Entries in Apnoea (10)

Friday
Jun082012

CPAP - It's well worth taking the time to get it right

Previously I'd used CPAP for a few days to try to get an idea of how my son felt as he started to use it.

Initially I tried it in the hospital where it was prescribed. I used it whilst awake using a variety of masks and pressures to see what high pressures felt like and to see how it responded to me exhaling, holding my breath, trying to talk and opening my mouth etc. Then I used it for a few nights. I wanted to know what problems he could encounter because he isn't able to move to correct them for himself, so I thought that if I were familiar with some of the problems it'd at the very least give me a frame of reference for when he told me what issues he was having.

For practical reasons I purchased an additional CPAP (technically an APAP machine - Auto CPAP). I chose the Resmed S9 Autoset, which to its credit doesn't look like a piece of medical kit; it looks more like a modern bedside clock radio. Yes, the pressures should be set by a professional and you need a prescription to buy one but it looks like a piece of consumer electronics, which is a great thing because it doesn't make your bedroom look like a High Dependency Unit.

 

Resmed also make coloured "skins" for the device which would be helpful when trying to introduce it to children as part of their therapy.

The S9 has a coloured display screen which allows the user to adjust the comfort settings and climate control and to allow them to see an instant indication of whether the mask is fitted properly along with a morning readout of your AHI (Apnoea Hypopnea Index).

The S9 records overnight summary data and detailed data to an SD card, which via the ResScan software allows you to see the following data: 

  • Respiratory Events via flags on the timeline (Central Apnoeas, Obstructive Apnoeas and Hypopneas)
  • Pressures chosen by the machine at any given time
  • An indication of snoring level
  • Flow (allowing individual breathing waveforms to be seen)
  • Leak
  • Flow Limitation (an indicator of the degree of obstruction)
  • Compliance data (how long I used it for)

An example of the data from one of the nights that my son used it is shown below.

All of this is very useful to have access to because it lets you see a record of the choices that the machine makes which helped me to trust that the machine wasn't going to deliver a high pressure unless there was a good reason to. This is all recorded automatically while you sleep at home (or in the sleep lab). Compared to a one-night study in a sleep lab (especially a split night study) the data may be a more realistic representation of your sleep because you'll be sleeping in a familiar place and adhering to your usual routine.

The output that we collected from the ResScan software was viewed by my son's doctors during his initial trials with CPAP before changing over to Bi Level ventilation (BiPAP / VPAP / BPAP)

 

 

I chose Resmed's Swift FX Nasal pillows as they left a lot of my face free, they didn't feel trapping and are easy to remove if I really felt like it in the night.

My son uses them with Bi-Level PAP and prefers them over a wide range of masks that he's experimented with, although he can't move below his shoulders he has learned to remove the Swift FX pillows by a head movement, so he feels comfortable using them as he knows that he can take it off if needed.

 

 

 

 

The S9 has an "AutoSet" mode where it can alter the delivery pressures as it deems necessary. The machine can be forced to work within a range of pressures. I decided to let the machine have a free reign and didn't force it to choose between limits. 

I managed to keep the CPAP on for most of the night, but I remember waking frequently and moving the tubing and to keep checking the machine because... well to be honest... I was nervous. The machine is very quiet which was another reason to check it every time I stirred in the night in case I'd managed to turn it off in the same way that I snooze the alarm clock. 

Over the few days I was tired because, as I said above, I'd been awake due to my own anxiety and the strangeness of it all, also I managed to get caught up in the tubing one night! The following evening I arrived home from work and dived face down into bed without CPAP. Due to my sleep debt over the previous few nights I experienced sleep paralysis and a lucid dream, so it wasn't all bad.

...and that's where my trial with CPAP ended.

However, recently I've fallen in love with CPAP and in particular Resmed's S9 Autoset (the photo above is my S9 beside my bed), and here's how it happened...

There's a lot to get used to with strange tubes and masks on you and your bed plus a new machine on the bedside table - and that's without getting used to the pressures that the machine delivers... considering this, my experience wasn't really a fair trial for CPAP, especially since it is considered to be the "Gold Standard" in treating obstrucitve sleep apnoea.

In hindsight, I suspect it would have been better to begin by choosing a low pressure and just wearing it to get used to the mask and tubing - almost a dress rehearsal before the therapeutic pressures are used.

My CPAP experience was well over a year ago and before the time that I started this blog and before the time that I realised that I had mild to moderate obstructive sleep apnoea. Now that I have a better understanding of my own sleep and have found various ways to reduce my AHI without CPAP I decided to give it another go and compare the results, after all we now had my son's "old" (barely used) S9 Autoset sitting in a cupboard doing nothing because he actually needed Bi-Level PAP.

