Category: Obstructive Sleep Apnea

The average academic grades of children and teens with moderate to severe obstructive sleep apnea are worse than the grades of students who have no sleep-disordered breathing, according to a research abstract presented June 8, 2010, in San Antonio, Texas, at SLEEP 2010, the 24^th annual meeting of the Associated Professional Sleep Societies LLC.

Results indicate that moderate to severe obstructive sleep apnea was linked to both lower academic grades and behavioral concerns expressed by parents and teachers. The results remained significant after adjustment for sex, race, socioeconomic status and sleep duration on school nights. Students with moderate to severe sleep apnea averaged a half-letter grade lower than those without any evidence of sleep-disordered breathing. None of the students with moderate to severe OSA had an "A" average, and 30 percent of them had a "C" average or lower. In contrast, roughly 15 percent of participants without sleep-disordered breathing had an "A" average, and only about 15 percent had a "C" average or lower.

"There was an impressive impact of sleep-disordered breathing on academic grades," said principal investigator and lead author Dean W. Beebe, PhD, associate professor of pediatrics in the division of behavioral medicine and clinical psychology at Cincinnati Children's Hospital Medical Center in Ohio. "That leaves the subjects with moderate to severe sleep apnea at a serious disadvantage."

Follow-up tests suggested that OSA was particularly associated with inattention and poor study skills in real-world situations, which could cause functional impairment at school. In contrast, there was no significant link between OSA and office-based tests that measured aspects of neurobehavioral functioning such as intelligence, memory and problem solving.

The study involved 163 overweight children and adolescents between the ages of 10 and 17 years. According to the authors, over­weight subjects were targeted because excessive weight is a primary risk factor for OSA in this age group. Participants' sleep was evaluated by overnight polysomnography, and parents reported whether or not their child snores. Forty-two students had moderate to severe OSA, which was defined as having an apnea-hypopnea index of more than five partial and complete breathing pauses per hour of sleep. Fifty-eight participants had mild OSA with an AHI of one to five; 26 students were snorers with an AHI of less than one and a parent report of snoring; and 37 of the children and teens had no sleep-disordered breathing.

School grades were reported by students and their parents, and student behavior was reported by parents and teachers. Office-based neuropsychological testing was performed to assess neurobehavioral functioning.

Beebe added that the negative effect of OSA on the academic success of children and teens could have ramifications that extend beyond the classroom.

"Academic performance in middle and high school has implications for adult outcomes, including high school graduation, college admission and completion, and adult mental illness and substance abuse," said Beebe. "Similarly, the poor attention and other deficits reported by both parents and teachers of subjects with obstructive sleep apnea raise concerns about the long-term prospects of teens with sleep-disordered breathing."

The study was supported by the American Sleep Medicine Foundation; and the National Heart, Lung, and Blood Institute and National Center for Research Resources of the National Institutes of Health.

Excessive sleepiness is more common in the U.S. than in Europe, which raises concerns for public health and safety, according to a research abstract presented June 8, 2010, in San Antonio, Texas, at SLEEP 2010, the 24^th annual meeting of the Associated Professional Sleep Societies LLC.

Results indicate that 19.5 percent of U.S. adults reported having moderate to excessive sleepiness, which was comparable between men and women. Furthermore, 11 percent of participants reported severe sleepiness, which was more prevalent in women (13 percent) than in men (8.6 percent).

"The prevalence of excessive daytime sleepiness is very high in the American population, much higher than what we observed in the European population," said principal investigator Dr. Maurice Ohayon, professor of psychiatry at Stanford University and director of the Stanford Sleep Epidemiology Research Center in Palo Alto, Calif. In a study published in the June 2002 issue of the journal Neurology, Ohayon reported that the prevalence of excessive daytime sleepiness in five European countries was 15 percent.

"Insufficient sleep is plaguing the American population and is one of the leading factors for excessive daytime sleepiness," Ohayon added.

The study also found that nearly 18 percent of participants reported falling asleep or being drowsy in situations that required a high level of concentration, such as during meetings or conversations. In these situations people with obstructive sleep apnea were three times more likely to be sleepy (odds ratio = 3.0), people with an insomnia diagnosis (OR = 2.6) and those who typically sleep for six hours or less (OR = 2.5) were over two times more likely to be drowsy, and people who perform night work (OR = 1.9) and those with a major depressive disorder (OR = 1.9) were nearly two times more likely to report sleepiness.

