Thursday, March 31, 2011

Epilepsy, a much-misunderstood disease

Jyoti Shelar, Mumbai Mirror, Mar 25, 2011, 12.45pm IST March 26 is marked as the day for busting myths about epilepsy, a much-misunderstood disease. Ever since Lance Armstrong went global with his fight against cancer and gave the disease a yellow elastic wristband to symbolise with, all other diseases worth their germs have a colour associated with the fight against them. Epilepsy has been vested with the colour purple in order to educate and create awareness about the much-misunderstood disease. Mumbai-based neurologist Dr Janak Nathan has been handed the reins for the job. Purple day, as it's called, will be organised on March 26th, when the doctor and his team of volunteers will take to Mumbai's streets, talking and educating people about the disease. Started in 2008 by nine-year-old Cassidy Megan in Nova Scotia, Canada, who also suffered from the disease, Purple day is the Epilepsy Association's effort to take this fight global. "The colour purple is associated with isolation and solitude. Due to myths and superstitions associated with the disease, many patients are isolated from society. The day will help in making people aware about the disease," says Nathan. Read the rest of the article here.

Potential Dangers Faced By Narcoleptics Who Smoke Cigarettes Considered

ScienceDaily (June 11, 2008) — A research abstract that will be presented on June 9 at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS), provides the first description of nicotine use by narcolepsy patients. Because people with narcolepsy can fall asleep suddenly and without warning, even while eating, walking or driving, those who smoke nicotine in bed are at a high risk of burning either themselves or the objects around them, or starting a fire, if they fall asleep. Further, the excessive sleepiness brought on by their narcolepsy may also complicate any attempt by them to quit the habit of nicotine use.

The study, authored by Lois Krahn, MD, of the Mayo Clinic in Scottsdale, Ariz., focused on unpublished data from a community-based study of narcolepsy, followed by a questionnaire distributed at last year's Narcolepsy Network national meeting to obtain more information. According to the results, in the community-based study, 62.5 percent of narcolepsy patients were past or present smokers. Seventeen questionnaires were completed, in which 47 percent of respondents were past or present nicotine users. All respondents identified nicotine as an effective in decreasing sleepiness. Thirty-seven percent fell asleep while smoking. Twenty-five percent smoked in bed. Burns were reported by 75 percent involving clothing, furniture or carpet. One respondent started a fire. One substituted nicotine patches for cigarettes years ago to continue a "powerful" means to decrease cataplexy. All tried to quit smoking, but described having difficulty because sleepiness worsened without nicotine.

Read the rest of the article here.

Female, Male Youth Report Different Concussion Symptoms

Female athletes who sustain a concussion report different symptoms than their male counterparts, according to research performed at the University of Virginia's Curry School of Education. Sue Saliba, an assistant professor of kinesiology in the Curry School, and Leah Frommer, now an assistant athletic trainer at the University of California at Santa Barbara, conducted the study while Frommer was a graduate student at U.Va. Frommer graduated from Curry in 2006 with a master's degree in athletic training and sports medicine.

The research revealed that in addition to headache, high school girl athletes were more likely to complain of neurological symptoms like sensitivity to light or sleeplessness. Their male peers, conversely, are more likely to report neuro-cognitive issues, like loss of memory or balance control. "We found a difference in the symptom type, and that's never been documented before," Saliba said. However, there was no difference in the students' recovery time. There are more than 1.6 million sport-related concussions reported each year in the United States. More than 5 percent of participants in high school contact sports are affected by concussions.

Their paper, "Sex Differences in Concussion Symptoms of High School Athletes," was published in the January/February issue of the Journal for Athletic Trainers. Read the rest of the article here.

Wednesday, March 30, 2011

A parent's guide to Section 504 in public schools

A parent's guide to Section 504 in public schools

This important civil rights law can provide educational benefits to kids with learning disabilities and/or AD/HD in public schools.
By Mary Durheim

Section 504 — just what exactly is it? You've probably heard about it, but every school district addresses Section 504 in a different manner. Some districts have even been heard to say, “We don’t do that in this district.” But in fact, compliance to Section 504, which is a federal statute, is not optional. This article attempts to answer basic questions pertaining to the implementation of Section 504 in public school systems.

What is Section 504?

Section 504 is a part of the Rehabilitation Act of 1973 that prohibits discrimination based upon disability. Section 504 is an anti-discrimination, civil rights statute that requires the needs of students with disabilities to be met as adequately as the needs of the non-disabled are met.

Section 504 states that: “No otherwise qualified individual with a disability in the United States, as defined in section 706(8) of this title, shall, solely by reason of her or his disability, be excluded from the participation in, be denied the benefits of, or be subjected to discrimination under any program or activity receiving Federal financial assistance...” [29 U.S.C. §794(a), 34 C.F.R. §104.4(a)].

Who is covered under Section 504?

To be covered under Section 504, a student must be “qualified ” (which roughly equates to being between 3 and 22 years of age, depending on the program, as well as state and federal law, and must have a disability) [34 C.F.R. §104.3(k)(2)].

Who is an “individual with a disability”?

As defined by federal law: “An individual with a disability means any person who: (i) has a mental or physical impairment that substantially limits one or more major life activity; (ii) has a record of such an impairment; or (iii) is regarded as having such an impairment” [34 C.F.R. §104.3(j)(1)].

What is an “impairment” as used under the Section 504 definition?

An impairment as used in Section 504 may include any disability, long-term illness, or various disorder that “substantially” reduces or lessens a student’s ability to access learning in the educational setting because of a learning-, behavior- or health-related condition. [“It should be emphasized that a physical or mental impairment does not constitute a disability for purposes of Section 504 unless its severity is such that it results in a substantial limitation of one or more major life activities” (Appendix A to Part 104, #3)].
Sleep Machismo: Viewing lack of sleep as a virtue.
March 29, 2011, 1:30 pm

Writing for USA Today’s Your Life, Dr. Qanta Ahmed spotlighted the term “sleep machismo“”

Americans, in general, are sleep deprived; as their doctors, those in my profession are often no different. Ours is a culture which values “Sleep Machismo,” a term coined by leading chronobiologist Dr. Charles Czeisler in his sentient article in the Harvard Business Review some years ago. I direct every patient who comes to see me to read this important paper; his ideas are that important. Sleep Machismo means valuing sleep loss over sleep, placing all activities above the basic human need of sleep and celebrating the machismo of the sleep-deprived. Americans perceive sleep as an expendable luxury, rather than a biological necessity. Day after day, week after week, we choose to defer bedtime in the interests of a favorite TV show, reading one more article, answering one more e-mail, or catching up on the phone. All the while, we are accumulating sleep debt — a debt which, like financial debt, incurs steep penalties. In 2006, Czeisler argued that “contemporary work and social culture glorifies sleeplessness in the way we once glorified people who could hold their liquor.”

