Category: Insomnia

Children who bask in the nighttime glow of a TV or computer don't get enough rest and suffer from poor lifestyle habits, new research from the University of Alberta has shown.

A province-wide survey of Grade 5 students in Alberta showed that as little as one hour of additional sleep decreased the odds of being overweight or obese by 28 per cent and 30 per cent, respectively. Children with one or more electronic devices in the bedroom — TVs, computers, video games and cellphones — were also far more likely to be overweight or obese.

"If you want your kids to sleep better and live a healthier lifestyle, get the technology out of the bedroom," said co-author Paul Veugelers, a professor in the School of Public Health, Canada Research Chair in Population Health and Alberta Innovates — Health Solutions Health Scholar.

Veugelers, director of the Population Health Intervention Research Unit that works with the Alberta Project Promoting active Living and healthy Eating (APPLE Schools), said the research is the first to connect the dots on the relationship between sleep, diet and physical activity among kids.

Nearly 3,400 Grade 5 students were asked about their nighttime sleep habits and access to electronics through the REAL Kids Alberta survey. Half of the students had a TV, DVD player or video game console in their bedroom, 21 per cent had a computer and 17 per cent had a cellphone. Five per cent of students had all three types of devices.

Some 57 per cent of students reported using electronics after they were supposed to be asleep, with watching TV and movies being the most popular activity. Twenty-seven per cent of students engaged in three or more activities after bedtime.

Researchers found that students with access to one electronic device were 1.47 times as likely to be overweight as kids with no devices in the bedroom. That increased to 2.57 times for kids with three devices, with similar results reported among obese children.

More sleep also led to significantly more physical activity and better diet choices, researchers found.

Co-author Christina Fung noted that children today are not sleeping as much as previous generations, with two-thirds not getting the recommended hours of sleep per night. In addition to healthy lifestyle habits, a good night's sleep has been linked to better academic outcomes, fewer mood disorders and other positive health outcomes, she said.

"It's important to teach these children at an earlier age and teach them healthy habits when they are younger."

The research was published in September by the journal Pediatric Obesity, in an early online release. The REAL Kids Alberta evaluation was funded through a contract with Alberta Health.

---

Journal Reference:

1. H. Chahal, C. Fung, S. Kuhle, P. J. Veugelers. Availability and night-time use of electronic entertainment and communication devices are associated with short sleep duration and obesity among Canadian children. Pediatric Obesity, 2012; DOI: 10.1111/j.2047-6310.2012.00085.x

Regardless of how much a high school student generally studies each day, if that student sacrifices sleep in order to study more than usual, he or she is more likely to have academic problems the following day. Because students tend to increasingly sacrifice sleep time for studying in the latter years of high school, this negative dynamic becomes more and more prevalent over time.

Those are the findings of a new longitudinal study that focused on daily and yearly variations of students who sacrifice sleep to study. The research was conducted at the University of California, Los Angeles (UCLA) and appears in the journal Child Development.

"Sacrificing sleep for extra study time is counterproductive," says Andrew J. Fuligni, professor of psychiatry and biobehavioral sciences and a senior scientist at the Jane and Terry Semel Institute of Neuroscience and Human Behavior at UCLA, who worked on the study. "Academic success may depend on finding strategies to avoid having to give up sleep to study, such as maintaining a consistent study schedule across days, using school time as efficiently as possible, and sacrificing time spent on other, less essential activities."

For 14 days in each of the 9th, 10th, and 12th grades, 535 students from several Los Angeles-area high schools reported in diaries how long they studied, how long they slept, and whether or not they experienced two academic problems — they didn't understand something taught in class or they did poorly on a test, quiz, or homework. The students represented a mix of socioeconomic and ethnic backgrounds.

Although the researchers expected that extra hours of studying that ate into sleep time might create problems in terms of students' understanding of what they were taught in class, they were surprised to find that diminishing sleep in order to study was actually associated with doing more poorly on a test, quiz, or homework (the opposite of the students' intent).

"As other studies have found, our results indicated that extra time spent studying cuts into adolescents' sleep on a daily basis, and it is this reduced sleep that accounts for the increase in academic problems that occurs after days of increased studying," Fuligni explained. "Although these nights of extra studying may seem necessary, they can come at a cost."

