Monday, December 26, 2011

Sleepiness During Real Driving at Night


We know that driving while sleepy is dangerous. Driving in the middle of the night is especially dangerous. Most studies of driving while sleepy have been on driving simulators, which are not the same as real driving. In the October edition of the Journal Sleep, a study was done to assess sleepiness on real driving. Researchers measured subjective sleepiness, the position of the car relative to the driving lane, objective measure of sleep by measuring brain waves, the duration of eye blinks, line crossing, and speed of vehicle. There were 18 normal sleepers in good health. Study subjects were monitored while driving during the day and night.

Results showed that subjective sleepiness, eye blink duration, and brainwave-measured sleepiness were higher during nighttime driving compared to daytime driving. Also, drivers were more likely to veer toward the middle of the road at night, and this is a new finding. The authors thought it could be due to desire not to go off the shoulder from sleepiness and from reduced visibility of the shoulder. Another new finding was that speed was slower at night and the authors thought this could be due to sleepiness and/or a need to be safer because of decreased visibility.

This study gives us more evidence of the dangers of nighttime driving. And the subjects in this study were healthy and not sleep-deprived. Imagine how much more dangerous these drivers would be if they had a sleep disorder and/or were sleep-deprived. Try to limit nighttime driving if possible. If you do drive at night, be safe and smart about it.

Monday, December 19, 2011

Obstructive Sleep Apnea and Psychiatric Patients

Obstructive sleep apnea is becoming more common, especially as obesity rates increase. Some of the medications used to treat psychiatric conditions can contribute to obesity, putting these patients at risk for OSA. There was data presented at the recent American Psychiatric Association where a screening questionnaire was given to patients that were admitted to the hospital for psychiatric illness. The screening tool is called the STOP BANG and can be downloaded from here. Of the 85 patients studied, 46 (54%) were positive on the OSA screening questionnaire and 10 of those (22%) had OSA confirmed. The researchers concluded that these 10 patients would have gone undiagnosed if not for the simple screening process. Since some of the symptoms of OSA overlap certain psychiatric illness (fatigue, sleepiness, insomnia), screening patients could help identify those at risk for OSA and get them the needed treatment.

Monday, December 12, 2011

Prevalence of Sleep Paralysis

Sleep paralysis occurs when a person becomes completely paralyzed when either going to sleep or waking up. The only muscles that can be moved are the eye muscles and the diaphragm. It is very frightening because the person is awake and usually thinks they are dead or have had a massive stroke. The symptoms last only a few seconds to minutes, but can recur regularly. It's associated with another sleep disorder called narcolepsy, but sleep paralysis can also occur by itself. It's a harmless condition by itself, but it's important to get evaluated and treated if it is part of narcolepsy.

A study was done recently to determine the lifetime prevalence of sleep paralysis. Researchers reviewed 35 studies on the condition and determined that almost 8% of the general population has had at least one episode. Prevalence was over 28% for students and 32% for psychiatric patients - possibly due to more disrupted sleep and changes in sleep schedules seen in those populations.

Monday, December 5, 2011

Difficulty Breathing During Anesthesia and Obstructive Sleep Apnea

I'm not an anesthesiologist, but I always learn cool things about sleep from them - after all they are always putting people to sleep. Apparently, there is an association between patients that are difficult to intubate and obstructive sleep apnea (OSA). Now there is a study that was done to determine if patients that are difficult to ventilate with an anesthesia gas mask are at risk for OSA. If so, then anesthesiologists would be able to identify potential patients and refer them on to a sleep center for diagnosis and treatment.

I can see the connection between difficulty using a mask to ventilate (abbreviated DMV) and OSA because the two conditions share similar risk factors - elevated weight, older age, male gender, increased upper airway crowding, and a history of snoring. When a patient is under general anesthesia, their throat is more relaxed and could collapse more easily. This could contribute to difficulty ventilating with a gas mask.

In this study, ten patients had sleep studies after full recovery from surgery and a minimum of 30 days after their operation. The sleep studies showed that all ten subjects had some degree of OSA, with 80% having moderate to severe OSA. The more difficult to ventilate with a mask, the more severe the OSA. The results are interesting but there are limitations to this study. The average time between surgery and the sleep study was 7 months and 2 days with a maximum time of 21 months. Therefore, keep in mind that patients could have gained weight during the time from their surgery to the sleep study, and that weight gain could have increased their risk of OSA. Also, all of the study subjects had similar characteristics known to be associated with OSA - elevated weight, large collar size, more snoring, more high blood pressure, and more daytime sleepiness than the general population. Therefore, these characteristics could be responsible for the high amounts of OSA, not the DMV. Finally, there was no control group, so it's not known how many patients without DMV would also be diagnosed with OSA.

Tuesday, November 29, 2011

Protein, Carbohydrates, and Alertness

There are a group of cells, small but important, in your lateral hypothalamus that contributes to daytime alertness. Loss of these cells is thought to be responsible for the sleep disorder narcolepsy. A group of researchers studied these neurons and the effect of carbs versus protein on their firing rates. They have already shown that carbs inhibit their firing, which could possibly explain 'sugar crashes', where you get sleepy soon after eating sugary foods.

During the current study, the results showed that protein activated the cells, meaning that protein could help keep you awake. Also, protein blocked the effects of sugar on the cells, meaning that you might be less sleepy from eating sugar if you ate it with protein. This makes sense, as diabetics are taught to eat protein with each meal, which could help reduce the negative effects of carbohydrates on insulin levels.

I wonder if people who do low carb, high protein diets are more alert than those on more traditional western diets or high carb diets. That would be an interesting study.

Monday, November 28, 2011

Long-Term Use of Provent for Obstructive Sleep Apnea


CPAP is the most effective and widely used treatment for obstructive sleep apnea (OSA). Recently a new device, called Provent (see picture) has been shown to be safe and effective in the short term treatment of OSA. It works by limiting exhalation through the nose, which results in a buildup of back pressure in the upper airway. This pressure holds the upper airway open during sleep.

In the Journal of Clinical Sleep Medicine is a study of long term Provent use in OSA. Of note, it is a 12 month extension of the short-term open label study done earlier. See my earlier post from March 2011 on this short term study. Thirty-four patients were analyzed at the 12 month time point.

The median use for the entire night was 89%. The results showed significant improvements in the severity of OSA when using Provent at 12 months. The median time spent snoring while wearing Provent was reduced by 74%. The Provent group also had significant reductions in the level of daytime sleepiness. For those patients that wore Provent at the 3 month mark and had a positive response to it, there was continued benefit at the 12 month mark. The authors concluded that Provent is an effective treatment option for many OSA patients.

Monday, November 21, 2011

Provigil and Physician Alertness

Physicians in certain specialties often stay up most or all of the night when they are on call, and then have to work the entire next day. This is very taxing mentally and physically. However, it is controversial whether this acute sleep deprivation affects how physicians perform at their job. Some say it puts patients at risk for errors, while others say it has little effect on experienced physicians.

Provigil (or Modafinil) is a stimulant medication approved for shift work disorder, narcolepsy, and excessive sleepiness associated with obstructive sleep apnea. It can help workers stay alert on their overnight shift. A study was done in London on 39 male physicians where they were given either 200mg of Provigil or a placebo after one night of sleep deprivation. They were given cognitive tests and asked to use a surgery simulator program to gauge their skills.

Results showed that those doctors that used Provigil did better on the cognitive testing, including working more efficiently, planning, working memory, had less impulsivity, and were better able to redirect their attention. However, no improvements were seen in the surgical simulator program. The study authors concluded that Provigil might help sleep deprived physicians to process information better, think more flexibly, and make decisions under pressure. However, it might not improve their performance on basic procedural tasks. I wonder if because these tasks have been done so often that they could do them well whether they are rested or not.

Friday, November 18, 2011

Insomnia and Heart Attack

Insomnia is a prevalent disorder, but there has not been much data linking it to physical disorders, like cardiovascular disease. Insomnia has been associated with the development of certain psychiatric disorders, most likely being depression. There is an abstract in the journal Circulation that assessed the risk of having a heart attack (aka 'MI' for myocardial infarction) in patients that have insomnia. The study was out of Norway and included 52,610 patients that were followed for an average of 11.4 years and assessed for incidence of MI and difficulty sleeping. The researchers adjusted the data for age, gender, marital status, education, shift work, blood pressure, lipids, diabetes, body mass index, physical activity, smoking, and alcohol consumption.

The results showed that patients who reported trouble falling asleep most nights over the previous month had a 45% higher risk for MI. Patients that reported difficulty staying asleep had a 30% increase risk for MI. And waking up unrefreshed more than once a week was associated with a 27% higher risk of MI.

The researchers do not know why difficulty sleeping would contribute to higher risk of MI. I noticed that one variable they did not account for was whether the patients had obstructive sleep apnea (OSA) or other cardiac or lung diseases that could contribute to insomnia and/or raise the risk of having an MI. OSA in particular is a common cause of chronic insomnia and several studies have linked it to heart attacks. Bottom line: If you have chronic insomnia, talk to your doctor or a sleep physician...your heart might thank you.

