Sleep and Sleep Disorder Ch. 1-4

circadian rhythms

from the Latin "circa-dies," meaning "about a day"; any process that fluctuates on a daily cycle of about twenty-four hours

Describe the typical sleep-wakefulness patterns in an average neonate. What is the likely total amount of sleep per day? Is there any REM sleep at this age? Does the average neonate know the difference between night and day?

Neonates sleep an average of sixteen to eighteen hours per day. The normal range, however, is quite large, ranging from as low as ten hours (and less) to over twenty hours per day. There is also very little day-night entrainment in the brief neonatal period, meaning that the typical neonate is equally likely to sleep during the day or night. Interesting too is the observation that REM sleep comprises about 50 percent of total sleep time in neonates, compared to 20-25 percent of sleep time in adults. Some increase in the amount of REM sleep continues throughout childhood, and it is a major basis for a leading theory that the function of REM sleep is to promote new long-term cognitive development.

Women often report disrupted sleep during what time?

menstrual periods pregnancy menopause

On average, how many hours per day do neonates sleep?

16-18

While early research suggested that the natural day/night cycle of the biological clock was about 25 hours, we now know that it is closer to which of the following?

24 hours

Randy Gardner stayed awake for ______ hours and showed _________ symptoms of mental illness as a result.

264; no

Current research suggests that REM sleep comprises what percentage of total sleep time in newborns?

50 percent

According to recent research, how much sleep do teens (ages 13-19) need?

9.5 hours

On average, what is the incidence of dream reports from REM awakenings?

90 percent

Give a definition of the concept of "sleep debt."

According to your textbook, the brain keeps an exact accounting of how much sleep it is owed, such that lost sleep must be paid back sooner or later, perhaps even hour for hour. It appears that healthy human adults require about one hour of sleep for every two hours awake. If not, you carry around a significant sleep debt (low MSLT score), which in turn means that you are at risk for falling asleep quickly at times that could be very serious.

What have animal sleep studies shown to be true?

All mammals show REM sleep.

What is the relationship between sleep deprivation and wakefulness?

All wakefulness is sleep deprivation.

What is a Zeitgeber? How many examples can you give in your daily living? According to current sleep research findings, what is the most important Zeitgeber of all?

As defined earlier, a Zeitgeber is a time-giver, and there seems to be an almost endless number of them in our daily lives. This includes many obvious examples, such as clocks, sunlight, interactions with family and friends, daily schedules (just knowing where you are often tells you the approximate time), but also more subtle cues, such as hunger pangs, achy muscles, street noises, etc. In the more recent free-running cave studies, sleep researchers found that light is indeed a powerful Zeitgeber, in fact the most powerful Zeitgeber of all, with the strongest entraining effects on our circadian rhythms.

What is the relationship between daytime sleepiness and your level of alertness? What is the most important consequence of the interaction of these two processes?

At any given time, how well we perform is a function of our position on the continuum of sleepiness versus alertness. If there is full alertness, with minimum sleepiness, performance will be at a peak; however, if there is excessive sleepiness, performance will be impaired. The difficulty stems from the fact that there is apparently much more sleepiness (and therefore impaired performance) in the world than anyone previously supposed.

Who was the first person to record the EEG, including the loss of alpha waves with sleep onset?

Berger

Who first collected dream reports from REM sleep?

Dement and Kleitman

Who founded the world's first full-time sleep disorders clinic?

Dement in 1970

How did the establishment of the first sleep clinic lead to the creation of the field of sleep medicine?

Dement opened the world's first sleep clinic at Stanford University in the spring of 1970 in order to expand his ongoing studies on narcolepsy. In so doing, he also came to appreciate entirely new disorders largely overlooked by previous clinicians, such as sleep apnea and other sleep issues. This initial effort has expanded greatly, so that there are now many hundreds of sleep clinics throughout the world, all devoted to sleep medicine, which is the prevention, diagnosis, and treatment of sleep disorders.

What is the prevalence of sleep debt in American society at large? Are there any groups that commonly show significant sleep debt?