These results raise public safety concerns, particularly regarding the potential for workplace injuries and drowsy driving accidents related to excessive sleepiness.

"The number of individuals sleepy or drowsy during situations where they should be alert is disturbing," said Ohayon. "Sleepiness is underestimated in its daily life consequences for the general population, for the shift workers and for the people reducing their amount of sleep for any kind of good reasons. It is always a mistake to curtail your sleep."

The cross-sectional study involved a representa­tive sample of 8,937 people aged 18 or over living in Texas, New York and California. They represented a total of 62.8 million inhabitants. Participants were interviewed by telephone on sleeping habits, health, sleep problems and mental disorders with Sleep-EVAL, a computer program that uses artificial intelligence to simulate some forms of human reasoning and manage specialized knowledge.

The study was supported by the Arrillaga Foundation, the National Institute of Neurological Disorders and Stroke of the National Institutes of Health, and an educational grant from Cephalon.

The American Academy of Sleep Medicine reports that behaviorally induced insufficient sleep syndrome is a form of hypersomnia that occurs when an individual persistently fails to obtain the amount of sleep required to maintain normal levels of alertness and wakefulness. It results from voluntary, yet unintentional, chronic sleep deprivation. Although the amount of nightly sleep needed to maintain daytime alertness varies among individuals, most adults need about seven to eight hours of sleep per night.

Excessive daytime sleepiness also is a symptom of other medical problems, including sleep disorders such as obstructive sleep apnea. OSA is a sleep-related breathing disorder that occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. Shift work disorder involves complaints of insomnia or excessive sleepiness, often accompanied by reduced alertness and impaired mental ability, occurring in relation to work hours that are scheduled during the usual sleep period. Daytime sleepiness also is the primary compliant for other forms of hypersomnia such as narcolepsy.

In an article published in the April 2008 issue of Sleep Medicine Reviews, Ohayon reported that previous studies have shown the prevalence of excessive daytime sleepiness occurring at least three days a week to be between four and 20.6 percent, with a prevalence of five percent for severe excessive daytime sleepiness. Last October the CDC released survey data showing that about 11 percent of respondents reported that they never got enough rest or sleep during the past 30 days.

The prevalence of mild sleep-disordered breathing in young children may fluctuate seasonally, suggests a research abstract presented June 7, 2010, in San Antonio, Texas, at SLEEP 2010, the 24^th annual meeting of the Associated Professional Sleep Societies LLC.

Results indicate that in summer and fall the prevalence of mild sleep-disordered breathing in elementary-school children increased steadily from June (21.6 percent) through September (37.2 percent) and then decreased from September through November (6.3 percent). Controlling for potential confounders such as age, body mass index, gender and race showed that the odds of mild sleep-disordered breathing in every month was significantly lower than in September.

"What surprised us most was the dramatic impact that season had on the prevalence of SDB," said principle investigator Edward Bixler, PhD, professor and vice chair for research in the department of psychiatry at Penn State University in Hershey, Pa. "The results are significant because they underscore the importance of evaluating a child's sensitivity to seasonal allergies when diagnosing and treating a child for SDB."

The study involved a random sample of 687 children in grades K-5. Their parents completed a brief questionnaire, and each child was evaluated between June and November during an overnight sleep study in the sleep laboratory. Mild sleep-disordered breathing was defined as having an apnea-hypopnea index (AHI) of one to five breathing pauses per hour of sleep.

In a study published in the June 2009 issue of the journal SLEEP, Bixler and his research team reported that nasal problems such as chronic sinusitis and rhinitis are significant risk factors for mild sleep-disordered breathing in children. However, the extent to which allergies may promote a seasonal variation in sleep-disordered breathing still needs to be determined.

The researchers added that the results may have implications for the development of pharmacologic treatment strategies for mild sleep-disordered breathing in children.

The study was supported by the National Center for Research Resources and the National Heart, Lung, and Blood Institute of the National Institutes of Health.

The American Academy of Sleep Medicine reports that approximately two percent of otherwise healthy young children have obstructive sleep apnea, a common form of SDB that occurs when soft tissue in the back of the throat collapses and blocks the airway during sleep. Most children with OSA have a history of snoring that tends to be loud and may include obvious pauses in breathing and gasps for breath. Parents often notice that the child seems to be working hard to breathe during sleep.

