Monday, May 30, 2011

Cleft Palate and Obstructive Sleep Apnea

Reuters has a summary about the risk of obstructive sleep apnea (OSA) and cleft palate in children. Two otolaryngologists from Children's Hospital of Pittsburgh, Drs. Todd D. Otteson and Jacob G. Robison studied the issue.

The physicians note that OSA is more common in children with cleft palate, whether or not they have a cleft lip, because of the anatomic differences caused by the birth defect and cleft palate surgery, which can reduce airway size. Symptoms of OSA seem to occur most commonly after cleft palate surgical repair, especially the pharyngeal flap procedure for velopharyngeal insufficiency (which can cause speech and swallowing difficulties).

The physicians suggest that surgeons who treat patients with cleft palate will have to weigh the risk of OSA and the need to improve the patient's speech surgically. They also recommends screening for signs and symptoms of OSA and to consider a sleep study if indicated.

Friday, May 27, 2011

Sleep-Wake Behavior and Chronic Fatigue Syndrome

In the journal Sleep, K Rahman et al published a study that assessed the relationship of sleep-wake behavior and chronic fatigue syndrome (CFS). Patients with CFS usually report unrefreshing and restless sleep. To date, scientists have not been able to figure out what makes CFS patients experience the subjective sleep disturbances. In addition, sleep studies have not confirmed objective sleep disturbances in patients with CFS, meaning that there is no evidence that CFS results from a sleep disorder. Researchers do feel that changes in sleep patterns and activity levels can maintain the symptoms of CFS.

This study attempted to determine if circadian rhythm disturbances could be responsible for the fatigue and unrefreshing sleep reported in CFS patients. The results, though, showed no differences in recordings of sleep pattern, sleep duration, daytime activity, or cortisol secretion (a marker of circadian rhythm) between CFS patients and control subjects. The authors concluded that a disruption in circadian rhythm is not associated with CFS.

Interestingly, despite no differences in objective sleep measures, all of the CFS patients in this study reported poor sleep quality. One finding that was different between CFS patients and the control subjects was a loss of vagal modulation of heart rate in CFS patients, which indicates a state of increased sympathetic arousal. Think of vagal modulation (or parasympathetic system) as the brakes of a car and the sympathetic system as the accelerator - thus, in CFS patients, the brakes do not work and the accelerator is going unchecked. There are studies that suggest that normal vagal modulation is needed to make sleep restorative. Therefore, the decrease in vagal modulation could be a biological explanation for the poor sleep quality reported by CFS patients.

It would be interesting to see if medications that increase vagal tone have been reported to make sleep more refreshing. If anyone knows of such reports, put it in a comment here.

Wednesday, May 25, 2011

Eye Diseases and Obstructive Sleep Apnea

A friend gave me a great review article entitled "The Eye and Sleep Apnea" written by Dr. Alan A. McNab in the 2007 edition of Sleep Medicine Reviews. Dr. McNab discusses a few eye diseases associated with obstructive sleep apnea (OSA), and I will summarize it for you.

The first condition is called floppy eye syndrome, characterized by "floppy" and enlargement of teh upper eyelids in obese middle-aged and older men. If the patient sleeps on one side, the eyelid on that side is affected more. Patients complain of excessive watering, stickiness, discomfort, and blurred vision in teh affected eyes - typically worse upon awakening. The condition is not too common, occurring in 2-5% of OSA patients. It can be a marker for more severe OSA, and CPAP may be all the treatment a patient needs. Others need surgery on the affected eyelid(s) despite CPAP therapy.

Glaucoma has also been associated with OSA. Another eye disorder is non-arteritic ischemic optic neuropathy (NAION) and a high proportion of NAION patients first report their visual loss on waking - meaning that the oxygen level decreases during apneas could be playing a role in their eye disease. I've gotten several referrals from ophthalmologists to rule out OSA as a contributor to their patient's NAION.

Patients with OSA can have headaches upon awakening and intracranial pressure of OSA patients measured overnight can be elevated in an episodic fashion, correlating with apneic episodes. This raised intracranial pressure can be associated with papilledema, or swelling of the optic nerve.

The bottom line is that there are eye diseases that can be related to OSA. Talk to your primary care doctor and/or eye doctor about your symptoms.

Monday, May 23, 2011

Sleep Apnea and Shaq



Many people have heard that Shaquille O'Neal has been diagnosed with obstructive sleep apnea (OSA). Harvard Medical School's Sleep Medicine Division has a great website about OSA and features a 4 minute video of Shaq. In the video, he describes his symptoms, the sleep study he had, and the treatment - in this case, it was CPAP.

The website also has great information about OSA for the general public.

Caffeine and Insomnia

MR Youngberg et al studied the relationship of caffeine, its metabolite, and insomnia - published in the Journal of Clinical Sleep Medicine. The authors report that nearly 90% of Americans regularly consume caffeine and other studies have shown that caffeine can disrupt sleep but also increase alertness. Having patients reduce or eliminate caffeine consumption, especially within 8 hours of bedtime, is a common recommendation we make to patients with insomnia.