Fuligni said the study's findings do not suggest that teens should spend less time studying overall, but that those teens who give up sleep to study more than usual are more likely to have academic problems the following day.

New research from Umeå and Uppsala universities has found high rates of sleep apnea in women, despite the condition usually being regarded as a disorder predominantly of males.

The study, published online ahead of print August 16 in the European Respiratory Journal, also suggested that women with hypertension and/or obesity were more likely to experience sleep apnea.

Obstructive sleep apnea is a condition in which there are frequent pauses in breathing during sleep. The incidence of the condition increases with age and it is considered more prevalent in men than in women. In this new study, researchers from Uppsala and Umeå University in Sweden aimed to investigate the frequency and risk factors of sleep apnea in women.

The study analysed 400 women from a random sample of 10,000 women aged 20-70 years. The participants answered a questionnaire and underwent a sleep examination.

The results found that obstructive sleep apnea was present in 50% of women aged 20-70 years. The researchers also found links between age, obesity and hypertension: 80% of women with hypertension and 84% of obese women suffered from sleep apnea.

Additionally, severe sleep apnea was present in 31% of obese women aged 55-70 years old.

Lead author Dr Karl Franklin said: "We were very surprised to find such a high occurrence of sleep apnea in women, as it is traditionally thought of as a male disorder. These findings suggest that clinicians should be particularly aware of the association between sleep apnea and obesity and hypertension, in order to identify patients who could also be suffering from the sleeping disorder."

A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute shows that a two-hour exposure to electronic devices with self-luminous "backlit" displays causes melatonin suppression, which might lead to delayed bedtimes, especially in teens.

The research team, led by Mariana Figueiro, associate professor at Rensselaer and director of the LRC's Light and Health Program, tested the effects of self-luminous tablets on melatonin suppression. In order to simulate typical usage of these devices, 13 individuals used self-luminous tablets to read, play games, and watch movies.

"Our study shows that a two-hour exposure to light from self-luminous electronic displays can suppress melatonin by about 22 percent. Stimulating the human circadian system to this level may affect sleep in those using the devices prior to bedtime," said Figueiro.

The actual melatonin suppression values after 60 minutes were very similar to those estimated using a predictive model of human circadian phototransduction for one-hour light exposures. "Based on these results, display manufacturers can use our model to determine how their products could affect circadian system regulation," said Figueiro.

The results of this study, together with the LRC predictive model of human circadian phototransduction, could urge manufacturers to design more "circadian-friendly" electronic devices that could either increase or decrease circadian stimulation depending on the time of day — reducing circadian stimulation in the evening for a better night's sleep, and increasing in the morning to encourage alertness. In the future, manufacturers might be able to use data and predictive models to design tablets for tailored daytime light exposures that minimize symptoms of seasonal affective disorder, and sleep disorders in seniors. Individuals would be able to receive light treatments while playing games or watching movies, making light therapy much more enjoyable than just sitting in front of a light box.

Along with Figueiro, co-authors of the study are LRC Director and Professor Mark S. Rea, LRC Research Specialist Brittany Wood, and LRC Research Nurse Barbara Plitnick.

Melatonin is a hormone produced by the pineal gland at night and under conditions of darkness in both diurnal and nocturnal species. It is a "timing messenger," signaling nighttime information throughout the body. Exposure to light at night, especially short-wavelength light, can slow or even cease nocturnal melatonin production. Suppression of melatonin by light at night resulting in circadian disruption has been implicated in sleep disturbances, increased risk for diabetes and obesity, as well as increased risk for more serious diseases, such as breast cancer, if circadian disruption occurs for many consecutive years, such as in nightshift workers.

"Technology developments have led to bigger and brighter televisions, computer screens, and cell phones," said Wood, who used the study as the basis for her master's thesis. "To produce white light, these electronic devices must emit light at short wavelengths, which makes them potential sources for suppressing or delaying the onset of melatonin in the evening, reducing sleep duration and disrupting sleep. This is particularly worrisome in populations such as young adults and adolescents, who already tend to be night owls."