This time I paid a lot more attention to my own AHI.

I also decided to eliminate the uncertainty of whether the machine was going to wake me with a high pressure during the night, so I did a gradual titration over several nights using the "Straight CPAP" setting of my son's backup Respironics BiPAP S/T.

I found myself making slow deliberate breaths while I tried to sleep. This wasn't particularly helpful, because (even if you aren't wearing CPAP) when you think about your breathing you find yourself consciously taking over, and to be honest this is something that our bodies do better if we don't let consciousness interfere with it.

However, I found myself calmly waking up every now then wondering why I wasn't breathing and finding that I had to consciously take a breath, I listened to machine respond, then dropped back off to sleep. This happened maybe 5 or 6 times that I remember during the night and wasn't anything like waking with a snort or a choke, in fact it felt quite strange. 

In the mornings I took a look at the data (the BiPAP S/T also records data to an SD Card that is readable via the Respironics Encore Viewer or Encore Pro software. 

I found an explanation for the breathless awakenings...

Whilst the obstructive apnoeas were few and far between, the machine had detected "Central Apnoeas". These are when the airway is open yet no air flows. This can be from a variety of causes, but from my own baseline sleep studies I know that my apnoeas are usually obstructive in nature, so I knew that these new Central Apnoeas were because my chosen pressure was too high.

If breathing is too effective at clearing CO2 from the bloodstream then central apnoeas can occur because during normal breathing the brain sends a signal to breathe when CO2 in the bloodstream reaches a certain trigger level. We then breathe causing gas exchange, (taking oxygen in and exhaling CO2), after which our bodies produce more CO2 which reaches the trigger level and the cycle begins again.

If the CO2 level is too low then the brain doesn't need to clear it, so doesn't send a signal to breathe. Our oxygen levels then drop which wakes us up and allows us to consciously take a breath.

I adjusted the pressure down by 1 cmH2O the following night, but I still wanted more data. Were these really "centrals"? A night wearing the Black Shadow Sleep Monitor whilst on CPAP confirmed that they were.

I switched machines back to the Resmed S9 Autoset because it allows you to see a lot more data as opposed to the trend data given by the Respironics BiPAP S/T. It actually allows you to look at the data at a much higher resolution (you can see every breath taken) so I could then verify any detected apnoeas for myself.

Along with the lower pressure setting, I set the S9's EPR (Expiratory Pressure Relief) to full (3) which drops the pressure down by 3cmH2O (or 1 or 2 cmH2O, depending on your chosen setting) when it detects that you are exhaling. This is very helpful, even for psychological reasons as not only does it help you to exhale, but it provides a form of tactile feedback letting you know that the machine is "listening" to you and not trying to force a gale into your nostrils whether you like it or not.

One interesting thing that the S9's additional data allowed me to see was the moment that I stopped doing those forced breaths I that I mentioned above. This is the moment that I fell asleep. 

I fell asleep fairly quickly, and woke once when I turned onto my side and found that I needed to adjust the nasal-pillows slightly.

The following morning I checked the data and found that the central apnoeas had cleared and my AHI was a very respectable 0.4 which varied over the next few nights but still remained under 1.0.

One night I found that the S9 data showed that I'd been quietly snoring, it was also on this night that my AHI was the highest that I've had so far whilst on CPAP (0.9), although this is still a fantastically low AHI.

So the next night I crept the pressures up by 0.4 cmH2O, only to find that the snoring cleared but some central apnoeas returned, so I dropped the pressures again. It became obvious that finding a pressure that was perfect for every night was going to be a challenge.

Of course I realise that there is going to be some "natural variation" from night to night due to factors such as body position and time spent in each sleep stage but wouldn't it be good to be able to pin down what the other less obvious variables are?

My main factors are related to body position (apnoeas are more likely and frequent when I sleep supine) and REM sleep (when muscle tone is decreased in the airway), but I suspect that other factors during the day play a part.

This is where the S9 Autoset excels: In AutoSet mode it adjusts the pressure it delivers based on your need at the time, so where "Straight CPAP" is limited because it can only give me one pressure throughout the night meaning that 8cmH20 may be too much for me at some parts of the night (causing Central Apnoeas), yet not adequate for other parts of the night) where 10 or 11 cmH2O is more appropriate.

I set my S9 to "Autoset" mode and adjusted the settings so that the machine would work within fairly restrictive limits just to get me comfortable with the idea. In the morning I could see from the ResScan software that the machine had delivered the maximum permitted pressure at some points in the night, so I gradually extended the pressure range over a few nights until the machine didn't reach my ceiling limit and was able to deliver the necessary pressures.

The following graph of the pressure that the S9 delivered over one of the later nights illustrates how my requirement varies through the night. 

