding the relevant info, I compiled the code below, which I'm posting for others to use (you can also download it here: zeo raw data code sample).

#!/usr/bin/python

# This is based off the Zeo Raw Data Library at the bottom of
# http://zeorawdata.sourceforge.net/starting.html
# This script is a much simpler version of how to log basic data than the cool
# and pretty GUI_Viewer from http://zeorawdata.sourceforge.net/examples.html
# This script is an easier example to steal from for simple logging/integration.

# By Marc MERLIN <marc_soft@merlins.org> / 2011/12/17
# License: GPLv3.

#gandalfthegrey [mc]$ ./logsleep.py
# 2011-12-17 12:19:10: HeadbandDocked
# 2011-12-17 12:19:15: HeadbandUnDocked
# 2011-12-17 12:19:22: Sleep state: Undefined
# 2011-12-17 12:19:52: Sleep state: Undefined
# 2011-12-17 12:20:22: Sleep state: Undefined
# 2011-12-17 12:20:52: Sleep state: Undefined
# 2011-12-17 12:21:22: Sleep state: Undefined
# 2011-12-17 12:21:52: Sleep state: Undefined
# 2011-12-17 12:22:22: Sleep state: Undefined
# 2011-12-17 12:22:52: Sleep state: Undefined
# 2011-12-17 12:23:22: Sleep state: Undefined
# 2011-12-17 12:23:52: NightStart
# 2011-12-17 12:23:52: Sleep state: Awake
# 2011-12-17 12:24:22: Sleep state: Awake
# 2011-12-17 12:24:52: Sleep state: Awake
# 2011-12-17 12:25:22: Sleep state: Awake
# 2011-12-17 12:25:52: Sleep state: Awake
# 2011-12-17 12:26:23: Sleep state: Awake
# 2011-12-17 12:26:32: HeadbandDocked

# System Libraries
import time
import sys

# Zeo Libraries
from ZeoRawData import BaseLink, Parser
from ZeoRawData.Utility import *

# User customizable variables
port = '/dev/ttyUSB0'

class Callbacks:
    def logtime(self):
	return time.strftime("%Y-%m-%d %H:%M:%S: ", time.localtime())

    def SliceCallback(self, slice):
        if slice['SleepStage']:
	    print self.logtime() + "Sleep state: " + slice['SleepStage']

    def EventCallback(self, logtime, version, event):
	print self.logtime() + event

if __name__ = "__main__":
    link = BaseLink.BaseLink(port)
    parser = Parser.Parser()

    callbacks = Callbacks()

    # Add Callbacks and Start the Link
    link.addCallback(parser.update)
    parser.addSliceCallback(callbacks.SliceCallback)
    parser.addEventCallback(callbacks.EventCallback)
    link.start()

    # Infinitely loop to allow the script to run continuously
    while(True):
        time.sleep(5)