Obstructive sleep apnea patients had reductions of grey-matter volume at baseline but showed significant grey-matter volume increase after three months of CPAP therapy, according to a research abstract presented June 7, 2010, in San Antonio, Texas, at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC.

Results indicate that obstructive sleep apnea patients showed focal reductions of grey-matter volume at baseline in the left hippocampus, posterior parietal cortex and right superior frontal gyrus. Significant grey-matter volume increases were observed after three months of continuous positive airway pressure therapy in hippocampal and frontal structures. No further improvement in gray-matter volume was observed after one year of CPAP therapy.

"OSA patients showed cognitive impairment associated with neurostructural damage affecting specific cerebral regions," said principal investigator Vincenza Castronovo, PhD, clinical psychologist and psychotherapist and sleep laboratory coordinator at the University Vita-Salute San Raffaele and San Raffaele Scientific Institute in Milan, Italy. "In addition, we show that most of the neuropsychological deficits are reversed after three months of treatment with CPAP and, for the first time, that such cognitive improvements parallel an increase of grey-matter volume in specific hippocampal and frontal brain regions. The increase of grey-matter volume in these regions is significantly correlated with the improvement at neuropsychological tests of executive functioning and short-term memory."

The study involved 17 patients with an apnea-hypopnea index (AHI) greater than 30 (i.e., more than 30 breathing pauses per hour of sleep), indicating severe obstructive sleep apnea. They were compared with 15 healthy controls. Brain scans were conducted by 3 Tesla magnetic resonance imaging (MRI), and a processing technique called "voxel-based morphometry" (VBM) was used to characterize regional cerebral volume and tissue concentration differences in gray matter by examining the entire brain. VBM increasingly is being used as a tool to examine patterns of brain change in healthy aging or neurodegenerative disease, as well as neuroanatomical correlates of behavioral or cognitive deficits and skills.

Castronovo added that measuring neuropsychological performance may help physicians assess OSA patients for treatment effectiveness.

"Our results also suggest that specific neuropsychological measures are valuable tools for the assessment of therapy success and can offer to patients and physicians the evidence that adherence to treatment can lead not only to clinical but also to brain-structural recovery," she said.

The National Institute of Neurological Disorders and Stroke reports that "gray matter" refers to the cerebral cortex, where the brain does most of its information processing. The cortex is a layer of tissue that has a gray-colored appearance because it lacks the myelin insulation that gives most other parts of the brain a white appearance.

According to the American Academy of Sleep Medicine, OSA is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe. It occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing that can produce abrupt reductions in blood oxygen saturation and reduce blood flow to the brain. Most people with OSA snore loudly and frequently, and they often experience excessive daytime sleepiness.

The treatment of choice for OSA is CPAP therapy, which provides a steady stream of air through a mask that is worn during sleep. This airflow keeps the airway open to prevent pauses in breathing and restore normal oxygen levels. Help for OSA is available at more than 2,000 AASM-accredited sleep disorders centers across the U.S.

Last year Castronovo reported that there was a large overlap in the pattern of brain activity in men with OSA and healthy controls during a working-memory task. But some regions were less active in men with untreated OSA, while additional brain regions such as the hippocampus showed increased activation. Then after three months of CPAP therapy, men with OSA showed decreases in the activation of the left inferior frontal gyrus and anterior cingulate cortex, and bilaterally in the hippocampus. The study, published in the September issue of the journal Sleep, supports the "compensation hypothesis," suggesting that the brain "recruits help" to maintain performance and compensate for the neural dysfunction caused by OSA.

A South Korean study published in the February 2010 issue of the journal Sleep found gray matter concentration deficits in multiple brain regions of newly diagnosed men with severe OSA, including limbic structures, prefrontal cortices and the cerebellum. In the March 2009 issue of the Journal of Sleep Research, a French study reported finding gray matter loss in multiple regions, including the thalamus, hippocampus and cerebellum.

According to new research presented on June 5, at the 19th Annual Meeting of the American Academy of Dental Sleep Medicine, the majority of U.S. dental schools have not adequately prepared their graduates to screen for sleep disorders, which affect more than 70 million adults in the U.S.