On the night above I woke myself up snoring after several hours (just before the red vertical line), so I raised the lower limit and went back to sleep, this is why the graph above shows the delivery of pressure that is lower than permitted minimum pressure at the start of the night.

Had I been prescribed straight CPAP based on the pressures titrated on this night then I would have had to have a constant pressure of between 10 and 11 cmH2O to eliminate all my obstructive apnoeas. However, the chances are that I would have then had more central apnoeas occurring. A compromise pressure of 9 cmH2O would have removed the majority of apnoeas but would have been inadequate when my obstructions were at their most severe. There could also have been central apnoeas occuring at this pressure for some of the night.

The textbook, "Sleep Medicine Pearls" by Richard Berry MD describes this well with a case study of a patient unable to tolerate the high pressures needed to treat his obstructive apnoea. If you have access to the book you can find the details under Patient #43. In fact the whole book is packed with case studies that provide a unique insight into treating sleep issues.

If high pressures can't be tolerated it may be preferable to have a lower than optimal pressure setting just to ensure that some benefit is obtained, although it is likely that these patients would benefit more from Bi-Level PAP which allows a much lower expiratory pressure.

In Autoset mode, the S9 allows low pressures but can deliver the higher pressures when necessary, giving you the flexibility (and comfort) of both in one setting. 

Some good news: my nose isn't as big as I thought...

I found that I woke up several times in the night and had to adjust the nasal pillows but each pack of Swift FX nasal pillows come with three sizes of pillows. I found that when I decreased the size of the nasal pillows to the medium size (although the large were comfortable and the leak minimal) the medium pillows were more comfortable and needed a lot less adjusting when I first put them on and hardly any throughout the night.  

I slept really well and took a look at the display screen on the S9 when I woke.

I was greeted by an AHI of 0.0 and a green smiling face telling me that the nasal pillows were a good fit and weren't excessively leaking.

The ResScan software also confirmed the Zero AHI

 

Now that I use the Autoset mode, my AHI is always under 1.0 regardless of what position I sleep in or even if I've had a glass of wine.

It actually feels good to sleep on my back again, I'd been using the Rematee side-sleeping belt for a while and found that I missed sleeping on my back. With CPAP I didn't ache when I woke up. CPAP was surprisingly unrestrictive and I soon learned a manoeuvre to clutch the hose and move it with me if I wanted to turn in the night.

To be fair I could have just let the S9 go on full unrestricted auto from day one and it would have delivered the same pressures, but from mine and my son's previous experience with Non-invasive Ventilation, a large factor in whether it is successful is down to whether the sleeper (patient) feels comfortable with it, yes the numbers are important (after all that is the whole point of the therapy), but the patient experience is also key as that alone will probably be the biggest factor in whether they are "compliant" with it (ie use it for 4 hours or more a night), after all many PAP machines don't allow the user to see their AHI data so they can only judge based on how it feels.  

Another part of the experience is the mask that is used. There is a wide choice of masks available, and it's important to find one that is right. Also humidification can help people feel more comfortable with PAP therapy, this is something else that should be available to them along with all manner of accesories such as hose holders - really anything that will prevent someone giving up. That said, CPAP therapy isn't right for everyone as my son's situation shows, so good communication with a committed Sleep Consultant is vital in order that the right treatment be offered. 

I think looking into things in this detail was necessary for me, although it was a rather involved way of getting used to CPAP and trusting it, it has been well worth it. I feel a lot more awake in the mornings (generally only sleeping for 7.5 hours now) and my AHI has been consistency the lowest it has been in probably 20 years.

I think the graph below speaks for itself.

CPAP is a clear winner and one that is likely going to be impossible to beat but that's not going to stop me trying out other apnoea remedies to see if they can come close.

CPAP has also made a huge difference to my snoring, the results of which I'll post in a few days. 

For the future: 

  • I'd like to see if the pressure requirement decreases if I take a dose of 5-HTP at bedtime.
  • Although I don't intend to change my nasal pillows, I would like to see what difference other masks make to the experience.

 

Useful Links

Michael F. Fitzpatrick, Christi E. D. Alloway, Tracy M. Wakeford, Alistair W. MacLean, Peter W. Munt and Andrew G. Day
Can Patients with Obstructive Sleep Apnea Titrate Their Own Continuous Positive Airway Pressure? 
(full text PDF available to non-subscribers via the link)

Gao W, Jin Y, Wang Y, Sun M, Chen B, Zhou N, Deng Y. 
Is automatic CPAP titration as effective as manual CPAP titration in OSAHS patients? A meta-analysis.

