Sleep Dynamic Therapy

Archive for September, 2007

Today, at my talk at Sandia National Laboratories, the audience was interested in my opinion on the recent article on sleep duration in relationship to premature death from heart disease. As I’ve pointed out previously, these studies are incomplete works because they are looking at a sleep quantity model. Yet, the real insight is mostly likely explained by underlying physiological sleep disorders that causes one group to sleep too long (for example, classic sleep apnea patients with hypersomnia) and one group to sleep too short (for example, sleep breathing patients with a co-occurring problem of insomnia). Both types of patients have an underlying physical sleep disorder, but they look very different due to their pronounced differences in sleep duration. So, is sleep duration the important risk, or is it really the underlying physical sleep disorder? Parsimony suggests that sleep breathing problems provide the best reason to explain premature death rates.

This report from the European Respiratory Society highlights two important problems in the way the media and bariatric researchers are framing the discussion about post-operative sleep breathing changes following significant weight loss. First and foremost, they only report the AHI, the apnea-hypopnea index, and not the RDI, the Respiratory Disturbance Index. Thus, it is safe to assume that the researchers did not use advanced respiratory technology to measure UARS events (a.k.a. flow limitation events), the subtle breathing patterns that also provoke sleep fragmentation and subsequent daytime impairment in ways quite similar to classic sleep apnea. The second issue is the comment that the surgical intervention reduced or eliminated snoring in some patients, as if to suggest that snoring is a reliable marker of sleep breathing problems.

In sum, we are faced with the dilemma that both the media and the bariatric researchers are accepting outdated metrics for assessing sleep-disordered breathing (SDB). In the first instance, the assumption is that the AHI tells the whole story. It’s wonderful news to hear that AHI drops post-weight loss, but by not defining and measuring the RDI, it is safe to assume that many of these patients still suffer from SDB that likely needs treatment. The commentary on snoring represents another outdated metric in that we know many patients don’t snore and have SDB, and there are some who do snore and don’t have SDB. Bottom line is that snoring doesn’t tell us a lot about someone’s SDB condition. Again, it’s wonderful news that snoring decreases or disappears with post-op weight loss, and it likely signals that SDB severity has decreased, but it doesn’t tell us whether or not the patient still suffers from SDB, and that is the most important issue in question about the patient’s sleep health.

Imagine if the heart surgeon told a patient, “Looks like we’ve cut down your coronary blockages by 50%.” No intelligent heart patient would be satisfied with such a claim. “Okay, but how much coronary blockage do I still have left?” Same goes for SDB, “how much SDB do these patients still suffer from?” is the question at hand.

A very interesting report on long-term treatment of ADHD with medications. The good news is that school performance is enhanced. The bad news is we don’t hear anything, at least in this mainstream media article, about whether Ritalin is treating a condition or the symptom of a condition. Considerable research has already shown that some ADHD type symptoms are related to sleep breathing or sleep movement conditions in children. Which means that treating the sleep disorders may improve some of these symptoms.

This article exemplifies the types of targets we are looking for in our new Snoozebusters.com site, which will provide our readers the opportunity to blog along with us to pull back the sheets on those stories that inadvertently cover up the pertinent sleep angle. Snoozebusters.com will also have a monthly award for the 3 best entries. More to come in a few weeks when Sound Sleep, Sound Mind is published and we re-launch our updated website sleeptreatment.com.

This report on a research article in the journal Hypertension discusses the connection between short sleep duration and an increase in high blood pressure in women. One of the key discussion points was the age factor (average 55 years-old) in the sample of women, and its implication of a menopausal effect. This point is interesting in the context of Guilleminault’s study on peri-menopausal women with insomnia who suffered from SDB, especially in the form of UARS. Remarkably, the research article in Hypertension does not cite Guilleminault’s work nor does it connect the dots between insomnia, UARS, and menopause as the more parsimonious path to hypertension. Conceivably, severe insomnia with sympathetic activation could cause increased vascular tone and resultant high blood pressure. Yet, given the knowledge that many peri-menopausal women with insomnia suffer from SDB and that SDB has been linked to hypertension, I would have liked to have seen more discussion on this hypothesis. Last, in their call for future studies, no mention was made for the need for overnight sleep studies (polysomnography), which, unfortunately, continues to reflect the outdated paradigm that insomnia patients do not need to be studied in the sleep lab.

Again, another high profile commentary on obesity and no mention of sleep. No discussion on how obesity worsens sleep breathing problems, which in turn may adversely influence eating behaviors, and no mention of how underlying poor sleep quality may influence eating behaviors and lead to obesity.