260202

Sleep Inertia, Naps, and Memory

3 Contact Hours

Sleep Inertia, Naps, and Memory

Notes

Care has been taken to confirm the accuracy of information presented in this course. The authors, editors, and the publisher, however, cannot accept any responsibility for errors or omissions or for the consequences from application of the information in this course and make no warranty, expressed or implied, with respect to its contents.

The authors and the publisher have exerted every effort to ensure that drug selections and dosages set forth in this course are in accord with current recommendations and practice at time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package inserts of all drugs for any change in indications of dosage and for added warnings and precautions. This is particularly when the recommended agent is a new and/or infrequently employed drug.

COPYRIGHT STATEMENT ©2006 Institute for Continuing Education Revised 2007

All rights reserved. The Institute of Continuing Education retains intellectual property rights to these courses that may not be reproduced and transmitted in any form, by any means, electronic or mechanical, including photocopying and recording, or by any information storage or retrieval system without the Institute’s written permission. Any commercial use of these materials in whole or in part by any means is strictly prohibited.

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Instructions for This Continuing Education Module

Welcome to the Institute for Continuing Education.

The course, test and evaluation form are all conveniently located within Notes this module to keep things easy-to-manage. To use the online method of taking the test and receiving your credits follow the steps below: 1. Read and understand the material. 2. After reading and studying the lesson, proceed to the test. 3. Take the test. Be sure to completely fill-in the answers. Use a pencil so if mistakes are made they can be neatly erased and corrected. 4. The final part is the lesson evaluation. Please fill out the evaluation as it helps us create a better learning experience for you. Feel free to add any comments you have about our service and any suggestions as to how we can improve. Completion of this form is essential to obtain continuing education credit. 5. The Online Exam is at this URL: http://www.ceu.org/courses_online/260202/exam260202.html 6. Alternatively, you can Fax the registration, test and evaluation form to (503) 218-7415. If you decide to Fax the test and evaluation, make sure all your information is darkened. The date on the certificate is the day it is faxed or the date of the postmark. 7. We recommend you return the materials to us via certified or registered mail. This insures against possible loss and provides you with a dated receipt of mailing. 8. Upon successfully passing the test, you will receive your certification in the mail. Certificates are dated the day of the postmark. The test will be processed and the certificates will be mailed out within 24 hours of receipt. Please allow one week for delivery. 9. A passing score is 75%. If your score is below 75%, we will send or fax you another answer form, at no additional charge, so you can retake the exam. READ the material. COMPLETE the test and evaluation form. RETURN the answer sheet and the evaluation form. SEND by certified mail to insure against loss. SAVE your receipt of mailing.

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Table of Contents SLEEP DEPRIVATION IN ADULTS...... 8 BACKGROUND...... 8 FACTS ABOUT SLEEP AND FATIGUE ...... 11

CIRCADIAN RHYTHM...... 11 Notes SLEEP DEBT...... 11 SLEEP INERTIA ...... 11 MICROSLEEPS ...... 12 THE MORNING BATTLEGROUND: WHY BIPOLAR KIDS CAN’T GET UP AND GET GOING...... 13 WHAT IS SLEEP INERTIA? ...... 14 THE TYPICAL ARCHITECTURE OF SLEEP ...... 14 THERMOREGULATORY DISTURBANCES...... 15 THE PINEAL GLAND ...... 16 WHAT CAN BE DONE ABOUT SLEEP INERTIA? ...... 17 IN CONCLUSION...... 19 ALERTNESS MANAGEMENT: STRATEGIC NAPS IN OPERATIONAL SETTINGS ...... 20 INTRODUCTION...... 20 ALERTNESS MANAGEMENT IN OPERATIONAL SETTINGS ...... 21 STRATEGIC NAPS AS AN ALERTNESS MANAGEMENT STRATEGY...... 22 BENEFICIAL EFFECTS OF NAPS...... 22 POTENTIAL NEGATIVE EFFECTS OF NAPS ...... 23 STRATEGIC NAPS IN AN OPERATIONAL SETTING ...... 24 IMPLEMENTATION IN OPERATIONAL SETTINGS...... 26 OTHER CONSIDERATIONS...... 26 SLEEP-WAKE STATE AND MEMORY FUNCTION ...... 28 INTRODUCTION...... 28 MEMORY IN WAKE AND LEVEL OF SLEEPINESS...... 28 MEMORY AT SLEEP-WAKE STATE TRANSITIONS...... 29 MEMORY DURING SLEEP ...... 30 ABOUT NAPS AND SLEEP INERTIA ...... 31 RISE AND SHINE? THAT’S NOT QUITE HOW IT WORKS, STUDY SAYS ...... 33

