“Xi – Kah – Vah”
“Xi – Kah – Vah” ….
I kept repeating this mentally hoping my old Transcendental
Meditation mantra would send me off to sleep. That was after I had repeated the
US Army relaxation technique that was guaranteed to bring on sleep. It was 3AM and I was still wide awake. Still worse – I was in a sleep lab trying to
find out why my AHI has been pegged for the past 3 months. AHI is the Apnea-Hypopnea Index and according
to the manufacturer of my CPAP machine is measure the number of apneic episodes
per hour that last longer than 10 seconds.
For the 20 years I have been on CPAP – the number has been 1-3, but 3
months ago it started going up to 10+ with no good explanation - other than
possible central sleep apnea in addition to obstructive sleep apnea.
My body weight and general life style has not changed at
all. I continue to get good overall
scores on my CPAP machine despite the AHI.
I consulted my sleep medicine doc and he decided to increase the
pressure and see if that worked. It did
not - so we decided to do another sleep lab test or polysomnography. It is a
big deal since you are observed and filmed, connected to electrodes (EEG, ECG,
OCG, laryngeal vibration, chest and abdominal respirations, legs (for RLS), and
masseters for bruxism.
An unsettling factor in the mix is that according to
polygenic risk analysis – I am loaded for Amyotrophic Lateral Sclerosis (ALS)
genes. And by loaded, I mean I am in the
100th percentile for risk. I
am not aware of central sleep apnea being the initial sign of ALS and neither
was my sleep medicine doc – but I do not want to be the first case report. So, I am hoping those genes remain quiescent
and do not express themselves.
I showed up at the lab at 8PM. A technician explained their protocol and
that after I was connected, I needed to contact her via the intercom if I
needed to get up at night. Under no
circumstances was I supposed to get up by myself because it would endanger all
the electrode connections. I told her I
was ready and she came back in and hooked me up over a period of about 20
minutes and then tested the connections. She also explained that I was not
going to be started on CPAP - it would be added later in the night only if I
needed it and then BiPAP would be added on top of that if I needed it. Since I already had a diagnosis of
obstructive sleep apnea (OSA) – that did not make a lot of sense to me. But I was not upset and wanted to proceed
with the ordered protocol. I watched TV
for about 20 minutes and it was lights out by 10PM.
It did not take long to realize that I was just laying there
thinking. I recalled my first
polysomnography in a sleep lab that was built in the Neurology Clinic of the
hospital where I worked. I had the
feeling at that time that I did not sleep a wink but the tech said – “Oh no you
slept all right and you have severe sleep apnea.” (AHI>50). Since that time, I have been 100% compliant
with CPAP. I use it every night – no
matter where I am.
I checked my watch and it was 1AM. Three hours of laying there thinking and no
sleep in sight. Time to try my sleep
reverie trick. Sleep reverie is a
reliable sign of sleep onset being very close and, in my case, it takes the
form of vivid and often nonsensical mental images. For example – the image of a man walking down
metal stairs from a loading dock. A man
working on an outboard motor. A
futuristic gray pickup truck driving down the road. A 500 ml beaker in front of a small flat
screen TV. These images flash for a few
seconds and I am asleep. Some time ago,
I thought I could speed sleep onset by recalling the early states of sleep
reverie. What did it feel like in the
body and brain just before the images started? I tried reproducing those sensations several
times and almost had it. I generated a
brief flash of sleep reveries and it was gone – I was still wide awake.
I checked my watch and it was 3AM. Still wide awake. Flash on my mantra, muscle relaxation, breathing
exercises, mindfulness exercises – all the tricks of the trade and I got
nothing. My mind is wandering to far away places. I am back in Africa in 1974 traveling up into
the Aberdare Mountains to visit friends.
I am 25 years old and traveling with a young woman who is 23. We are travelling in a high-speed taxi called
a matatu. They come in various
forms but this one is a small Toyota pick up truck with a metal enclosure over
the back. My travelling companion and I
are crammed into that enclosure with a dozen villagers trying to get up into
the mountains. Every time I get out of
one of these things - I kiss the ground.
Many people were killed in matatus every year. I remember how cool that
young woman was. I flash ahead to hiking
in the bamboo forest with her future husband and a mutual friend. I flash ahead to getting overrun by soldier
ants at his house up in the mountains and wondering if we were going to survive
that night. In the end we were saved by
a paraffin refrigerator - ants do not
cross a line of kerosene.
I checked my watch again and it was 5AM. The technician’s voice came over the
intercom:
“You are not sleeping.”
“I know – I came close a few times – but never fell asleep.”
(referring to the aborted sleep reveries).
“Do you want to just get up and leave?”
“I suppose”.
The technician came in and took about 10 minutes to
disconnect all the electrodes. I had 6
piles of salt and electrode paste on my scalp.
“It should come off with just shampoo. Your doctor will look
at the study. He may decide to have you
come back and give you a sleeping pill.”
I thought about what happened on the way home calling on my
years of studying sleep. I have had insomnia since I was a little
kid with night terrors – but I only stayed awake all night long when it was
necessary for my role as a physician. The first time was covering the coronary
care unit as an intern and believing that another intern and I were responsible
for a person on a balloon pump who was actively bleeding. Even as a
psychiatrist there were the occasional all-nighters – typically catatonic
patients who had questionable intake or agitation and aggression that did not
respond to the usual measures. And of
course, complicated medical problems that always seemed to end up on my
unit. It got worse with the electronic
health record because I could see almost everything from home. But none of that is a problem in
retirement. My sleep is generally normal
and I have no problem getting at least 6-7 hours per night.
The behavioral aspect of sleep provides some clues. We all learn to fall asleep in a certain
environment. The environment I am used
to is hooked up to a CPAP machine. It
has a certain sensation and noises. The
air splint from the pressure creates a certain internal sensation. Even though
I was not bothered by trying to sleep without it – the lack of those sensations
may have been the reason I could not sleep at all.
A second issue was the bed.
I was handed a remote control and advised I could adjust the firmness of
the mattress with the remote. I did it
at every time check dropping it by 30 percent each time. By 5AM I was down to 30 (where 100 is the firmest). I recently changed my home mattress and it
required a trial before I could find an exact replacement. There is a literature on mattress qualities
and sleep that looks at firmness, temperature, and materials. Most of the studies are interested in sleep
but some look at spinal alignment and pain.
The results are generally mixed probably due to patient
characteristics. For example, although one
review (1) finds that a medium firm mattress may work for most people –
there are still are those at both ends of the spectrum that sleep better with
very firm or soft mattresses. I
purchased my last mattress based on a study that I think was in the British
Journal of Medicine (BMJ) suggesting that pillow top mattresses may work
the best. With the replacement I tried a firm orthopedic mattress that resulted
in back pain every day. A new pillow top
worked very well. The sleep lab bed did
not seem to change at all with the remote control and that may also have been a
factor.
So how do you fail a sleep study? The short answer is by not sleeping but there
are complicating factors. I am waiting
to find out if there will be a modified protocol and watching my AHI.
George Dawson, MD, DFAPA
1: Caggiari G, Talesa
GR, Toro G, Jannelli E, Monteleone G, Puddu L. What type of mattress should be
chosen to avoid back pain and improve sleep quality? Review of the literature.
J Orthop Traumatol. 2021 Dec 8;22(1):51. doi: 10.1186/s10195-021-00616-5. PMID:
34878594; PMCID: PMC8655046.
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