Researchers from the University of California — Los Angeles (UCLA) School of Dentistry surveyed each of the 58 U.S. dental schools to determine the average number of curriculum hours offered in dental sleep medicine (DSM). DSM focuses on the management of sleep-related breathing disorders, such as snoring and obstructive sleep apnea (OSA), with oral appliance therapy (OAT) and upper-airway surgery.

Forty-eight schools responded to the survey, indicating that dental students spend an average of 2.9 instruction hours during their four years of dental school studying sleep disorders.

According to lead author Michael Simmons, DMD, D. ABOP, part-time instructor at both UCLA and USC, sleep medicine is being introduced at the majority of U.S. dental schools, but the total hours taught are inadequate given the epidemic proportion of people with OSA.

More than 18 million Americans suffer from OSA. An estimated 80 to 90 percent of patients with OSA are undiagnosed and more go untreated. Untreated sleep apnea can raise a patients' risk for heart attack, stroke, hypertension, diabetes, and obesity, among other health problems and premature death.

The survey asked which sleep topics were taught, which treatments were covered, and which departments were responsible for the teaching of dental sleep medicine.

Results show that classroom topics covered diagnosis of obstructive sleep apnea, sleep bruxism, snoring and upper-airway resistance syndrome, and treatments including oral appliance therapy, continuous positive airway pressure and surgery. Eight schools also discussed at-home sleep tests, which dentists can use to monitor treatment success.

Oral Surgery, TMJ/Orofacial Pain, Oral Medicine, Prosthodontics, and Orthodontics, were the most common academic departments that taught sleep medicine. The researchers were surprised by the variety of dental departments teaching sleep disorders, and that DSM could not be attributed to any particular discipline.

The authors suggest that because dentists see patients on a regular basis, they can notice early warning signs of sleep disorders.

"Dental students and dentists need to screen for sleep-related breathing disorders as part of patients' routine work-ups. Then, with additional interest and adequate training, they can learn to co-treat these serious medical conditions with their patients' physicians as an integral part of the sleep medicine team," said Simmons.

— Sleep disorders are common among bus and tram drivers in Gothenburg, Sweden: a quarter say that they have problems with daytime sleepiness, which could affect safety. Such are the results of a new study from the Sahlgrenska Academy at the University of Gothenburg, Sweden, presented at the annual Swedish Sleep Medicine Congress in Gothenburg on 21-23 April.

The third annual Swedish Sleep Medicine Congress, organised by the Swedish Sleep Research and Sleep Medicine Society (SFSS), was recently held in Gothenburg, Sweden. Around 250 researchers, doctors and invited guests from around the world took part in the congress, which ran from 21 to 23 April. A number of new research findings which could lead to improved treatment and diagnosis of various sleep disorders were presented at the congress, as well as new knowledge about sleep mechanisms, our biological clock and the impact of sleep disorders on society in general.

Among the speakers were scientists from the Sahlgrenska Academy reporting on their latest research results, including Mahssa Karimi, a doctoral student from the Center for Sleep and Vigilance Disorders. Her research project looked at the incidence of sleep disorders in 116 bus and tram drivers in Gothenburg. The study found that 23% have problems with pronounced daytime sleepiness, 28% have trouble getting to sleep, 29% suffer from restless legs, and 19% have sleep apnea (pauses in breathing while asleep which can result in tiredness and difficulty concentrating during the day).

"We looked more closely at the drivers with sleep apnoea because previous studies have shown that these patients run a clearly increased risk of accidents due to drowsiness," says Karimi. The drivers with sleep apnea were treated with a CPAP machine, where a breathing mask is used to maintain a positive pressure in the airways, keeping them open and so preventing snoring and apnea while asleep. "The study showed that these drivers stopped having apnea episodes during the night and also had significantly lower blood pressure and, above all, greatly reduced daytime sleepiness," says Karimi.

The researchers had to actively look for sleep disorders in the group of professional drivers who had not already sought medical assistance for their problems. They found a large number of sleep disorders in these drivers which in many cases significantly affected their alertness and concentration. When the drivers received treatment for these disorders, there was a clear improvement.

"Our findings suggest that it's important to systematically examine professional drivers and other professional groups entrusted with the safety of others in order to be able to treat any sleep disorders, as their work demands alertness and concentration at all times," says Karimi.

A study in the April 15 issue of the Journal of Clinical Sleep Medicine shows that having a sleep disturbance is associated with clinically meaningful reductions in health-related quality of life, and the magnitude of this effect varies by race and sleep disorder.