SNOOZE, YOU WIN ...... 35 GETTING THE PERFECT NAP ...... 37 HOW LONG IS A GOOD NAP? ...... 37 SLEEPINESS AND FATIGUE...... 38

FIGHTING THE “BODY CLOCK” ...... 39

FATIGUE AND IMPAIRMENT...... 40

FATIGUE-RELATED ERRORS ...... 41

DROWSY DRIVING...... 42

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SLEEP LOSS AND HEALTH...... 42

SUMMARY...... 43

EXAMINATION ...... 45

Notes

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Notes

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Sleep Inertia, Naps, and Memory Course # 260202 3 CEUs

Learning Objectives Upon successful completion of this course, you will be able to: Notes • Define and discuss what is meant by “sleep inertia”. • Explain its symptoms, epidemiology, frequency of occurrence. • List the potential treatments and preventive actions that can be taken regarding sleep inertia.

The media has recently been full or stories regarding something commonly referred to as Sleep Inertia, and this CEU offers you a brief review of what is being said, and some facts about the phenomenon.

Sleep Inertia May Be More Debilitating Than Sleep Deprivation

BOULDER, Colo., Jan. 10 - While a sleep-deprived medical resident’s cognitive impairment may be similar to that of an uncoordinated drunk, the impairment of a resident who is shaken awake from a nap may be even worse, researchers here said.

But the cognitive effects of so-called sleep inertia-the state of grogginess and disorientation commonly experienced on waking-only last for minutes, said Kenneth P. Wright Jr. Ph.D., of the Sleep and Chronobiology Lab at the University of Colorado here.

Still, sleep inertia may sometimes affect the performance of doctors, emergency medical technicians, and firefighters, Dr. Wright and colleagues reported in a research letter published in the Jan. 11 issue of the Journal of the American Medical Association.

The study involved eight men and one woman, all paid volunteers from 20 to 41 years old. They were free of medications, alcohol, nicotine, recreational drugs, and caffeine for three weeks before the study, verified by toxologic analysis. The volunteers’ professions were not disclosed.

For six nights, the volunteers got a good night’s sleep (about eight hours) in the lab. On the morning after the sixth night, they were awakened and immediately given a cognitive performance test involving adding randomly generated, two-digit numbers.

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Volunteers were given the test at 20-minute intervals in the morning and hourly intervals for the rest of the day and night. They were deprived of sleep for the next 26 hours, being tested all the while, so the researches could compare the effects of sleep deprivation to those of sleep inertia the volunteers experienced in the morning.

Notes On average over the 26-hour study period, the volunteers scored 23 correct answers on a 28-question test. Immediately after waking, however, the average score was at a rock-bottom of 17. Twenty minutes later, the score rose to 23.

The score climbed to 25 four hours later and leveled off during the day, with a dip in the afternoon, and sank again after one night of sleep deprivation to 21-still much better than the average score immediately upon waking, the researchers noted.

“This is the first time anyone has quantified the effects of sleep inertia,” Dr. Wright said. “For a short period, at least, the effects of sleep inertia may be as bad as or worse than being legally drunk.”

The study has implications for medical professionals who are often called on to tend patients in crisis on a moment’s notice, often at odd hours, Dr. Wright said. Medical residents, for example, who may work 80 hours or more per week and who catnap at times, could be prone to make simple math mistakes when calculating dosages of medicine during bouts of sleep inertia, he said.

“The present results may have important implications for occupations in which sleep-deprived personnel are expected to perform immediately on awakening from deep sleep, including physicians, truck drivers and pilots arising from on-board sleeper berths, and public safety and military personnel,” the study authors concluded.

Sleep Deprivation in Adults

Background Studies on the effects of sleep loss on neurobehavioral functions, especially neurocognitive performance, have two primary emphases: 1. specification of the properties of tasks (e.g., cognitive versus physical; long versus short duration) that make them sensitive to sleep loss; and 2. specification of the aspects of performance (e.g., cognitive processing speed versus accuracy, declarative versus implicit memory processes) that are impacted by sleep loss.