Tuesday, November 15, 2011

Sleep Disturbance in Breastfed verses Formula-Fed Babies

My wife breastfed our children because we were taught it is healthier than formula feeding. I never heard that breastfeeding could permanently disrupt sleep in the baby and mother - but apparently this is common knowledge. However, research presented at the 2011 American Academy of Pediatrics National Conference and Exhibition showed that the sleep disturbance in breastfed babies is temporary.

Researchers gathered data from questionnaires and compared the sleep habits of 89 breastfed infants to 54 formula-fed infants at baseline and at follow up visits at 3, 6, 12, and 18 months later. At baseline, the breastfed infants woke up more at night and were less likely to wake up in their own bed (I guess meaning the mom brought the infant to her room to sleep). The breastfed infants also took more daytime naps than the formula-fed infants. But at the six month follow up, the only difference was that the breastfed infants were less likely to wake up in their own bed. By nine months, all differences in sleep had disappeared, and these persisted for the 12 and 18 month follow ups.

The study lead author said that the results should be reassuring to parents that want to breast feed, but have heard that it can permanently disrupt sleep more than formula feeding. Currently, the American Academy of Pediatrics recommends breastfeeding as long as possible and at least to 12 months.

Thursday, November 3, 2011

Sleep Duration in Tokyo Versus Other Major Cities

I saw a report about sleep deprivation from the World Sleep Federation, which occurred in Kyoto in October 2011. The report was about a joint study between Stanford University and Ajinomoto Compnay, a Japanese foodmaker that sells a sleep supplement called Glyna. The study was a survey of 180 office workers, aged 30 to 60, from Tokyo, Paris, New York, Shanghai, and Stockholm. The Tokyo office workers averaged only 6 hours of sleep each night, with the National Sleep Foundation recommending 7 to 9 hours as ideal. Only 23% reported getting more than 7 hours of sleep each night. The workers attributed their sleep difficulties to work and personal stress, outdoor noise, the weather, and other reasons. The Tokyo workers got 36 minutes less sleep than New Yorkers and 54 minutes less than Parisians.

It could be that the Tokyo workers really do get the least amount of sleep among the 5 cities surveyed. It also could be that Japanese workers are getting more sleep than they think, and are just especially poor at judging their own sleep amounts. Or, there could be bias in this study since it was sponsored by a company that makes a product to help people sleep. If the Japanese really are getting that little sleep, could it be that their culture values sleep deprivation because it could mean they are spending more time at work? Unfortunately, sleep deprivation is unhealthy and perhaps an educational campaign might improve sleep duration in all office workers.

Restless Legs Syndrome and High Blood Pressure in Middle-Age Women

Restless legs syndrome (RLS) is a neurological disorder characterized by an urge to move the legs while resting in the evening. It gets more common with age. It can lead to insomnia and more recent studies are linking it to cardiovascular disease, as I have blogged about here and here.

Now there is a study in Hypertension: The Journal of the American Heart Association about RLS and high blood pressure (HTN) in middle aged women. Researchers conducted a cross-sectional study of 65,544 nurses aged 41-58 years old who reported RLS symptoms based on self-administered questionnaires. Women with diabetes and arthritis were excluded as these conditions can mimic RLS symptoms. Information about blood pressure values and HTN was collected via questionnaires. Adjustments were made for age, race, body mass index, physical activity, menopausal status, smoking, use of analgesics, and intake of alcohol, caffeine, folate, and iron. Compared to women without RLS symptoms, the odds were 1.2 times higher of having HTN if the women had RLS symptoms. And the more often the women had RLS symptoms, the higher the reported blood pressure values.

The results of this study are interesting, but caution is warranted. Since all of the data is from self-reported questionnaires, it can be difficult to make concrete conclusions. We don't know if the women really had RLS or one of the many mimics, since they were not examined by any physicians. Also, we don't know if the women had limb movements in sleep which could be more important for HTN than RLS by itself. Finally, we don't know if the women had sleep apnea, which would have required a sleep study. Sleep apnea is a strong risk factor for HTN and could contribute to the results seen because sleep apnea can bring on or worsen RLS. Bottom line: If you have RLS symptoms, please talk to your doctor or a sleep physician.

Tuesday, November 1, 2011

Oropharyngeal Examination to Predict Sleep Apnea Severity


In obstructive sleep apnea (OSA), there have been few physical exam findings that accurately correlate with the risk of having OSA. Elevated body mass index (BMI), increased neck circumference, male gender, older age, and elevated blood pressure all relate to increased risk of OSA. Other characteristics, such as the shape of the back of the mouth, have not been strongly predictive of OSA. However, in the October edition of the Archives of Otolaryngology - Head & Neck Surgery is a study about a certain way sleep physicians classify the level of crowding in the back of the mouth. It's called the Friedman tongue position (FTP), after Dr. Friedman, an ENT surgeon who does research in this area. The picture at the top left shows the FTP classification, with level 1 (upper left picture) being the least crowded and level 4 (lower right) being the most crowded. In my experience, the more crowded the back of the mouth (as in levels 3 & 4), the higher risk of having significant upper airway collapse while asleep that results in OSA.

In the study, researchers assessed 301 patients with an average age of 51 who presented to a sleep lab for suspected OSA. On physical exam, these study subjects were 71.1% were male, had a mean BMI of 29.8, and a neck circumference of 40.5 cm. Results of their sleep study showed that 94% had some degree of OSA - meaning that the population studied was relatively high risk. Subjects with FTP levels of 2 and 3 accounted for 74.1% of the whole population studied. And 14.3% had an FTP level 1, with 11.6% having an FTP level 4. In the first analysis, researchers found that the size of the tonsils, the size of the uvula, BMI, neck circumference, nasal airflow, and age were related to OSA severity. However, in the multiple regression model, only the FTP score showed a relevant relationship to OSAS severity.

The study authors concluded that since the FTP score is almost the only measurement related to OSA severity, a simple oropharyngeal examination can provide key information on this issue. And, since researchers think that almost 80% of patients with OSA have not been diagnosed, I think the FTP level could be an easy screening tool for primary care physicians to assess the potential risk of OSA and get their patients treated.

Monday, October 31, 2011

Obstructive Sleep Apnea Linked To Sexual Dysfunction

Untreated obstructive sleep apnea (OSA) has been linked to impotence in men and loss of libido in women. Many women report to me in my clinic that they are just too tired ot have sex. However, there are not many formal studies about women with OSA and sexual dysfunction. In the September edition of the Journal of Sexual Medicine, researchers studied the sexual functioning of women with OSA. They studied 80 female patients (28 to 64 years old) who were diagnosed with any severity of OSA after a sleep study. Sexual functioning was assessed with subjective questionnaires and the subjects' responses were compared to a population sample.

The results showed that females with OSA had a higher risk of sexual "distress" and sexual dysfunction. The sexual dysfunction was not related to OSA severity, meaning that even mild OSA can impact their sexual functioning. It's not clear whether treatment of their OSA improves sexual functioning. My clinical experience, however, is that women who report an improvement in sleep quality and daytime sleepiness with OSA treatment do report an improvement in sexual functioning.

Monday, October 24, 2011

Sleep Hygiene Education and College Students

I saw an abstract in the Journal of American College Health where researchers did online surveys of students about their sleep quality and quantity. The students were mostly freshman and many reported problems with sleep that were related to sleep environments that were not conducive to sleep - the room has too much light, too warm, or too noisy. Also, the students had a difficult time winding down before bed and went to bed feeling unprepared for the next day.

The researchers did an educational campaign on campus that included information in the campus newspaper and posters placed in dorms about sleep hygiene. The sleep hygiene tips are the ones commonly presented in other sources of media and include topics like sleep-wake schedule, caffeine, exercise, and sleep environment. The students were then surveyed again and some reported an improvement in sleep quality / quantity after the sleep hygiene educational campaign.

This study does have some limitations (in the way it was carried out) and other studies have not shown that sleep hygiene by itself helps chronic insomnia, but these students were not diagnosed with that disorder. Despite its limitations, this study points out that simple interventions like sleep education can be helpful in improving the sleep habits of college students. And better sleep could improve academic performance.

Monday, October 17, 2011

Duty Hour Restrictions and Resident Education

A few weeks ago, I posted about the financial implications of limiting the number of hours that resident physicians can work. Dr. Schuh and others have done a study on how limiting residents' work hours impact their education.

In this study, they surveyed resident sleepiness, personal study hours, quality of life, and resident satisfaction and faculty satisfaction during two separate months - one where the residents worked the usual hours and the other where the residents worked the new hours reduction as proposed by the Institute of Medicine.

The results showed that end-of-work shift sleepiness, mean weekly sleep hours, personal study hours, and hours spent in lectures did not differ between the control and intervention months. Resident quality of life declined in the intervention month. Resident education satisfaction declined as well, for issues related to continuity of care, patient hand-offs, and knowledge of their patients. Faculty satisfaction declined during the intervention month too. One issue brought up by an editorial on the study was that briefer shifts mean more patient hand-offs, and this could increase physician-to-physician miscommunication and medical errors.

The study authors concluded that limiting resident work hours negatively impacts their education and that further studies are needed prior to implementing widespread duty hour changes.