In the study, the participants were divided into three groups. The first group viewed their tablets through a pair of clear goggles fitted with 470-nm (blue) light from light emitting diodes (LEDs). This was a "true positive" condition because the blue light is known to be a strong stimulus for suppressing melatonin. The second group viewed their tablets through orange-tinted glasses, capable of filtering out the short-wavelength radiation that can suppress melatonin; this was the "dark control" condition. The third group did not wear glasses or goggles. Each tablet was set to full brightness.

In order to accurately record personal light exposures during the experiment, each subject wore a Dimesimeter close to the eye. The Dimesimeter is a small calibrated light meter device developed by the LRC that continuously records circadian light and activity levels."

The research team established that duration of exposure and the distance between the eye and the display, which determines the amount of light reaching the back of the eye, affects melatonin levels. Melatonin suppression after a one-hour exposure to the tablet was not significantly affected. However, after a two-hour exposure there was significant suppression.

The type of task being performed on the tablets also determines how much light is delivered to the cornea and, therefore, the impact on evening melatonin levels. As shown by the team's Dimesimeter measurements, the range of photopic illuminance levels at the cornea from the tablets alone varied from 5 lux, which is not likely to affect melatonin, to over 50 lux, which would result in measurable melatonin suppression after a two-hour exposure. Therefore, before any generalizations can be made, it is important to measure how much light one is receiving from these self-luminous devices.

Until manufacturers develop more "circadian-friendly" electronic devices that increase or decrease light exposure based on time of day, Figueiro has several recommendations to reduce their effects on sleep. "We recommended dimming these devices at night as much as possible in order to minimize melatonin suppression, and limiting the amount of time spent using these devices prior to bedtime."

The study was funded by Sharp Laboratories of America.

---

Journal Reference:

1. Brittany Wood, Mark S. Rea, Barbara Plitnick, Mariana G. Figueiro. Light level and duration of exposure determine the impact of self-luminous tablets on melatonin suppression. Applied Ergonomics, 2012; DOI: 10.1016/j.apergo.2012.07.008

— Is sleep learning possible? A new Weizmann Institute study appearing August 26 in Nature Neuroscience has found that if certain odors are presented after tones during sleep, people will start sniffing when they hear the tones alone — even when no odor is present — both during sleep and, later, when awake. In other words, people can learn new information while they sleep, and this can unconsciously modify their waking behavior.

Sleep-learning experiments are notoriously difficult to conduct. For one thing, one must be sure that the subjects are actually asleep and stay that way during the "lessons." The most rigorous trials of verbal sleep learning have failed to show any new knowledge taking root. While more and more research has demonstrated the importance of sleep for learning and memory consolidation, none had managed to show actual learning of new information taking place in an adult brain during sleep.

Prof. Noam Sobel and research student Anat Arzi, together with Sobel's group in the Institute's Neurobiology Department in collaboration with researchers from Loewenstein Hospital and the Academic College of Tel Aviv — Jaffa, chose to experiment with a type of conditioning that involves exposing subjects to a tone followed by an odor, so that they soon exhibit a similar response to the tone as they would to the odor. The pairing of tones and odors presented several advantages. Neither wakes the sleeper (in fact, certain odors can promote sound sleep), yet the brain processes them and even reacts during slumber. Moreover, the sense of smell holds a unique non-verbal measure that can be observed — namely sniffing. The researchers found that, in the case of smelling, the sleeping brain acts much as it does when awake: We inhale deeply when we smell a pleasant aroma but stop our inhalation short when assaulted by a bad smell. This variation in sniffing could be recorded whether the subjects were asleep or awake. Finally, this type of conditioning, while it may appear to be quite simple, is associated with some higher brain areas — including the hippocampus, which is involved in memory formation.

In the experiments, the subjects slept in a special lab while their sleep state was continuously monitored. (Waking up during the conditioning — even for a moment — disqualified the results.) As they slept, a tone was played, followed by an odor — either pleasant or unpleasant. Then another tone was played, followed by an odor at the opposite end of the pleasantness scale. Over the course of the night, the associations were partially reinforced, so that the subject was exposed to just the tones as well. The sleeping volunteers reacted to the tones alone as if the associated odor were still present — by either sniffing deeply or taking shallow breaths.