Read the rest of the article here.
Implantable device for sleep apnea studied

March 29, 2011 By Katy Cosse

The National Institutes of Health estimates one in 10 adults over 65 (a total of 18 million Americans) suffers from obstructive sleep apnea (OSA), a disorder in which obstruction in the upper airway can lead to interrupted breathing and sleep. In OSA, the tongue and other tissues of the throat obstruct the airway during sleep, blocking breathing for sometimes up to a minute. These events can occur multiple times throughout the night and severe OSA has been linked with increased risks for cardiovascular disease, diabetes, stroke and accidents resulting from daytime drowsiness. This spring, two UC researchers are collaborating in an international, multi-center trial on an investigational device for treatment of OSA. The STAR (Stimulation Therapy for Apnea Reduction) trial will evaluate the safety and efficacy of the Inspire Upper Airway Stimulation (UAS) therapy in patients with moderate to severe OSA. The UAS therapy, manufactured by Inspire Medical Systems, is an implantable device designed to prevent airway obstruction during sleep. The device, implanted near the clavicle, is connected to a stimulation lead positioned near the airway. There, the lead delivers timed, mild stimulation to the hypoglossal nerve on each breathing cycle.

Read the rest of the article here.
Advanced sensors provide new look at how seizures begin By James M. Connolly Tuesday, March 29, 2011 Researchers at Massachusetts General Hospital and Brown University used sensors, advanced recording techniques and new data handling techniques to track the activity of individual neurons during a seizure. The researchers concluded that different groups of neurons play different roles at different times during a seizure, which is contrary to the commonly-held view that seizures are characterized by massively synchronized activity. The research is being published in Nature Neuroscience, according to a press release from MGH. “Our findings suggest that different groups of neurons play distinct roles at different stages of seizures,” said the paper’s senior author Sydney Cash of the MGH Department of Neurology, in the press release. “They also indicate that it may be possible to predict impending seizures, and that clinical interventions to prevent or stop them probably should target those specific groups of neurons.” Read the rest of the article here.

CHOP Doc: Don't Let Fear Get in the Way of Vaccinations

CHOP Doc: Don't Let Fear Get in the Way of Vaccinations

Paul A. Offit, MD, didn’t mince words when he spoke to a crowd at Holy Redeemer Hospital yesterday. His message was clear — get yourself and your kid vaccinated. Offit, Chief of Infectious Diseases at Children’s Hospital of Philadelphia, addressed and debunked myths about vaccinations to a crowd of about 30 people, many of which were parents and physicians. Offit said emphatically that vaccines don’t cause diseases like Alzheimer’s or autism. With regard to autism, Offit said there have been 14 studies, on three continents, involving over 100,000 people — the studies consistently show that there is no link between the MMR vaccine and autism. He added that the doctor who first proposed the idea in 1998 has since been disgraced. He also pinpointed, to the day, when vaccines first started to be vilified (see the video). Offit said not getting vaccinated is tantamount to selfishness. “When you choose not to get a vaccine, you make the choice for others,” he said. Read the rest of the article here.
The Causes of an Epilepsy Seizure
MC Kelby March 29, 2011 - 6:15pm

According to the Epilepsy Foundation, more than three million Americans are affected by epilepsy and more than ten percent of Americans will experience a seizure during their lifetime. Also, more than 200,000 new cases of epilepsy are diagnosed each year. A person is only diagnosed with epilepsy if they have two or more seizures. Epileptic seizures occur when the brain’s electrical system malfunctions. Also, during a seizure neurons fire faster than normal. They can fire as high as 500 times per second. This surge of energy runs through the brain and can cause the individual to lose consciousness, lose bladder control, shake or convulse, drool or cry out. In people diagnosed with epilepsy, this can happen rarely or hundreds of times per day. Seizures may last only one or two minutes. However, the confusion after a seizure may last a few minutes longer. If an epileptic seizure is severe, the seizure can cause brain damage. For those diagnosed with epilepsy, 80 percent of epileptic seizures can be controlled with surgery and medications. Read the rest of the article here.

New stereo-EEG method can detect epileptic foci during surgeries
Published on March 30, 2011 at 6:50 AM

The neurosurgery department of HUCH (Helsinki University Central Hospital) has started to utilize stereo-EEG method for localizing the epileptic focus in severe epilepsy for epilepsy surgery purposes. The department is also getting ready to introduce the so-called deep brain stimulation (DBS) therapy in the treatment of epilepsy. The first two stereo-EEG explorations in Finland were carried out by neurosurgeons of the Epilepsy surgery team in Helsinki University Central Hospital this spring. The method reinforces other examination methods already in use and opens an excellent opportunity in the exploration of the electric activity of both the surface and the deep brain structures during epileptic seizures. The examination also enables exact localization of the functionally important areas of the brain and improves safety of epilepsy surgery at a later stage. The stereo-EEG examination was developed already in the 1960's, but the recent modifications of the method in the last few years have made it safer and more feasible. The introduction of the method at HUCH benefits particularly patients with severe, drug resistant epilepsy.

Read the rest of the article here.

Tuesday, March 29, 2011

A Century Later, Jury’s Still Out on Caffeine Limits By MURRAY CARPENTER Published: March 28, 2011 The latest skirmish in the caffeine wars — this one involving the high levels of caffeine in so-called energy drinks, especially those consumed by children — recalls one of the earliest. It happened a century ago this month, in a courtroom in Chattanooga, Tenn. The trial grabbed headlines for weeks and produced scientific research that holds up to this day — yet generated no federal limits for caffeine in foods and beverages. Those levels remain virtually unregulated today. As two researchers recently wrote in The Journal of the American Medical Association, nonalcoholic energy drinks “might pose just as great a threat to individual and public health and safety” as alcoholic ones, and “more research that can guide actions of regulatory agencies is needed.” Nobody used the term “energy drink” in 1911, but the drink that was on trial in Chattanooga contained as much caffeine as a modern Red Bull — 80 milligrams per serving. The drink was Coca-Cola. Harvey Washington Wiley, the “crusading chemist” who led the Bureau of Chemistry in the United States Department of Agriculture, had brought a lawsuit against the Coca-Cola Company, accusing it of adulterating the drink by adding a harmful ingredient: caffeine. (Current levels of caffeine in a Coke are much lower.) Read the rest of the article here.
To the brain, getting burned, getting dumped feel the same By Matt McMillen, Health.comMarch 28, 2011 5:21 p.m. EDT Science has finally confirmed what anyone who's ever been in love already knows: Heartbreak really does hurt. In a new study using functional magnetic resonance imaging (fMRI), researchers have found that the same brain networks that are activated when you're burned by hot coffee also light up when you think about a lover who has spurned you. In other words, the brain doesn't appear to firmly distinguish between physical pain and intense emotional pain. Heartache and painful breakups are "more than just metaphors," says Ethan Kross, Ph.D., the lead researcher and an assistant professor of psychology at the University of Michigan, in Ann Arbor. The study, which was published in the journal Proceedings of the National Academy of Sciences, illuminates the role that feelings of rejection and other emotional trauma can play in the development of chronic pain disorders such as fibromyalgia, Kross says. And, he adds, it raises interesting questions about whether treating physical pain can help to relieve emotional pain, and vice versa. "What's exciting about these findings," he says, "is that they outline the direct way in which emotional experiences can be linked to the body." Read the rest of the article here.