Difficulties with sleep debt are very common in American teenagers and young adults. (There is not much doubt that other countries show the same or similar patterns; however, most of the research has to date been conducted in the United States.) In addition, these difficulties also occur in a variety of occupational groups, such as airline pilots, medical professionals, interstate truckers, athletes, and the military. Your textbook gives an accurate description of the many difficulties commonly experienced by members of these groups. No doubt, many of us could add other groups to this list.

Why were the results of the sleep deprivation study with Peter Tripp biased?

He secretly took large doses of a stimulant drug during the study.

What have studies shown about the interaction of sleep debt and alcohol intake?

In the presence of high sleep debt, even very little alcohol can be deadly.

What is the current thinking about the biological clock?

It is responsible for clock-dependent alerting. Its sole function is to promote alert wakefulness. It functions only at certain times.

What is the current thinking about the homeostatic sleep drive?

Its sole function is to promote sleep.

Describe the common sleep of teenagers, especially as it leads to the Delayed Sleep Phase Syndrome (DSPS). How common is this pattern and what problems, if any, occur as a consequence?

Many sleep scientists and others are gradually becoming aware that there is a very serious problem of sleep debt in teenagers in the United States. This is because there is a combination of facts and circumstances that are true of most teenagers, and, sadly, these facts and circumstances are not compatible with one another. Consider the following: Research on sleep in teens has shown that, contrary to previous beliefs, the average teenager needs about 9.5 hours of sleep per day, making them more like ten- to twelve-year-olds than young adults. An estimated 80 percent of teenagers in this country show an owl type of sleep-wakefulness cycle; that is, their peak of alertness occurs later at night, and their morning low point occurs correspondingly later. This is called the Delayed Sleep Phase Syndrome (DSPS) and is described in Lesson 5. Parents often become more permissive about enforcing bedtime rules with their teenage children, compared to their younger children, thus inadvertently promoting the DSPS daily schedule. Teenagers are more impaired by sleep debt than adults. In other words, equal amounts of sleep debt in teenagers and adults will produce greater difficulties and other symptoms in teenagers. Most high schools in the United States have changed to the so-called early start times, with the high school starting about an hour earlier than the lower grades. This is especially hard on owls. A large majority of college freshmen (average age seventeen to nineteen) living in dormitories continue to show the owl lifestyle, with similar consequences. And there is little reason to expect much change in college upperclassmen and many others in the twenty to twenty-five age group. The consequence of these facts is that the average level of sleep debt in many high school and college students is alarmingly high. These students report that they require several hours to feel awake in the morning, often doze in morning classes and in the early afternoon as well, and have difficulty staying awake when driving late at night. No doubt they are at risk for a number of additional difficulties.

Summarize the procedures and conclusions of the early free-running cave studies as to the apparent length of a day as determined by the biological clock.

Many studies have been conducted in years past to study the effects of removing all Zeitgebers from a person's living space for periods of several weeks or a month. This procedure is not so simple, since time-givers are almost ubiquitous. One of the most successful procedures has been to move volunteers to an underground apartment, such as a fairly deep cave, removing all time-related contact with the surface. The volunteers were instructed to free run, that is, sleep or engage in daily activities solely on the basis of their own preference. Curiously, the results from the early cave studies indicated that the volunteers seemed to prefer a twenty-five-hour day, such that they reversed their days and nights (sleeping all day and awake all night) after a short two weeks, even though they had no knowledge that they were doing so. As a result, sleep researchers for many years talked about the apparent fact that our internal biological clock seems to prefer a twenty-five-hour day, rather than a twenty-four-hour day, something of a puzzlement, to say the least.

How do the more recent cave studies differ from the earlier work?

More recently it was discovered that the light levels in the cave studies, though low by most of our daily standards, were still maintained at a level to permit daily waking activities. On the chance that this low level of light might have had some entraining effect, further studies were conducted with all light removed. Under these conditions, it was discovered that the true cycle for the biological clock is very close to twenty-four hours.

What happens to the amount of REM sleep over the course of a night? On average, when does the longest REM sleep period occur?

Most REM sleep occurs in the second half of the night. The initial REM periods in the first hours of sleep can be quite short. On average, each successive period of REM sleep is longer than the one that preceded it. Therefore, the REM periods in the second half of the night become larger and larger, so that the longest REM period often occurs just prior to waking in the morning.