Results indicate that physical health-related quality of life in African-Americans who snored frequently, had insomnia symptoms or reported excessive daytime sleepiness was significantly worse than in Caucasians. African-Americans with insomnia also had significantly more physical limitations than Hispanics. However, when mental health-related quality of life was evaluated, it was Hispanics with frequent snoring, insomnia symptoms or excessive daytime sleepiness who had significantly greater mental distress than Caucasians. African-Americans with insomnia also had significantly worse mental health than Caucasians.

"The study highlights the increased disparities among African- and Latino-Americans compared with Caucasians even in the sleep and health-related quality of life domain," said lead author Carol M. Baldwin, PhD, RN, FAAN, Southwest Borderlands Scholar and director of the Center for World Health Promotion and Disease Prevention in the College of Nursing and Health Innovation at Arizona State University in Phoenix, Ariz.

The study involved a secondary analysis of data from the Sleep Heart Health Study, a multi-center study that recruited participants from seven regions of the U.S. Eighty-six percent of the 5,237 people in the current study were Caucasian, nine percent were African-American and five percent were Hispanic. The Hispanic participants were predominantly of Mexican heritage residing in Arizona, with a smaller number of Puerto-Rican participants from the New York cohort. All participants were 40 years of age or older, and their mean age was 63.5 years.

The presence of obstructive sleep apnea was detected by overnight, in-home polysomnography. Snoring and insomnia — defined as trouble falling asleep, staying asleep or waking too early — were assessed using the Sleep Habits Questionnaire. The Epworth Sleepiness Scale was used to evaluate daytime sleepiness.

Health-related quality of life was assessed with the physical and mental composite scales of the Medical Outcomes Study 36-item short form survey. According to the authors, low scores on the physical scale suggest limitations in self-care and physical activities, severe bodily pain and frequent tiredness. A low score on the mental scale indicates frequent psychological distress, as well as social and role disability due to emotional problems.

The study found that sleep disturbances were common, with 46 percent of people having at least mild sleep apnea, 34 percent reporting frequent snoring, 30 percent having insomnia symptoms and 25 percent reporting excessive daytime sleepiness. Frequent snoring was significantly more common among Hispanics (41 percent), and excessive daytime sleepiness was significantly more common among African-Americans (32 percent). There were no statistically significant differences in the distribution of obstructive sleep apnea or insomnia symptoms by race.

According to Baldwin, the study could help reduce health disparities and improve outcomes by advancing "tailored care" in sleep medicine.

"These findings support the need for sleep clinicians to use culturally-responsive sleep education, assessment and intervention approaches, as well as depression, anxiety and other relevant mood and socioeconomic-status measures," she said.

The authors cautioned that the correlational nature of the study did not allow for an analysis of causality. Baldwin added that the causes of differences in health-related quality of life can be complex and may include such factors as lifestyle and activity patterns, diet, sleep architecture and access to health care.

However, the study suggests that the impact of sleep disorders on daily living and general well-being may be similar to that of other chronic conditions. The mean score profiles for health-related quality of life in people with sleep apnea and other sleep symptoms were similar to those that have been previously reported for patients with hypertension and type 2 diabetes.

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Journal Reference:

1. Carol M. Baldwin, Ann-Margret Ervin, Mary Z. Mays, John Robbins, Shirin Shafazand, Joyce Walsleben, Terri Weaver. Sleep Disturbances, Quality of Life, and Ethnicity: The Sleep Heart Health Study. Journal of Clinical Sleep Medicine, 2010; 6 (2): 176-183 [link]

Obstructive sleep apnea is associated with an increased risk of stroke in middle-aged and older adults, especially men, according to new results from a landmark study supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health.

Overall, sleep apnea more than doubles the risk of stroke in men. Obstructive sleep apnea is a common disorder in which the upper airway is intermittently narrowed or blocked, disrupting sleep and breathing during sleep.

Researchers from the Sleep Heart Health Study (SHHS) report that the risk of stroke appears in men with mild sleep apnea and rises with the severity of sleep apnea. Men with moderate to severe sleep apnea were nearly three times more likely to have a stroke than men without sleep apnea or with mild sleep apnea. The risk from sleep apnea is independent of other risk factors such as weight, high blood pressure, race, smoking, and diabetes.