 

 

Monday
Jun042012

Sleep Onset Apnoeas / "Throat Closing"

One of the search terms that people find this blog with surprised me by how frequently people search for it, there are several variations but these two sum things up well:

  • Throat closes as I go to sleep
  • Choke as I fall asleep

I hadn't really considered this before but I really should have done because it happens to me, and one of my parents. Normally when I experience those throat-closing moments they are accompanied by the first snore / cluck / snort of the night, a flash of whatever broken dream images were going through my mind and the knowledge that I'll soon be asleep. I guess it's something that a lot of us experience but don't really talk about it because it sounds a little strange.

Polite and usual "sleep chat" is usually along the lines of "Did you sleep well?" and not much deeper than that which is a shame because it's such a fascinating subject that few of us speak about because many (wrongly) consider sleeping to be a waste of 8 hours and some even see it as a weakness ("Sleep is for wimps" etc etc).

I've been using CPAP for a month or so now and have been adjusting my own pressures based on the sleep study data that I record each night. When I reviewed each night's data, one of the things that stood out about breathing as we drop off to sleep was how it changes at sleep onset (the moment that a sleep lab would declare that we are now asleep).

This becomes more pronounced with CPAP (or at least for me as a relative newcomer to using CPAP for myself) because when I first switch the machine on at night I instantly become aware of my breathing and try to control it. Oddly, consciously controlling our breathing is something that we don't do very well and it is best left when our bodies do it for us automatically. Can you imagine the chaos that would result if we had to consciously take every breath or control every heartbeat?

The following is a few minutes of data representing my breathing as I was dropping off to sleep whilst wearing CPAP. It's taken from Resmed's ResScan software (click for a larger version).

The breathing on the left is when I was awake, it is clearly different to the smooth regular breaths on the right side of the graph. Falling asleep is what brought about the change as I "forgot" to consciously breathe and my body took over.

So far so good, but on several nights I noticed that the handover from from awake breathing to asleep breathing wasn't so smooth... 

Notice how there are gaps in my breathing? This is from a night where some apnoeas were still occuring; I remember that as I was falling asleep I experienced at least two of those "throat closing" moments. The apnoea briefly woke me as left me realising that a moment before I was asleep, which also seemed to shift the hypnagogia into my conscious mind and then into my memory because this night was also a night that I remembered a lot of it.

Several different images and phrases came and went as I drifted off to sleep. The Zeo recorded that I briefly entered REM as I fell asleep (possibly causing a loss in muscle tone resulting in apnoeas)...

This is something that I see on many nights when I look at my Zeo data, but in the interest of accuracy, Zeo do point out that if your sleep is generally healthy with 7-9 hours per night and no feelings of tiredness during the day that this brief period of REM could be wake being misinterpreted as REM. It could be that N1 sleep mixed with brief periods of wake (from my respiratory arousals) were interpreted as REM by the Zeo (as wake is so similar to REM). 

The following night my sleep looked very different and I achieved a lot more REM along with no apnoeas or hypopneas recorded at sleep onset, intriguingly the Zeo data doesn't show me passing through REM as I fell asleep. So this could actually be REM, although this could also be because there were no respiratory related arousals during the transition from wake to sleep.

With the Black Shadow Sleep Monitor I've seen that less significant respiratory events are linked with altered REM sleep, in my case a series of hypopneas leading to a Lucid Dream. This raises an interesting issue that may provide some insight into dream formation.

I used to be comfortable with those throat-closures before I knew I had Sleep Apnoea as they had become so familiar to me. I used to use them as a way of knowing that I'd soon be asleep. In a strange way I will be sad if they go because after each "cluck" or snort I'd briefly wake and commit the partial dream or hypnagogic image to memory and would be able to study sleep as I drifted off.

Famously people have used a technique that relies on waking from hypnagogia in order to remember it which involves napping in a chair whilst holding a metal spoon over a metal tray or plate. Once you drop off to sleep you automatically release the spoon, causing a clattering sound which then wakes you allowing you to recall what you saw and heard.

I see my sleep onset apnoeas as such a system, alebit a naturally occuring one. I think that during the times that I want the best of both worlds of having the apnoeas at sleep onset but sleeping safely for the remainder of the night that I will experiment with setting a RAMP on my CPAP which delays the maximum pressure by up to 45 minutes, giving me time to explore the hypnagogic world.

Knowing that I have obstructive sleep apnoea and that the first apnoeas of the night are usually at sleep onset, I would suggest that anyone who experiences these throat-closures at sleep onset should at the very least be aware that they could have Obstructive Sleep Apnoea and look out for other symptoms. The best thing to do it get it checked professionally as it could also be a sign of another condition such as Acid Reflux (GERD) or Laryngospasm.