What strategies can you list to deal with DSPS in a teenager? Use your best judgment or the suggestions on pages 408-410 in your textbook. Ask your parents. Ask your friends.

Not all of the strategies will work for all teenagers, but perhaps some of them will be more successful than others. A thoughtful teenager or concerned parent could undoubtedly add to the list. Among the strategies discussed in your text are the following: Take more afternoon naps. Use bright light to advantage in the morning and dim in the evening (the essence of light therapy). Limit TV, radio, and so on after 9 p.m. Avoid exciting activities after 9 p.m. Learn how to avoid caffeine from all sources in the evening. Get rid of after-school jobs. In addition, considerable research has shown that there are significant positive effects on sleep by starting and maintaining a regular conscientious program of aerobic exercise, such as running, biking, swimming, walking, etc.

In what stage does REM sleep occur?

REM activity occurs in sleep stage 1

What did Dement's studies of REM deprivation show?

REM deprivation produces increased REM pressure.

What does research on total sleep deprivation in animals show?

Rats die after about sixteen days.

What is the relationship between sleep deprivation and fatigue?

Research on sleep deprivation has consistently shown that the most striking effect of sleep deprivation is an accumulated feeling of fatigue, which can grow to be overwhelming if the deprivation continues unabated. At the same time, many performance measures show a corresponding decline from peak, including increased errors and accidents.

Is the sleep of teenagers more like adults or like children, aged ten to twelve? In what way?

Research on sleep in teens has shown that, contrary to previous beliefs, the average teenager needs about 9.5 hours of sleep per day, making them more like ten- to twelve-year-olds than young adults.

What is the difference between larks and owls as depicted within the opponent-process model. Are there any age differences in incidence of owls versus larks?

Research on the opponent-process model has increased our knowledge about so-called larks and owls. Larks are persons who prefer to arise early in the day and feel most alert in the morning, whereas owls prefer to say up late and feel most alert at night. As we will see, there are large age effects on these processes, such that adolescent and young adult groups show many more owls, and elderly groups show more larks.

What, if any, are the similarities between the effects of sleep deprivation and those of alcohol?

Sleep deprivation is also very similar to alcohol intoxication in its negative effect on performance. Therefore, a little sleep deprivation, plus a little alcohol, can have a big effect. Oftentimes, individuals who do not understand this relationship might think there is no harm in having one or two drinks at a time when they are seriously fatigued. However, the fatigue potentiates, or increases, the effect of the alcohol, placing them at far greater risk than they realize.

Give a brief summary of the reasons why each of the following is an important person in the history of sleep research: Sigmund Freud, Hans Berger, Nathaniel Kleitman, Eugene Aserinsky, and William Dement.

Sigmund Freud: Freud rekindled much of our interest in dreams and dreaming. Working over 100 years ago, Freud's contributions were widely praised and criticized alike. Freud worked before the discovery of sleep brain waves or REM sleep, hence much of his writing about dreams is now out of date. Hans Berger: A German physician, he was the first to observe and report human brain waves in 1930, including alpha waves and the fact that brain waves changed with sleep onset. Nathaniel Kleitman: A physiologist, he directed a sleep laboratory at the University of Chicago for decades. It was in his laboratory that REM sleep was discovered. Eugene Aserinsky: He was the first to observe periods of rapid eye movements in sleeping infants in the early 1950s. William Dement: Following Aserinsky's discovery, Dement, with Kleitman, was the first to observe the high frequency of dream reports out of REM sleep. He founded the first sleep clinic, and the area of sleep medicine, at Stanford University in 1970.

Describe the age-related changes in incidence of sleep apnea, from young children to the elderly. What age group shows the highest incidence of sleep apnea?

Sleep apnea is a sleep disorder that shows clear age effects. This disorder occurs rarely in infants and children, increases notably in the middle-aged, and is most common in the elderly. Estimates of the incidence of sleep apnea in the elderly run as high as 30-40 percent, though it is difficult to know with certainty. While complete cures are rare, there are steps that can be taken to alleviate the symptoms of sleep apnea, described in Lesson 6.