They also report for the first time a link between sleep apnea and increased risk of stroke in women. Obstructive Sleep Apnea Hypopnea and Incident Stroke: The Sleep Heart Health Study, was published online March 25 ahead of print in the American Journal of Respiratory and Critical Care Medicine.

Stroke is the second leading cause of death worldwide. "Although scientists have uncovered several risk factors for stroke — such as age, high blood pressure and atrial fibrillation, and diabetes — there are still many cases in which the cause or contributing factors are unknown," noted NHLBI Acting Director Susan B. Shurin, M.D. "This is the largest study to date to link sleep apnea with an increased risk of stroke. The time is right for researchers to study whether treating sleep apnea could prevent or delay stroke in some individuals."

Conducted in nine medical centers across the United States, the SHHS is the largest and most comprehensive prospective, multi-center study on the risk of cardiovascular disease and other conditions related to sleep apnea. In the latest report, researchers studied stroke risk in 5,422 participants aged 40 years and older without a history of stroke. At the start of the study, participants performed a standard at-home sleep test, which determined whether they had sleep apnea and, if so, the severity of the sleep apnea.

Researchers followed the participants for an average of about nine years. They report that during the study, 193 participants had a stroke — 85 men (of 2,462 men enrolled) and 108 women (out of 2,960 enrolled).

After adjusting for several cardiovascular risk factors, the researchers found that the effect of sleep apnea on stroke risk was stronger in men than in women. In men, a progressive increase in stroke risk was observed as sleep apnea severity increased from mild levels to moderate to severe levels. In women, however, the increased risk of stroke was significant only with severe levels of sleep apnea.

The researchers suggest that the differences between men and women might be because men are more likely to develop sleep apnea at younger ages. Therefore, they tend to have untreated sleep apnea for longer periods of time than women. "It's possible that the stroke risk is related to cumulative effects of sleep apnea adversely influencing health over many years," said Susan Redline, M.D., MPH, professor of medicine, pediatrics, and epidemiology and biostatistics, at Case Western Reserve University in Cleveland and lead author of the paper.

"Our findings provide compelling evidence that obstructive sleep apnea is a risk factor for stroke, especially in men," noted Redline. "Overall, the increased risk of stroke in men with sleep apnea is comparable to adding 10 years to a man's age. Importantly, we found that increased stroke risk in men occurs even with relatively mild levels of sleep apnea."

"Research on the effects of sleep apnea not only increases our understanding of how lapses of breathing during sleep affects our health and well being, but it can also provide important insight into how cardiovascular problems such as stroke and high blood pressure develop," noted Michael J. Twery, Ph.D., director of the NIH National Center on Sleep Disorders Research, an office administered by the NHLBI.

The new results support earlier findings that have linked sleep apnea to stroke risk. SHHS researchers have also reported that untreated sleep apnea is associated with an increased risk of high blood pressure, heart attack, irregular heartbeats, heart failure, and death from any cause. Other studies have also linked untreated sleep apnea with overweight and obesity and diabetes. It is also linked to excessive daytime sleepiness, which lowers performance in the workplace and at school, and increases the risk of injuries and death from drowsy driving and other accidents.

More than 12 million American adults are believed to have sleep apnea, and most are not diagnosed or treated. Treatments to restore regular breathing during sleep include mouthpieces, surgery, and breathing devices, such as continuous positive airway pressure, or CPAP. In people who are overweight or obese, weight loss can also help.

These treatments can help improve breathing and reduce the severity of symptoms such as loud snoring and excessive daytime sleepiness, thereby improving sleep-related quality of life and performance at work or in school. Randomized clinical trials to test whether treating sleep apnea lowers the risk of stroke, other cardiovascular diseases, or death are needed.

"We now have abundant evidence that sleep apnea is associated with cardiovascular risk factors and diseases. The next logical step is to determine if treating sleep apnea can lower a person's risk of these leading killers," said Redline. "With stimulus funds, our research group is now developing the additional research and resources to begin answering this important question."

Through funding from the American Recovery and Reinvestment Act, the NHLBI is awarding approximately $4.4 million to Redline to conduct the first NIH-funded comparative effectiveness study of treatments for sleep apnea. In the two-year multi-center pilot study, SHHS researchers and others will compare the cardiovascular effects of adding either CPAP or supplemental oxygen during sleep to standard care in patients with moderate to severe sleep apnea who are at high risk for cardiovascular disease events such as heart attack or stroke.