Saturday
May122012

Mandibular Advancement Devices: #1 Snoremate

If you've never seen one of these devices before, imagine it as a two gumshields stuck together, with the gumshield for the lower teeth fixed so that it forces the wearer to jut their jaw forward. The mandible is the jawbone, hence the term "Mandibular Advancement"

The idea behind this is that forcing the jaw forward creates more room in the airways by shifting muscles and fat forward slightly, reducing the likliehood and severity of airway obstruction.

Mandibular advancement (either by a specially made dental device, or by surgery) is a tried and tested concept of reducing snoring and sleep apnoea, so I'm not really putting that to the test, but rather I'm trying out the off the shelf concept, although my snoring is sleep-apnoea related, so unless the device can remedy the apnoea, I doubt that it will affect my snoring. 

SnoreMate

This is an off-the-shelf (but custom fit) mandibular advancement device (MAD).

The SnoreMate is made from a thermoplastic that you dip in hot water to make it soft, then bite into it to form a custom fit for your teeth. The SnoreMate can be adjusted by re-dipping it in hot water if you feel the need to advance your lower jaw more to increase the effectiveness of the mouthpiece, something that I did after a few nights of using it.

It was easy to mould, and is the most comfortable of the two mouthpieces that I've tried so far (the other device being the SomnoFit) which I found was too bulky to be comfortable for me). I was surprised that on the first night It stayed in place until around 2am, and on subsequent nights (to get used to it before I monitored it) it remained in place until the morning. It was actually quite easy to get used to. In fact it was surprisingly comfortable, so I purchased a second Snoremate and moulded that one slightly further forward rather than risk losing the comfortable positioning of the first one.

However, there are a couple of drawbacks to the mouthpiece, the main one is saliva build-up! I found myself waking at night just to swallow and clear my mouth. The other drawback is that my gums and a couple of teeth ached for a few of hours in the morning.

As far as snoring reduction went, using the method explained in this post, I was very surprised. I imagined that everything I used in addition to the Rematee would either improve on the Rematee's effect or make no change. I think that the graph shows why I was surprised...

The SnoreMate actually made my snoring louder! This would have been very annoying for anyone in the house as I managed to reach 98db (about the volume of a drill drilling!). This is an unacceptable volume when you consider that I was already sleeping on my side and wearing a mandibular advancement device. Although to be fair, it is an anti snoring device, and my snoring is more than snoring, it's related to sleep apnoea.

In the following clip it resembled a moose-call.

However, I had a lower AHI for the three nights (mean 2.05) with one of the nights using Snoremate with the Rematee giving me my lowest ever AHI of 0.77.

If I had to speculate as to why the snoring increased in volume (and sounded slightly different in tone) yet the AHI was lower, I'd have to say that it was probably due to the fact that, by design, it is impossible to breathe through your mouth with the SnoreMate, so the air has a to take a different path through the nasal passages, rather than through the open mouth of the snorer.

Even wilder speculation:  The SnoreMate was probably doing what it was intended to and tightening / stretching the muscles in the airways meaning that they were less prone to relaxing, hence less hypopneas. Again, further speculation, but it is possible that this also caused the snoring to be louder in the same way that in deflating a balloon a screech caused by keeping the neck taut is louder and higher pitched that if you were to let the neck relax causing a quieter lower-tone rapserry sound.

I was so intrigued by this hint that it was working, that I've made an appointment at my dentist to have a professional Mandibular Advancement Device constructed for me and I'm looking forward to being able to compare the results. My hope is that the professional device will allow me to further advance my jaw, keeping my airway muscles even tighter, elimating my apnoeas and maybe my hypopneas (and hopefully snoring too).

Monday
Apr232012

Sleep Paralysis as a Result of Nocturnal Disturbances and Respiratory Events?

A few years ago I had three instances of sleep paralysis in the same night, leading to finally meeting "The Stranger In The Room". Since then I haven't been afraid of sleep paralysis, in fact I've welcomed it as it's a fairly easy way to initiate a lucid dream.

The other night I experienced sleep paralysis which progressed to an Out of Body Experience (OOBE) then to a Lucid Dream, and it's given me more of an insight into a possible mechanism, which seems to fit with the episode that occurred a few years ago, only this time I was wearing 2 sleep monitors so I've been able to "capture" some elements of it and piece together my theory of the events.

This has led me to realise that there are common factors in the events leading up to sleep paralysis and the subsequent spontaneous lucidity.

 

I'll begin by describing what happened several years ago. I'm well aware that it didn't happen literally, but bear with me as I think it's best to describe it as it appeared before taking it apart scientifically. I've put the account in a quote-box, so if you really can't bear hearing other people's dreams you can easily skip over it...