Thursday, October 13, 2011

CPAP's Long-Term Effects on the Heart

Obstructive sleep apnea (OSA) increases the risk of cardiovascular disease and CPAP has been shown to improve heart structure in the short-term. In the journal Chest, there is an article about how CPAP improves heart structure when used long-term. Researchers studied 47 patients with severe OSA who did not have heart failure. The patients' heart structure was evaluated with echocardiography and cardiac MRI at the start of the study and then serially for one year.

After as little as three months of CPAP use, echocardiography showed improvement in heart structure and lung blood pressures - and these changes continued to improve over the one year follow up. Cardiac MRI showed improvement in heart structure starting at 6 months of CPAP use, and improvements continued over the one year follow up.

The researchers point out that the results are limited by the fact that none of the patients had heart failure at the start of the study, so we really don't know if the same improvements would be seen in those with heart failure and long-term CPAP use.

Saturday, October 8, 2011

Insufficient Sleep in Adolescents Linked to Health-Risk Behaviors

There is a study in Preventive Medicine by the CDC examining the associations between insufficient sleep, defined as less than 8 hours on average on school nights, and health-risk behaviors. Researchers used survey data from 12,154 U.S. high school students. They found that sleeping less than 8 hours on school nights was associated with a higher risk of the following: cigarette, marijuana, and alcohol use; current sexual activity; feeling sad or hopeless and seriously considered attempting suicide; physical fighting, not being physically active, computer use at least 3 hours per day, and drinking soda more than 1 time per day. There was no difference in the amount of television watched between those who slept more or less than 8 hours.

The study authors concluded that insufficient sleep was associated with many health-risk behaviors and that lack of adequate sleep may be a warning sign for parents that their teenagers could have other problems.

I don't believe that the study authors think that teenagers will engage in more healthy behaviors if they get more sleep on school nights. I do wonder if the associations are as strong if teens make up for the lost sleep on the weekends.

Thursday, October 6, 2011

Leg Movements In Sleep and Cardiovascular Disease

Periodic leg movements in sleep (PLMS) are repetitive jerks of one or both legs at night while asleep. The bedpartner notices the leg jerks much more frequently than the patient. The leg jerks can wake up the patient, but usually the awakening is so brief that the person never notices it. These awakenings, however, can lead to daytime sleepiness. PLMS get more common with age. Sometimes they are associated with restless legs syndrome which is the uncomfortable urge to move the legs at night before falling asleep.

Studies have begun to suggest that PLMS can increase the risk of cardiovascular disease and neurocognitive deficits (like memory or concentration problems). Researchers think this occurs because the leg movements cause activation of the sympathetic nervous system - in some cases hundreds of times per night. This nervous system activation can temporarily increase blood pressure and heart rate - over time, this could damage the heart and blood vessels.

There is a study in the journal Circulation where researchers performed in-home sleep studies on 2911 men greater than 65 years old to assess for PLMS and followed them for upto 4 years to assess how many went on to develop cardiovascular disease. Results showed that 70% of the men had PLMS. Patients that had even a mild amount of PLMS had greater rates of cardiovascular disease. Those with more frequent PLMS had 25-30% greater risk of developing cardiovascular disease than those without PLMS.

I wonder if the men with PLMS had subtle obstructive sleep apnea (OSA), as repetitive leg movements in sleep can be due to collapse of the airway. OSA is known to increase the risk of cardiovascular disease. Even if the patients in this study had true PLMS not from OSA, it is not clear if treating the PLMS will reduce the risk of developing cardiovascular disease - more studies are needed for that. In the meantime, it is important to talk to your doctor if your bedpartner notes that you jerk your legs at night while asleep.

Monday, October 3, 2011

Financial Impact of Intern and Resident Duty Hour Changes on Training Institutions.

Interns are physicians who are in their first year of specialty training after graduating medical school. Residents are physicians that are still undergoing specialty training but have completed their internship year. Traditionally, these physicians in training have worked very long hours (ask my lovely wife!). This worked well for the training institutions, as interns' and residents' salaries are paid for by Medicare, meaning hospitals got cheap physician labor. However, medical errors have been blamed on physician fatigue and some physicians have had car accidents after falling asleep behind the wheel after being up all night on call. Over the past several years, there has been a movement to limit work hours of interns and residents in an effort to improve patient safety and physician health. In July 2011, new guidelines were instituted where interns can only work a maximum of 16 hours continuously and must have on-site supervision at all times. Residents can work upto 28 consecutive hours when they are on call.

There is a study in the July edition of the Journal of General Internal Medicine that reviewed how the new work hour limits will affect the financial health of the hospitals that train interns and residents. The results showed that the duty-hour changes would cost $177 to $982 million annually on a nationwide scale. The associated training environment changes will cost an additional $204 million annually. If medical errors decline by 7.2-25.8%, net costs to major teaching hospitals will be zero.

To make up for the extra hours not worked by interns and residents, hospitals would have to hire other providers. The cost of using these other workers depends on the type of worker used to substitute for the interns and residents. The study showed that the total direct annual cost nationwide would be up to $1.34 billion using nurse practitioners/physician assistants, $1.64 billion using attending physicians, $820 million hiring additional residents or $1.42 billion using a mixture of substitutes.

The study authors concluded that if the reforms in duty hours are successful at reducing patient errors, then the cost associated with the new rules will be a good value for the money from a societal perspective.

Thursday, September 29, 2011

New Surgical Treatment for Obstructive Sleep Apnea

The most effective treatment for obstructive sleep apnea (OSA) is continuous positive airway pressure (CPAP), which is pressurized air delivered with a mask worn with all sleep. Not every patient tolerates CPAP and numerous surgical alternatives to CPAP have been developed. No surgical treatment works as well as CPAP.

One type of surgery is called genioglossal advancement, which is a fancy way of saying that the base of the tongue is pulled closer to the lower jaw. By doing this, the space behind the tongue is enlarged, meaning that the amount of OSA could be significantly reduced.

Siesta Medical has just received FDA approval for their EncoreTM surgical treatment for OSA - see the picture below. From their website..."The EncoreTM System is used in a minimally invasive surgical procedure where the tongue is suspended forward with the intent of preventing collapse of the airway during sleep. The procedure is performed under local or general anesthesia by Ear, Nose and Throat Specialists, also known as Otolaryngologists. During the procedure, an intra-tissue suture passer is used to place a suspension loop in the tongue which is then attached to the base of the chin with a knotless bone anchor. The EncoreTM System greatly simplifies tongue suspension and provides the surgeon excellent control of positioning and tensioning of the suspension loop."

Monday, September 26, 2011

Insomnia and Depressed Adolescents

Approximately 5 to 6% of adolescents develop depression, and remission rates for treatment are low. Studies have shown that about 3/4 of depressed adolescents have insomnia. Insomnia is known to produce poor outcomes in depressed adults, but studies have not been done on insomnia's effect on depressed adolescents.

Research was presented at the 24th Congress of the European College of Neurospsychopharmacology about adolescents with depression and insomnia. For the study, data was examined from the Treatment for Adolescents with Depression Study. In that study, 439 adolescents (age 12 to 17 years old) were randomized to 12 weeks of treatment with Prozac, psychotherapy, Prozac plus psychotherapy, or placebo.

The results showed that 64% of the participants had insomnia and that those with insomnia had more severe depression at the beginning of the study. Depressed adolescents with insomnia were more likely to report suicidal thoughts and their depressive episodes were more prolonged.

At 6 weeks of treatment, those with insomnia responded less than those without insomnia, but at 12 weeks, the response rate did not differ significantly between the 2 groups. The study authors concluded that insomnia could slow adolescents' response to depression treatment, and that adding insomnia treatments early in the course of depression treatment could speed up recovery.

Thursday, September 22, 2011

Night Owls and Nightmares

I came across an abstract in the August 25th online edition of the journal Sleep and Biological Rhythms about the relationship between nightmares and sleep time preference. Researchers administered questionnaires to 264 medical students, ages 17 to 26 years old. They assessed if the students were morning (morning lark) or evening (night owl) types, the quality of their sleep, and how frequently they experience nightmares.

The results showed that men were more likely than women to be night owls. Night owls were more likely to report poor sleep quality, daytime sleepiness, and distrubing nightmares than morning larks. The authors point out that night owls are more likely to have substance abusers, bulimia, other sleep disorders, ADHD, suicidality, and mood disorders. Also, night owls could have increased stress because of the difficulty holding down a job or attend classess if you are not able to wake up until the late morning. These factors could explain why night owls are more prone to nightmares.

Monday, September 19, 2011

Sleep Disturbance, Blue Light Transmission, and Yellow Lenses

Our biological clocks control important daily activities like sleeping. Sleep scientists have known for years that morning light exposure can regulate our biological clock to the 24 hour cycle. In particular, blue light appears to be the strongest clock stimulator. It tells our brains it's time to be awake by stimulating cells in the back of the eye, which then tell the sleep-wake centers deep in our brains.

As we age, the lenses in our eyes turn more yellow-brown in color - this color change can filter out blue light. This means that less blue light gets in to the back of the eye, so that the brain is not told as strongly when to be awake. This could result in sleep disturbances as older people's body clocks do not follow the typical 24 hour cycle. And, sleep quality has been shown to improve after cataract surgery, which is a replacement of the lens.