The SHHS draws on a resource of existing, well‑characterized and established cohort studies of cardiovascular and lung diseases supported by the NHLBI. A cohort is a well‑defined group of participants who share a common background or characteristic and are being followed for an extended length of time. For this study, SHHS researchers add assessment of sleep to data collection in ongoing studies including the Atherosclerosis Risk in Communities (ARIC) Study sites in Washington County, Md., and Minneapolis; the Cardiovascular Health Study (CHS) sites in Sacramento, Calif., Washington County, Md., and Pittsburgh; the Framingham Offspring and Omni cohorts in Framingham, Mass.; the Health and Environment and Tucson Epidemiologic Study cohorts in Tucson, Ariz.; the Strong Heart Study sites in Arizona, Oklahoma, and South Dakota; a Reading Center at Case Western Reserve University in Cleveland, Ohio; and the University of Washington in Seattle (Coordinating Center 1994‑1999). The Johns Hopkins University Bloomberg School of Public Health serves as the Coordinating Center.

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Journal Reference:

1. S. Redline, G. Yenokyan, D. J. Gottlieb, E. Shahar, G. T. O'Connor, H. E. Resnick, M. Diener-West, M. H. Sanders, P. A. Wolf, E. M. Geraghty, T. Ali, M. Lebowitz, N. M. Punjabi. Obstructive Sleep Apnea Hypopnea and Incident Stroke: The Sleep Heart Health Study. American Journal of Respiratory and Critical Care Medicine, 2010; DOI: 10.1164/rccm.200911-1746OC

 A British study finds that the condition known as floppy eyelid syndrome (FES) is strongly associated with obstructive sleep apnea (OSA), implying that when doctors see FES in a patient, they should also look for OSA, and vice-versa.

The study, published in April's Ophthalmology, the journal of the American Academy of Ophthalmology, describes factors shared by OSA and FES and specific findings on how FES develops that will help doctors better diagnose and treat patients.

People with OSA face several health challenges-at worst, they are at risk of dying of oxygen deprivation when breathing slows or stops during sleep. OSA can contribute to or be aggravated by high blood pressure, diabetes, obesity and other systemic problems. Researchers led by Daniel G. Ezra, MD, MRCOphth, of Moorfields Eye Hospital, London, England, found the strong OSA-FES association in a case-controlled study of 102 patients tracked between 1995 and 2008; 102 matched controls were also tracked.

"About one-third (32 of 102) FES patients in our study also had OSA," Dr. Ezra said. "The significant association of the two disorders was evident even when we considered and controlled for patients' body-mass index (BMI, an indicator of whether obesity was a factor). FES is often considered a disease of overweight, middle-aged men, but our study did not find a patient cluster based on age, gender or BMI," he added.

People with FES have rubbery-textured upper eyelids that may easily flip up during sleep, exposing the "whites of the eyes," which can lead to dry, irritated eyes and/or discharge. The Moorfields research and other studies suggest that central nervous system arousal may be impaired in OAS suffers, so they do not wake up as people normally do when breathing slows or stops, or when the eyelid is subjected to extreme stress. People with OSA often preferentially sleep on one side, which could result in intense, repeated pressure on the eyelid on that side of the face. A combination of these factors may contribute to or cause FES. The Moorfield report notes that FES resolved in an OSA patient who was treated with a continuous positive airway pressure mask.

Also, the Moorfields study confirms earlier findings that FES is associated with keratoconus, in which the cornea thins out and becomes cone-shaped. Patients with FES often rub their eyes excessively, perhaps contributing to keratoconus. Eye M.D.s (ophthalmologists) should recognize that visual problems in patients with FES may be due to keratoconus- rather than dry eye disease or other surface irritation-and treat them accordingly, the researchers say.

In a separate study, Dr. Ezra and colleagues followed 78 FES patients who had had been treated surgically for FES at Moorfields Eye Hospital within a 13 year period that began in 1995. Of the surgical methods used, better outcomes resulted for the procedures known as medial and lateral canthal placation, and upper lid lateral tarsal strip. But outcomes for all procedures were less favorable than reported in earlier studies; the Moorfields study attributes this difference to their study's longer follow-up period.

