60. Charting the course of N24

27 October 2010 at 09:25 | Posted in Circadian rhythm, DSPS, Sleep diary | 27 Comments
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Keeping a sleep log or a sleep chart is one of the keys to getting a proper diagnosis of a circadian sleep disorder.  Oftentimes someone will describe their sleep patterns, but it’s not always clear from the description when exactly they sleep.  For example, someone will say they “keep going to bed later and later.”   Depending on what they mean, that could either describe Non-24 Hour Sleep-Wake Cycle Disorder (N24) or a gradually worsening case of Delayed Sleep Phase Syndrome (DSPS).    But a quick look at a sleep chart will usually clear up the distinction.

My eponymous co-blogger Delayed2Sleep, who has, of course, DSPS, has posted several of her sleep logs.   Today I am going to post some of my sleep charts.  My name is LivingwithN24 and I have, you guessed it, N24.

One thing I should note to start is that I have always charted my sleep on a vertical chart, whereas D2S has used a horizontal layout, so you’ll need to rotate the charts to compare them.  I have also “double-plotted” some of my sleep charts.  That means each line on the chart encompasses 48 hours.  That’s a standard method in sleep studies as it helps the patterns to stand out more clearly.

I have had N24 for many years.  Here are two pages from a chart of my sleep I compiled in 1991.   In those days I kept my charts on graph paper.

These charts show a textbook case of N24.   The phrase “textbook case” is not a metaphor here; the medical journal articles about my case are commonly cited in reviews of circadian sleep disorders.  So there is no doubt you are looking at a case of N24 sleep.  One can see that the sleep chart of an N24 shows a characteristic diagonal pattern as the bedtime and waking time slides gradually later each day.  Unlike the case of DSPS, the delay does not stabilize at a particular clock time.  Someone with DSPS may for example end up going to bed always around 6am for an extended period.   Someone with N24 who goes to bed at 6am on Monday will likely go to bed at 7am on Tuesday, 8am on Wednesday, 9am on Thursday etc. until  they have gone all the way around the clock.  The delay is not always by one hour — I just chose that for simplicity.  In my case I tended to delay 1.5 hours per day, meaning my “day” was actually 25.5 hours.

One can see in this chart that there is some irregularity in the sleep times, and there may also be daytime naps.  Both of these showed up a lot in January and February of that year.  But there is a nonetheless a clear pattern to the sleep.  In some months such as March, April and May it stands out especially clearly.

It might also be of interest to compare these charts to another type of chart.  In circadian medicine a technique called actigraphy is used. The patient wears a device called an actimeter on their wrist which records movement.  Since people tend to move about a lot more when awake than when asleep, actigraphy can be a way of confirming the sleep times of a patient with N24 or DSPS.  Here is an actigraphic chart of my sleep from around the same time as the sleep logs.   The difference is the black squiggles on the actigraphic chart show time awake, rather than asleep, but the same diagonal pattern is present.

Now those charts are from 1991.  The readers of this blog are clever folks and have no doubt noticed it is now 2010. I did this for a reason.  Most of the studies of N24 have looked the subjects at one point in their lives.   Few, if any, have examined how the sleep patterns of N24 change over the course of many years.  I have noticed a number of changes in my sleep between 1991 and today.

One thing I noticed is that it is much more difficult to control my N24 with lights, darkness and sleeping medications.  In fact, over this summer it became impossible.  So in September I stopped using the lightbox and the sleeping pills to see what my sleep would do on my own.

Here is a sleep chart I made for the last 5 weeks (Sept 18-Oct 25, 2010).  Instead of making the chart by hand I used the SleepChart program from supermemo.com.

This is quite different from the 1991 charts.  While there is still a recognizable diagonal drift of the sleep times, it is much more erratic.  The times of sleep are much less regular.  Also there is a marked tendency to show two or more periods of sleep instead of one for each circadian day.

In some ways this pattern of sleep is in between that of Non-24 Hour Sleep Wake Cycle Disorder and that of Sleep Wake Cycle Disorder – Irregular Type.   In the irregular type of sleep disorder, the person sleeps at almost random times of day or night and for varying lengths of time.  Usually there are several short periods of sleep scattered at various time around the clock.

My sleep has not become completely irregular, but it is getting there.  This is, to put it mildly, not a good thing.  N24, bad as it is, has a least a little predictability to it.  I could never predict my sleep out several weeks as some very regular N24s could do.  But I could at least predict it fairly well 5 or 6 days out.   Now I can barely predict what it will do from one day to the next and the urge to sleep or be awake comes upon me at almost random times.

Usually irregular sleep patterns are associated with conditions involving brain damage (injuries, tumors) or deterioration (dementia).   However I suspect that in cases of severe circadian disorder the circadian system may deteriorate over time, leading to an evolution towards an irregular sleep pattern.   My co-blogger has remarked that her DSPS sleep has some irregular elements as well.