In the Sleep Journal, a study was done to examine the relationship between aging lenses in the eye and sleep disturbances. Researchers took 970 people ages 30 to 60 years old and asked them if they often suffer from insomnia or if they had bought prescription medications for sleeping disorders within the past year. A positive response to either inquiry was counted as a "sleep disturbance." The researchers also measured the amount of blue light transmitted through their lenses.

The results showed that 24.4% of the participants had a sleep disturbance. Also, the less blue light transmitted, the higher the risk of a sleep disturbance, even after correcting for age, sex, diabetes, smoking, and risk of ischemic heart disease. The study authors recommend that prescribing physicians reconsider sleep aids in patients that have undergone cataract surgery - they might not need them anymore.

Thursday, September 15, 2011

Insomnia and US Work Performance

Insomnia symptoms are very common and have been associated with workplace deficits. Kessler et al have published results of their study in the Sleep Journal regarding insomnia and its effects on work performance in Americans. The researchers surveyed 7428 employed health plan subscribers by telephone. Insomnia and workplace performance were assessed with validated questionnaires. Comorbid conditions that could decrease workplace performance were also assessed.

The results showed that insomnia occurred in 23.2% of the survey participants. Lost work performance due to insomnia occurred in 20.3% of the sample. About 1/3 of that 20.3% was due to missed days of work with the other 2/3 being low performance at work. These numbers translated to 8 days per year of lost work performance at a cost of $2,280 for each worker with insomnia after controlling for comorbid conditions. At the population level, this means that insomnia is associated with 253 million days of lost work performance at a cost of over $63 billion.

The study authors discussed the relevance of their findings and whether workplace screening and treatment programs for workers with insomnia would be cost-effective from an employer's perspective. The study authors point out that most insomniacs do not seek treatment despite effective treatments like cognitive behavioral therapy. They recommend controlled workplace effectiveness trials to obtain return-on-investment estimates of workplace insomnia interventions.

Thursday, September 8, 2011

Valerian and Insomnia in Post-Menopausal Women

About half of post-menopausal women experience sleep disturbances such as insomnia. In the September issue of the journal Menopause is a study about the effect of valerian on sleep quality in post-menopausal women. There were 100 participants ranging in age from 50 to 60 years old. They were given an insomnia questionnaire, but I do not think they were diagnosed by a sleep physician. They did not have sleep studies.

The women were randomly assigned to take either concentrated valerian extract or a placebo twice daily. It's not clear why the participants were given the medications twice daily. Usually, insomnia medications would be given at or near bedtime only. The results showed that the women who took the valerian reported 30% improvement on their scores on the insomnia questionnaire, compared to only 4% improvement in those taking placebo. The women reported no side effects from valerian.

The study authors concluded that valerian improves sleep quality in post-menopausal women experiencing insomnia. Some caution is warranted here. Other studies have not shown such a dramatic effect for valerian. The women taking the valerian might feel sleepy in the daytime due to taking it twice daily. The women taking placebo would not feel sleepier in the daytime. This could introduce bias, as the women taking the valerian might figure out that the are taking the active medicine and expect to sleep better or just think they are sleeping better, because they are getting the real thing. Valerian is not regulated by the FDA, so you really do not know what you are getting when you buy a bottle off the shelf - the pills might not contain any valerian at all!

Also, these women were not diagnosed with insomnia, but did have poor sleep quality. However, the etiology for the insomnia is not known. Being post-menopausal can decrease sleep quality, but so can obstructive sleep apnea (OSA), and the risk of OSA goes up significantly in women after menopause. So instead of reaching for the valerian (or any other sleep aid), discuss your symptoms with your doctor first.

Deep Sleep, High Blood Pressure, and Elderly Men

There is an abstract in the journal Hypertension from August 2011 about the relationship between sleep stages and development of high blood pressure (a.k.a. HTN). There are three stages of sleep - light non-REM sleep, deep sleep, and REM (a.k.a. dream) sleep. Researchers studied 784 men greater than 64 years old who did not have HTN with an in-home sleep study. After a mean follow up of 3.4 years, 243 developed HTN. Analyses of the results demonstrated that developing HTN was associated with low oxygen levels, increased light non-REM sleep, and decreased deep sleep. After adjusting for age, nonwhite race, study site, and body mass index, only deep sleep was associated with developing HTN. The association was not reduced even after accounting for sleep duration, sleep fragmentation, and severity of sleep-disordered breathing (e.g. obstructive sleep apnea).

The researchers concluded that reduced deep sleep may contribute to adverse blood pressure in men. Unfortunately, the percentage of sleep that is deep sleep normally reduces with age in men and women. At the current moment, there is not a reliable way to increase deep sleep percentage without sleep deprivation or using medications.

Saturday, September 3, 2011

Female Hormone Therapy and Insomnia Symptoms

In the journal Menopause is a study about the effects of stopping hormone therapy on sleep in women going through menopause. Researchers analyzed data from 1405 women (average age 60 years) who were randomized to either continue their hormone therapy, stop it for one month, or stop it for two months. The women filled out sleep questionnaires at the beginning of the study and three months later.

The results showed that compared to the women who continued therapy, those women who stopped therapy for two months reported 46% more days with trouble falling asleep and sleeping poorly, and 31% more days waking too early. The effect on sleep of the one month therapy stoppage was less pronounced but still statistically significant. The results held up even when potentially confounding factors like alcohol use, body mass index, age, race, and ethnicity were taken into account.

The researchers hypothesized that the women who stopped therapy had insomnia symptoms because of a return of vasomotor symptoms like hot flashes. This could be true and I also think there could be another contributor. Female hormones have been shown to improve muscle tone in the upper airway, which could theoretically reduce obstructive sleep apnea. It could be that stopping the female hormones cause the women to experience more insomnia from a worsening of underlying obstructive sleep apnea.

The take home message is that if you are going to stop female hormone therapy, be prepared for potential worsening of sleep quality. Instead of reaching for a sleep aid, discuss your symptoms with your doctor first.

Thursday, September 1, 2011

Insomnia in Cancer Patients

Researchers in Canada assessed 962 patients undergoing cancer surgery for insomnia symptoms and followed them for 18 months. At the time of their surgery, 59% of patients reported insomnia symptoms, with 28% meeting criteria for an insomnia disorder, meaning they took more than 30 minutes to fall asleep at least three times per week. A year and a half later, 36% of study participants reported insomnia symptoms. Insomnia rates were greater in women than men, which reflects what we normally see in the general population.

The etiology of the insomnia was not evaluated in this study, but the findings are important because they bring attention to an important aspect of cancer patients' health. Hopefully, oncologists will include sleep quality in their assessments, and refer those patients with a possible sleep disorder to a sleep center for help.

Monday, August 29, 2011

Predicting Response to Non-Medication Insomnia Treatment


Some insomnia researchers think that chronic insomnia is a disorder of the autonomic nervous system (ANS), the part of our body that controls processes that we generally are not able to consciously control - like heart rate, pupil dilation, etc. It is felt that insomniacs have an overactive ANS that makes it more difficult to sleep. One way to measure the activity of the ANS is by recording the variability of the heart rate. Specifically, the frequency of the heart rate variability has been correlated with ANS activity.

In the August edition of the Journal of Clinical Sleep Medicine, researchers have come up with a non-medication way of treating insomnia. This treatment stimulates the vestibular system, which is part of the inner ear that controls balance. In the current study, they hypothesized that heart rate variability could predict who might respond to vestibular system stimulation.

The researchers studied healthy people over two nights. They slept their normal amount on the first night. But on the second night, they made the subjects go to bed 4 hours earlier to simulate a sleep onset insomnia. Also, the subjects were randomly assigned to receive either one hour of vestibular stimulation or sham therapy on that second night before bed. The results showed that in those subjects who fell asleep faster on the second night with the vestibular treatment had different heart rate variabilities than those that did not respond to vestibular treatment. And this variability was most pronounced in subjects > 35 years old.

The study authors suggest that future research might focus on the relationship between the ANS and insomnia, and how to predict response to various insomnia therapies. This would allow sleep physicians to better treat the various types of insomnia patients - since some respond to medications and some do not. Right now, it's very difficult for us to tell who is going to respond - but the results of the current study are encouraging.

Thursday, August 25, 2011

Urinary Leukotrienes and Pediatric Obstructive Sleep Apnea

Pediatric obstructive sleep apnea (OSA) is on the rise, especially as our children struggle more with obesity. Kids that have enlarged tonsils and/or adenoids are also at risk for OSA. Some researchers believe inflammation plays a role in OSA as well. There is a study in the Sleep Journal about leukotrienes, which are markers of inflammation. The study included 282 children aged 2 to 12 years old who snored regularly at least 4 nights per week. All of the children had sleep studies to check for OSA. On the morning after the sleep study, the researchers measured a specific leukotriene, aka LTE4, in their urine.

The results showed that the more severe the OSA (defined as mild, moderate, or severe), the higher the LTE4 levels. Also, urinary LTE4 levels were higher in the children with OSA that were overweight versus normal weight children with OSA. Finally, there was an association between enlarged adenoids / tonsils and OSA, but only for normal weight children.