Monday, March 28, 2011

Prevent colon cancer with sleep By Dr. Richard Beliveau, Special to QMI Agency Last Updated: March 28, 2011 2:00am The risk of colorectal cancer is strongly influenced by lifestyle habits, particularly diet and physical activity. However, recently obtained data suggests that the length and quality of one's sleep could also play a significant role in the development of this cancer. In our busy society, sleeping is often seen as a waste of time, to the point that sleep deprivation has become normal, rather than an exception. For example, while people at the beginning of the 1960s got an average of seven hours to 8.5 hours of sleep per night, nearly 50% of people today sleep less than seven hours per night. Spread out over a year, this lack of sleep robs us of, on average, the equivalent of a month-and-a-half of sleep, based on our needs. However, sleep is without a doubt the part of our life with the most underestimated impact on our health: * It allows us to recharge the body's energy reserves. * It is critical for growth in children, as it is during the night that the secretion of growth hormones is at its highest. * It allows for the development of memory. "Take advice of your pillow," is a saying that has a biochemical and neurological origin. * It is important for the stabilization of emotions and mental balance. Read the rest of the article here.
Parents can encourage good sleep habits in their kids at a young age 4:25 PM, Mar. 25, 2011 When bedtime rolls around, everyone is ready to go right to sleep, right? If only. Sometimes getting your child to bed can be a struggle. Following the bedtime tips below and staying consistent with them can ease the bedtime battles and have the whole family drifting off to dreamland. “It’s really important to start good sleep habits from the beginning,” said Adria Lind, a family support specialist at the Parent Connection in Menasha. “It just sets the stage.” “Sleep is important for all stages of growth,” said Dr. Kevin Gentile, a pediatrician with Affinity Medical Group, pediatric department in Neenah, noting that sleep helps with physical growth, development of the brain and even with moods. Studies show that just the tiniest decrease of sleep in time can build up and lead to issues in school attention and concentration, Gentile said. In addition, children need to have healthy sleep patterns that will help them later in life. Make sure your child is getting enough sleep. Lack of sleep can lead to drama such as meltdowns and tantrums, even hyperactivity. Read the rest of the article here.
ABSTRACT: Interleukin-1β Biosynthesis Inhibition Reduces Acute Seizures and Drug Resistant Chronic Epileptic Activity in Mice.

Maroso M, Balosso S, Ravizza T, Iori V, Wright CI, French J, Vezzani A. Neurotherapeutics. 2011 Mar 24. [Epub ahead of print]

Experimental evidence and clinical observations indicate that brain inflammation is an important factor in epilepsy. In particular, induction of interleukin-converting enzyme (ICE)/caspase-1 and activation of interleukin (IL)-1β/IL-1 receptor type 1 axis both occur in human epilepsy, and contribute to experimentally induced acute seizures. In this study, the anticonvulsant activity of VX-765 (a selective ICE/caspase-1 inhibitor) was examined in a mouse model of chronic epilepsy with spontaneous recurrent epileptic activity refractory to some common anticonvulsant drugs. Moreover, the effects of this drug were studied in one acute model of seizures in mice, previously shown to involve activation of ICE/caspase-1. Quantitative analysis of electroencephalogram activity was done in mice exposed to acute seizures or those developing chronic epileptic activity after status epilepticus to assess the anticonvulsant effects of systemic administration of VX-765. Histological and immunohistochemical analysis of brain tissue was carried out at the end of pharmacological experiments in epileptic mice to evaluate neuropathology, glia activation and IL-1β expression, and the effect of treatment. Repeated systemic administration of VX-765 significantly reduced chronic epileptic activity in mice in a dose-dependent fashion (12.5-200 mg/kg). This effect was observed at doses ≥ 50 mg/kg, and was reversible with discontinuation of the drug. Maximal drug effect was associated with inhibition of IL-1β synthesis in activated astrocytes. The same dose regimen of VX-765 also reduced acute seizures in mice and delayed their onset time. These results support a new target system for anticonvulsant pharmacological intervention to control epileptic activity that does not respond to some common anticonvulsant drugs. Source.
Developmental Problems May Accompany Epilepsy By Rick Nauert PhD Senior News Editor Reviewed by John M. Grohol, Psy.D. on March 28, 2011 New research suggests children with epilepsy are more likely to have psychiatric symptoms — with gender playing a role in the type of developmental issue. In a study of Norwegian children, scientists discovered girls had more emotional problems, while boys had more hyperactivity/inattention problems and issues regarding peer relationships. The study is available to view online in the journal Epilepsia. Previous studies have shown that children with epilepsy are at increased risk of developing behavioral problems and psychiatric disorders including anxiety, depression, and attention-deficit/hyperactivity disorder (ADHD). In a 2003 population-based study, psychiatric disorders were reported in 37 percent of children with epilepsy, while children with diabetes and those in the healthy control group were much lower at 11% and 9%, respectively. Medical evidence, however, has not clearly established when children or teens with epilepsy may be vulnerable to developing psychiatric issues, or how gender influences psychopathology in epilepsy.
Read the rest of the article here.

Sunday, March 27, 2011

Dear Friends, This show tonight (9 pm in Houston) is about the brother of a friend and colleague of mine. Please take a moment to watch this and recall the great sacrifices that are being made by our friends and neighbors.

Saturday, March 26, 2011

What are febrile seizures? An FAQ about Febrile Seizures

What are febrile seizures? An FAQ about Febrile Seizures 

Febrile seizures are convulsions brought on by a fever in infants or small children. During a febrile seizure, a child often loses consciousness and shakes, moving limbs on both sides of the body. Less commonly, the child becomes rigid or has twitches in only a portion of the body, such as an arm or a leg, or on the right or the left side only. Most febrile seizures last a minute or two, although some can be as brief as a few seconds while others last for more than 15 minutes.
The majority of children with febrile seizures have rectal temperatures greater than 102 degrees F. Most febrile seizures occur during the first day of a child's fever. Children prone to febrile seizures are not considered to have epilepsy, since epilepsy is characterized by recurrent seizures that are not triggered by fever.

How common are febrile seizures?

Approximately one in every 25 children will have at least one febrile seizure, and more than one-third of these children will have additional febrile seizures before they outgrow the tendency to have them. Febrile seizures usually occur in children between the ages of 6 months and 5 years and are particularly common in toddlers. Children rarely develop their first febrile seizure before the age of 6 months or after 3 years of age. The older a child is when the first febrile seizure occurs, the less likely that child is to have more.

What makes a child prone to recurrent febrile seizures?

A few factors appear to boost a child's risk of having recurrent febrile seizures, including young age (less than 15 months) during the first seizure, frequent fevers, and having immediate family members with a history of febrile seizures. If the seizure occurs soon after a fever has begun or when the temperature is relatively low, the risk of recurrence is higher. A long initial febrile seizure does not substantially boost the risk of recurrent febrile seizures, either brief or long.

Are febrile seizures harmful?

Although they can be frightening to parents, the vast majority of febrile seizures are short and harmless. During a seizure, there is a small chance that the child may be injured by falling or may choke from food or saliva in the mouth. Using proper first aid for seizures can help avoid these hazards (see section entitled "What should be done for a child having a febrile seizure?").
There is no evidence that short febrile seizures cause brain damage. Large studies have found that children with febrile seizures have normal school achievement and perform as well on intellectual tests as their siblings who don't have seizures. Even when seizures are very long (more than 1 hour), most children recover completely, but a few might be at risk of subsequent seizures without fever (epilepsy).
In other words, between 95 and 98 percent of children who experience febrile seizures do not go on to develop epilepsy. However, although the absolute risk remains small, some groups of children--including those with cerebral palsy, delayed development, or other neurological abnormalities--have an increased risk of developing epilepsy. The type of febrile seizure also matters:; children who have prolonged febrile seizures (particularly lasting more than an hour) or seizures that affect only part of the body, or that recur within 24 hours, are at a somewhat higher risk. Among children who don't have any of these risk factors, only one in 100 develops epilepsy after a febrile seizure.