 

I briefly mentioned in this post that as far as getting over the fear of sleep paralysis goes, the turning point for me was a night several years ago when my son had a chest infection causing his nocturnal oxygen levels to drop lower and more frequently than usual meaning that I had to carry out assisted coughing and nasal suction several times. Needless to say our night was very disturbed and we were both very tired. This was the second such night in a row.

On three occasions when I returned to my bed I suffered from sleep paralysis. It was something that I'd grown used to because it had been occurring roughly once every couple of months from the age of around 13.

I'd be laying in bed listening out for his oximeter alarm, then I'd get the familiar whistle in my ears, a crackling noise, then my body would feel crushed and each muscle would feel as if someone had deflated it squashing me further into the bed. Then the familiar (but still frightening) feeling of someone watching me as I lay there struggling trying to talk but only managing a throaty "uugh" noise.

By the third time I almost found it funny (maybe because it had never happened to me so frequently, so this time it felt familiar, almost to the point that I knew I was safe). I kept telling myself that my body was effectively asleep. "Okay, so my body is asleep but somehow I (whatever makes me me) is awake, so that 'me' is going to get up".

"I" then rose above my sleeping self about a foot or two, rolled left (now facing the wall), then floated to the foot of the bed and ended up standing on the floor looking back at my sleeping-self.

This all seemed normal at the time. 

It was then that I could finally see the person that had been watching me. He was standing next to me at the foot of the bed. He stepped aside, smiled and gestured towards the mirror at the end of my bed. Then I passed through the mirror, through the wardrobe and then through the wall into my son's room next door. A few moments later I was back in my bed, awake and able to move.

The feeling was incredible, even if it did leave me a bit confused as to whether I was really awake this time. From that moment on I have not been afraid of sleep paralysis.

Now here's a brief account of the episode I had the other night, then I'll draw some parallels between the two nights...

I'd had little sleep the previous night as I had to be awake around 3am for a journey to Manchester. When I got home I was tired, so after dinner I made a point of not staying up late (bed by 9pm). Keen to carry on my experiments with 5-HTP I took 200mg of 5-HTP, connected some channels of the Black Shadow sleep monitor (SPO2, Pulse, Airflow, Body Movement and Sound), put the Zeo headband on, started to record the raw Zeo data with ZeoScope and went to sleep. I was also wearing the Rematee belt (as is normal for me now).

I was asleep within 6 minutes (a fair indicator of sleep-debt). Another indicator of sleep-debt is the fact that I was briefly in REM sleep within 9 minutes of getting into bed!

At 4:02am (I know this from the raw data) I was woken from REM by a noise near my bedroom window. I woke suddenly thinking that I had an intruder. I shuffled round the bed a bit listening for more noises and then lay there replaying the noise in my head trying to make it fit with a known noise. At the time I also considered that it was a hypnagogic noise. It was a multiple banging noise, and I imagined it was probably a picture falling off the wall and bouncing on the wooden floor.

I'd spent around 10 minutes trying to work out a cause of the noise as I dozed in and out of sleep, then the familiar whistling noise of Sleep Paralysis stirred me. I got excited and tried to turn it into an OOBE by pushing "myself" from my head, but that just stopped the noise so I stopped too. Then the whistling returned and I tried rolling "myself" out of my body. It worked, I sat on the edge of the bed and felt sad that I'd actually woken myself up. It turned out to be a false-awakening because I then floated to the end of the bed, realised that I was still dreaming, and from that moment on was in a lucid dream (albeit of the out-of-body variety).

I went to my bedroom door, floated out into the hallway (something I've never been able to do before as doors usually take me to the wrong place).

It was dark, so I put my hand into the adjacent room and tried to put the light on except there wasn't a switch, just a lump of plastic. Again, this prompted me to stay lucid. So I went to the front door (in search of the cause of the noise). As I got to the front door I hesitated because I really wanted the door to take me outside and I was afraid that it would take me to the wrong place (despite the earlier door working correctly), so I "poured" myself through the letterbox and ended up outside on the driveway.

It was still dark outside, and I had trouble seeing, I imagined that this was because I knew that my eyes were shut because I was asleep, so I took my dream-hands and prised open my dream-eyelids in a way that only someone who has ever had conjunctivitis will know. Then it became daylight.

On my driveway was a postman in a bright red fleece. Instantly I was standing next to him and he acknowledged me. I was confused because I knew that this was a dream so expected that I was ghost-like and he wouldn't be able to see me. (I didn't realise it at the time but I was losing lucidity and becoming the observer of the dream again rather than the creator).

The postman apologised for the noise and said that he'd been trying to get a large parcel through the tiny letterbox.

I thanked him, took the parcel and opened my front-door, only to find myself back in bed and waking up.