Describe the sleep of the normal elderly, especially as it leads to Advanced Sleep Phase Syndrome (ASPS).

Sleep of the elderly is often more disrupted than in younger groups. They show more awakenings and fewer episodes free of interruption. In contrast to teenagers, the elderly commonly show a shift in their day-night cycle toward the so-called lark lifestyle. That is, they peak earlier in the evening, go to bed earlier, awaken earlier, and feel that they do their best work in the mornings—all quite the opposite of teenagers. The lark type of schedule is termed the Advanced Sleep Phase Syndrome (ASPS), which is discussed with the DSPS in Lesson 5.

Describe the manner in which melatonin contributes to the high incidence of DSPS in teenagers.

Sleep scientists have puzzled for some time over the reasons for the increased incidence of DSPS (owl) day-night cycles in teenagers. A very significant component in the entire process seems to be the hormone melatonin, which is believed to play a crucial role in setting the biological clock. That is, melatonin levels normally increase at night (and in the winter), but decrease during the day (and in the summer). Curiously, it is also known that a decrease in melatonin levels signals the body to begin puberty. Consequently, teenagers experience decreased melatonin levels as a normal part of development, but the trade-off is a DSPS day-night cycle.

What are the characteristics of the human brain wave during sleep stage 1? Sleep stage 2? Sleep stage 3? Sleep stage 4?

Sleep stage 1: Alpha waves disappear and are replaced by beta waves (18-30 Hz) and theta waves (6-8 Hz). Sleep stage 2: Sleep spindles (14 Hz) and large slow K-complexes appear. Sleep stage 3: First appearance of large slow (1-2 Hz) delta waves up to 50 percent of the time Sleep stage 4: Delta waves present more than 50 percent of the time

How do sleep patterns change after the neonatal period over the course of the first year?

Some early day-night entrainment begins to appear after four weeks, albeit not marked or consistent at first, and again some babies show this sooner and some show this later. After two to three months, the average infant can definitely be expected to be more awake during the day and asleep more at night. By five to six months, a clear and consistent day-night pattern should be established, with morning and afternoon naps, and total sleep time still at least twelve to fifteen hours per day.

Which form of selective sleep deprivation produces greater negative effects, REM deprivation or NREM deprivation?

Studies of selective sleep stage deprivation (REM deprivation versus NREM deprivation) have also been conducted. In general, the effect of REM deprivation remains unclear, in spite of many efforts to shed light on this question. On the other hand, NREM deprivation appears to have the same negative effect as total sleep deprivation, strongly suggesting that NREM sleep is biologically more necessary than REM sleep.

Do we really need to sleep, or is it just an unnecessary habit? Explain your answer.

Studies with lower animals have shown that total sleep deprivation is ultimately fatal, perhaps in as few as sixteen days. Corresponding studies in human subjects are not possible, for legal and moral reasons.

Describe the normal process of accumulating sleep debt over an average day. Does the sleep debt accumulate at a constant or irregular rate?

The accumulation of sleep debt or sleep load, which produces the homeostatic sleep drive, is illustrated in your textbook in Figure 4.1 on page 82. Theoretically, a healthy fully refreshed person would show zero sleep debt on awakening from a full night of sleep; however, the person in your textbook shows a small sleep debt on arising in the morning. The diagram also indicates that the person's sleep debt accumulates at a constant rate throughout the period of wakefulness, reaching a peak at the person's bedtime around midnight. This illustrates the concept that all wakefulness is sleep deprivation.

Identify examples in your personal experience where either the external day-night cycle or your internal biological clock caused you to make a major change in your plans or behavior.

The answers to this question will vary from person to person. However, there were two in the Commentary portion of this lesson. One was the unexpected effect of jet lag on a trip to Norway, and the second was the (again) unexpected consequences of living in an environment with no electricity. No doubt you have had your own experiences—and lessons learned!

What is the length of the average sleep cycle in adults?

The average sleep cycle in healthy adults is about 90 minutes; however, it can range from a low of about 80 minutes up to about 110. The cycle in young children is lower, averaging about 60 minutes.

In spite of the fact that daytime sleepiness is a very common complaint among clients in a sleep clinic, the objective measurement of this complaint was an unsolved problem for many years. Explain why this was true.