What should be done for a child having a febrile seizure?

Seizures are frightening, but it is important that parents and caregivers stay calm and carefully observe the child. To prevent accidental injury, the child should be placed on a protected surface such as the floor or ground. The child should not be held or restrained during a convulsion. To prevent choking, the child should be placed on his or her side or stomach. When possible, gently remove any objects from the child's mouth. Never place anything in the child's mouth during a convulsion. Objects placed in the mouth can be broken and obstruct the child's airway. Look at your watch when the seizure starts. If the seizure lasts 10 minutes, the child should be taken immediately to the nearest medical facility. Once the seizure has ended, the child should be taken to his or her doctor to check for the source of the fever. This is especially urgent if the child shows symptoms of stiff neck, extreme lethargy, or abundant vomiting.

How are febrile seizures diagnosed and treated?

Before diagnosing febrile seizures in infants and children, doctors sometimes perform tests to be sure that seizures are not caused by something other than simply the fever itself. For example, if a doctor suspects the child has meningitis (an infection of the membranes surrounding the brain), a spinal tap may be needed to check for signs of the infection in the cerebrospinal fluid (fluid that bathes the brain and spinal cord). If there has been severe diarrhea or vomiting, dehydration could be responsible for seizures. Also, doctors often perform other tests such as examining the blood and urine to pinpoint the cause of the child's fever.
A child who has a febrile seizure usually doesn't need to be hospitalized. If the seizure is prolonged or is accompanied by a serious infection, or if the source of the infection cannot be determined, a doctor may recommend that the child be hospitalized for observation.

How are febrile seizures prevented?

If a child has a fever most parents will use fever-lowering drugs such as acetominophen or ibuprofen to make the child more comfortable, although there are no studies that prove that this will reduce the risk of a seizure.
Prolonged daily use of oral anticonvulsants, such as phenobarbital or valproate, to prevent febrile seizures is usually not recommended because of their potential for side effects and questionable effectiveness for preventing such seizures.
Children especially prone to febrile seizures may be treated with the drug diazepam orally or rectally, whenever they have a fever. The majority of children with febrile seizures do not need to be treated with medication, but in some cases a doctor may decide that medicine given only while the child has a fever may be the best alternative. This medication may lower the risk of having another febrile seizure. It is usually well tolerated, although it occasionally can cause drowsiness, a lack of coordination, or hyperactivity. Children vary widely in their susceptibility to such side effects.
In addition, some children are prone to having very long (lasting an hour or more) febrile seizures. When a child has had a long febrile seizure, subsequent ones might also be long. Because very long febrile convulsions are associated with increased risk of developing epilepsy, some doctors will suggest the child be treated with a rectal form of the drug diazepam to stop the seizure and prevent it from becoming long. The parents of a child who had a very long febrile seizure may wish to consult their doctor about this possibility.

What research is being done on febrile seizures?

The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), sponsors research on all forms of febrile seizures in medical centers throughout the country. NINDS-supported scientists are exploring environmental and genetic risk factors that may make children susceptible to febrile seizures. Scientists are also working to pinpoint factors that can help predict which children are likely to have recurrent or long-lasting febrile seizures.
Investigators continue to monitor the long-term impact that febrile seizures might have on intelligence, behavior, school achievement, and the development of epilepsy. For example, scientists conducting studies in animals are assessing the effects of febrile seizures, and especially very long seizures, on measures of intelligence and on the development of epilepsy. In particular they are trying to see if they can predict which children experiencing a very long febrile seizure might be at a higher risk for these problems, and how this risk can be lessened or prevented.
Investigators also continue to explore which drugs can effectively treat or prevent febrile seizures and to check for side effects of these medicines.
Where can I get more information?
For more information on neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute's Brain Resources and Information Network (BRAIN) at:
P.O. Box 5801
Bethesda, MD 20824
(800) 352-9424
Information also is available from the following organizations:
Epilepsy Foundation
8301 Professional Place
Landover, MD 20785-7223
Tel: 301-459-3700 800-EFA-1000 (332-1000)
Fax: 301-577-2684

Intractable Childhood Epilepsy Alliance
PO Box 365
6360 Shallowford Road
Lewisville, NC 27023
Tel: 336-946-1570
Fax: 336-946-1571

"Febrile Seizures Fact Sheet," NINDS.
NIH Publication No. 06-3930

Publicaciones en Español

Prepared by:
Office of Communications and Public Liaison
National Institute of Neurological Disorders and Stroke
National Institutes of Health
Bethesda, MD 20892

Sleep Dictionary

The world of sleep and sleep disorders contains a great many words and terms that are not used in our daily lives. As you read through the material posted at the website, you may run across a sleep term which you don't understand. In many situations, there will be a highlighted word in that article that will link you directly to a definition, either in the article or here in this Sleep Dictionary. You may also hear or read other sleep terms. Hopefully, those terms will also be defined here in this dictionary, to help you understand their meaning.

If you can't find a definition or explanation in this Sleep Dictionary, please send us a suggestion to add that term to our list. We want this list to include all of those sleep words and phrases that you want to know about. We'll review your suggestion and consider adding those new definitions to our list.

To find your word or phrase quickly, please click on the letter that is the first letter of your word, and you will move to the beginning of that section of the Sleep Dictionary.

A top of page

Advanced Sleep Phase Syndrome (ASPS) - a circadian rhythm disorder in which sleep onset occurs in early evening and as a consequence, wakefulness occurs in early morning. This disorder is more common in the elderly.

alpha waves - EEG (brain) wave activity that occurs during quiet wakefulness, such as when the eyes are closed. The frequency of alpha waves is between 8 to 12 hertz (cycles per second). It is indicative of the wakeful state in humans.

alternative medicine - any of the various practices or healing methods for treating illness that are not taught in a traditional curricula of a U.S. or U.K. medical school. Some of these include homeopathy, herbal remedies, acupuncture, meditation, chiropractic medicine, and faith healing.

anticonvulsant - a class of drugs that work to suppress sensory disturbances; they are often used to treat epileptic seizures.

antidepressant - a type of drug traditionally used to relieve or prevent psychiatric disorders associated with depression, but also used in the treatment of cataplexy, hypnagogic hallucinations, and sleep paralysis.

antihistamine - a drug that inhibits histamine, a compound that mediates inflammation and produces allergic reactions; antihistamines are a common ingredient in over-the-counter sleeping pills because of their sedative effect.

anxiolytics - a drug that relieves anxiety.

apnea - derived from Greek translated as "want of breath;" episodes of non-respiration during sleep that last at least 10 seconds. See central, chronic, or mixed sleep apnea.

arousal - "Partial" arousal is an abrupt change from a "deep" stage of NREM sleep (stage 3-4) to a "lighter" one (stage 2 or 1). "Full" arousal means awakening. During an arousal, your muscle tone increases, your heart may beat faster and you may move.

augmentation - a result of prolonged use of dopaminergic agents in which symptoms (of Restless Legs Syndrome) are chased into the daytime sometimes necessitating daytime dosing.

automatic behavior - performing activities or tasks with little or no recollection of the event.

awakening - "Spontaneous" awakenings most often start while you are in REM sleep, although you may awaken from NREM sleep, as well. When you are awake, your brain waves are of the alpha or beta pattern (see brain wave rhythms), your muscle tone is high and you can move voluntarily.