The researchers theorized that the broken up sleep and low oxygen levels caused by OSA was linked with the elevated LTE4 levels - and this marker of inflammation was elevated even in mild OSA. However, they were unable to determine if the elevated LTE4 levels come before or after the children developed OSA. The researchers speculated that perhaps medications that block leukotrienes could be used in the management of pediatric OSA, such as in normal weight patients with milder cases.

Monday, August 22, 2011

Pregnancy, High Blood Pressure, and Sleep-Disordered Breathing


Pregnant women snore more and have more nasal congestion than non-pregnant women. And pregant women with high blood pressure (a.k.a. gestational HTN) or pre-eclampsia (a.k.a. gestational HTN with protein in the urine) have even more snoring and nasal congestion. Some studies have suggested that women with getstational HTN or pre-eclampsia have a high prevalence of obstructive sleep apnea (OSA).

In this month's Sleep Journal , there is an article about pregnant women with gestational HTN and OSA. Study participants were at least 18 years old during their first and only pregnancy and had gestational HTN or pre-eclampsia. Controls were matched for gestational age and had no high blood pressure or protein in the urine. Results showed that women with gestational HTN were more obese than controls. There was a higher frequnecy of self-reported regular snoring and nasal congestion in women with gestational HTN vs controls. The women with gestational HTN also reported lower sleep quality but there was no difference in daytime sleepiness between the two groups. Sleep studies showed that women with gestational HTN had less total sleep time, lower sleep efficiency, and a lower percentage of REM sleep than the controls. Finally, 50% of women with gestational HTN had OSA compared to 12% of pregnant women without gestational HTN.

The authors point out that the higher OSA frequency in the women with gestational HTN could be due to the higher obesity rates, as OSA and obesity go hand-in-hand. But these findings are important because even mild OSA can affect blood pressure in non-pregnant patients. And recent data have shown that short-term relief of mild OSA with CPAP can improve blood pressure in pre-eclamptic patients. Therefore, it is important to screen pregnant women with gestation HTN for snoring, sleep quality, and OSA.

Thursday, August 18, 2011

Sleep Apnea and Dementia Risk in Women

In the August 10th edition of JAMA is a study about the relationship of obstructive sleep apnea (OSA) and dementia. Researchers believe that memory can be impaired by untreated OSA, but it's not clear if memory is affected by broken up sleep and/or oxygen level dips as a result of the OSA.

Researchers studied 298 women (average age ~82 years old) without dementia at the start of the study. All of them had a sleep study at the beginning of the study. Interestingly, 105 of them had OSA that was at least moderate in severity. The researchers than tested the women for dementia 5 years after their sleep study.

After adjusting for other variables, the results showed that 31% of the women without OSA and that 45% of the women with OSA developed some form of dementia 5 years after their sleep study. Also, the memory defects were associated with oxygen level dips rather than broken up sleep.

One question raised is if treating the OSA will reduce the risk of getting dementia. Also, will this finding extend to men? More studies are needed to answer those questions.

Monday, August 15, 2011

Fragmented Sleep and Memory


Researchers published a study at the end of July in the Proceedings of the National Academy of Sciences about the effect of sleep fragmentation and memory in mice. Studies have shown memory problems can occur when sleep is frequently disrupted. However, scientists are not sure if the memory problems are due to shorter total sleep time, poor sleep quality, reduction in a particular sleep stage (e.g. dream or REM sleep), or from the annoyance of being repetitively awaken.

In this study, the researchers used a new technique to isolate the effects of sleep fragmentation from overall sleep quality. The mice's brains were prodded awake every 60 seconds for one night, and this resulted in measurable memory problems. The interesting part is that the frequent awakenings did not reduce REM or deep sleep percentages, the total amount of sleep, or appear to cause the mice any stress.

The researchers suggest that new skills and information are committed to memory during sleep when our brains replay recently learned actions or sequences. The frequent awakenings interrupt that process such that the memories can be lost or compromised before they are stored.

Friday, August 12, 2011

Compression Stockings and Sleep Apnea


Chronic venous insufficency is a disorder of the leg veins that can result in fluid accumulation in the legs and ankle swelling. When patients with chronic venous insufficiency lay down at night to sleep, some of the fluid is redistributed to the other parts of the body, including the head and neck. This can cause swelling in the neck, which can increase risk of sleep apnea. In fact, one research group in Italy has shown that in patients with chronic venous insufficiency, OSA severity was linked to the amount of fluid being redistributed from the legs to the neck region overnight.

Compression stockings can be used to treat chronic venous insufficiency. Now, that same Italian research group has just completed another study about using compression stockings to treat OSA. Twelve non-obese patients with OSA and chronic venous insufficiency were randomly assigned to either wear compression stockings for one week or not (the control period). After the week, each patient did the opposite for another week - a.k.a. crossover trial design. The results showed that at the end of the compression stocking-wearing period, there was a 62% reduction in leg fluid volume compared to the control period. There was a 60% reduction in neck circumference. Finally, there was a 36% reduction in the severity of OSA, from 48.4 to 31.3.

These findings are exciting, as chronic venous insufficiency is common with OSA. The results raise some important questions as well. Does the effect persist if compression stockings are worn for longer periods of time? Will other treatments for chronic venous insufficiency also reduce OSA severity? Will the compression stockings work in obese patients, in contrast to the non-obese and relatively healthy patients in this study? Finally, will the use of compression stockings also reduce the clinical signs of OSA like daytime sleepiness?

Monday, August 8, 2011

Children, Sleep, and the Television


I saw this article in the journal Pediatrics. Researchers surveyed about 600 parents about their preschool children's sleep and sleep problems, their TV viewing habits, and the content of television shows. The more TV that children watched in the evening and the more violent content they watched during the day, the more likely they were to experience sleep problems. It did not matter whether the violent programs were animated or live-action, or whether the kids were watching the shows with their parents.

This makes sense to most people. When I watched the Wizard of Oz with my then five year old daughter, she had nightmares that night - my wife said, "Way to go, sleep doctor daddy!" What is even more interesting about this study is that most of the violent content watched was actually children's programming - but these shows were more appropriate for 7 - 12 year olds, rather than preschool age.

Another interesting point about the study was that about 8% of preschoolers with a bedroom TV were tired during the day, compared with only 1% without a TV in their bedroom.

I am a strong believer that kids, especially young ones, should not have electronic devices in their rooms - they make it hard for kids to fall and stay asleep. Also, do not let your preschool children watch scary television - even if you think they can handle it. Stick with shows that have a PG-Y rating.

Friday, August 5, 2011

Crowne Plaza Hotel and Snoring


The Crowne Plaza Hotel chain, owned by InterContinental Hotels Group, recently unveiled a room designed to minimize snoring. The rooms have soundproofed walls and sound-absorbing headboards. A white noise machine is provided in the room. They provide a wedge pillow for the snorer to sleep on - this could reduce snoring some by changing the angle of the upper airway and lessening gravity's affect. Finally, there is an anti-snore pillow which uses magnetic fields to open the airway and stiffen the soft palate. I was all for this until the anti snore pillow with magnets. I've never heard of it and am not sure how the magnets will improves snoring at all. But the other additions should make the snoring less bothersome to the other person.

I would add that ear plugs might help. Minimizing alcohol consumption and other sedating medications before bedtime could reduce snoring. Sleeping on your sides, rather than your back, can reduce snoring in some. And if the snorer has obstructive sleep apnea, they should bring their CPAP with them to the hotel. Both people will sleep better with that.

Wednesday, August 3, 2011

Sleep Apnea, Sleepiness, and Blood Sugar Control


At the Sleep meeting this year in Minneapolis, researchers presented some preliminary data from the GLYCOSA study, which is designed to evaluate the impact of CPAP therapy on blood glucose control in patients with obstructive sleep apnea (OSA) and type 2 diabetes. The data are interesting because of some surprising findings. Researchers think that untreated OSA can make it more difficult for diabetics to control blood sugar - and we thought that the more severe the OSA, as measured by the number of times the patient has apneas each hour of sleep, the worse the blood sugar control.

However, in this study, there was no association between sleep apnea severity and blood glucose control. The surprising finding was that those patients who described themselves as feeling sleepy (based on a standardized scale), were more likely to have poorly controlled blood glucose, even when the researchers controlled for OSA severity, age, sex, race, clinic site, waist size, and body mass index.

Researchers are not able to explain these findings at this time. They do suggest that endocrinologists might be able to screen diabetics who might have poorly controlled blood sugars by assessing their level of sleepiness during office visits.

Monday, August 1, 2011

Communication Technologies and Sleep


There is a review in the journal Sleep Review of modern communication and media technologies and sleep. The National Sleep Foundation did a poll this year about these technologies and how they affect Americans' sleep. They found that 95% of Americans, aged 13 - 64, use some type of electronic device (TV, cell phone, computer, or video game) during the hour before bed. The younger people tended to use more interactive communication media like social networking and video games, whereas the older people tended to watch more television in the hour before bed.

More than half of those who use the cell phone in the hour prior to bedtime leave the phone and the ringer on next to them while they sleep. About 10% said that they were awakened at least a few nights each week due to a phone call, email, or text message. Obviously, these sleep disrupting communication devices can worsen, or even cause, insomnia.