The essential problem with the measurement of daytime sleepiness is that it is an inherently subjective judgment on the part of the client, and it is communicated verbally, again an unreliable process because of the variability in people's style of communication. There are many examples in the history of science where it was simply not possible to measure an internal phenomenon reported verbally.

Explain how we can determine the presence of sleep by use of brain wave recordings.

The fact that brain waves change when we go to sleep has probably promoted more objective sleep research than any other known fact about sleep. Brain wave recording is not an intrusive procedure, meaning that is it is not especially risky or harmful and an all-night recording is a routine procedure in all sleep labs.

Discuss the concept of fatigue. What are some of the consequences of high levels of fatigue?

The idea that all wakefulness is sleep deprivation is fundamental to our understanding of fatigue. Sleep deprivation begins when we awaken and accumulates throughout our entire period of wakefulness. If, on the following night, we sleep one hour less than we require, then we have acquired one hour of sleep debt. Do this eight nights in a row, and there is a sleep debt of eight hours—one full night of sleep that the brain is owed. And, until there is a substantial payback, performance suffers.

What is the likelihood that we will ever be able to dispense with sleep all together?

The idea that we might someday be able to dispense with sleep entirely is an intriguing question that many have raised over the years. For example, is sleep really only a pointless habit that we have somehow acquired? However, the results of deprivation studies, especially those showing fatal effects in lower animals, provide irrefutable evidence that we will not be giving up our sleep any time soon, and probably never.

What are the life events that are unique to women and also likely to produce sleep disruption? Describe the nature of the disruption.

The life events that are biologically unique to women are menstrual periods, pregnancy, and menopause. During each of these events, there are important biological processes that are highly likely to influence sleep. However, the woman's knowledge, attitudes, and experiences with each of these processes can, in turn, greatly affect her perceptions and cognitive and emotional responses to the event. In other words, there is probably as much biology as there is psychology involved in each of these events. Many women experience sleep problems near their menstrual periods. Some report disrupted sleep at this time, while others report an increase in nighttime sleepiness. During pregnancy many women report disturbed sleep, most especially during the last trimester, when the simple task of finding a comfortable sleeping position becomes a major challenge. A common consequence is an increase in daytime sleepiness, which can have further effects. Reportedly, menopause frequently leads to increased insomnia. This is no doubt due in part to the biological processes. For example, hot flashes can occur many times in one night. In addition, the knowledge that the process is occurring can, itself, have an assortment of cognitive and emotional effects with sleep-disrupting consequences.

Where in the brain is the biological clock located? How does this interact with light and the visual system?

The location of the biological clock has been reasonably well established as the suprachiasmatic nuclei (SCN) located directly over the optic nerves, and therefore directly influenced by visual activity. Your textbook has an excellent and up-to-date description of the specific mechanisms whereby visual activity affects the SCN, which in turn adjusts our circadian processes.

What is the upper limit of sleep deprivation in humans? What are the inherent risks in exploring this question?

The longest that anyone has stayed awake is 264 hours, a record set by an eighteen-year-old young man, Randy Gardner, in the 1960s. He had a sizable group of assistants, supporters, and colleagues to verify his achievement, and he did not use any artificial aids such as caffeine or other stimulants, unlike Peter Tripp, whom we learned about in Lesson 1. There was apparently no ill effect on Randy, other than massive fatigue, according to the study's conclusion. Others may have attempted to top his record in the intervening years; however, this is generally very unwise, based on what we now know about the effects of sleep debt, as well as the fatal effects in animal studies, as an extremely unsafe procedure.

How does sleep differ from similar states, such as coma, general anesthetic state, or death?

The most obvious difference between sleep and coma, anesthetic state, or death, is that sleep is immediately reversible

Summarize the previous versus current thinking about the biological clock being a unitary versus dual process.

The previous belief was that the homeostatic sleep drive was a unitary process with a dual responsibility, something that is logically inconsistent. That is, it was responsible for our feeling drowsy when tired or sleep deprived, and alert when fully rested. Eventually, however, sleep scientists realized the inherent difficulty in ascribing two outcomes to a single cause. How could a single drive for sleep accomplish two ends? The answer, of course, is that it is not a unitary process after all—it is a dual or two-sided process, and thus was born the notion of the opponent-process model of sleep and wakefulness.

