Wednesday, January 21, 2015

Sleep and screen time in children

Studies have been demonstrating that some children are getting too little sleep, and that technology is driving some of the sleep deprivation. Studies have also shown that TV in a child's bedroom has been linked to less sleep. And interactive media devices like smart phones and video games may be more disruptive to sleep. This is in contract to TV viewing, which is a passive activity. Also, interactive devices are held very close to the face, meaning that light from the screens on these devices is more likely to interrupt melatonin secretion at night, which may further disrupt sleep. Finally, these interactive devices can disrupt sleep by text messages, which is not a problem with TV viewing.

This study was a cross-sectional survey of about 2000 4th and 7th graders in Massachusettes. They asked children about their TV viewing, small screen use (like cell phone, Ipad, etc), and various sleep parameters. Results showed that 54% of kids slept near a small screen and 75% slept with a TV in the room. Not surprisingly, a higher proportion of seventh graders slept near a small screen than 4th graders.

Children who slept near a small screen reported 21 fewer minutes of sleep per weekday when compared to those who did not sleep near a small screen. This effects was independent of having a TV in the room. Children who slept in a room with a TV reported sleeping 18 fewer minutes during the weekday than those without a TV in their room. This was independent of sleeping near a small screen. The results showed that the association between the screens and sleep duration resulted from a later bedtime. Sleeping near a small screen, but not a TV in the room, was associated with a 1.39 times the prevalence of perceived insufficient sleep or rest, even after adjusting for sleep duration. Not surprisingly, longer time watching TV or playing video games was associated with shorter weekday sleep duration, again accounted for by later bedtimes. And each hour spent watching TV or playing video games was associated with a higher prevalence of perceived insufficient sleep or rest. Interestingly, physical activity reduced the association between video games and perceived insufficient rest or sleep.

The study authors concluded that the small screens affect sleep quality more than TV viewing because of the stimulating content, calls, and audible text messaging while sleeping. They also mentioned that other mechanisms may contribute. For example, consuming caffeinated beverages near bedtime, evening exposure to bright light, and increased cognitive / emotional / physiologic arousal after playing video games, interacting on social media, or watching exciting / frightening TV content.

Wednesday, January 14, 2015

Obstructive sleep apnea in childhood and adolescence

There is limited study data about the natural course of obstructive sleep apnea (OSA) in children. This study looked at OSA incidence and remission from middle childhood (ages 8-11 years) through late adolescence (ages 16-19 years). It also studied if risk factors for OSA that were present in middle childhood remained in adolescence. This was a retrospective study from a larger sleep and health study.

Of note, OSA in children is typically defined as full or partial collapse of the airway at least 1 time an hour. In this study, the authors used a more conservative measure of 5 or more airway collapses per hour. The results showed OSA was present in 4.7% of middle childhood aged kids and in 4.3% of adolescents. And only 8.7% of those with OSA in middle childhood still had OSA in adolescence - meaning almost 91% of cases of OSA resolved between middle childhood and adolescence. And of those whose OSA had remitted by adolescence, only 24% had had tonsillectomy, the treatment of choice for OSA in children. So in 3 out of 4 cases, the OSA went away on it's own, without surgical intervention. Of the children without OSA, only 4% went on to be diagnosed with OSA in adolescence.

Unlike OSA, habitual snoring was much more persistent from middle childhood to adolescence. Half of the snorers in middle childhood were still snoring in adolescence, yet most of them did not go on to develop OSA as adolescents. However, when the study authors lowered the threshold for diagnosing OSA, 32% of middle childhood snorers went on to develop OSA in adolescence.

Risk factors for middle childhood OSA were African American race, preterm status, and neighborhood distress. However, these were not risk factors for OSA in adolescents. Instead, the risk factors were male sex and history of tonsillectomy or adenoidectomy. Finally, adolescents with OSA had a higher body-mass index (marker for obesity) compared to adolescents and middle childhood kids without OSA. The authors speculated that the changing risk factors may reflect the fact that upper airway changes occur from middle childhood to adolescence, especially regression of tonsils. Thus, other factors like male gender and obesity would be more important in adolescents. The authors go on to explain that the risk factor of prior tonsillectomy in adolescents with OSA may be due to other risk factors that reflect a predisposition for upper airway collapse in sleep.

The authors concluded that screening for OSA could be age specific given the different risk factors present at the different ages. Also, the cutoff values for OSA may need to be altered given the child's age - using a more liberal cutoff for younger children and a more conservative one for older children. This is already being done at many sleep centers, where the sleep physician can use adult criteria or pediatric criteria cutoff values for children aged 13 and older.