The problem with the interactive media and video games is that these devices tend to be more stimulating, and this can make it more difficult to sleep if these devices are used in the hour before bed. Also, we sit close enough to monitors on laptops and desk tops, that the light from the screen can interfere with melatonin secretion, the hormone that signals your brain that it's night and time for bed. That pre-sleep hour should be relaxing, with only dim light and minimal stimulation.

I see this as a large public health issue, especially with generation Z kids (age 13-18 year olds), who are intertwined with these interactive communication devices. Public education might be able to address this problem, as the right amount of sleep can be so important to mental health, physical health, and overall development.

Thursday, July 28, 2011


An interesting study in the American Journal of Clinical Nutrition about sleep deprivation and calorie consumption. Thirty men and women in their 30's and 40's, all of about normal weight, lived and slept in a research center during 2 different 5-night periods. During one of the visits, participants were allowed to sleep 9 hours each night. During the other 5-night visit, the participants were only allowed to sleep 4 hours per night. During both 5-night periods, they were fed strict diets for the first four days, then allowed to eat whatever they wanted on the fifth day.

The results showed that regardless of the sleep schedule they were on, the participants burned a similar amount of calories, about 2600 calories per day. In those that slept only four hours, they fed themselves about 300 more calories on average on that final day than when they slept 9 hours.

The researchers propose that sleep is involved in how your body manages hormones that are involved in hunger and food choices when you're hungry. The difference between 9 and 4 hours is dramatic, and I wonder if people would eat more calories if they got 5, 6, 7, or 8 hours of sleep? More studies are needed to answer this and other questions about the relationsip between sleep, sleep deprivation, and obesity.

A New Way to Control Pressure in CPAP for Obstructive Sleep Apnea

In the June edition of the Journal of Clinical Sleep Medicine is an article about Fisher & Paykel's SensAwake system. The authors describe how long-term compliance with CPAP varies from 29 to 83%. One of the factors that affects usage is perception of excessive pressure. Many of the new CPAPs have a comfort feature that allows the user to ramp the pressure up from the lowest setting to the prescribed pressure over a certain number of minutes. If a patient wakes in the middle of night, however, they would have to reach over and activate the CPAP ramp again. The SensAwake system allows the CPAP machine to evaluate the breathing patterns of a CPAP user while it is being worn. If the SensAwake CPAP detects a breathing pattern characteristic of being awake, then it automatically lowers the pressure. This will prevent the patient from having to lower the pressure with the ramp manually. The SensAwake will then automatically increase the pressure once it detects breathing patterns consistent with sleep. Thus, SensAwake might reduce the time a patient is awake at night with the CPAP on.

The hope is that the SensAwake will make the CPAP pressure more comfortable (and possibly lower) if and when the user wakes up in the middle of the night. In the study, 42 patients were randomly selected to wear either a regular CPAP or one with SensAwake for the first night in the lab. On the second night in the lab, the patient wore the other type of CPAP. The results showed that there was no difference in the amount of time patients spent awake at night, no difference in the stages of their sleep, and no difference in the patients' perception of therapy between the regular CPAP and the SensAwake one.

These results are not surprising. In my experience, when the overwhelming majority of patients wake in the middle of the night with their CPAP on, they do not complain of the pressure being too high - they report that they can't even tell if the CPAP is on because they have acclimated to the pressure while asleep. Also, a significant amount of patients don't like the ramp feature after they have worn a CPAP for several weeks. So I imagine the SensAwake feature might disturb those patients as well, since it automatically activates the ramp feature.

To be fair to the SensAwake system, this study only measured one night's effects. We need long-term studies to determine its effect on long-term compliance.

Monday, July 25, 2011

Insomnia, Western Medicine, and India

I saw an article in Reuters Health about drug companies pushing western medications in countries like Inida. The article was in reference to a newspaper ad published in India by the pharmaceutical company Abbott. The ad does not mention the drug Abbott makes, but uses a research finding to draw attention to insomnia by "scaring" consumers.

The ad says "research shows that sleeping less than 6 hours per night leads to a 48% increase in developing or dying from heart disease." This research is from a real study, but the underlying message implies that sleeping 6 or more hours will protect from heart disease - which is not necessarily true. There is a link on the ad to a website featuring Abbott's insomnia drug, Zolfresh, which is the same as Ambien. The concern is that this ad will drive demand for insomnia medications, with Indian consumers thinking they may protect their heart if they take a sleeping pill. This isn't necessarily true, as there are several studies showing an increased mortality rate for those taking sleeping pills, even when controlling for other medical diseases.

Apparently, incomes are rising, insurance coverage is expanding, and there is more chronic disease among people of India. This translates into a large, untapped market for pharmaceutical companies. The companies say they are raising awareness of disease and illness by running these ads - perhaps they are. However, on the ad in question, there is no mention of behavioral treatment for insomnia - which would be the preferred treatment modality by most sleep physicians. There are 10 questions that consumers can answer about their sleep. If they answer positive to just one of those, the ad suggests you talk to your doctor. I guess that's a good thing, as long as that doctor is able to do a thorough sleep assessment or refer those patients to sleep physicians.

Thursday, July 21, 2011

Nasal Masks vs. Full-Face Masks During CPAP Titrations

In the July edition of the Sleep Journal is an article about using different types of CPAP masks during CPAP calibration studies. Currently most patients with suspected obstructive sleep apnea (OSA) have the diagnosis confirmed by a sleep study. If that patient will be using CPAP for treatment, than usually the patient spends a second night in the sleep lab to have the CPAP calibrated (or titrated) to the optimal settings while the patient is asleep. During this titration study, the mask(s) used can make a big difference. But, as the study authors point out, there are few studies done to help sleep technologists decide which type of mask to use on the titration study - over the nose (nasal) or over the nose and mouth (FFM) mask.

In this study, researchers randomly assigned 24 patients with OSA to two separate titration nights - one with the nasal mask and the other with the FFM. For the nasal mask titrations, the researchers had the patient wear a chin strap to keep the patient's mouth from opening which would prevent mouth leak. These patients were titrated using "smart" CPAP machines in the lab, which are capable of finding the optimal pressure settings automatically. In other words, these patients' CPAP's were not calibrated manually, as is the standard. This was on purpose to minimize human variability. The final pressure determination though was chosen by a sleep physician after they reviewed the titration study.

The results showed that the optimal pressure chosen by the sleep physician was no different for the nasal vs the FFM. Also, the automatic CPAP chose similar pressures whether it was a nasal or FFM. Fifty-four percent of patients had pressure differences that were less than 2 cm whereas 46% had pressure differences of 2 cm or greater between the two mask types.

Patients also rated nasal masks as better fitting and more comfortable than FFM, which has been my clinical experience. Perceived sleep quality was not different for the nasal mask vs FFM. Titrations done with the FFM, compared to the nasal mask, did have increased mask leak, more mouth dryness, increased residual respiratory disturbance and arousal indexes, decreased slow wave sleep, and decreased total amount of total sleep time on the titration night.

The results of this study support using nasal masks rather than FFM for titration studies. This has been my experience as well. Sometimes, sleep technologists have to use a FFM because the patient has persistent mouth leak on a nasal mask, even with the chin strap. Using the best type of mask may improve CPAP compliance as patients early experiences with CPAP tend to predict long-term usage.

Tuesday, July 19, 2011

Sleep-Disordered Breathing and Polycystic Ovarian Syndrome

An interesting abstract in the Journal of Pediatrics about polycystic ovarian syndrome (PCOS). PCOS is an endocrine disorder that affects the ovaries and produces menstrual abnormalities, excess male hormones, and elevated weight. Since many girls with PCOS are overweight, they are at increased risk of sleep-disordered breathing (SDB) like obstructive sleep apnea, excessive daytime sleepiness (EDS), and the metabolic syndrome.

Researchers studied 103 girls with PCOS and 90 controls, all ages 13-18 years old. Both groups were matched by age, ethnicity, and body mass index (BMI). The results showed that SDB occurred in 46% of the girls with PCOS versus 28% in controls. EDS occurred in 54% of girls with PCOS versus 36% of controls. The metabolic syndrome occured in 43% of girls with PCOS versus 16% of controls.

This means that girls with PCOS have a higher risk of having SDB and EDS than girls without PCOS, regardless of obesity. The researchers suggest that patients diagnosed with PCOS be referred to sleep physicians if they exhibit EDS or other sleep disturbances.

Saturday, July 16, 2011

Better Sleep and Daytime Functioning When Parents Set Bedtimes in Adolescents

There is an interesting article in the June edition of the Sleep Journal about parents setting bedtimes for adolescents, and the impact this can have on sleep and daytime functioning. Many adolescents are sleep-deprived these days due to early school start times, need to complete homework, after school activities like work and sports, and of course, smart phones / TV / video games in the bedroom.

Researchers surveyed 385 adolescents aged 13-18 years old, and 17.5% of them said their parents set their bedtime. Naturally, this was an age dependent finding, with more younger children reporting parent-set bedtimes than older children. But the interesting part was that those children that had parent-set bedtimes went to bed 23 minutes earlier, slept 19 minutes more on school nights, reported less datyime fatigue, and had less trouble staying awake during the day. There was no difference in the reported time it took to fall asleep, whether the parent or adolescent set the bedtime.