But caffeine does not affect every person the same. This may be a genetic phenomenon, meaning that some metabolize caffeine more rapidly than others. There also could be tolerance to the alerting effects with regular use.

The authors studied the effects of low-to-moderate amounts of caffeine in normal sleepers and those diagnosed with insomnia. The results showed no differences in the two groups with respect to self-reported caffeine intake, caffeine and caffeine metabolite blood levels, and the last time of day caffeine was consumed. The authors concluded that neither caffeine nor its metabolites are significantly associated with sleep disturbance in patients with and without insomnia.

Now, before you insomniacs reach for the coffee pot just before bed, I would argue that perhaps some people can handle caffeine within 8 hours of bed, but others can not. You should experiment with your caffeine intake to see how your sleep quality is affected. Reducing caffeine intake alone is unlikely to "cure" someone's insomnia, but it can be an important part in an overall, tailored behavioral treatment plan.

Friday, May 20, 2011

Cardiovascular Disease and Worsening Sleep Apnea

Cross-sectional studies have linked sleep-disordered breathing, like obstructive sleep apnea (OSA), to cardiovascular disease (CVD) including coronary artery disease, congestive heart failure, and stroke. The most frequent assumption is that OSA increases the risk of CVD.

HA Chami et al studied the association of incident cardiovascular disease (iCVD) with worsening of OSA. In this study, the iCVD refers to the number of cardiovascular disease diagnoses over a five year period. The study authors wanted to determine if iCVD causes or worsens OSA. The study was published in the journal Circulation.

The results showed that iCVD was associated with worsening of OSA after adjusting for age, sex, race, site, chagne in body-mass index, cahnge in neck circumference, and difference in percent sleep time spent in teh supine position and with further adjustment for baseline blood pressure, cholesterol, smoking, and change in medication use. The results did not show that iCVD could bring on OSA where it did not previously exist.

The authors concluded that OSA is a risk factor for OSA and also that CVD can potentially worsen (but not cause) OSA. The mechanism is not understood, but it could be related to instability in how we control our breathing while asleep. Cardiac disease could contribute to breathing instability, which could then worsen OSA.

These findings reinforce the complex relationship between heart health and sleep health, and how important it is for cardiac patients to discuss their sleep with their cardiologists and primary care physicians.

Wednesday, May 18, 2011

Night Owls and Dietary Habits

In the online edition of the journal Obesity is a study about late night eating habits. Psychologists studied 51 people, 23 late sleepers (average bedtime 3:45 a.m.) and 28 normal sleepers (average bedtime 12:30 a.m.). Study participants recorded their eating and sleeping in logs and had objective sleep measurements with wrist actigraphy.

Late sleepers ate 248 more calories per day, ate twice as much fast food, ate half as many fruits and vegetables, and drank more full-caloire soda than the participants with normal sleep times. The late sleeepers consumed the extra calories during dinner and later in the evening when everyone else was asleep. Left unchecked, this amount of extra calories could lead to a 2 pound weight gain per month!

The study researchers don't know if the late sleepers consume the extra calories beacuse they prefer more high-calorie foods or because there are less healthful options late at night. It could also be that there is a circadian effect, meaning that staying awake later than normal could lead to hormone changes that affect metabolism and appetite. This, in part, could explain the fact that people who work third shift have increase risk of obesity, cardiovascular, and gastrointestinal disorders.

Saturday, May 14, 2011

Poor Sleep, Insulin Resistance, and Diabetes

Diabetics who have difficulty controlling their blood glucose levels have a greater risk of complications, reduced quality of life, and reduced life expectancy. Researchers studied the association of sleep quality in diabetics. Results were published in the online version of the 3-16-11 edition of Diabetes Care.

Sleep duration and quality were estimated from 6 days of wrist actigraphy, a home sleep-measuring device worn on the wrist. Insomnia was defined as self-reported difficulty falling asleep or waking up in the night three or more times per week plus average sleep efficiency of <80% based on actigraphy.

The results showed no association between sleep measures and fasting glucose, insulin levels, or insulin resistance in the 115 subjects without diabetes. In the 40 subjects with diabetes, insomnia was associated with a 23% higher fasting glucose level, a 48% higher fasting insulin level, and an 82% higher amount of insulin resistance.

This suggests that diabetics with insomnia could have a more difficult time controlling their diabetes. The next step is to see if improving sleep quality will improve long term outcomes and quality of life for diabetics.

Thursday, May 12, 2011

Obstructive Sleep Apnea, Truckers, and the FMCSA

There is an effort by the Federal Motor Carrier Safety Administration (FMCSA) to comprehensively revise the agency's rules aimed at making it harder for unfit drivers to either get medical clearance or evade detection. One area the agency is targeting is obstructive sleep apnea (OSA). During this upcoming August, the FMCSA will ask the medical review board (MRB), made up of a panel of physician advisors, on how it should proceed.