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Journal References:

1. Daniel G. Ezra, Michèle Beaconsfield, Mano Sira, Catey Bunce, Richard Wormald, Richard Collin. The Associations of Floppy Eyelid Syndrome: A Case Control Study. Ophthalmology, 2010; 117 (4): 831 DOI: 10.1016/j.ophtha.2009.09.029
2. Daniel G. Ezra, Michèle Beaconsfield, Mano Sira, Catey Bunce, Sabrina Shah-Desai, David H. Verity, Jimmy Uddin, Richard Collin. Long-term Outcomes of Surgical Approaches to the Treatment of Floppy Eyelid Syndrome. Ophthalmology, 2010; 117 (4): 839 DOI: 10.1016/j.ophtha.2009.09.009

A study in the Feb. 15 issue of the Journal of Clinical Sleep Medicine shows that patients with severe obstructive sleep apnea (OSA) report a significantly lower frequency of nightmares than patients with mild or no sleep apnea, indicating that OSA suppresses the cognitive experience of nightmare recall.

Results show that the percent of participants with frequent nightmare recall decreased linearly as sleep apnea severity increased. Frequent nightmare recall, occurring at least weekly, was reported by 71.4 percent of people who did not have OSA and 43.2 percent of patients with mild OSA, which was defined as an apnea-hypopnea index (AHI) of five to less than 15 breathing pauses per hour of sleep. The rate of frequent nightmare recall decreased to 29.9 percent in patients with moderate OSA (AHI of 15 to less than 30) and 20.6 percent in patients with severe OSA (AHI of 30 or more). Sleep apnea severity in people who reported infrequent nightmare recall (mean AHI of 40.3) was significantly higher than in those who frequently recalled nightmares (mean AHI of 24.6).

According to principal investigator Jim Pagel, M.S., M.D., associate clinical professor at the University of Colorado Medical School system and director of the Sleep Disorders Center of Southern Colorado in Pueblo, the decline in frequency of nightmare recall may be attributed to the sleep fragmentation that is caused by OSA. This leads to a reduction in the amount of rapid eye movement (REM) sleep, which is the sleep stage when nightmares generally occur.

"The results were somewhat surprising, since nightmares are frequently reported by patients with sleep apnea," said Pagel. "It is plausible that patients who successfully utilize continuous positive airway pressure (CPAP) therapy see an increase in the frequency of nightmares, as treatment increases the amount of REM sleep per night."

According to the American Academy of Sleep Medicine, nightmares are coherent dream sequences that seem real and become increasingly more disturbing as they unfold. Emotions usually involve anxiety, fear or terror, and dream content most often focuses on imminent physical danger or other distressing themes. Nightmares may result in post-awakening anxiety and difficulty returning to sleep. Approximately 50 percent to 85 percent of adults report having at least an occasional nightmare, and about two percent to eight percent of the general population have a current problem with nightmares.

This retrospective study involved 393 consecutive patients who were evaluated by overnight polysomnography at the Sleep Disorders Center of Southern Colorado over a two-year period. Their mean age was 50.5 years with a range of 13 to 82 years, and 67 percent of participants were male. The mean AHI was 34.9, indicating a high frequency of severe OSA.

Questions concerning dream and nightmare recall frequency were incorporated into a general sleep questionnaire. Dream and nightmare recall were classified as infrequent when reported once a month or less, or frequent when reported at least weekly. About 52 percent (205 people) reported frequent dream recall, and 34 percent (134 people) reported frequent nightmare recall. Analysis confirmed that dream recall and nightmare recall were not associated.

The authors noted that the study clearly demonstrates that increasingly severe OSA has a much greater negative effect on reported nightmare recall frequency than it does on reported dream recall.

About OSA

According to the American Academy of Sleep Medicine, OSA is a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe. It occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing that can produce abrupt reductions in blood oxygen saturation. Most people with OSA snore loudly and frequently, and they often experience excessive daytime sleepiness. The treatment of choice for OSA is CPAP therapy, which provides a steady stream of air through a mask that is worn during sleep. This airflow keeps the airway open to prevent pauses in breathing and restore normal oxygen levels.

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Journal Reference:

1. Jim Pagel et al. The Nightmare of Sleep Apnea: Nightmare Frequency Declines with Increasing Apnea Hypopnea Index. Journal of Clinical Sleep Medicine, (in press)