B top of page

bedtime - defined as the time when one attempts to fall asleep (as distinguished from the time one gets into bed).

beta waves - EEG (brain) wave activity with a frequency of 13 to 35 hertz (cycles per second) that is typically seen in active wakefulness and also associated with taking psychotropic drugs, in which the eyes blink repeatedly.

benzodiazepine - a class of central nervous system depressants; examples include Valium (diazepam), Klonopin (clonazepam), Restoril (temazepam), and Halcion (triazolam); useful for managing insomnia, Restless Legs Syndrome, Periodic Limb Movement Disorder, sleepwalking, and REM Behavior Disorder.

bilevel positive airway pressure - an air compressor that blows a higher pressure for inhaling and a lower pressure for exhaling. BiPAP is generally used for apnea patients who can not tolerate high constant air pressure with CPAP.

bimaxillary advancement - a surgical procedure in which the upper and lower jawbones and teeth are moved forward and held in place with titanium plates and screws so that soft tissue structures are pulled forward, creating more space for the tongue.

"biological clock" - the term used to describe an internal timing mechanism that exists in most living systems and is thought to be located in the suprachiasmatic nucleus. It is the current explanation by which various cyclical behaviors and physiological processes are regulated and synchronized with environmental events.

biological rhythm - a regular pattern or cycle of change in an organism related to a physical variable, such as heart rate, body temperature, sleep-wake cycle, and so on.

BiPAP - an acronym for Bilevel Positive Airway Pressure; an alternative therapy to CPAP for the treatment of obstructive sleep apnea that allows for choosing a separate respiratory and expiratory pressure.

Brain-Wave Rhythms - Patterns of electrical activity of the brain. They include:

Alpha Rhythms - Most consistent and predominant during relaxed wakefulness, particularly when your eyes are closed or you are in the dark. Alpha rhythms cycle eighteen times per second.
Beta Rhythms - Usually associated with alert wakefulness. They are faster than Alpha waves, cycling about thirteen to thirty-five times per second.
Delta Rhythms - Occur chiefly in deep sleep stages 3-4, also known as slow-sleep. Delta Rhythms cycle less than four times per second.
Theta Rhythms - Associated with the light sleep stage 1 and 2. These cycle four to eight times per second.

bright light therapy - a treatment used to treat circadian rhythm disturbances; also used to treat Seasonal Affective Disorder (SAD).
bruxism - also called teethgrinding; a parasomnia characterized by the grinding or clenching of teeth during sleep.

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cataplexy - a temporary decrease or complete loss of muscle control triggered by an emotional response that is often seen in narcoleptics. Also, a sudden, dramatic drop in muscle tone and loss of deep reflexes, which leads to muscle weakness or paralysis (an attack may cause a person to collapse). It is usually triggered by an emotional stimulus such as laughing or being startled, or by some sudden physical exertion. Cataplexy is a symptom of narcolepsy, a neurologic disorder that causes excessive sleepiness.

central nervous system - also called the CNS; the part of the nervous system that consists of the brain and the spinal cord, which are responsible for the coordination of all motor and mental activities.

central sleep apnea - episodes of non-respiration during sleep for 10 second or longer that is caused by the brain failing to signal the respiratory muscles to breathe.

chronic insomnia - regular sleeplessness that lasts for more than three weeks and is persistent without treatment.

chronobiology - the scientific study of biological rhythms and timing mechanisms, sleep-wake cycles, heart rate, hibernation cycles, and body temperature.

circadian - a cycle that lasts about 24 hours.

circadian rhythms - the process of biological variations over 24 hours, coordinated by the suprachiasmatic nuclei in the brain, which regulate body temperature, hormone secretions, and other physiological functions.

cognitive-behavioral therapy - psychological therapy which focuses on changing attitudes and beliefs related to sleep and insomnia.

complementary medicine - the science of combining one or more conventional treatments with one or more alternative treatments to aid in the healing process. For example, treatment for insomnia might include a medication in combination with relaxation therapy.

compulsive hyperphagia - a disorder of excessive and compulsive overeating; it is often accompanied with other disorders, such as hypersexuality and hypersomnia, and is also associated with Kleine-Levin syndrome.

continuous positive airway pressure - also called CPAP; a type of therapy used to effectively treat obstructive sleep apnea in which an air compressor forces air through the nose and into the airway by way of a light mask worn over the nose during sleep.

cortisol - (the same as hydrocortisone) a steroid hormone produced in the adrenal gland that influences the metabolism of various cell types.

CPAP - an acronym for Continuous Positive Airway Pressure; an effective therapy used to treat obstructive sleep apnea.

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Delayed Sleep Phase Syndrome (DSPS) - a circadian rhythm sleep disorder characterized by difficulty achieving sleep onset in the evening and difficulty waking up at a desired time in the morning. It involves a desired sleep time out of sync with physiologic sleep time.

delta waves - EEG activity with a frequency of less than 4 hertz (cycles per second) that is most often seen in Stage 3 and 4 of non-REM sleep.

delta sleep - also called slow wave sleep; a term used to describe the stages of sleep characterized by delta waves. It is regarded as the most restorative time of sleep.

dopaminergic agents - a class of drugs synthesized with the neurotransmitter dopamine and is most often used to treat Parkinson's patients; often helpful in managing Restless Legs Syndrome and Periodic Limb Movement Disorder.

dreams - periods of intense vivid imagery during sleep, often associated with rapid eye movements.

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electroencephalogram - also called an EEG; the measurement and recording of brain wave activity. Frequency measurement in hertz ranges from below 3.5 per second (delta), 4 to 7.5 second (theta), 8 to 12 second (alpha), and above 13 second (beta). Electrodes are typically placed at C3 and C4 positions on the scalp.

electromyogram - also called an EMG; the measurement and recording of muscle activity, particularly under the chin, along the jaw, and on the legs.

electro-oculogram - also called an EOG; the detection and recording of eye movements, essential for determining the different sleep stages.

endogenous circadian pacemaker - an internal mechanism in the brain, thought to be at the site of the suprachiasmatic nucleus, that drives periodic processes, such as the sleep-wake cycle, body temperature, and cortisol release, in the human circadian timing system.

enuresis - also called bed-wetting or sleep enuresis; uncontrolled urination during sleep. This disorder is more common in children and often related to maturation; however, repeated nocturnal bed-wetting can indicate other physical or emotional problems.

excessive daytime sleepiness - sometimes called excessive sleepiness, the inability to stay awake during the normal wake period of a sleep-wake cycle or may involve involuntary sleep. Common causes include: insufficient sleep, sleep apnea, narcolepsy, and insomnia.

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"Factor S" - a substance in the cerebrospinal fluid that has sleep-inducing properties.

fragmentation - the interruption of any stage of sleep due to appearance of another stage or waking. Sleep fragmentation connotes repetitive interruptions of sleep by arousals and awakenings.