I then pressed then event-marker on the Black Shadow Monitor and recorded what I remembered of the dream before getting out of bed.  

There are a few key similarities that I think are worthwhile extracting from these accounts, and some I've only become aware of in light of the lucid-dream I had the other night.

  • Sleep debt from previous night
  • Disturbed Sleep that night
  • Waking and being fully alert during the night before returning to bed
  • Remaining alert for an anticipated noise
  • Sleep Paralysis leading to a dream which became lucid ending with me going off in search of the source of the noise.

In the morning I was keen to playback the audio recording of the night's sleep to see if the sound was real, or hypnagogic in nature. I also wanted to see what the various monitors managed to show of this experience.

It turned out the sound was real and the Black Shadow's microphone was sensitive enough to capture it. It was possible to hear a car driving past the house (causing me to stir) followed 6 seconds later by the sound that I heard: it sounded like a rat-a-tat-tat on the letterbox but I still couldn't identify the noise.

The first sound is much clearer through headphones or good speakers.

 

The next morning when I went to my car I found the cause of the noise. The passing car had lost a plastic hubcap which had hit the front of my house (my bedroom wall) and spun on the concrete before settling down, in a similar way to a spinning coin running out of energy on a tabletop.

Looking at the graphs from the Black Shadow and the Zeo, it became fairly clear that this wasn't the trigger for the dream, but it was a very important factor because it caused me to wake up fully. I was very alert as I listened out for the cause of the noise, I was anxious and to be honest a little afraid. This likely put me in a state of heightened awareness and self-consciousness, which on some level carried over for the next few minutes into the dream.

I've annotated the 30 minutes covering the noise and finally waking from the lucid dream (click for a larger version).

The raw single-channel EEG data is displayed at the top. I've selected the point that I first woke after hearing the noise. This section aligns with the marker in the brainwave frequency lines (coloured as indicated by the key). 

The hypopneas were the likely cause of the sleep paralysis. I suspect the third one was the trigger as body movement is shown after the first and second along with the noise of bedclothes moving, so sleep paralysis had not set in by then.

I suspect the evening went something like this:

  1. Initial car and hubcap noise occurred
  2. I woke suddenly causing a rise in delta wave "noise" as I moved.
  3. My heartrate more than doubled to 101 bpm (startled and fear) (in line with the delta increase)
  4. I lay in bed listening for further sounds until...
  5. I drifted to sleep and quickly went into REM
  6. My respiratory issues are exacerbated by REM so hypopneas followed (yellow blocks)
  7. I had micro-awakenings due to the hypopneas (shown by the blue blocks and reduced pleth)
  8. Due to my heightened state I failed to go back into normal REM and became aware that I was asleep.
  9. Possibly the final hypopnea ended the dream.
  10. I laid still for a few moments before dictating the contents of the dream into the microphone

So I suspect that to reliably induce sleep paralysis and/or lucid dreaming two factors are required;

  1. True wakefulness in the night, not just snoozing a 4am alarm
  2. A cause of micro-arousals / micro-awakenings.

 

Wild speculation...

I was hoping for a clear indication of something on the EEG and frequency tracings.

The brainwave frequency analysis in more detail with the purple section believed to be the dream.

If I had to be pushed to look for a trend then I'd say that there was a slight increase in Alpha waves (blue) during the time identified as the dream-period also becoming nearly equal to the Theta wave activity (green) at one point, which declines as I wake, but that is possibly stretching things too far at the moment. However, this overlapping (or meeting) of Theta and Alpha occurs in other places in my sleep (and wake) without any memory of lucidity, so I imagine that finding a simple pattern from a single EEG site is unlikely as things are likely a lot more complicated than that.

For the future

I hope to record the events surrounding more sleep paralysis / lucid dreaming episodes and document any trends that arise rather than just basing my hypothesis on one night.

I'd like to learn to signal to the Zeo that I'm dreaming using eye movements, so that I can further pinpoint when lucidity occurs. Maybe this signal could be on a regular basis (or as regular as the dream permits) to help pinpoint when lucidity begins and ends and normal dreams take over.

 Links

The Stranger in the Room / The Presence / The Dweller on the Threshold / Guardian of the Threshold in literature, religion and folklore

Sleep paralysis and psychopathology - Mume & Ikem "Sleep paralysis occurs frequently after arousal from REM sleep""

Sunday
Mar112012

Sleeping Position: Get off your back!

When you have a multi-channel sleep study, one of the "channels" that is examined is the position that you sleep in.

At first this may seem a strange thing to monitor, after all if you manage to achieve sleep, who cares how your inert body is positioned? 

