Monday, January 30, 2012

Relationship Between Food Intake and Sleep Pattern

Studies have shown a link between short sleep duration and obesity, but few studies have researched food intake and sleep patterns. There is a research study in the Journal of Clinical Sleep Medicine that analyzed the correlation between food intake and sleep patterns in healthy individuals. They studied 52 healthy, non-obese individuals ages 19 - 45 years old who were sedentary, not taking medications, non-smokers, and who spent regular times in bed at night.

Their food intake was determined by a self-report food diary for 3 consecutive days preceding a sleep study. The results showed that none of the 52 participants had any sleep disorders. Analysis of the data showed that food intake, mainly in the evening period, was correlated with several variables related to sleep patterns. More specifically, higher food intake close to bedtime was associated with decrease sleep quality, especially in women. Women took longer to fall asleep if they ate high fat and carbohydrate meals before sleeping. Also, eating a high fat meal close to bedtime decreased dream sleep. The authors speculated that a full stomach could make it more difficult to sleep.

Monday, January 23, 2012

New Treatment for REM Sleep Behavior Disorder

REM Sleep Behavior Disorder (RBD) is a form of sleepwalking where patients will enact their dream while asleep. This dream enactment behavior is not normal, as usually we are completely paralyzed while dreaming. If RBD occurs, patients can accidentally hurt themselves or their bedpartner while sleeping. RBD can occur during certain neurological disorders like Parkinson's Disease. RBD usually responds to a medication called Klonopin, but not every patient finds it beneficial.

A study was published in the Journal of Clinical Sleep Medicine about a non-medicine treatment of RBD. The study authors note that some patients with RBD wake up easily to bedpartners voice when they start moving while dreaming. This stops the potentially injurious behavior and results from the fact that dream (or REM) sleep is a very light stage of sleep, and all of us are easily awoken from that stage of sleep.

In this study, researchers attached a bed alarm to the torso's of four patients with RBD. When the patient tried to sit up while dreaming, the alarm was triggered and a taped recording of the bed partner's voice would calmly tell them to wake up. The results showed that all four patients had a dramatic reduction in dream related behaviors and injury. None of the patients felt it was a burden to use the alarm and they felt it reduced their anxiety about going to bed because they knew they would not likely hurt themselves or their bedpartner while asleep.

This form of therapy would not work in traditional sleepwalking, which occurs out of slow wave (or deep) sleep. In fact, such an alarm is likely to worsen traditional sleepwalking. Therefore, it would be best to use it only for RBD.

Monday, January 16, 2012

Loneliness and Sleep

There is an interesting article in the November edition of the Sleep Journal about the relationship between loneliness and sleep. The study authors describe a previous study that showed that loneliness was associated with more frequent awakenings, but not with the total duration of sleep. The authors feel this makes sense from an evolutionary perspective, as humans may wake up more frequently to ensure safety if sleeping alone.

The study participants were Hutterites, a communal group from South Dakota that sound similar to the Amish. They chose this group because they may be among the most socially connected group in the United States. Eligible participants were at least 19 years old. The study authors recorded the participants' subjective reports of loneliness, depression, anxiety, stress, sleep quality, and daytime sleepiness. Actual sleep duration and number of awakenings was measured for 7 continuous days via a home sleep study device called an actigraph. Actigraphy does not actually measure sleep, but it is a good correlate to an actual sleep study done in a sleep lab. Also, actigraphy can not rule out sleep-fragmenting disorders like sleep apnea or periodic leg movements.

The results showed that perceived loneliness was associated with more awakenings at night as measured by the actigraph. Interestingly, loneliness was not correlated with subjective increase in awakenings or sleep duration, and it was not significantly associated with actigraph-derived sleep duration. The effect of loneliness persisted even when controlling for negative affect (depression). Also, loneliness was not associated with increase report of subjective daytime sleepiness.

The authors point out that the results do not determine if loneliness causes worse sleep or if worse sleep contributes to loneliness. It could be that multiple awakenings lead to more loneliness, rather than the other direction. This is because depressive feelings were not associated with sleep fragmentation. Also, it is the perception of loneliness that is associated with sleep fragmentation, rather than marital status and number of family members the participants reported. This means that even if someone was married and had plenty of social relationships, they would still have more fragmented sleep if they felt lonely.

Monday, January 9, 2012

Sleep and Fibromyalgia in Women

Sleep problems are very common in people that have fibromyalgia syndrome(FMS). I saw an abstract for a study published in the journal Arthritis and Rheumatism that was done to determine the prevalence of sleep problems in FMS. Over 12,000 women without FMS were followed for upto 13 years and asked about sleep problems and FMS symptoms. Of note, no physicians diagnosed these women with either FMS or a sleep disorder - all the information was self-reported by the women themselves. The results showed that there was a dose-dependent relationship between sleep problems and FMS - meaning that the more frequent a woman reported sleep difficulties, the more likely she would also have FMS. The association was especially strong in women greater than 45 years old.

The results do not help us understand if FMS leads to sleep problems or the reverse. Since diagnoses were not made by physicians, it's difficult to know if the women with sleep problems had insomnia secondary to the FMS or another sleep disorder like obstructive sleep apnea, which can cause insomnia and is more common as we age. I have had patients with FMS feel like they can tolerate their pain better when they sleep better - this implies that sleep difficulties at least contribute to pain tolerance.

Monday, January 2, 2012

Ramelteon and Driving the Next Day

Certain medications for insomnia have been shown to impair driving performance the morning after they are taken. These medications are valium-like compounds called benzodiazepines. However, Rozerem (ramelteon) has not been shown to impair driving the next day. There is a study in the Journal Sleep about the effect of ramelteon on driving performance that I found rather interesting.

Researchers studied 30 healthy volunteers without insomnia. They gave them a dose of zopiclone (similar to Lunesta but not approved for use in the United States), a dose of ramelteon, and a placebo dose on three separate nights. They picked zopiclone because prior studies have shown it can impair driving the next day. Researchers and subjects did not know which pill they were getting each night. They let the patients sleep 7.5 hours and then tested their driving ability on an actual road, as opposed to a driving simulator. They also tested their balance 1.5 hours after taking the pill, meaning they had to be woken up after falling asleep. Finally, they gave them a battery of thinking, memory, and motor tests the morning after they took each pill.

The results showed no serious adverse effects occurred. The most common ones were decreased attention, sleepiness, and fatigue. Contrary to what was expected, ramelteon significantly impaired driving performance, thinking, and memory tests the next morning. Zoplicone did as well, but this was expected. Ramelteon's affect on driving was as strong as having a blood-alcohol concentration of 0.05%, which has been shown to impair driving. The legal limit in most states is 0.08%.

The authors conclude that patients taking ramelteon should be cautioned about driving, since they could experience impairment on the morning after taking it.