Deep Sleep Plays Role In Visual Learning

A relationship has been observed between deep sleep and the ability of the brain to learn specific tasks. Researchers at Brigham and Women's Hospital (BWH) have now shown that the processes that regulate deep sleep may affect visual learning.
"These findings show that deep sleep is important for visual learning and possibly the ability of the brain to learn new tasks," said Daniel Aeschbach, researcher in the Division of Sleep Medicine at BWH and lead author of the study.
Deep sleep, also called slow wave sleep, is a period of non-rapid-eye-movement sleep when very large brain waves, called slow waves, can be observed in the EEG, which is a recording of the brain waves. Slow waves are thought to reflect the need for sleep, but their exact function is unknown. Researchers sought to determine the function of these waves in visual learning.
Aeschbach and colleagues trained healthy subjects on a visual learning task in which they were required to determine on a computer screen the orientation of a few dashes that were embedded in a field of horizontal dashes. Subjects were tested on their accuracy of performing this task before and after they had slept for a period of four hours. One group of subjects slept normally, with no interruptions, and their visual skill in performing the task improved after sleep. In another group, researchers suppressed the occurrence of slow waves by playing targeted acoustic tones while subjects were asleep. The tones did not wake the subjects, but prevented them from slipping into deep sleep as monitored on the EEG. This group was also tested in the visual task after sleep and their skill did not improve.
Researchers suggest that these findings could have clinical implications for conditions like depression and insomnia, as well as aging, which are associated with learning deficits and also a reduction of deep sleep.
This research was funded by awards from the National Alliance for Research on Schizophrenia and Depression, the Milton Fund of Harvard University, and the National Institutes of Health.

Obstructive sleep apnea taking disease pattern

A study in the Dec. 15 issue of the Journal of Clinical Sleep Medicine is the first to show the full clinical picture of comorbid conditions associated with obstructive sleep apnea (OSA), quantify their frequency of occurrence and reveal their possible interrelationships.
Results show that the number of cases of Obstructive sleep apnea peaks between the ages of 0-4 years, is low during adolescence, and then rises from 25-29 years to a peak at 55-59 years. The rates are slightly higher for girls than boys in the 0-4 age group (9.4% and 6.7%) and the 5-9 age group (6.0% and 3.9%), and the occurrence rate in males is higher than in females after 20-24 years of age.
According to the study's co-author,Chin Moi Chow , PhD, Senior of health sciences, at the University of Sydney, this study will have a significant impact on the understanding of the disease pattern of Obstructive sleep apnea and conditions associated with it.
"This research provides a clinical picture of Obstructive sleep apnea from over six million hospital admissions of all medical conditions and those associated with OSA, and describes its occurrences according to age and gender groups," Chow said.
Findings indicate that Obstructive sleep apnea patients are high users of health-care services, with comorbid conditions most often involving cardiovascular diseases, endocrine/metabolic diseases (mainly diabetes) and respiratory diseases. Comorbid conditions most frequently appearing with OSA in adults are essential hypertension, obesity, hypercholesterolemia, type 2 diabetes, past or current tobacco use, and ischemic heart conditions.
Data plotting shows that the onset and peak occurrences of obesity and OSA are identical. From obesity onset there is a latent period of five years for the development of hypertension and type 2 diabetes and 15 years for chronic ischemic heart conditions.
A random dataset from the years 1999 through 2004 was extracted using a Health Outcomes and Information Statistical Toolkit. The data set was a representative collection of hospital records in the Inpatient Data Collection System of New South Wales, the most populated Australian state. The data included patient records from 278 public hospitals and 180 private hospitals.
The extracted dataset contained a total of 1.51 million hospital records. Four percent of all records – representing 60,197 patients - had a principal or secondary diagnosis of Obstructive sleep apnea, with a male to female ratio of 2.6:1. The authors report that previous knowledge of disease associations with OSA was fragmented and did not explain possible interrelationships between comorbid diseases. The data mining technique was used to provide the full clinical picture of comorbid conditions associated with Obstructive sleep apnea.

MRI May Help Reduce Effects Of Sleep Apnea

Using cardiac magnetic resonance imaging, Ohio State University Medical Center researchers are able to assess the effects of a common treatment for sleep apnea on heart structure and function in otherwise healthy individuals.
“Little data exists on continuous positive airway pressure’s therapeutic effects on the heart’s right side, so we are leveraging the advantages of imaging to see if the treatment helps these patients,” says Dr. Ulysses Magalang, medical director of Ohio State’s Sleep Disorders Center and first author of the study that appears in the Journal of Clinical Sleep Medicine.
Researchers found that continuous positive airway pressure therapy improves heart structure with improvements in the volume of the right ventricle.
“By getting clear pictures of the heart in these patients, we were able to better understand the cardiovascular consequences of obstructive sleep apnea. These results can be used to guide treatments to reduce death and disability due to heart disease,” says Dr. Subha Raman, medical director of the cardiac magnetic resonance and computerized tomography program at Ohio State’s Richard M. Ross Heart Hospital, and also senior author of the study.
Drs. Magalang and Raman recently collaborated on a study published in the journal Experimental and Clinical Endocrinology & Diabetes showing a possible link between sleep apnea and heart disease, which is the leading cause of death responsible for 29 percent of people worldwide. The researchers identified a substance that may prevent atherosclerosis.
Affecting approximately 12 million Americans, obstructive sleep apnea is a condition in which breathing is interrupted for brief periods during sleep. These repetitive disruptions, known as intermittent hypoxia, occur when oxygen levels drop below normal levels.
Continuous positive airway pressure therapy is administered by a device that delivers continuous positive airway pressure during sleep. The device encompasses a mask worn over the nose, tubing and a fan that delivers enough air pressure to keep the throat open, preventing obstruction of the airway, and reversing the negative consequences of sleep apnea on the heart.