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genioglossus muscle - a muscle that attaches from the back of the tongue to a region on the back of the chin and serves to advance, retract and depress the tongue.

genioglossus advancement - a surgical operation that detaches the genioglossus muscle from its insertion point and reattaches it in a more advanced position in order to pull the back of the tongue forward, enlarging the air space behind the tongue.

glossectomy - the surgical reduction or removal of the tongue, used to open the lower airway or to remove cancerous tissue.

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Hertz (Hz) - the unit of measurement for cycles per second; used to measure EEGs.

homeostatic - (homeostasis, n.) the balanced state of the living body (i.e. temperature, chemistry, blood pressure, sleep and wakefulness, and so on), despite variations in the environment.

hyoid advancement - a surgical operation in which the hyoid bone is moved forward and either attached to the Adam's apple or to the jawbone, enlarging the air space behind the tongue.

hyoid bone - a C-shaped bone in the upper neck positioned above the Adam's apple with muscle attachments to the back of the tongue, as well as the sides of the lower throat.

hypersomnia - also called excessive (daytime) sleepiness or somnolence; the inability to remain awake during an individual's normal wake period.

hypnagogic hallucinations - vivid, often frightening, dream-like images and sounds experienced at REM sleep onset, usually accompanied by fear and anxiety; a characteristic feature of narcolepsy.

hypnic jerk - also called sleep starts; the sensation of falling and then a physical jerk into wakefulness, usually during Stage 1 sleep.

hypnotic - also called a sleeping pill, sedative, or a sedative-hypnotic medication; a medication that causes drowsiness, induces sleep onset, and/or maintains sleep.

"hypnotoxin" - also called sleep promoting substance (SPS); the term coined by Henri Pieron in 1907 that described a sleep-inducing substance thought to be in the cerebrospinal fluid.

hypopnea - an episode of abnormally slow or shallow respiration during sleep that lasts longer than 10 seconds. Hypopnea differs from apnea in that some airflow is present.

hypothalamus - the region at the base of the brain involved in autonomic processes such as temperature regulation, food intake, and emotional activity, and thought to be important in the role of sleep and wakefulness.

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idiopathic - occurring spontaneously and without known cause.

idiopathic hypersomnia - a disorder of excessive sleepiness in which the affected individual sleeps longer than normal (greater than 10 hours), is excessively sleepy, falls asleep at inappropriate times, and frequently takes naps. Its exact cause is unknown.

insomnia - the inability to sleep applied to the general complaint of having trouble falling or staying asleep; insomnia is a symptom usually caused by underlying problems. See also transient, short-term, chronic, and sleep onset insomnia.

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jet lag - a condition that occurs following air travel through multiple time zones (usually 3 of more zones) and is characterized by various psychological and physiological effects, such as fatigue, gastrointestinal disturbances, and irritability, caused by a disruption in circadian rhythms.

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K-complex - high voltage EEG activity that consists of a sharp upward component followed by a slower downward component and lasts more than .5 seconds; required for definition of Stage 2 non-REM sleep.

Kleine-Levin syndrome - a disorder distinguished by recurrent hypersomnia, compulsive overeating, and hypersexuality and first described by Willi Kleine in 1925 and then by Max Levin in 1929.

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lark - also called a morning person or morning lark; a person who prefers go to bed early in the evening and rise early in the morning. This tendency becomes more common in the elderly.

laser-assisted uvulopalatoplasty (LAUP) - a surgical procedure for the treatment of habitual loud snoring or obstructive sleep apnea that involves removal of the back edge of the palate, the uvula, and if present, the tonsils.

latency period - an interval. Sleep latency is the interval from "lights out" until sleep begins. REM latency is the period from the beginning of sleep to the first appearance of rapid eye movement (REM) sleep.

L-Dopa - also called dopaminergic agents; a dopamine-enhancing class of drugs most often used to treat Parkinson's patients; often helpful in managing Restless Legs Syndrome and Periodic Limb Movement Disorder. Examples include L-Dopa with Sinemet (carbidopa), Permax (pergolide), and Parlodel (bromocriptine).

"leucomaines" - the name for the poisonous substances that supposedly accumulated during the day and passed from the blood to the brain. Leo Errera proposed that these substances in the 1880s were the cause of sleep.

light box - a commercially available, electrically-powered instrument that provides artificial light; a treatment option for patients with Seasonal Affective Disorder, Advanced Phase Sleep Disorder, or Delayed Phase Sleep Disorder.

light therapy - a treatment for various disorders including seasonal affective disorder, depression, hypersomnia, and delayed phase sleep disorder. It involves properly timed exposure to bright light to promote a normal sleep-wake cycle and decrease sleep disturbances.

lingualplasty - a surgical procedure that involves a resection of the tongue with additional removal of side wedges in order to reduce the back of the tongue and open the lower airway.

lingual tonsils - tonsil-like tissue on the back part of the tongue.

lux - a measure of light intensity; the unit used by light box manufacturers to describe light output.

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maintenance of wakefulness test - also called MWT, a test that consists of four 20-minute trials conducted every 2 hours and is used to determine a patient's ability to stay awake during the day. Contrary to a MLST, the MWT is scored on the patient's ability to remain awake during the trials.

melatonin - in nature, a hormone that is secreted by the pineal gland in the brain in response to darkness, and has been linked to regulation of circadian rhythms; a derivative of melatonin marketed as a health food supplement is commercially available.

mental imagery - the process of creating images in the mind.

microsleep - a lapse from wakefulness into sleep that lasts just a few seconds.

mixed sleep apnea - the combination of central and obstructive sleep apnea.

montage - the term applied to the testing variables and their order on polysomnogram paper or a computer monitor, such EEG, EOG, heart rate, and so on.

MSLT - the acronym for multiple sleep latency test; a test used to study and document excessive daytime sleepiness by way of a series of naps at two-hour intervals.

multiple sleep latency test - a test used to study and document excessive daytime sleepiness by way of a series of naps at two-hour intervals.

MWT - an acronym for the maintenance of wakefulness test, in which four 20-minute trials are conducted every two hours and the patient is encouraged to stay awake.

myoclonus - see nocturnal myoclonus.

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narcolepsy - a physical condition characterized by episodes of inappropriate and often involuntary sleep in the form of naps that may last a few minutes to hours; usually accompanied by cataplexy, sleep paralysis, and hypnagogic hallucinations.

National Sleep Foundation (NSF) - established in 1990 as an "independent nonprofit organization dedicated to improving public health and safety by achieving public understanding of sleep and sleep disorders."

negative sleep conditioning - a psychological state perpetuated by self-induced stress and anxiety of needing to attain sleep; specifically, it refers to an inability to sleep at night in one's own bed.

neuron - a type of nerve cell (or brain cell) that has a central cell body (axon) and long endings (dendrites) specialized to receive, conduct, and transmit signals in the nervous system.

nightmare - a sleep-disrupting dream that is often recalled in detail. An anxiety-filled dream that often wakes the sleeper from REM sleep. It is distinguished from "sleep terror," which is sudden, partial arousal from NREM sleep that may cause the sleeper to cry out in fright but that seldom includes vivid images.

night owl - also called a night person or evening person; a name applied to someone who prefers to stay up into the night or early morning and arise in late morning.

nocturia - also called nycturia; frequent urination at night that results in arousal of sleep and rising frequently to go to the bathroom. It can be caused by urological problems, infection, a tumor, or medication and has been associated with the development of obstructive sleep apnea.

nocturnal - of the night or night-related; the opposite of diurnal.

nocturnal myoclonus - a brief rapid twitch that occurs at night as a result of a sudden contraction of one or more muscle groups; former name of Periodic Limb Movement Disorder.

non-REM sleep - a state of sleep characterized by four stages that range from light dozing to deep sleep; 75% of sleep is spent in non-REM sleep. In stages 3 and 4 of NREM sleep, there is a decrease in blood pressure, muscle activity, and respiratory rate as the sleeper relaxes.

normal hypersomnia - a disorder in which the affected individual requires more sleep than normal, i.e. more than 10 hours of sleep per day, and which may be the result of a genetic predisposition. Normal hypersomniacs are also called "naturally long sleepers."

