Tags: Circadian rhythm, DSPS, Non-24, Sleep research, Suprachiasmatic nuclei
The online N24 community has decided to name November 24 as N24 Awareness Day. We are encouraging bloggers and tweeters and anyone else with a platform to help spread awareness and knowledge of Non-24-Hour Sleep-Wake Disorder (N24).
The web page which links to these efforts is here (click on the N24 Day Logo):
One important advance was a paper by Kitamura et al. which measured the intrinsic circadian period in 6 patients with N24. They compared it with two groups of individuals without a circadian disorder. One group had an intermediate circadian preference. The other group had an evening preference. The latter group however did not have DSPS, only a preference for being active later in the day.
Kitmura et al. found that the intrinsic period of the N24s was 24.5 hours, which was significantly longer than that of the intermediate types, but not significantly longer than that of the evening types. The average period of the N24s was longer than that of the evening types but because of the great degree of overlap between those groups the difference was not significant. The longest period found in an evening type subject was nearly identical to the longest period among the N24 subjects (around 24.7 hours).
These results suggest that a longer-than-average intrinsic period is a component of N24, but it is not the only causative factor. Other factors, such as differences in phase angle between sleep and temperature rhythms, as found in several studies, may play a role.
Another paper, by An et al. did not discuss N24 explicitly, but the results may have import for those with the condition. They studied the effect of Vasoactive Intestinal Peptide (VIP) on shifting of circadian rhythms in mice and in cell cultures from the SCN. They found that VIP depending on time and dose could either enhance or reduce the mutual synchronization of SCN cells. Further, when SCN cells were less tightly synchronized together, they adapted more quickly to phase changes. This suggests that by manipulation of VIP levels it may be possible to increase the adaptability of the SCN to phase changes. Since N24s with a longer period need to change phase every day if they are trying to maintain a normal schedule, this approach might be of help. It might also help people with DSPS when trying to shift to an earlier sleep phase.
–posted by LivingwithN24 (James Fadden)
Kitamura S, Hida A, Enomoto M, Watanabe M, Katayose Y, Nozaki K, Aritake S, Higuchi S, Moriguchi Y, Kamei Y, Mishima K. Intrinsic circadian period of sighted patients with circadian rhythm sleep disorder, free-running type.Biol Psychiatry. 2013 Jan 1;73(1):63-9.
An S, Harang R, Meeker K, Granados-Fuentes D, Tsai CA, Mazuski C, Kim J, Doyle FJ 3rd, Petzold LR, Herzog ED. A neuropeptide speeds circadian entrainment by reducing intercellular synchrony. Proc Natl Acad Sci U S A. 2013 Nov 12;110(46):E4355-61.
Tags: Circadian rhythm, Circadian rhythm sleep disorder, Sleep inertia, Support
Sleep inertia refers to temporary cognitive problems, low levels of alertness and vigilance, and impaired motor dexterity immediately upon awakening from an episode of sleep. The ability to perform mental and/or physical tasks including learning is deficient for a period of time. Executive functioning may be especially impaired; decision-making can be impaired by 50%. Sleep inertia has been shown to be a robust, quantifiable process.
That’s the fancy way of saying that one feels groggy, slow, disoriented and a bit stupid for a while after getting up.
Normal people experience sleep inertia on abrupt awakening from a nap of more than 30 minutes and on abrupt awakening in the middle of the night. It may last from 5 minutes to an hour or more. The stage of sleep may be of some importance for the degree of impairment and how long it lasts. Some degree of sleep inertia is possible even when the sleep from which a person has awoken may have fully dissipated their sleep need
“Circadian misalignment is the basis for all circadian rhythm sleep disorders. These disorders are often associated with impairments of cognitive performance that can have adverse effects on school and work performance, overall quality of life, and safety.” [Reid et al] Sleep inertia is common in circadian rhythm disorders and it seems to be more severe and long-lasting here than in normal people. On top of this, people going to work or school by 9 a.m. are getting up in the middle of their biological night where sleep inertia has been shown to be 3.6 times worse than in “daytime”.
A few recent quotes from people in our support group
show that we find sleep inertia to be a major problem:
–The people I was traveling with even thought I was dead on one occasion because of my usual “coma” type sleep/difficulty waking.
–My son does that comatose thing when he is sleeping too. NOTHING will wake him. SO the sleep doc’s office calls and says to be sure and wake him on schedule. I just said “Huh? That’s supposed to be funny, isn’t it?”
–I have the very deep sleep characteristic as well… I’ve slept through fire alarms, even a jackhammer tearing up the street literally right outside my window. […] I’ll also apparently have limited conversations with people while still asleep, though I’ll have no recollection. My college roommate told me I would crawl halfway down the ladder from my bunk and turn off my alarm clock with my foot, still dead asleep.
