Sleep
From Holoprosencephaly
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The anatomy of sleep
Nerve-signaling chemicals called neurotransmitters control whether we are asleep or awake by acting on different groups of nerve cells, or neurons, in the brain. Neurons in the brainstem, which connects the brain with the spinal cord, produce neurotransmitters such as serotonin and norepinephrine that keep some parts of the brain active while we are awake. Other neurons at the base of the brain begin signaling when we fall asleep.
In addition, sleep patterns are also directly affected by the pineal gland, a tiny pine cone-shaped structure located in the back of the brain’s diencephalon region. It is considered part of the body’s endocrine system because it secretes hormones but also considered part of the body’s nervous system because it receives visual nerve stimulation.
This gland functions to support the body’s biological clock that regulates patterns of sleep, hunger, female reproductive cycle and behavior. Visual signals received by the pineal body allow it to determine day length and lunar cycles. Melatonin, a hormone, is secreted in response to these signals. Higher levels of melatonin cause the body to feel tired or depressed. The secretion of melatonin is inhibited by the presence of sunlight.
Children with congenital malformation of the brain’s diencephalon region may experience problems with sleep and some of the other body functions managed by the pineal gland.
The physiology of sleep
Sleep is a protective function that allows for repair and recovery of the tissues following activity. Since sleep and wakefulness are influenced by different neurotransmitter signals in the brain, foods and medicines that change the balance of these signals affect whether we feel alert or drowsy and how well we sleep.
During sleep, we usually pass through five phases of sleep: stages 1, 2, 3, 4, and REM (rapid eye movement) sleep. These stages progress in a cycle from stage 1 to REM sleep, then the cycle starts over again with stage 1. We spend almost 50 percent of our total sleep time in stage 2 sleep, about 20 percent in REM sleep, and the remaining 30 percent in the other stages. Infants, by contrast, spend about half of their sleep time in REM sleep.
During stage 1, which is light sleep, we drift in and out of sleep and can be awakened easily. Our eyes move very slowly and muscle activity slows. People awakened from stage 1 sleep often remember fragmented visual images. Many also experience sudden muscle contractions called hypnic myoclonia, often preceded by a sensation of starting to fall. These sudden movements are similar to the "jump" we make when startled.
When we enter stage 2 sleep, our eye movements stop and our brain waves (fluctuations of electrical activity that can be measured by electrodes) become slower, with occasional bursts of rapid waves called sleep spindles. In stage 3, extremely slow brain waves called delta waves begin to appear, interspersed with smaller, faster waves. By stage 4, the brain produces delta waves almost exclusively. It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. There is no eye movement or muscle activity. People awakened during deep sleep do not adjust immediately and often feel groggy and disoriented for several minutes after they wake up. Some children experience bedwetting, night terrors, or sleepwalking during deep sleep.
When we switch into REM sleep, our breathing becomes more rapid, irregular, and shallow, our eyes jerk rapidly in various directions, and our limb muscles become temporarily paralyzed. Our heart rate increases, our blood pressure rises, and males develop penile erections. When people awaken during REM sleep, they often describe bizarre and illogical tales – dreams.
The first REM sleep period usually occurs about 70 to 90 minutes after we fall asleep. A complete sleep cycle takes 90 to 110 minutes on average. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep. As the night progresses, REM sleep periods increase in length while deep sleep decreases. By morning, people spend nearly all their sleep time in stages 1, 2, and REM.
People lose some of the ability to regulate their body temperature during REM, so abnormally hot or cold temperatures in the environment can disrupt this stage of sleep. If our REM sleep is disrupted one night, our bodies don't follow the normal sleep cycle progression the next time we doze off. Instead, we often slip directly into REM sleep and go through extended periods of REM until we "catch up" on this stage of sleep.
Problems with sleep deprivation
Sleep appears necessary for our nervous systems to work properly. Too little sleep leaves us drowsy and unable to concentrate the next day. It also leads to impaired memory and physical performance and reduced ability to carry out math calculations. If sleep deprivation continues, hallucinations and mood swings may develop. Some experts believe sleep gives neurons used while we are awake a chance to shut down and repair themselves. Without sleep, neurons may become so depleted in energy or so polluted with byproducts of normal cellular activities that they begin to malfunction. Sleep also may give the brain a chance to exercise important neuronal connections that might otherwise deteriorate from lack of activity.
Problems like stroke and asthma attacks tend to occur more frequently during the night and early morning, perhaps due to changes in hormones, heart rate, and other characteristics associated with sleep. Sleep also affects some kinds of epilepsy in complex ways. REM sleep seems to help prevent seizures that begin in one part of the brain from spreading to other brain regions, while deep sleep may promote the spread of these seizures. Sleep deprivation also triggers seizures in people with some types of epilepsy.
Deep sleep coincides with the release of growth hormone in children and young adults. Many of the body's cells also show increased production and reduced breakdown of proteins during deep sleep. Since proteins are the building blocks needed for cell growth and for repair of damage from factors like stress and ultraviolet rays, deep sleep may truly be "beauty sleep." Activity in parts of the brain that control emotions, decision-making processes, and social interactions is drastically reduced during deep sleep, suggesting that this type of sleep may help people maintain optimal emotional and social functioning while they are awake.