Wednesday, January 7, 2015

Flying with your CPAP

I get asked about this regularly by my patients. This article is about traveling with a CPAP. Since using CPAP therapy with all sleep will maximize effectiveness, you should bring your CPAP with you when you travel. Of course, don't forget to bring all of the accessories, especially the power cord. Most CPAP machines these days come with a canvas bag to carry the device. I advise my patients to carry the device on board, not checking it as luggage. This is because the CPAP may be damaged during luggage handling or transportation in the plane, or your luggage may be lost. You will need to show the TSA agent the CPAP equipment. Nowadays, they will be used to it, and you will see many other travelers with their CPAPs. You may also need to bring a letter from your physician or a specialized luggage tag that says the CPAP is a medical device that has been prescribed for you.

Some travelers, especially on overnight flights, will want to use their CPAP's on the plane. You will need to check with the airline to see if their planes have power sources and if you can sit near enough to one to plug in your CPAP. Be sure to ask what kind of power source the plane has, as you may need an adapter. Some of my patients have gotten small travel CPAPs that operate on battery power.

If you use the humidifier chamber, don't try to bring distilled water on the plane. Best to buy it at your destination, if available.

Wednesday, December 24, 2014

Depression and obstructive sleep apnea

Depression is a common disorder that exists along with obstructive sleep apnea (OSA). The exact relationship between the two disorders is not known. OSA may contribute to depression due to sleep loss, sleep disruption, and cognitive effects of intermittent low oxygen levels to the brain. Also, weight gain and sleep disruption from depression could exacerbate OSA. Some, but not all of my patients report that their depression gets better with treatment of OSA.

This study is a meta-analysis of research looking at the effects of CPAP and oral appliances on depressive symptoms (as obtained by depression questionnaires) in adults with OSA. The results showed small improvements in depressive symptoms with OSA treatment. The greatest benefit was seen in those patients with the worse depression scores at baseline.

Wednesday, December 17, 2014

Insomnia and mortality

Chronic insomnia is a frequent problem, and several studies have attempted to link insomnia with medical problems, even death. However, it's not clear from these studies that the relationship is as stated. One methodology problem with these studies is the fact that most of them define insomnia based solely on the research subjects' description of their sleep quality. In other words, secondary causes of insomnia are not ruled out with objective testing like sleep studies. This abstract is about research done on subjects with chronic insomnia. I don't have access to the actual article, so my analysis of the study is limited. I can't tell from the abstract if the research subjects had secondary causes of insomnia ruled out with sleep studies.

Researchers used data from a community-based cohort and categorized subjects into having either persistent, chronic insomnia, only intermittent insomnia, or no insomnia. The researchers defined persistent based on the subjects' description of their sleep quality over a six year period. They then determined when the subject died for up to a 20 year period. The researchers also examined levels of a marker of inflammation called serum C-reactive protein (CRP). There were 1409 research subjects - 249 with intermittent insomnia and 128 with persistent insomnia. The results showed that the subjects with persistent insomnia were 58% more likely to die than those without insomnia. Those with intermittent insomnia were not more likely to die than those without insomnia. Of note, most of the deaths were cardiovascular. CRP levels were higher in those with persistent insomnia than in those with either intermittent or no insomnia. The authors noted that CRP levels were associated with increased mortality by themselves. However, adjustment for CRP levels did not notably change the association between persistent insomnia and mortality. Also, the results were adjusted for confounders such as age, sex, body mass index, smoking, physical activity, alcohol, and sedatives.

Wednesday, December 10, 2014

Obstructive sleep apnea and exercise capacity

This study is a cross-sectional evaluation of the relationship between obstructive sleep apnea (OSA) and exercise capacity. According to the authors, how OSA affects exercise capacity is not clear, as prior studies have conflicting results. In this study, researchers did sleep studies on participants and put them into two groups. Those with no or mild OSA, and those with moderate or severe OSA. They then measured their exercise capacity and compared the results. The main finding was that OSA was associated with decreased exercise capacity. And more severe OSA was associated with worsening exercise capacity. The mechanism behind why OSA would affect exercise capacity is not clear. The authors speculate that it could be due to changes in energy pathways, changes in muscle fiber structure, and/or changes in blood vessels in muscles - thought to be a result of low oxygen levels associated with OSA.

Wednesday, December 3, 2014

Smoking and sleep

This article describes research about reducing cigarette smoking in your sleep. The study in the article involves using a psychological concept of learning called respondent conditioning - think of Pavlov and his dog, at outlined in this Wikipedia article. The study participants were all smokers who expressed desire to quit. Researchers paired the smell of cigarettes with a foul odor when participants were asleep. Supposedly, the participants unconsciously associated the foul smell with the smell of cigarettes and ended up smoking 30% less. There was no smoking reduction in participants that were exposed only to cigarette smoke when asleep or if the participants were exposed to both smells, but while awake.

Two other interesting points about this study. The first one is that the participants did not remember the smells they were exposed to in their sleep. Also, it appeared that a light stage of non-dream sleep was was the most effective stage of sleep that was associated with reduced smoking. The authors concluded that conditioning can occur in sleep and that this technique may be used in other addictions.