The researchers concluded that the findings from this study support the potential benefit of parent limit-setting around bedtimes for adolescents. Of note, the differences in sleep parameters disappeared on the weekends, when parents did not set bedtimes for the adolescents. This further strengthens the positive effect that the parent-set bedtimes had on sleep.

Possible Mechanisms of Central Apneas in Obstructive Sleep Apnea Syndrome

An article in the June edition of the Sleep Journal is about the different types of apneas seen in patients with obstructive sleep apnea syndrome (OSA). This post is going to be on the technical side, so reader beware. There are two main types of apneas. Obstructive ones are the more common type, and occur when the upper airway (or throat) collapse. Central apneas occur when the throat remains open, but there is no breath due to a communication problem between the brain and lungs. An analogy might help explain it better. Imagine our respiratory system is like a garden hose attached to a spigot. If you turn the spigot on, but pinch off the hose, you get little or no water flow - that is like an obstructive apnea. If you turn off the spigot, but leave the hose alone, you get no water flow - that is like a central apnea.

In OSA, patients usually have mostly obstructive apneas, but can occasionally have central ones as well. Researchers are not clear why this occurs. There is speculation that in patients with both types of apneas, there are at least two mechanisms in place. One is that the throats of these patients collapse more easily than individuals without OSA - this leads to the obstructive apneas. The second is that there is an instability in the control of breathing in patients with OSA. What this means is that the brain likes to have a precise level of carbon dioxide (CO2) in the blood - if it gets too high, your brain will make you breathe harder and faster to bring down the CO2 level. If the CO2 level gets too low, your brain makes you breathe less or even not at all to allow the CO2 level to rise up to normal. If you have an obstructive apnea, your lungs are still trying to breathe, but can't due to the closed throat. After the obstructive apnea is over, however, some people's brain overcompensates and breathes too hard and too fast. This reduces the CO2 level and the brain reduces breathing rates to make the CO2 level rise - this compensation can lead to the central apneas seen in OSA.

In this study, researchers studied the differences between patients with OSA that had pure obstructive apneas and no central apneas, and those with predominant obstructive apneas but with some degree of central apneas. Using sophisticated tools, they determined that patients with predominant OSA had more respiratory control instability than those that had pure OSA. In other words, the patients with predominant OSA were more likely to have their spigots turned off. Both groups had the same upper airway collapsibility, so that does not explain why the predominent OSA group has central apneas. These findings could help researchers figure out ways to treat patients that have non-obstructive apneas as part of their OSA syndrome.

Thursday, July 14, 2011

Air Leak and Adherence to Auto-titrating CPAP

In the June edition of the Sleep Journal is an article about the association of air leak and adherence to auto-titrating continuous positive airway pressure (APAP). Before we get to the study, let me explain about APAPs.

Normally, a patient that is suspected to have obstructive sleep apnea (OSA) has an overnight sleep study in the sleep lab. After that, the patient will have to spend another night in the sleep lab to calibrate the CPAP to determine the appropriate settings.

Some sleep centers and other physicians have attempted to shorten the above process. Some use home sleep studies (a separate topic altogether) to make the diagnosis. Instead of a CPAP titration study, they will send the patient home with an APAP that is able to automatically calibrate itself while the patient sleeps at home. Usually this is done for a week or two, then the APAP and patient come back to the clinic where the APAP data is downloaded. The physician can then set the APAP to a fixed, unchangeable pressure that hopefully corresponds to what the pressure would be had the patient been calibrated in the sleep lab initially.

In the current study, researchers set up 96 patients with such a model. Home study / questionnaire diagnosis of OSA followed by a week of APAP and then 5 more weeks of straight CPAP. These patients were not diagnosed or calibrated in a sleep lab. The researchers were interested in the association of air leaks in the APAP systems and APAP compliance. The results showed that larger air leaks during APAP therapy was associated with poor adherence compared to smaller air leaks. The researchers speculated why air leaking might reduce adherence. If the air leak was because of mouth opening, this could cause mouth / throat dryness, which then could decrease compliance. Also, the APAP might not perform as well with a leak in the system, as normally APAP is a closed system under pressure. If the APAP can not respond to the OSA as easily because of the leak, then the APAP might not have been as effective and this could reduce adherence.

One thing the researchers did not mention is the noise level that occurs when the APAP leaks. Normally, an APAP that is not leaking is whisper quiet. But the air leaks can be quite loud, disturbing the patient and a bedpartner. This could lead to reduced compliance.

Tuesday, July 12, 2011

Sleep Duration and Obesity in Children

This post is about a study on childhood sleep duration and obesity in the British Medical Journal. There is alot of interest in determining whether sleep deprivation contributes to obesity in children and adults. Other studies have shown a link, and I have posted about it.

In this study, researchers took annual measurements of children as they aged from 3 to 7 years old. Sleep was measured at home with an actigraph, a form of home sleep study. The children wore the actigraph for 5 consecutive nights at ages 3, 4, and 5 years of age. Dietary intake was assessed over three days at ages 3, 4, and 5 years. It's not clear why sleep and dietary data were not collected for ages 6 and 7. Other data were collected about the children and their families.

The results showed that BMI tended to decrease slightly with age, and the average BMI was not elevated in the children. Average BMI's varied from 16.5 to 17.1, with overweight being defined as BMI 25-30. Data about the average fat mass index was not provided for unclear reasons. The sleep durations, as measured by the actigraph, were very similar across the three age ranges - 3 year olds averaged 11.1 hours per night, 4 year olds averaged 11.0 hours per night, and 5 year olds averaged 11.1 hours per night of sleep.

Stopping right there, and freely admitting I am not a statistician, these numbers seem pretty similar with regard to BMI and sleep duration. However, when the numbers were crunched by the researchers, they concluded that children who sleep less (at ages 3 - 5 years old) have a significantly higher risk of having a higher BMI at age seven, even after adjustments for other risk factors that have been implicated in regulation of body weight. In fact, each additional hour of sleep per night at ages 3 to 5 is associated with a reduction in BMI of 0.49 at age 7. The researchers and I agree that this is a pretty small effect when applied at the individual level. The researchers state that this small difference could become important for public health, when the data are applied to population levels. Also, the differences in BMI were more commonly due to an increase deposition of fat mass, rather than an accumulation of fat free mass (muscle or bone, eg).

This study did not examine the underlying reasons why shorter sleep durations might contribute to obesity. It could be due to hormonal, dietary, or behavioral factors.

Sunday, July 10, 2011

Nasal Steroid Sprays and Pediatric Obstructive Sleep Apnea

Medscape has a review of a study in the June issue of the Archives of Otolaryngology - Head & Neck Surgery about how nasal steroid sprays may improve obstructive sleep apnea (OSA) in children.

Researchers compared the amount of an inflammatory cytokine called interleukin-6 (IL-6) in adenoids removed from children who were treated with a nasal steroid spray to controls who did not receive any nasal spray. The results showed that the adenoid cells released less IL-6 in those children who received the nasal steroid spray. The authors think that reducing IL-6 levels could reduce inflammation in the nasopharynx, which could improve nasal airflow, and consequently improve OSA.

These results are exciting because it could mean that treating nasal airway inflammation with a nasal spray might be an alternative to surgery in treating mild OSA in children.

Friday, July 8, 2011

FAA and Air Traffic Controller Fatige

I saw in the LA Times that the FAA has announced new rules to prevent air traffic controllers from falling asleep on the job. Currently, air traffic controllers caught sleeping on the job, even if on break, can be fired because the agency says that the controllers need to be available for recall at all times. Since April, the FAA said there has been 7 instances of controllers sleeping on the job and 2 others where the controllers did not respond to attempts to contact them.

So the FAA's new plan is that controllers who are sleepy can listen to the radio or read to stay alert during overnight shifts when air traffic is light. The ruling still does not allow the controllers to take naps, even though that would be the most effective way to improve alertness. This makes no sense - if I'm sleepy, reading is probably not going to keep me alert. Physical exercise, napping, and perhaps some caffeine might, but not the radio or reading. I wonder if the American Academy of Sleep Medicine will get involved in this, to help guide the FAA in their attempts to combat controller fatigue.

Wednesday, July 6, 2011

Sleep Extension and Athletic Performance

There is a fascinating article in the July edition of the Sleep Journal about how sleeping longer can improve athletic performance. Sleep researchers have documented how sleep deprivation can negatively impact cognitive performance like memory and reaction time as well as mood. Some sleep deprivation studies have even shown that sleep loss can impair weight-lifting and cardiopulmonary functioning. However, there have been few studies about the effect of sleeping longer on athletic performance. The authors of this study believe that the vast majority of college students, especially athletes, suffer from chronic sleep deprivation due to academic, athletic, and social demands on their time - and this sleep debt could impact athletic performance.

In this study, the 11 subjects were college basketball players at Stanford University. They kept their normal sleep times of 6-9 hours per night for 2-4 weeks at baseline. Researchers than had them extend their sleep duration to a minimum of 10 hours of sleep per night for 5-7 weeks. While traveling, participants were allowed to nap during the daytime if their schedule did not allow them to sleep the full 10 hours at night. The sleep extension aspect occurred during the regular basketball season.

