Wednesday, September 17, 2014

Brain changes before and after CPAP treatment for obstructive sleep apnea

Some studies have shown changes in the white and gray matter of the brain from untreated obstructive sleep apnea (OSA). The gray matter refers to cell bodies in the brain and is generally on the outer surface. White matter is the connections between the cell bodies and some of the supporting cell types - it's deeper in the brain, meaning below the gray matter.

This study sought to evaluate white matter changes and impact on cognition in patients with OSA, and if the changes were reversible with CPAP therapy. The researchers studied 17 patients with severe OSA and compared them to similar patients that did not have OSA. The treated patients were evaluated at baseline, 3 months, and at 12 months - however, the controls were only evaluated at baseline. CPAP use was monitored objectively with downloads from each unit.

Results showed changes in white matter in the untreated OSA patients. There was only limited improvement with 3 months of CPAP, but there was significant improvement at 12 months of CPAP. This is an exciting study because it suggests that the brain damage inflicted by untreated severe OSA may be reversible with regular, prolonged CPAP treatment.

Wednesday, September 10, 2014

Benefit of CPAP use in older people with obstructive sleep apnea

Here is a study about obstructive sleep apnea (OSA) treatment in elderly people. It was done in the UK over 12 months in those 65 years and older with OSA. Subjects were randomized to get CPAP treatment or no CPAP treatment. Those who did not get CPAP received advice on minimizing daytime sleepiness through sleep habits, napping, caffeine use, and weight loss. The main purpose of the study was to see if CPAP use reduced sleepiness levels and if CPAP is cost-effective.

Results showed that subjective sleepiness was reduced to a greater extent in those that received CPAP treatment. As expected, the reduction in sleepiness levels was greatest for those who started out with the highest sleepiness levels. CPAP use reduced healthcare usage, which offset the cost of the CPAP - the authors concluded that CPAP use is cost effective for older patients.

Other outcomes were measured as well. CPAP use did not improve cognitive function or blood pressure. CPAP did improve total cholesterol levels at 3 months, but not at 21 months. Night time urination, and home and driving accidents were not improved with CPAP use.

What is most interesting to me about this study is that CPAP improved sleepiness despite a low amount of CPAP use by the participants. Good CPAP usage is generally defined as using CPAP at least 4 hours per night on 7 out of 10 nights. In this study, usage was about 2 hours per night on average.

Wednesday, September 3, 2014

American Pediatric Association "Let Them Sleep" statement

The American Pediatric Association recently released a statement that middle and high school students start school at 8:30 AM or later. Sleep-related research supports the later school start time so that adolescents can get more sleep per night. The recommended amount of sleep for teenagers is 8.5 to 9 hours per night, with the majority of teens not getting close to that. Chronic sleep deprivation has been linked with obesity, diabetes, mental health problems, and reduced academic performance.

The statement goes on to explain that teens lack of sleep is complex and involves homework, extracurricular activities, after-school jobs and use of technology that can keep them up late on week nights. So just delaying school start times may not improve teens' sleep duration if other lifestyle changes are not made. The most obvious one is restricting screen time at night.

Wednesday, August 27, 2014

Astronauts and sleep

This article discusses a study published in the journal Lancet about the sleep patterns of astronauts in space. Since I don't have access to the Lancet article, I don't have all of the details. The article however states that the astronauts are scheduled to get 8.5 hours per day of sleep. On average, they managed to sleep about 6 hours. And 78% of them used sleeping pills about half of the time.

The article goes on to quote someone from NASA who states that the study demonstrates valuable insights into sleep deprivation experienced by astronauts in space. However, I'm not sure it does, but I am basing this on the article, not the actual study. The article doesn't give me any insight, only leads to more questions. Why are astronauts expected to sleep 8.5 hours per night? Who came up with that number? How was sleep measured in the astronauts? Subjective or objective information? For the astronauts that did not sleep the full 8.5 hours, were they sleepy in the daytime? Did they actually exhibit any signs of sleep deprivation? Why did the astronauts take sleep aids? Was it because they were told they needed to sleep 8.5 hours, but most realized they would not be able to do that because the amount of sleep they actually need is less?

Wednesday, August 20, 2014

Drowsy driving

Driving while drowsy continues to be a significant problem. It affects drivers of all age. I'm just referring to drivers who fall asleep at the wheel - also drivers who are sleep deprived enough to impair their reaction times on the road. This level of impairment can be difficult for a driver to recognize. Therefore a sleepy driver may push on, continuing to drive because they have not actually fallen asleep.

Here is a link to recent statistics from the National Highway Traffic Safety Association citing that approximately one in four motor vehicle accidents is due to drowsy driving. Someday, sleep researchers may come up with a reliable and simple test of sleepiness that drivers could use to determine if they shouldn't drive. They could take a brief nap first. Although, this all may be moot if Google makes driver-less cars a reality.

Wednesday, August 13, 2014

Weight gain after tonsil removal for obstructive sleep apnea

Children with obstructive sleep apnea (OSA) can have reduced growth rates. The primary treatment of OSA in children is removing the tonsils adenoids, referred to as an adenotonsillectomy. After this procedure, studies have shown an increase in weight. However, some kids that are overweight before adenotonsillectomy put on even more weight after the surgery.

This study looked at two groups of children, ages 5-10 years old, who had OSA. One group got adenotonsillectomy and the other group received no treatment - just watchful waiting. Sleep studies and height / weight measurements were repeated 7 months later. Results showed that body weight and body mass index (BMI) increased in both groups of patients. This may be because the sleep apnea severity improved in both groups. It's unclear why that happened, especially with the weight gain. I would think that would make the sleep apnea severity worse in the untreated group.

What was remarkable about the study, however, was that after adjusting for baseline weight and other variables, the weight gain experienced by those that had the adenotonsillectomy was significantly greater than the group that received no treatment. In those children who were already overweight at the start of the study, 52% became obese after adenotonsillectomy vs 21% in the group that did not receive treatment. The researchers proposed several mechanisms for weight gain after adenotonsillectomy: increased calories consumed, unhealthy food choices, decreased energy burned due to reduced work of breathing, improvement in blood oxygen levels, and increased growth hormone secretion.

The authors recommend monitoring weight, nutritional counseling, and encouragement of physical activity after adenotonsillectomy for OSA in children.

Wednesday, August 6, 2014

Sleep apnea surgery

Continuous positive airway pressure (CPAP) remains the most effective treatment for obstructive sleep apnea (OSA). As many of you may know, CPAP is not well tolerated and usage of CPAP remains a significant problem. Some patients decide to pursue upper airway surgery for their OSA. However, surgery tends to be the least effective option for adults. In children, surgery is often the treatment of choice - it works quite well in fact. In adults, the more common procedure is called a uvulopalatopharyngoplasty or UP3. This involves removing the tonsils, the uvula, and part of the soft palate. A newer procedure called coblation channeling of the tongue or CCT involves surgically reducing the volume of the tongue. This article discusses research out of Australia showing a combination of UP3 with CCT may be more effective than either procedure alone. This may provide better results to patients who suffer from OSA but can not tolerate CPAP.