–Of course it doesn’t help that I won’t be anywhere close to alert for at least an hour after waking up if it’s morning…
–No one could understand how I could always be late for work; my bosses said “please just call and let us know if u will be late.”. What the? There was never any recollection of turning off multiple alarms (if I did–maybe they ran out–I could never figure it out). How could I call in my sleep? ;). No options, if you are deaf, you can’t hear, and it’s like I was deaf or in a coma.
–I too have slept through fire alarms, normal alarms, building work in my room at one point etc. My parents always said I could sleep through a nuclear blast 😛 And I also talk in my sleep when someone’s trying to wake me up — not much though, just enough to reply “yes, I’m getting up” or something similar.
–The last time I was working regularly I had to budget at least an hour to get dressed because I could count on “losing” about 30 minutes every morning. Just standing in the middle of the kitchen or in the shower asleep.
–Similarly, I set an alarm for three hours before class starts (takes 10-20 minutes to walk to class) because I seriously lose time when I wake up, especially if I wake up after fewer than an optimal number of hours of sleep. I don’t know if I sleep standing or not, but I definitely haze out and lose time.
–My boss can’t understand my DSPS. And now I have an accommodation so I can work noon to 8:30 pm and still I don’t hear the alarms and often wake up half an hour before I need to be at work, thus I am often (OK, almost always) a little bit late even at noon. I was told at work that since my supervisor was going to be on vacation, I’d need to come in to work at 8am for that week. (I have a medical disability accommodation). I explained it to them like this….if I was in a wheelchair, and my boss normally did something like climbing a ladder to replace lightbulbs, would you expect me to figure out a way to do that in her absence? Would you remove a wheelchair ramp for a week for someone and expect them to crawl up a few steps for a week?
–I do wanna point out, my partner is the least DSPS person I know, he’s very average, sleeps 8 hours if allowed, but does very well on 6, works full time 9-5 without a problem. My point is, he’s normal 😛 And if you set an alarm for his middle of the night, he will also be comatose-like and a total zombie even if he does manage to hear it and get up. And he’s actually fallen asleep in the shower/kitchen while getting ready for work before, when he’s had to get up at hours like 3-4am (which is very rare). So I don’t think that this type of sleep is DSPS or N24 specific .
Bruck D, Pisani DL. The effects of sleep inertia on decision‐making performance. Journal of Sleep Research. 1999; 8: 95–103.
Matchock RL. Circadian and sleep episode duration influences on cognitive performance following the process of awakening. International Review of Neurobiology. 2010;93:129-51.
Achermann P, Werth E, Dijk DJ, Borbely AA. Time course of sleep inertia after nighttime and daytime sleep episodes. Archives italiennes de biologie. 1995 Dec;134(1):109-19.
Groeger JA, Lo JC, Burns CG, Dijk DJ. Effects of sleep inertia after daytime naps vary with executive load and time of day. Behavioral Neuroscience. 2011 Apr;125(2):252-60.
Reid KJ, McGee-Koch LL, Zee PC. Cognition in circadian rhythm sleep disorders. Progress in Brain Research. 2011;190:3-20.
Scheer FA, Shea TJ, Hilton MF, Shea SA. An endogenous circadian rhythm in sleep inertia results in greatest cognitive impairment upon awakening during the biological night. Journal of Biological Rhythms. 2008 Aug;23(4):353-61.
66. Next post: 67. Blogathon: “Dear Diagnosis”
Tags: Body clock, Circadian rhythm, Circadian rhythm sleep disorder, Support
CSD-N is now set up to accept paying members. Charter membership (before 31 March 2012) is just US$25. The organization needs many members to increase its clout in working for its goals. See the “Join us” page on the website.
There’s a new organization for us: Circadian Sleep Disorders Network – advocating for people with misaligned body clocks. It’s incorporated as a non-profit in the USA and very soon will be accepting paying members.
Its mission statement:
- Circadian Sleep Disorders Network is a non-profit organization dedicated to improving the lives of people with chronic circadian rhythm disorders.
- We aim to increase awareness within the medical community and among the general public, to provide emotional support and practical ideas for people living with these disorders, to encourage research into circadian rhythms, and to advocate for accommodations in education and employment for people with circadian rhythm sleep disorders.
The website, under construction, is at CSD-N.org. There you’ll find a two-sided brochure which may be downloaded and freely distributed; it is available in both A4 format and 8.5×11 letter size.
Here’s wishing the new organization a long and useful life.