Neurons that control sleep interact closely with the immune system. This probably happens because cytokines, chemicals our immune systems produce while fighting an infection, are powerful sleep-inducing chemicals. Sleep may help the body conserve energy and other resources that the immune system needs to mount an attack.
Diagnosing Sleep Problems
People who have chronic sleep problems should be referred to a specialized sleep center that can perform a test called polysomnography. This test records the patient's brain waves, heartbeat, and breathing during an entire night. With this information recorded, a physician will be able to identify abnormalities and work toward treating the condition.
Treating Sleep problems
Some children with HPE and other neurological disorders have difficulty initiating and maintaining sleep. You should contact your physician about how to deal with this problem.
Chloral Hydrate has helped several of these children. Some parents report that dizaepam (Valium) also helps. These medications may become habit forming and after a prolonged use may lose their effectiveness.
There is a non-narcotic alternative called Melatonin. Some have found melatonin to be useful in such children.
These are some helpful tips if your physician recommends this option: Melatonin is available over-the-counter and can be purchased at just about any pharmacy or General Nutrition Center. It comes in 1mg, 3mg, and 5mg tabs. They can be given by mouth or crushed via G-tube with some water. 3mg is typically the beginning dose (in everyone) and then move up or down based on effect. Some children have received up to 15 mg without significant adverse effects. The time required to see an effect is usually about 30 minutes to one hour. Remember that melatonin is not a sedative. Parents are often disappointed after giving a single dose because it didn't seem to work. Parents need to be encouraged to give it regularly, the same time every night. It is more effective after a few weeks rather than immediately.
(Information provided by The Carter Center: http://www.stanford.edu/group/hpe/support/FAQ.html)
Other helpful suggestions:
-Keep a routine:
Go to bed at a set time each night and get up at the same time each morning. Disrupting this schedule may lead to insomnia. "Sleeping in" on weekends also makes it harder to wake up early on Monday morning because it re-sets your sleep cycles for a later awakening.
-Exercise:
Try to exercise 20 to 30 minutes a day. Daily exercise often helps people sleep, although a workout soon before bedtime may interfere with sleep. For maximum benefit, try to get your exercise about 5 to 6 hours before going to bed.
-Relax before bed:
A warm bath, reading, or another relaxing routine can make it easier to fall sleep. You can train yourself to associate certain restful activities with sleep and make them part of your bedtime ritual.
-Sleep until sunlight:
If possible, wake up with the sun, or use very bright lights in the morning. Sunlight helps the body's internal biological clock reset itself each day. Sleep experts recommend exposure to an hour of morning sunlight for people having problems falling asleep.
-Don't lie in bed awake:
If you can't get to sleep, don't just lie in bed. Do something else, like reading, watching television, or listening to music, until you feel tired. The anxiety of being unable to fall asleep can actually contribute to insomnia.
-Control your room temperature:
Maintain a comfortable temperature in the bedroom. Extreme temperatures may disrupt sleep or prevent you from falling asleep.
Sleep Apnea
Sleep apnea is a disorder of interrupted breathing during sleep. It usually occurs in association with fat buildup or loss of muscle tone with aging. These changes allow the windpipe to collapse during breathing when muscles relax during sleep. This problem, called obstructive sleep apnea, is usually associated with loud snoring (though not everyone who snores has this disorder). Sleep apnea also can occur if the neurons that control breathing malfunction during sleep.
During an episode of obstructive apnea, the person's effort to inhale air creates suction that collapses the windpipe. This blocks the air flow for 10 seconds to a minute while the sleeping person struggles to breathe. When the person's blood oxygen level falls, the brain responds by awakening the person enough to tighten the upper airway muscles and open the windpipe. The person may snort or gasp, then resume snoring. This cycle may be repeated hundreds of times a night. The frequent awakenings that sleep apnea patients experience leave them continually sleepy and may lead to personality changes such as irritability or depression.
Sleep apnea also deprives the person of oxygen, which can lead to morning headaches, a loss of interest in sex, or a decline in mental functioning. It also is linked to high blood pressure, irregular heartbeats, and an increased risk of heart attacks and stroke. Patients with severe, untreated sleep apnea are two to three times more likely to have automobile accidents than the general population. In some high-risk individuals, sleep apnea may even lead to sudden death from respiratory arrest during sleep.
Patients with the typical features of sleep apnea, such as loud snoring, obesity, and excessive daytime sleepiness, should be referred to a specialized sleep center for testing.
Treatment
If sleep apnea is diagnosed, several treatments are available. Mild sleep apnea frequently can be overcome through weight loss or by preventing the person from sleeping on his or her back.
Other people may need wear a nasal cannula that delivers a prescribed amount of oxygen or special devices while sleeping, like C-Pap or Bi-Pap (machines that assist in maintaining an open airway) or surgeries (like tonsillectomy and/or adenoidectomy) to correct the obstruction. People with sleep apnea should never take sedatives or sleeping pills, which can prevent them from awakening enough to breathe.
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If you have any concerns, please don't hesitate to discuss your concerns with your child's doctor(s).
For information about dealing with other potential health problems, treatments and medications, please visit our Miscellaneous Health Information category.
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