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obstructive sleep apnea (syndrome) - also called OSA; a common form of apnea, in which the airway is blocked, resulting in a lack of respiration and a momentary interruption of sleep; usually caused by physical abnormality.

opiate - a class of codeine-derived, controlled narcotics, such as Tylenol #3, Percocet (oxycodone), Darvon (propoxyphene) and methadone; used to manage severe cases of Restless Legs Syndrome and Periodic Limb Movement Disorder.

OTCs - an acronym for over-the-counter medications, those that are available for purchase without a prescription.

OSA - an acronym for obstructive sleep apnea; a common form of apnea

otolaryngology - the medical study of the ears, nose, and throat (ENT)

over-the-counter medications - drugs that available to the general public without a prescription.

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paradoxical therapy - an effective therapeutic approach to conquering insomnia that asks the insomniac to do the exact opposite of trying to fall asleep.

parasomnia - a term used to describe uncommon disruptive sleep-related disorders, such as sleepwalking, sleep talking, and nightmares.

pavor nocturnus - a term derived from Latin pavor, terror, and nocturnus, at night. See also sleep terrors.

Periodic Limb Movement Disorder - also called PLMD, Periodic Limb Movement Syndrome, or PLMS; a condition in which the legs or arms twitch or move involuntarily and periodically during sleep.

periodic limb movement index - the record of the number of leg or arm movements during each hour of sleep measured by sensors placed on the legs and arms.

Pickwickian syndrome - the first term applied to obstructive sleep apnea, originally described by Charles Dickens in 1836. It referred to people who were excessively sleepy, loud snorers, and overweight.

PLMD - an acronym for Periodic Limb Movement Disorder; a condition in which the legs or arms twitch or move involuntarily and periodically during sleep.

polyp - a projecting growth or mass, usually benign, that forms in a mucous membrane and in the nasal passages, causes obstructed airflow.

polysomnogram - also called a PSG, sleep study, or sleep test; a non-invasive test that records vital signs and physiology during a night of sleep. It includes measurements from an EEG, EMG, and EOG, as well as respiratory airflow, blood oxygen saturation, pulse rate, heart rate, body position, and respiratory effort.

postprandial dip - a slight drowsiness caused by a natural drop in body temperature, particularly in early afternoon and after a meal.

post-traumatic hypersomnia - a disorder of excessive sleepiness that appears within 18 months of a traumatic event involving a central nervous system-related accident.

primary snoring - snoring not associated with apnea.

Process C - the natural behavior and tendency, regulated by human circadian rhythms, to sleep during the "sleepy phase" of the body, usually between 11:00 p.m. and 7:00 a.m.

Process S - also known as the homeostatic process, it is the disposition of a normal person who is sleep-deprived to become sleepy when awake, and sleep deeper and longer when sleep is achieved.

pupillometry - the measurement of pupil diameter and activity as related to alertness or sleepiness. This test is used more for research rather than a diagnostic assessment.

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radio-frequency tissue ablation - a technique that uses radio-frequency waves via a needle electrode placed under the surface of the tissue, resulting in contraction and subsequent shrinkage of excessive tissues that cause snoring.

recurrent hypersomnia - a disorder of excessive sleepiness that occurs weeks or months apart, often accompanied with other disorders such as hypersexuality or compulsive eating.

relaxation therapy - also termed relaxation imagery; various methods or techniques for the alleviation of insomnia that help to relax the mind and the body and which can facilitate sleep onset.

REM latency - the period of time in the sleep period from sleep onset to the first appearance of REM sleep.

REM onset - the designation for commencement of a REM period.

REM percent - the proportion of total sleep time constituted by the REM stage of sleep.

REM Rebound or Recovery - an increased amount of REM sleep for a few nights after a period of REM deprivation. REM rebound may occur after several days without sleep, or upon withdrawal from certain drugs, including some sleeping pills, that suppress REM sleep. Increased amounts of REM sleep may be reflected by disturbing dreams.

REM sleep - also known as "paradoxical" sleep, this state of sleep is characterized by rapid eye movement (REM), muscle paralysis, and irregular breathing, heart rate, and blood pressure. Dreaming takes place during REM sleep.

respiratory disturbance index (RDI) - a record of the number and duration of apnea episodes, both obstructive and central, during each hour of sleep. An RDI of greater than 5 is regarded as abnormal.

Restless Legs Syndrome - also called RLS; a neurological disorder of unknown cause that causes irrepressible twitching and creeping sensations in the legs while sitting or lying down.

RLS - an acronym for Restless Legs Syndrome; a disorder that causes irrepressible and uncontrollable tingling sensations in the legs.

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SAD - an acronym for seasonal affective disorder; a disorder with depression-like symptoms that occurs in the late fall because of less light exposure and diminishes with the onset of spring.

SCN - an acronym for suprachiasmatic nuclei and sometimes called the endogenous circadian pacemaker; small structures in the brain, sensitive to the presence or absence of light, that coordinate circadian rhythms.

seasonal affective disorder - a disorder characterized by depression, sleeping too much, overeating, diminished sex drive, working less productively, and other depression-related symptoms that occurs in the mid-to-late fall due to less light exposure. Symptoms usually diminish with the onset of spring.

sedative - also called a sleeping pill or hypnotic; a medication that causes drowsiness, induces sleep onset, and/or maintains sleep.

selective serotonin reuptake inhibitors - a class of antidepressants that assist nerve impulses along pathways using the neurotransmitter serotonin; effective in treating narcolepsy symptoms. Examples include: Zoloft, Prozac, and Paxil.

septoplasty - a surgery sometimes used to treat obstructive sleep apnea in which a small incision is made inside a nostril, and the cartilage and bone of the septum is straightened.

septum - the divider between the two nasal passages; if deviated (crooked), the septum can obstruct the nasal passages.

serotonin - a neurotransmitter found in brain stem cells and other parts of the central nervous system; in animal studies, the inhibition of the formation of serotonin led to severe insomnia.

short-term insomnia - temporary sleeplessness that arises because of ongoing stress, a temporary illness, or a traumatic experience.

sleep - a physical and mental resting state in which a person becomes relatively inactive and unaware of his or her environment.

sleep apnea - episodes of non-respiration during sleep that last at least 10 seconds and occur 5 times per hour of sleep; see central, chronic, or mixed sleep apnea.

sleep architecture - the structure of the sleep cycle and wakefulness as it occurs over a period of sleep.