Instead of a static snapshot of sleep which classifies the disorders as DSPS, N24 or irregular, research needs to look at sleep disorders as dynamic, evolving conditions.  If someone has say, heart disease, we understand it will manifest itself differently at age 20 and 40 and 60.  The same may be the case with circadian disorders.  I had some sleep abnormalities from birth, classic DSPS from age 15 to 27, and N24 from then on.  Now I seem to be trending towards irregular sleep.   My approach to coping with this condition will have to change as well, but how that will happen I don’t yet know.

–posted by LivingWithN24 (James Fadden)


Next post:  61.  Questions and answers about Non-24


56. 2010: more sleep logs

16 August 2010 at 09:41 | Posted in Circadian rhythm | 5 Comments
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Uploading more sleep logs here, last half of 2010.   It’s looking like Irregular sleep-wake disorder which usually occurs after brain injury or in dement elderly.   I don’t seriously mean that I’ve earned that diagnosis and would rather blame the schedule on medication changes, the too-warm weather or something unidentified.

Sleep diary

Twice in this period (above) I’ve done my “36-hour trick”, that is stayed up for about 36 hours.  These just happen unplanned for some reason.   As a trial I’m using the expensive Circadin rather than the cheap melatonin for a while.   The effect is at least not negative, but not much else.  The hope was to get back to 8 uninterrupted hours a night.

More later!


Next post:  57. coming soon


52. 2010: sleep logs

23 May 2010 at 15:02 | Posted in Circadian rhythm | 30 Comments

By popular demand (at least two people), here’s my blank sleep log form.  I drew it in Paint and saved it as a .gif file.  The yellow lines show the nighttime that I try to sleep within.

Four week sleep diary

January 2010.  Short days with brilliant sunshine.  Looks like I was determined to sleep during the day and sparsely.  However the average sleep per 24 hours was my usual 8.6 hours.

February 2010.  Better!

March and April 2010.  However did I manage to get on such a regular, normal sleep schedule?  I travelled nine timezones to the west, and the effect lasted for weeks!

But I came back home, and immediately took up my usual bad habits.  Does anyone have an explanation for this?!

WordPress won’t (apparently) let me add more images to this post.   I’ll have to do a new 2010/2011 one some day.

Posted by “D”    


Next post: #53.  Light therapy: white, blue or maybe green?  _________________________________________________________

xlix. 2009: sleep logs

4 February 2010 at 22:53 | Posted in Circadian rhythm | 18 Comments
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As “D” gets the forms filled out, her (my) sleep logs will appear here.  They are of interest primarily to myself and my sleep specialist, Prof. Holsten.  But if you see a long-term pattern, do let me know.  What I see for sure is that I am affected by melatonin and/or bright light.  Next experiment will be to cut the melatonin and see what just morning bright light does.

Sleep Diary

Sleep Diary

The doctor said: "WHAT happened here?"

Umm, I just tried a couple of weeks without melatonin and light therapy, is all.  

More weeks free of melatonin

Back on track

Back on track, such as it is.  My “normal” with the help of melatonin and light therapy.

Posted by Delayed2Sleep (aka “D”).  Updated 22 February 2010.


Next post:  l.  A Man with Too Long a Day (by L)


xli. Coincidence & update

6 June 2009 at 23:50 | Posted in Circadian rhythm | Leave a comment
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Chapter three begins a year-to-the-day after the end of Chapter two.   A coincidence.  (I so wanted to call it serendipity but don’t want to add to the misuse of that word.)

In this last year I’ve retired but kept on with melatonin at night, my light box in the “morning” and keeping my sleep diary every day.  Plus a tiny dab of melatonin late afternoon and yellow goggles in the evening, when I don’t forget. 

The schedule has not become as regular as I’d thought and hoped, even though wake time is preferably “by 1 p.m.”  About every other month the  sleep specialist reminds me that he, at the beginning, had said that he couldn’t promise regularity, a “cure”.  And that he thought that my circadian period is “upwards of 28 hours”.

After five years of daily melatonin, I tried eight weeks without, thinking that, given the chance, my system might land on its own schedule.  Nope.  Those sleep diaries show chaos:  sleep whenever, rarely for 3-4 hours, often for 12-14 hours, night or day.  When I happened to get up between 9 a.m. and 2 p.m. I did use the light box.  There’s no sign of a system, most particularly not any sign of Non-24, for which I’m glad.  When I showed the diary to the specialist, he pointed at those eight weeks and asked: “What  happened here?”

It took only a few days back on melatonin to get back where I was before; here’s a typical 4 weeks:

4weekDIARY jpeg

BTW, as you can see, the sleep diary is now simplified, with four weeks to the page.  With 28 days across and 24 hours down, midnight in the middle as before, symbols at the top for melatonin use and at the bottom for use of light box, the filled in sleep parts of each column show clearly how (ir)regular my sleep pattern is.  Illustrated is, believe it or not, a month that the specialist was quite happy about:  “That may be the best month you’ve had.”


Next:  xlii. Researchers mentioned here


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