Control of dream sleep

The neurobiology of sleep is complicated - so many pathways in our brains seem to affect sleep and the different sleep stages. For example, the pons, a part of the brainstem, is thought to be the major part of the brain generating dream sleep. This article and abstract summarize elegant research demonstrating that a group of neurons in the medulla, which is below the pons, can generate signals that start dream sleep. The researchers postulate that these medullary neurons project up into the pons. This finding is interesting in that the medulla is responsbile for unconscious processes that regulate heart rate, blood pressure, and breathing, as well as other autonomic features. These research results may bolster the argument that dreams are not from the conscious brain, but more of an automatic process like breathing or heart rate. Unfortunately, these findings don't help us understand the function of dreaming any better than our current understanding.

Alcohol is not a good sleep aid

Here is another study showing what we already knew about the effect of alcohol on sleep. It may help some fall asleep faster, but it leads to sleep disruption in the second half of the night. The article rightly cautions people not to rely on alcohol to help them sleep. In addition to being addictive, alcohol suppresses REM or dream sleep.

Throat muscle paralysis mechanism discovered

Obstructive sleep apnea (OSA) occurs when the throat closes too much during sleep. And when we dream, the throat (as well as other muscles) close the most, as the brain temporarily "paralyzes" our muscles so we don't act out the dreams we are having. This article discusses research showing how the brain paralyzes the throat muscles when we dream, which could lead to OSA. This is exciting (at least to me) and has implications for future medical treatments for OSA.

Stomach sleeping and erotic dreaming

This article describes research showing that in people who slept more on the their stomach, reported dream content that was more sexual in nature, including being tied and locked up. Dreams were also more likely to be about being persecuted in stomach sleepers. The researchers speculated that sleeping on your stomach may deprive your brain temporarily of oxygen which could result in the type of dream content reported by the subjects. I'm not sure about the decreased oxygen levels with sleeping on your stomach. However, it could be that some patients inadvertently bury their face in the pillow which could been be misinterpreted by their sleeping brain as being tied up or locked up. Also, I am not convinced you can control the content of your dream by the position that you sleep in. It may be better just to sleep in a position that is most comfortable.

Treating dream sleep-related obstructive sleep apnea

In last month's edition of the Journal of Clinical Sleep Medicine is an article by Dr. Su and others about treating a subtype of obstructive sleep apnea (OSA) that is defined as occurring mainly during dream (REM) sleep - I'll call it REM OSA for short. To give you some background, our sleep can be broken down into two categories: Dream or REM sleep and non-REM sleep. OSA typically occurs in both stages, but can be more prominent in REM sleep. And as described above, some patients have OSA almost exclusively in REM sleep.

Sleep researchers are not sure if REM OSA causes the same type of daytime symptoms as regular OSA - and are thus not sure if treatment will improve quality of life. REM OSA is more common in females and in those with smaller neck circumferences. In this study, Dr. Su assessed daytime functioning with questionnaires to see if CPAP helps.

The results did show that treating REM OSA with CPAP improved daytime functioning, including improved sleepiness, fatigue, mood, and overall status. They concluded that patients with REM OSA should be treated with CPAP. This has been my clinical experience as well.

Traumatic Memories, Emotional Reactions, and Sleep

Here is an interesting study printed in the January edition of the Journal of Neuroscience. Researchers showed study subjects neutral and traumatic pictures and assessed their ability to remember them as well as the emotional responses. For one group, they showed the pictures shortly after they woke up and the other group saw them right before going to bed. The results showed that recognition of the pictures was greater when the pictures were shown right before sleep, demonstrating that sleep (particularly dream sleep) is helpful in laying down memories. But, the emotional reactions were less if they were shown the pictures right after getting up and not allowed to sleep. The emotional reaction was the same or even intensified in those that saw the images right before bed - and this was especially true in those that had more dream sleep. This implies that depriving oneself of sleep or at least not sleeping for 12 hours after witnessing a traumatic event could reduce the negative emotional reaction to the event. This could have clinical applications in how psychiatrists treat post-traumatic stress disorder.

Sleep Disorders and Parkinson's Disease

Medscape has an article from the Movement Disorders Society 14th International Congress on Parkinson's Disease and Movement Disorders. In the article, it describes research linking falling out of bed while asleep and Parkinson's Disease.

I see this occur in my practice too, and I'll explain what is happening. Normally, our bodies are temporarily paralyzed in dream sleep, so that we don't act out our dreams while asleep. In patients with Parkinson's or Parkinson's-like disorders, that dream paralysis mechanism doesn't always work so well. If this occurs, patients can act out their dreams, with screaming, arms waving, or even attempting to get out of bed. Since patients are responding to their dreams, they often fall right after getting out of bed, sometimes injuring themselves. This problem is referred to as REM sleep behavior disorder.

This might sound ironic, as Parkinson's disease patient's have difficulty moving while awake, but could be moving too much while asleep. Sometimes, this can lead to daytime sleepiness. Unfortunately, Parkinson's disease itself and the medications used to treat Parkinson's disease can lead to daytime sleepiness.

Just to complicate matters more, REM sleep behavior disorder can be worsened by untreated obstructive sleep apnea. Certain medications can worsen the movements in dream sleep as well. So, if a patient is moving too much in their sleep, the exact cause can be difficult to figure out.

Fortunately, REM sleep behavior disorder is usually treatable with medications and making the bedroom environment as safe as possible when the patient sleeps.