"sleep center" - a localized area in the brain believed to regulate sleep.

sleep cycle - the cycle in which non-REM and REM sleep alternate in 90- to 110- minute phases. A normal sleep pattern has 4 to 5 sleep cycles.

sleep debt - the deficiency of sleep created when personal sleep requirements are not met.

sleep deprivation - a mental and physical state that arises when sleep has not been attained or has been inhibited. In some cases, it can cause an inability to concentrate, loss of memory, and rarely, hallucinations and erratic behavior.

sleep disorders - physical and psychological conditions or disturbances of sleep and wakefulness, usually caused by abnormalities that occur during sleep or by abnormalities of specific sleep mechanisms.

sleep efficiency - the proportion of sleep in the period potentially filled by sleep; that is, the ratio of total sleep time in bed.

sleep hygiene - the practice of achieving and maintaining proper habits to promote good sleep.

sleep latency - the period of time measured from "lights out," or bedtime, to the commencement of sleep.

sleep maintenance insomnia - one or more episodes of wakefulness that occur later in the night and may be due to medical illness, primary sleep disorders, or depression.

sleep medicine - the science of the study of sleep and its processes; also refers to the clinical practice of assessing and treating sleep disorders.

sleep mentation - the imagery and thinking (and emotion) experienced during sleep.

sleep onset - the transition from the awake to the sleep state, normally into NREM stage 1 (but in certain conditions, such as infancy and narcolepsy, into REM.) Most polysomnographers accept EEG slowing, reduction and eventual disappearance of alpha activity, presence of EEG vertex spikes and slow rolling eye movements (the components of NREM stage 1) as sufficient for sleep onset; others require appearance of stage 2 wave forms. (See sleep latency, sleep stages.)

sleep onset insomnia - insomnia characterized by a delay in falling asleep, lasting 30 minutes or longer, at the time when one goes to bed; it is most commonly caused by anxiety.

sleep paralysis - a brief loss of muscle control that occurs at the onset of sleep or upon awakening; a condition usually associated with narcolepsy. May last from a few seconds to a few minutes. Occurs in one in twenty healthy people but is more common in those with narcolepsy.

sleep restriction therapy - a behavioral treatment developed by Dr. Arthur Spielman and colleagues that follows a simple principle: Restrict time in bed to only the number of hours asleep, then increase time in bed as sleep efficiency increases.

sleep spindles - a pattern of EEG waves that consist of a burst of 11 to 15 hertz waves that last for .5 to 1.5 seconds; an identifying feature of Stage 2 sleep.

sleep talking - also called somniloquy; a parasomnia characterized by talking during sleep.

sleep terrors - also called pavor nocturnus or night terrors; a parasomnia characterized by episodes of screaming or shouting and occasionally, sleepwalking. Sleep terrors are usually associated with fear and anxiety.

sleep-wake cycle - the repeated pattern over 24 hours that consist of periods of sleep alternating with periods of wakefulness.

sleepwalking - also called somnambulism; a parasomnia characterized by walking or performing other complicated activities while asleep.

Slow Wave Sleep (SWS) - synonymous with sleep stages 3 and 4.

snoring - the noise produced by a sleeping individual in which the soft palate and the uvula vibrate during respiration.

somnambulism - see also sleepwalking; a parasomnia characterized by walking or performing other complicated activities while asleep.

somniloquy - (somniloquism) see also sleep talking; a parasomnia characterized by talking during sleep.

somnolence - also called excessive sleepiness or excessive daytime sleepiness; the inability to stay awake during the normal wake period of a sleep-wake cycle. It can be measured by a multiple sleep latency test (MSLT)

somnologist - a specialist in the study of sleep and in the diagnosis and treatment of sleep disorders.

somnoplasty - a non-invasive procedure that uses radio frequency to reduce structures in the mouth in the treatment of snoring and obstructive sleep apnea.

Stage 1 sleep - the brief, dozing stage of non-REM sleep in which a person transitions to very light sleep and can be awakened easily, characterized by low voltage EEG and slow rolling eye movements; 5% of non-REM sleep is spent in Stage 1.

Stage 2 sleep - the stage of consolidated sleep in non-REM sleep characterized by sleep spindles and K-complexes; 45% of non-REM sleep is spent in Stage 2.

Stage 3 sleep - the stage of deeper sleep in non-REM sleep characterized by delta waves interspersed with smaller, faster waves; 12% of non-REM sleep is spent in Stage 3.

Stage 4 sleep - the stage of very deep sleep in non-REM sleep almost exclusively composed of delta waves and the stage in which sleep terrors or sleepwalking may occur; 13% of non-REM sleep is spent in Stage 4.

stimulant - a type of drug, such as Cylert, Ritatlin, and Dexedrine, that stimulates the central nervous system; often used to treat excessive daytime sleepiness.

stimulus control - an effective insomnia technique developed by Dr. Richard Bootzin and colleagues which proposes that an individual has 10 minutes to fall asleep. If sleep is not achieved, the person must get up, go into another room, and return to bed only when sleepy. Also called the 10-minute rule.

suprachiasmatic nuclei - also called the SCN or the endogenous circadian pacemaker; small structures in the brain, sensitive to the presence or absence of light, that coordinate circadian rhythms.

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teethgrinding - also called bruxism; a parasomnia characterized by the grinding or clenching of teeth during sleep.

The 10-Minute Rule - a relaxation and sleeping technique that suggests that an individual who has laid awake in bed for an estimated 10 minutes to get up, go into another room, relax by doing something boring, and then return to bed when sleepy.

tonsils - masses of lymphoid tissue at the back of both sides of the mouth whose primary function is fighting infection.

tonsillectomy - surgical removal of the tonsils.

total sleep period - the period of time measured from sleep onset to final wakening. In addition to total sleep time, it is comprised of the time taken up by arousals and movement time until wake-up. (See Sleep Efficiency).

total sleep time - the amount of actual sleep time in a sleep period; equal to total sleep period less movements and awake time. Total sleep time is the total of all REM and NREM sleep in a sleep period.

tracheostomy - also known as a tracheotomy; a surgical procedure that creates an opening in the windpipe via the neck in order to insert a tube that facilitates breathing. This procedure is reserved for patients with severe sleep apnea.

transient insomnia - sometimes called adjustment sleep disorder or situational insomnia, it is sleeplessness that lasts a few consecutive nights and is often triggered by stress or excitement.

turbinate - also called the nasal concha; any of three bones (lowest, middle, and upper) within the nose that are surrounded by soft tissue and form the sides of the nasal cavity.

turbinate reduction - a surgical procedure used to reduce the size of an enlarged turbinate, which can improve the size of the nasal airway, thereby relieving obstructive sleep apnea.

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UPPP - an acronym for uvulopalatopharyngoplasty; the surgical procedure for the removal of the uvula and tightening of loose tissue in the back of the throat.

"urotoxins" - coined by Abel Bouchard in 1886, a term he used to describe toxic agents excreted in the urine during sleep.

uvula - the tissue that hangs down in the back of the throat.

uvulopalatopharyngoplasty - also called UPPP; the surgical procedure for the removal of the uvula and tightening of loose tissue in the back of the throat.

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vigilance testing - the process of assessing the level of alertness during wakefulness in a clinical or research setting. It may include a series of tests such as the Epworth Sleepiness scale, pupillometry, reaction time tests, a MLST, or MWT.

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wakefulness - a brain state that occurs when a healthy individual is not asleep.