Sleep position affects several aspects of our sleep, for example when I sleep on my back I find that:

  • I experience more sleep paralysis
  • I experience more body twitches as sleep begins
  • It's also known that breathing is harder when sleeping flat on your back (supine), it is for this reason that patients with higher level spinal injuries are recommended to sleep with their head inclined and foot of their bed lowered as this can actually increase their vital capacity
  • GERD / Acid Reflux / Heartburn is affected by sleeping position. Raising the head of your bed can prevent or at least reduce reflux episodes.

However, in this blog-post I'm going to concentrate on another major effect that supine sleeping has on the sleeper...

Supine sleeping can dramatically increase the number of obstructive apnoeas and hypopneas a sleeper has through the night!

The reason for this is that gravity has a greater effect on the muscles and soft tissues that relax in sleep and cause obstructive apnoeas. If you can lie on your side then gravity doesn't affect them in the same way, and can go some way to keeping the airways open during sleep.

Invariably we move around in our sleep so I needed a way to monitor my sleeping position as my monitor doesn't have this ability.

More sophisticated sleep study devices do this automatically, and there is actually an iPhone app that can do this for you too: Somnopose, after a couple of night of experimenting with the app you should be able to get a fairly accurate reading. You will probably be surprised how many times you actually turn over in your sleep.

This was actually quite easy for me to do manually as I already had my infra-red camera watching me for several nights during sleep. I then analysed the video to determine my sleep position. As well as recording continuously, the camera creates a new file every time it detects movement, so all I had to do was flick through the files and record the position on a chart alongside my oxygen desaturations. I did also plot a chart of body position against detected apnoeas, but the chart below shows things clearly enough.

 

 s=supine (back), p=prone (front), l=left down, r=right down

It was no surprise to see that the majority of my apnoeas and hypopneas occurred when I was sleeping on my back.

On several nights I deliberately began sleep on my side, but always woke to find myself flat on my back again and with a high AHI recorded. I needed a way to prevent myself from turning over in the night.

Years ago, a solution to positional obstructive sleep apnoea was to "sew a tennis ball into the back of your pyjamas", this had a "Princess and the Pea" type effect on the sleeper and caused them to be uncomfortable if they turned over and slept on their back.

Nowadays there are more sophisticated solutions, and the one that I put to the test is called the "REMATEE Bumper Belt". It's a neoprene belt that velcro fastens around your chest. At the back of the belt are pockets into which you place inflatable "bumpers". Sounds strange?


It may be clearer if I show you a photo of what I'm describing. Rather then subjecting you to a screen-capture from my camera, I'll use a product photo instead (click for a larger version).

It's surprising how quickly you get used to it.

My belt also has shoulder straps to stop it turning round in the night although when it first arrived I was slightly daunted by the idea of being strapped in, so I decided to tuck the shoulder straps into the pouches that held the bumpers.

I found that if the belt was tight enough then I didn't need to use the shoulder straps, but it does take a few nights of trial and error to get used to how tight to wear it and how much air to put in the bumpers.

 

 

When the belt first arrived I tried it out for a few nights without monitoring my breathing and found that it did affect my Zeo stats. It increased my REM sleep. It also reduced the number of awakenings that I had through the night.

Initially, it seemed to decrease Deep (SWS) Sleep but this stopped and my SWS actually increased after a few nights of using it. (See graphs below).

 

Then I began my five nights of recording my breathing...

Again I followed my rules for determining my 5-night mean data with the obvious exception of not beginning the night by sleeping on my back. I also didn't take any of the supplements discussed in this blog, and I stopped the vitamins and minerals on the Friday beforehand to try to eliminate the effects of those on my sleep.

The results were clear:

The REMATEE belt kept me off my back and reduced my oxygen desaturations:

 

 s=supine (back), p=prone (front), l=left down, r=right down

My AHI each night was dramatically reduced:

This brought my 5-day mean AHI down to 1.70.

 

This makes the REMATEE the most effective method that I've found so far to reduce my AHI. 

The reduction in respiratory events (reflected by the reduced AHI) also had a positive knock-on effect on my Zeo data...

Considering that most of my respiratory events happen in REM sleep, it makes sense that when the number of events was reduced, my REM increased (because it was not being broken by me waking up to breathe). As already discussed, my Slow Wave Sleep (deep) also increased.

Will I carry on using the REMATEE? Definitely.

As a follow up, I plan to combine the REMATEE belt with my 5-HTP routine as both seem to reduce my AHI through different mechanisms. Maybe their combined effect will be greater than as individual methods.

 

Additional Links

The REMATEE Bumper Belt is available in the UK from Intus Healthcare: 
http://www.eu-pap.co.uk/rematee-neoprene-bumper-belt.html

REMATEE http://www.antisnoreshirt.com/