Sleep times were measured subjectively by sleep diaries and objectively by a home sleep monitor worn on the wrist. Athletic performance was measured by a timed sprint and free throw and 3 point accuracy. All performance measures were performed after each regular practice session in the late afternoon. Reaction time was also measured twice daily by a hand-held computer device. Daytime sleepines and mood were recorded with subjective questionnaires.

The results showed that the players increased objective sleep time by 111 minutes during the sleep extension time period. Reaction time improved significantly during the sleep extension portion compared to the baseline. Daytime sleepiness went from a level that is considered borderline sleepy to completely normal during the sleep extension. Mood, self-perception, and subjective performance during practices and games all improved with sleep extension.

The authors pointed out that the athletes were able to fulfill their typical personal, work, and training obligations while also extending their total sleep time, meaning that sleep extension is a realstic option to improve performance. Also, the authors felt that the athletic performance measures (sprint time and shooting accuracy) got better from more sleep, rather than more practice, because they chose performance measures that were very familiar to the athletes and who had become quite proficient at them prior to the onset of the study. The authors did point out that this was a small study with no matched controls.

In conclusion, the results of this study demonstrate that increased sleep durations in college athletes can significantly improve athletic performance, overall well-being, and mental performance. Since the mental aspect to training and competition is so important, the results of this study are even more impressive. Perhaps more sleep will become an integral factor along with nutrition, conditioning, and coaching in enhancing athletic peformance.

Tuesday, July 5, 2011

Impaired Driving Simulator Performance in Treated Obstructive Sleep Apnea

Another interesting article in the June edition of the Journal of Clinical Sleep medicine about driving simulator performance. Studies have shown that untreated obstructive sleep apnea (OSA) impairs driving performance. Studies have also shown that treating OSA with continuous positive airway pressure (CPAP) improves driving simulator performance and reduces accident risk. However, these studies have some methodological limitations, such as driving simulator programs that are too short (less than 20 minutes, for example). Finally, other studies have shown that CPAP treatment may only be partially effective at restoring cognitive function, cortical activation, and daytime sleepiness, meaning that even treated OSA patients could have persistent, impaired driving performance.

The researchers studied patients with severe OSA and healthy controls to see if 3 months of CPAP therapy could improve driving performance in simulators of 90 minutes, similar to a long, country drive. The results showed that patients with untreated severe OSA had impaired driving simulator performance compared to matched controls. And 3 months of CPAP therapy did improve performance, but not to the same level as matched controls. This means that despite adequate treatment for OSA, these patients could be at increased risk for driving accidents compared to drivers without OSA.

As this study was small, it will be interesting to see it repeated in a larger population, as the public health implications could be dramatic.

Friday, July 1, 2011

Truck Drivers and Online Assessment of Obstructive Sleep Apnea

A study done in the June edition of the Journal of Clinical Sleep Medicine describes data from an online self-assessment of obstructive sleep apnea (OSA) done by truck drivers anonymously. Some estimates say that OSA occurs in 1 in 4 commercial drivers. I blogged about this in May.

This study was a web-based survey of the Berlin Questionnaire, a valid screening tool used to assess risk of OSA. The Berlin has three sections - sleepiness, snoring, and body-mass index (BMI) and high blood pressure (HTN). If the Berlin was positive (indicating elevated risk of OSA), the driver was provided a link to a local sleep center for further evaluation.

The results of the survey showed that ~56% of respondents were positive on the Berlin and that 78% were positive on the BMI / HTN section. Seventy percent were obese, defined as a BMI >30. Witnessed apneas were reported in 21% of responders and almost 21% admitted to falling asleep while driving!

The results stress the importance of testing and treating commercial drivers. How to identify those drivers at risk is still being debated. Hopefully we will have some guidelines from the Federal Motor Carrier Safety Administration at the end of this summer.

Wednesday, June 29, 2011

Stillbirths and Sleep

There was a study published in the British Medical Journal about sleep and stillbirth. One hundred and fifty five womean that were at least 28 weeks pregnant were asked questions about sleep position, sleep duration, time of day they sleep, snoring, daytime sleepiness, and urinating at night.

The results show that the risk of still birth is higher when pregnant women sleep on their back or right side, compared to their left side. The researchers think that on the back or right side, blood flow to the fetus might be reduced. Risk of stillbirth was higher in those pregnant women who slept regularly during the day and who slept longer than average at night. Also, there was higher risk of stillbirth in pregnant women who woke up to empty their bladders less than two times per night. Finally, there was no link between snoring, daytime sleepiness, and risk of stillbirth.

This was a small study and relied on women's self-report. Most people are not aware of how much time they sleep in any position, so these results should be interpreted carefully.

Monday, June 27, 2011

Sleeping Positions

Someone forwarded an article to me about the "best" and "worst" sleep positions. The article said that sleeping on your back is best and on your stomach is worst. They stated the "pros" and "cons" of all three positions, most of which I agree with. Of note, most of us change positions a few times each night, whether you remember it or not.

Sleeping on your back can reduce neck and back pain for some. If your head is elevated, back sleeping can decrease acid reflux disease. In theory, back sleeping could reduce wrinkles because gravity pulls your face skin onto your skull. The article also said back sleeping can be more supportive to your breasts, which could reduce breast sagging.

Side sleeping can also help some with neck and back pain, as well as reduce snoring. However, it can increase wrinkles and breast sagging because of the effect of gravity. Also, side sleeping is good for pregnancy, especially in the 2nd and 3rd trimesters.

Finally, stomach sleeping can further reduce snoring, but can exacerbate neck and back pain as the spine is not supported in this position.

Friday, June 24, 2011

Insomnia and Brain Cooling

A research study was presented at the annual Sleep meeting in Minneapolis about treating insomnia by cooling the brain - called frontal cerebral thermal transfer. The study included 24 patients, half with insomnia and half without. The study subjects wore soft, plastic caps with circulating water that could be cooled to different temperatures. The results showed that in those with insomnia that were treated with the maximal cooling temperature fell asleep in 13 minutes and slept 89% of the time they were in bed. This is compared to the subjects without insomnia who fell asleep in 16 minutes and slept for 89% of the time they were in bed.

The researchers do not know why the cooling helps but they do have a theory. People with insomnia have increased metabolism in the front part of their brain. And cooling that part of the brain may reduce metabolism enough to improve sleep quality. This cooling cap could be an alternative to sleeping pills.

Thursday, June 23, 2011

Restless Legs Syndrome and Erectile Dysfunction

A poster was presented at the annual Sleep meeting in Minneapolis involving research about restless legs syndrome (RLS) and erectile dysfunction (ED). Researchers studied 11,000 men with an average age of 64 years old and without ED, diabetes, or arthritis. The results showed that men with RLS were about 50% more likely to develop ED, even after controlling for age, weight, smoking status, antidepressant use, and other chronic diseases. Also, the more frequently the men experienced RLS symptoms, the more likely they were to develop ED. Researchers do not know why RLS and ED are linked, but some theorize that low dopamine levels could be involved. It is believed that low dopamine can contribute to RLS. It would be interesting to study whether medications that improve RLS that affect the brain's dopamine system can also improve ED.

Tuesday, June 21, 2011

Snoring and Carotid Artery Disease

There is an intersting article in the June edition of the Sleep Journal about how snoring damages the lining of carotid arteries, which are the large arteries in our necks that supply blood to the brain.

The authors of this study had already shown that heavy snoring is an independent risk factor for carotid atherosclerosis (hardening of the artery). It was postulated that the vibration from snoring damaged the lining of the walls of the carotid arteries, which than could lead to atherosclerosis.

In this study, researchers put a vibratory sound, similar to human snoring, next to the carotids in anesthetized rabbits for six hours. Just this one time exposure to snoring vibrations damaged the lining of the carotid artery. The results of this study are interesting because prior epidemiologic studies with self-reported snoring have been contradictory with regards to harmful effects of snoring. But it has been arugued that the reliance on self-reported snoring is inaccurate, particularly in the absence of a bed partner to hear the snoring. And objective measurements of snoring have not been a routine part of sleep medicine. The results of this study have public health implications, as snoring is estimated to occur in almost half of the population. If snoring does damage adjacent blood vessels, this could increase stroke risk. Therefore, as a field, perhaps it is time we sleep physicians developed ways to quantify snoring and to take snoring more seriously.

Sunday, June 19, 2011

Exercise, Diabetes, Sleep Apnea, and Death

I saw a report about a study presented at the annual meeting of the Endocrine Society. The study involved male veterans with diabetes and obstructive sleep apnea (OSA). Apparently, good exercise capacity is associated with a lower mortality risk in patients with type 2 diabetes. Also, studies have shown that patients with OSA have an increased mortality risk compared with those without OSA.

In this study, researchers measured the fitness levels of 567 male veterans averaging 62 years old. After taking other risk factors into account, like race, smoking, and medication use, the study results showed that men with low fitness levels had a 75% higher risk of death than those with high fitness levels. The change in death risk was proportional to the fitness level too.

This study is important because diabetes and OSA are both increasing in prevalence, probably a result of the increasing obesity rates. And as weight goes up, fitness levels generally go down. One thing I don't know is if the patients with OSA were being treated with CPAP, which might help lower their death risk, regardless of fitness level.