Describe the process of clock-dependent alerting. Does alerting show a consistent process of increasing or decreasing during the day, or are there peaks and valleys?

The second half of the model is termed clock-dependent alerting, because it is an alerting process that is determined by the biological clock, independent of the sleep debt. This component is illustrated in Figure 4.2, page 83 in your text. The daily cycle of alerting, in contrast to the sleep drive, has two peaks—one roughly midmorning and one in the early evening, plus two low points, one in the early afternoon and one in the middle of the night. While details about the neural mechanisms of this component remain unclear, a variation of the Multiple Sleep Latency Test (MSLT) has provided excellent data showing that on average these peaks and low points in alertness do in fact occur as described, a critical detail in validating the overall model.

What are the characteristics of the human brain wave during wakefulness?

There are two primary wave forms during normal wakefulness: (1) Alpha waves, which are very regular from cycle to cycle and occur in the frequency range of eight to twelve cycles per second, known as Hertz or Hz; and (2) beta waves, which are low amplitude and irregular from cycle to cycle in the range of eighteen to thirty Hz. Because of their regular wave form, alpha waves are easily recognized on visual inspection. While most people show a mixture of alpha and beta while they are awake, the normal range is quite broad. Some people show alpha almost 100 percent of the time, and some people show no alpha at all. Both of these extremes occur in normal healthy individuals.

What are the procedural steps in the Multiple Sleep Latency Test (MSLT)? How does the MSLT provide a measure of daytime sleepiness

To conduct an MSLT, clients are connected to a sleep recording apparatus in the standard manner at 10 a.m., noon, 2 p.m., 4 p.m., and 6 p.m. and told each time to go to sleep. Using the EEG recording to determine the moment of sleep onset, the average time to go to sleep for the five sessions is calculated. If the average time is zero to five minutes, it is scored "extreme sleep tendency," five to ten minutes is "borderline," ten to fifteen minutes is "manageable," and fifteen to twenty minutes is "excellent alertness." In other words, those who go to sleep more quickly are showing greater daytime sleepiness.

Describe the average sleep patterns in a toddler. What is the role of naps at this age?

Toddlers (children ages one to three) generally show well-established day-night sleep cycles, averaging about twelve hours per day and one to two daily naps. REM sleep comprises 40-50 percent of total sleep time throughout the toddler years.

Describe the average sleep patterns in childhood, from the toddler years to age ten. What parasomnias appear at this age? Is there an age-related explanation for the parasomnias?

Total sleep time decreases to about ten hours by age ten. Many observers believe that children are the world's best sleepers, and there is some basis for this opinion. Children typically go to sleep quickly, they rarely awaken in the night, and they wake up refreshed and active in the morning. At the same time, many of the parasomnias first appear in the toddler/childhood years. A parasomnia is a disordered behavior that occurs during sleep, without disrupting the sleep itself. A simple example might be sleep talking, although this behavior is seldom serious enough to be called a disorder. It is because of the greater incidence of parasomnias in children that a leading suggestion as to their cause is that they are somehow due to an "immature nervous system." The most frequently reported sleep disorders in children are sleepwalking, night terrors, and bedwetting.

Describe the full opponent-process model of sleep and wakefulness. Are there any predicted highs and lows over the course of a normal day? If so, when do these highs and lows occur?

When the two components (homeostatic sleep drive and clock-dependent alerting) are combined, the result is the full opponent-process model, depicted in Figure 4.3, page 84. The level of wakefulness resulting from the combination of the two components is shown by the line drawn horizontally between the two. The model predicts that individuals will experience an average of two peaks in wakefulness each day, one midmorning and one in the early evening. In contrast, there should also be two low points, one in the early afternoon and another beginning at bedtime.

DSPS and ASPS are typically presented and discussed as sleep disorders, with DSPS being more common in teenagers and ASPS more common in the elderly. Is each of these always a disorder requiring treatment of some kind? Or is it possible that there may be circumstances where the owl's or lark's daily schedule can be safely left alone?