Since 2008, the MRB has supported stricter regulatory standards for OSA, by stating that all drives should be screened for OSA. The MRB recommended that a driver with a body-mass index (BMI) of 30 or more should not be allowed certification until that driver has had a sleep study. The MRB said that a diagnosis of OSA should not necessarily bar a driver from certification, but that certification should be conditioned on the OSA severity, its impact on driver's sleepiness, and whether the driver is getting treatment. It also recommended criteria for denying medical certification, including a crash associated with falling asleep at the wheel and failing to comply with prescribed OSA treatment.

Currently, there is confusion in the medical community about OSA because the MRB made the above recommendations in 2008 but the FMCSA has not made them into rules yet. Some examiners have adopted the MRB recommendations as requirements, while others are awaiting for more guidance from the FMCSA. Perhaps we will get that this summer.

Monday, May 9, 2011

Men's Thoughts, Sex, Sleep, and Food

There was a study done to see if the urban legend that men think about sex once every seven seconds is true. Psychologists asked 163 college women and 120 college men to carry around small tally counters, and asked them to record each time they thought about food, sleep, or sex. On average , the men had sexual thoughts slightly more than once each waking hour and women about half that. But the men had thoughts about food and sleep about as often as sexual thoughts.

The psychologists theorized that men could be more aware then women of their own physical state at any given time, or that men are more comfortable recording such thoughts than women. In the women who reported they care more about what others thought about them, were less likely to report food or sexual thoughts - perhaps because of the social stigma of food and sex with females. Women were equally as likely to report sleep-related thoughts, perhaps because there is no stigma with sleeping.

Friday, May 6, 2011

Sleep-Deprived Brains Turn Themselves Off

Researchers in Wisconsin and Italy discovered that when rats were kept awake four hours past their usual bedtime, parts of their brains began to turn themselves off, neuron by neuron, even though the rat was still awake. The shutdown of the neurons was random, but progressive - this was what the researchers thought was responsible for the rats decreasing performance on a task where they had to find a sugar pellet. Researchers said there is no reason to believe this progressive shutdown does not occur in humans.

This finding is important because it means that there could be performance decrements when tired or sleepy, and these decrements could occur before the person even realizes it. There are implications for drivers and those who operate heavy machinery who happen to be sleep-deprived. It could also affect test-taking in sleep-deprived students.

Thursday, May 5, 2011

Sleep Duration, Sleep Quality, and Cardiovascular Disease Risk

I just came across a blurb about the MORGEN Study (Monitoring Project on Risk Factors and Chronic Diseases in the Netherlands) which explores the associations of sleep duration and sleep quality with cardiovascular disease (CVD) and coronary heart disease (CHD).

Researchers surveyed more than 20,000 men and women ages 20 to 65 years old about their sleep quality and quantity. The followed them for 10 - 15 years and recorded morbidity and causes of death. Sleep quality was assessed by asking "Do you usually rise feeling rested?"

The results showed that people who slept less than 6 hours per night had a 15% higher risk of incident CVD and 23% higher risk of CHD, compared to people with normal sleep duration (7-8 hours per night). On its own, there was no increased risk of CVD in patients with normal sleep duration, but reduced sleep quality. However, in those with poor quality sleep and short sleep duration, there was a 65% increase risk of CVD and an 85% increase risk of CHD when compared to people who had good quality sleep and slept normal duration. Interstingly, there was no correlation between sleeping longer than 8 hours and CVD, a finding which contradicts other studies.

There is no mention of obstructive sleep apnea or obesity, which could affect sleep duration, sleep quality, and increase CVD and CHD risk.

The bottom line is that if you are sleeping less than six hours per night, and feel your sleep is poor quality, talk to your doctor. Your heart health could be in jeopardy.

Monday, May 2, 2011

Short Sleepers

There is an article in the Wall Street Journal about people who need less than six hours of sleep per night - a.k.a short sleepers. Short sleepers are less common than most people think. In fact, the article quotes a famous sleep psychiatrist, Dan Buysse, who says that there only 5-6 true short sleepers for every 100 people that make such claims. People who tolerate six hours or less of sleep per night for the work week are not what we call short sleepers. If you can sleep longer on the weekend, than you are not a short sleeper. You are sleep-depriving yourself during the work week and catching up on lost sleep on the weekends. Short sleepers sleep < 6 hours seven days a week.

We don't know why some people are short sleepers. It can start in childhood and can run in families. There is no way a person can teach themselves to be a short sleeper either.

Short sleepers tend to be more energetic, outgoing, optimistic, and ambitious. Their metabolism tends to be higher than regular sleepers. The article in the WSJ thought this was confusing, since sleep deprivation is linked to obesity. However, it could be argued that true short sleepers are not sleep-deprived. Finally, short sleepers tend to have higher tolerance for physical pain and psychological setbacks.

Currently, researchers are attempting to find out the genetics behind short sleepers. This could have applicability in our fast-paced modern lifestyle. In the mean time, get some sleep...enough sleep.