The next day, the now awake subjects again heard the tones alone — with no accompanying odor. Although they had no conscious recollection of listening to them during the night, their breathing patterns told a different story. When exposed to tones that had been paired with pleasant odors, they sniffed deeply, while the second tones — those associated with bad smells — provoked short, shallow sniffs.

The team then asked whether this type of learning is tied to a particular phase of sleep. In a second experiment, they divided the sleep cycles into rapid eye movement (REM) and non-REM sleep, and then induced the conditioning during only one phase or the other. Surprisingly, they found that the learned response was more pronounced during the REM phase, but the transfer of the association from sleep to waking was evident only when learning took place during the non-REM phase. Sobel and Arzi suggest that during REM sleep we may be more open to influence from the stimuli in our surroundings, but so-called "dream amnesia" — which makes us forget most of our dreams — may operate on any conditioning occurring in that stage of sleep. In contrast, non-REM sleep is the phase that is important for memory consolidation, so it might also play a role in this form of sleep-learning.

Although Sobel's lab studies the sense of smell, Arzi intends to continue investigating brain processing in altered states of consciousness such as sleep and coma. "Now that we know that some kind of sleep learning is possible," says Arzi, "we want to find where the limits lie — what information can be learned during sleep and what information cannot."

---

Journal Reference:

1. Anat Arzi, Limor Shedlesky, Mor Ben-Shaul, Khitam Nasser, Arie Oksenberg, Ilana S Hairston, Noam Sobel. Humans can learn new information during sleep. Nature Neuroscience, 2012; DOI: 10.1038/nn.3193

People who drive commercial vehicles, such as buses, taxis, trucks and airplanes, could be incorrectly reporting their symptoms of sleep apnea due to their fears of endangering their employment, according to a new study.

The research will be presented on 1 September 2012 at the European Respiratory Society's (ERS) Annual Congress in Vienna.

People with the sleep apnea suffer frequent disruptions to their breathing during sleep, leaving them with headaches, drowsiness and sometimes depression during the day. Obstructive sleep apnea is a well-established risk for traffic accidents and commercial vehicle drivers could lose their license if their illness is perceived to be compromising safety while driving.

The regular treatment for sleep apnea is continuous positive airway pressure (CPAP), which uses a mask and other equipment to generate a stream of air to keep the upper airway open during sleep. As commercial drivers regularly do shift work, they don't follow regular patterns of sleep and also do not always sleep in one place; this makes adherence to CPAP treatment more difficult.

Researchers examined 37 commercial vehicle drivers with sleep apnea and compared them with a control group of 74 patients. Both groups had similar characteristics of age, body mass index (BMI) and similar numbers of disturbances suffered on average during the night. Both groups also underwent treatment using CPAP.

Levels of sleepiness were then analyzed using the Epworth Sleepiness Score; a well-established short questionnaire used to give levels of sleepiness during the day time. The survey provides a score, which is the sum of 8 items and can range between 0 and 24.The higher the score, the higher the person's level of daytime sleepiness

At the start of the study, commercial drivers reported an average score of 8.1 on the sleepiness scale, compared with an average of 11.0 reported by non-commercial drivers, despite a similar number of disturbances at night between the two groups. The difference was also seen after 6 months of treatment using CPAP therapy with the drivers reporting an average sleepiness score of 4.8 and non-drivers reporting an average of 7.7.

The results also showed that drivers received less treatment (only receiving CPAP for an average of 75% of days, compared with 83%) and also had more unscheduled visits to the clinic, which suggests they were struggling with their symptoms.

The authors speculate that the lower scores reported by the commercial drivers could be due to drivers under-scoring their sleepiness levels for fear of losing their license permissions.

Lead author, Dr. Werner Strobel from University Hospital, Switzerland, said: "Our study suggests that commercial drivers are playing down their levels of sleepiness for fear of losing their jobs. Although this is very difficult to prove, both the group of drivers and the group of non-drivers began the study with a similar number of disturbances during the night. You would therefore expect their reports of sleepiness to be similar to begin with, however the drivers estimated their levels of sleepiness as lower than the non-drivers. This pattern continued throughout the course of the study, with drivers reporting lower symptoms, yet receiving less treatment and making more unscheduled visits to the clinic.