While DSPS is almost always regarded as an adjustment issue in teenagers, because of their daytime school responsibilities, it is not equally true that ASPS is an issue for the elderly, especially if they are retired and relatively free of external daytime demands.

Can one make a case that Edison's invention of the electric light has created a relatively sleep-deprived society?

Your textbook makes a strong and provocative case that Edison's invention of the electric light bulb is singularly responsible for much of the widespread sleep debt in modern society. Doubtless, the light bulb makes an owl-like lifestyle much more convenient than ever before in history. For the last hundred years, most of us have taken for granted that there will always be enough light to do our chores or whatever else we choose to do at any hour—or so we think! As a result, many members of our culture as a whole stay up later and later, even though there is nothing allowing us to sleep later in the morning.

Zeitgeber

a German noun meaning "time giver"; any of the many environmental indicators of clock time, for example, your watch, daylight, traffic noises, etc. Note that German nouns are always capitalized

jet lag

a temporary loss of entrainment that occurs after rapid (hence, jet) east-west travel across a number of time zones; the more time zones, the greater the effect

Which of the following is a suggested solution for dealing with sleep debt in teens?

allowing afternoon naps light therapy avoiding exciting activities after 9 p.m.

free running

an experimental condition wherein all Zeitgebers are removed to study effects on entrainment

biological clock

an internal neural mechanism that regulates body and behavioral functions on a twenty-four-hour schedule or circadian rhythm

Which of the following is defined as an internal neural mechanism that regulates body and behavioral functions on a 24-hour schedule?

biological clock

According to the opponent-process model, wakefulness at any given moment is a product of which of the following?

clock-dependent alerting and sleep debt

Studies have shown that large sleep debts are alarmingly common in which group?

college students interstate truck drivers nurses and physicians

The incidence of sleep apnea is greatest in which age group?

elderly

Which of the following is most likely to show an advanced sleep phase syndrome (lark) daily schedule?

elderly

Which of the following has occurred when a biological process and clock time are in synchrony?

entrainment

How often do REM periods occur on average in the normal human adult?

every ninety minutes

What was found to be the cause of the Exxon Valdez tragedy?

excessive sleep debt

What does a mean score of 2-3 minutes on the MSLT indicate?

extreme sleep tendency

When do parasomnias, such as sleepwalking and night terrors, often first appear?

in toddlers/children

In setting the day/night sleep/wake cycle of the biological clock, which is the most important Zeitgeber?

light

Compared to adults, what is the effect of equal amounts of sleep debt in teenagers?

more impairment than adults

The process of clock-dependent alerting predicts that on average there will be two daily peaks in alerting. When do these occur?

morning and early evening

What happens to the amount of sleep stages 3 and 4 over the course of a night?

most of the sleep stages 3 and 4 occur in the first ninety-minute cycles of the night, or at least in the first half of the night

The statement "The brain keeps an exact accounting of how much sleep it is owed" seems to be correct

nearly all of the time.

entrainment

occurs when a biological process and clock time are in synchrony

As a rule of thumb, an average adult requires ___________ of sleep for every ____________ awake.

one hour; two hours

Your textbook states that we are in the midst of a pandemic of fatigue caused by which of the following?

our "work hard, play hard" ethic

Which term refers to an individual who prefers to stay up late at night and who often feels most alert in the evening?

owl

Sleep scientists' work with teens has shown that their frequent delayed sleep phase syndrome produces an increase in the number of _________ among teens.

owls

Give a definition of sleep

sleep is a suspension of normal consciousness, a reflection of the fact that we generally have little or no memory for events during sleep

When are sleep spindles in the EEG normally first observed?

sleep stage 2

If an individual produced an EEG with delta waves present 60 percent of the time, what would it be scored as?

stage 4 sleep

According to research, where is the biological clock located?

suprachiasmatic nucleus

Does deprivation of REM sleep disrupt or harm one's mental health? What about the effect of total sleep deprivation on one's mental health?

the only established effect of REM deprivation is the buildup of REM pressure, referring to the increased amount of REM sleep after several nights of REM deprivation total sleep deprivation does not produce personality change, although irritable mood shifts are fairly common.

chronobiology

the study of clock-time effects on biological and behavioral processes