Next post: 65. Sleep inertia
Tags: Chronobiology, Circadian rhythm, Diagnosis, Sleep disorder, Sleep research
Funding of sleep research by the National Institutes of Health (NIH) is prioritized according to the National Sleep Disorders Research Plan. The plan resulted from 1993 legislation establishing the National Center on Sleep Disorders Research with the mandate, in part, to:
- Conduct and support research, training, health information dissemination, and other activities with respect to a basic understanding of sleep and sleep disorders, including research on biological and circadian rhythms, chronobiology, and other sleep-related topics.
The first such plan was dated 1996. The second and current one is from 2003: http://www.nhlbi.nih.gov/health/prof/sleep/res_plan/sleep-rplan.pdf
The present Sleep Disorders Research Advisory Board, chaired by Charles A. Czeisler and with Michael Twery as Executive Director, has been working for a year or so on a revision. The 2011 research plan will provide a guide for future scientific sleep and circadian research, both basic and clinical.
While the 2003 plan is organized under such headings as Basic sleep science, Enabling technology, and Pediatrics, the 2011 plan will be organized around research goals.
The draft of April 2011 contains five goals. They are concerned with, in short version:
- Sleep and circadian functions and mechanisms
- Factors contributing to sleep and circadian disorders and disturbances
- Prevention, diagnosis and treatment of sleep and circadian disorders and circadian disruption
- Dissemination of sleep and circadian research findings
- Sleep and circadian research training, to accelerate the pace of discovery
There appears to be a greatly increased emphasis on circadian disorders and research in this draft. The word ‘sleep’ appears seldom alone; it’s always ‘sleep and circadian’.
Those of us with circadian abnormalities are perhaps most happy with goal 4. Health care professionals, educators, policy makers and the general public are at present largely unaware of the results of research to date, and the resulting ignorance leads to misdiagnosis of most of us. The research community knows a great deal more than the medical community does, and dissemination of that knowledge should have high priority.
Next post: 64. Circadian Sleep Disorders Network
Tags: Body clock, Circadian rhythm, Disability, Japanese study, Non-24, Prevalence, Sleep disorder
About 50% of the totally blind have Non-24-hour Sleep-Wake Cycle Disorder while it is very rare among sighted people. People with Non-24 cannot adjust to the environmental 24-hour cycle.
If Hayakawa et al. are to be believed, there have been only 96 cases of N24 in sighted people reported in studies, worldwide, ever. The first 39 were reported in 26 separate studies dated 1970-2003. Hayakawa’s group reported on 57 cases in a report in 2005*. These 57 were diagnosed in Japan in 1991-2001. So what have I learned from that paper?
Are there equally many men and women? No, there are more than two and a half times as many men.
Is Non-24 about as common as the other Circadian Rhythm Disorders (CRDs)? No, the other CRDs together, primarily DSPS, are six times as common.
Do people with Non-24 have anything else in common physically? No. Eye examinations, blood counts, serum biochemistry, electrocardiography, electroencephalography and brain MRIs show nothing special.
Socially? 89% were unmarried and 39% were unemployed.
Had they any health problems in common before the onset of free-running? 28% had psychiatric problems (obsessive-compulsive, adjustment, schizoprenia, anxiety or depression and often associated social withdrawal), not remarkably higher than the general population. But more than a fourth had DSPS before developing Non-24.
How old were they at the onset of Non-24? 86% were ten to twenty-nine years old, none younger than ten. Sex had no effect on the age of onset. (None of the subjects was over 50.)
Do the hours of sleep correlate to the length of the endogenous circadian cycle? Most of the subjects’ cycles were between 24.5 and 25.5 hours, with only one having a cycle longer than 26.5 hours. Subjects slept between less than 7 hours to more than 12, with the majority sleeping 9-11 hours. But there was no correlation between the period of the sleep-wake cycle and sleep length, and neither was affected by sex nor employment status.
How debilitating is the disorder? “98% had a history of disturbed social functioning due to inability to regularly attend school or work.”
Do people with Non-24 often develop psychiatric problems after the onset of the disorder. Yes, but depression only, not the other disorders. “It is possible that these patients had tried to adapt themselves to their social life and failed, leading to psychological stresses that could have precipitated their depression.”
How does Non-24 in sighted people differ from that of people who are blind? The blind generally have a shorter circadian period, and it doesn’t fluctuate over time. In sighted people, the period tends to be longer when sleep onset is in the daytime than when a person falls asleep during nighttime.
*Tatsuro Hayakawa, Makoto Uchiyama, Yuichi Kamei et al. Clinical Analyses of Sighted Patients with Non-24-Hour Sleep-Wake Syndrome: A Study of 57 Consecutively Diagnosed Cases. SLEEP 2005;28(8):945-952
Next post: 62. Psychiatric misdiagnosis of N24