"We can assume from these results that commercial drivers with sleep apnea symptoms could be under-reporting their sleepiness in order to protect their job. These results should be taken into account by healthcare professionals who are treating this group of people."

Dan Smyth from the Irish Sleep apnea Trust, said: "We know that an above average number of people involved in commercial driving have sleep apnea. It is also known that many of them, mainly through ignorance of the condition and fear of losing their livelihood, are afraid to report it to their employer or seek help. The findings of this study confirm the current situation and show further evidence that Relative Advocacy and Support Groups, with the support of our legislators, must deliver a positive message on the benefits of treating Sleep apnea to the Transport Industry."

Abstracts from the ERS Congress will be publicly available online August 26, 2012.

People with Parkinson's disease performed markedly better on a test of working memory after a night's sleep, and sleep disorders can interfere with that benefit, researchers have shown.

While the classic symptoms of Parkinson's disease include tremors and slow movements, Parkinson's can also affect someone's memory, including "working memory." Working memory is defined as the ability to temporarily store and manipulate information, rather than simply repeat it. The use of working memory is important in planning, problem solving and independent living.

The findings underline the importance of addressing sleep disorders in the care of patients with Parkinson's, and indicate that working memory capacity in patients with Parkinson's potentially can be improved with training. The results also have implications for the biology of sleep and memory.

The results were published this week in the journal Brain.

"It was known already that sleep is beneficial for memory, but here, we've been able to analyze what aspects of sleep are required for the improvements in working memory performance," says postdoctoral fellow Michael Scullin, who is the first author of the paper. The senior author is Donald Bliwise, professor of neurology at Emory University School of Medicine.

The performance boost from sleep was linked with the amount of slow wave sleep, or the deepest stage of sleep. Several research groups have reported that slow wave sleep is important for synaptic plasticity, the ability of brain cells to reorganize and make new connections.

Sleep apnea, the disruption of sleep caused by obstruction of the airway, interfered with sleep's effects on memory. Study participants who showed signs of sleep apnea, if it was severe enough to lower their blood oxygen levels for more than five minutes, did not see a working memory test boost.

In this study, participants took a "digit span test," in which they had to repeat a list of numbers forward and backward. The test was conducted in an escalating fashion: the list grows incrementally until someone makes a mistake. Participants took the digit span test eight times during a 48-hour period, four during the first day and four during the second. In between, they slept.

Repeating numbers in the original order is a test of short-term memory, while repeating the numbers in reverse order is a test of working memory.

"Repeating the list in reverse order requires some effort to manipulate the numbers, not just spit them back out again," Scullin says. "It's also a purely verbal test, which is important when working with a population that may have motor impairments."

54 study participants had Parkinson's disease, and 10 had dementia with Lewy bodies: a more advanced condition, where patients may have hallucinations or fluctuating cognition as well as motor symptoms. Those who had dementia with Lewy bodies saw no working memory boost from the night's rest. As expected, their baseline level of performance was lower than the Parkinson's group.

Participants with Parkinson's who were taking dopamine-enhancing medications saw their performance on the digit span test jump up between the fourth and fifth test. On average, they could remember one more number backwards. The ability to repeat numbers backward improved, even though the ability to repeat numbers forward did not.

Patients needed to be taking dopamine-enhancing medications to see the most performance benefit from sleep. Patients not taking dopamine medications, even though they had generally had Parkinson's for less time, did not experience as much of a performance benefit. This may reflect a role for dopamine, an important neurotransmitter, in memory.

Scullin and Bliwise are planning an expanded study of sleep and working memory, in healthy elderly people as well as patients with neurodegenerative diseases.

"Many elderly people go through a decline in how much slow wave sleep they experience, and this may be a significant contributor to working memory difficulties," Scullin says.

The research was supported by the National Institute of Neurological Disorders and Stroke (R01 NS050595) and the National Institute of Aging (F32 AG041543).