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Underlying this research has been controversy regarding the likely nature of sleep loss-induced performance deficits (e.g., whether they reflect true deficits in physiological function of the brain, a motivational effect reflecting reprioritization of the reinforcement hierarchy, an initiation of sleep onset mechanisms in the face of waking performance, or some combination of these processes). This controversy has not been resolved due to lack of a basic understanding of the function(s) of sleep, the Notes physiological processes affecting recuperation during sleep, and the neurobiology of sleepiness.

Implicit in this research has been the assumption that total and partial sleep deprivation produce qualitatively similar decrements in brain function and/or motivation levels that differ only in degree. As a result, the overwhelming majority of studies in which the relationship between sleep and performance have been explored have utilized the more efficient total sleep deprivation procedures, and very few studies have examined the effects of chronic sleep restriction. Further, of these few studies only a very small subset have included adequate and objective verification of compliance with the sleep restriction regimen being studied.

Nevertheless, partial sleep deprivation is more pervasive than total sleep deprivation. Epidemiological studies suggest that mean sleep duration has decreased substantially as proportionally more people are awake more of the time. These decreases are due, in part, to expanded possibilities for nighttime activities that accompanied the introduction of electric light and other technologies, and to the more recent trend toward expansion of both manufacturing and service sectors to 24 hour-per-day operations. Sleep restriction appears to be an almost inevitable consequence of nighttime shift work.

Because of the scarcity of chronic sleep restriction experiments despite a wealth of total sleep deprivation/performance studies, theoretical and practical questions remain: 1. What are the physiological processes mediating neurobehavioral performance deficits resulting from sleep loss? 2. What accounts for the wide individual differences that emerge in the ability to maintain performance during s leep loss? 3. Do the physiological and neurobehavioral responses to chronic partial sleep loss differ from those resulting from total sleep loss? 4. Relative to the adverse neurocognitive and physiological effects of sleep loss, is there habituation/adaptation or potentiation/sensitization to repeated exposure to sleep loss? 5. Are there physiological and/or behavioral adaptations or dysfunctions in sleep or circadian physiology in response to

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chronic sleep restriction (e.g., a change in sleep itself or the brain’s recovery response to chronically inadequate sleep)? 6. Are the neurobehavioral and physiological effects of chronic partial sleep loss different at different circadian phases? 7. What are the physiological processes that affect restoration of

cognitive performance capacity during recovery sleep, and are Notes these processes reflected in any currently measured sleep parameters? 8. How much recovery sleep is required following chronic partial sleep loss vs. total sleep deprivation? 9. What are the effects on neurobehavioral functions of long term (weeks, months, years) exposure to a typical work or school schedule of 5 or more days of sleep restriction followed by 2 days of recovery?

Research on sleep loss countermeasures in healthy adults, including pharmacological and non-pharmacological interventions such as napping strategies, is also of increasing practical and theoretical relevance. There is a need for experiments on the efficacy, long-term effectiveness, and safety of repeated use of traditional stimulants (e.g., caffeine, d- amphetamine, methylphenidate) and novel wake-promoting agents (e.g., modafinil) for maintenance of performance in healthy adults engaged in emergency and/or continuous operations. Complementary studies of sleep-inducing and/or phase-shifting drugs (e.g., benzodiazepine agonists, melatonin) to enhance sleep and subsequent alertness/performance (e.g., for those engaged in shift work, transmeridian travel, or recovery from continuous operations) will likewise continue to expand from the clinical to the operational realm.

Napping strategies and sleep scheduling will constitute at least part of any comprehensive strategy to maintain alertness and performance during extended continuous operations. Cell phones, beepers, and other communication devices can put some workers in a perpetual “on-call” status in which sleep might be interrupted by need for rapid decisions and/or other duty-related tasks. Studies of sleep inertia (and sleep inertia countermeasures), therefore, will be of increasing relevance and importance. Finally, the physiological effects of acute and chronic sleep loss in vital organ systems other than the brain have only just begun to be explored.

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Facts about Sleep and Fatigue

Circadian Rhythm Circadian rhythms are physiological cycles that follow a daily pattern. We are “programmed” by our circadian rhythms to sleep at night and to be awake during the day. Notes

During nighttime hours and to a lesser extent during afternoon “siesta” hours, most types of human performance are significantly impaired, including our ability to drive.1

Problems occur if we disrupt our natural sleep cycles (eg by staying awake during the night), do not get enough sleep, or get poor quality sleep. Circadian rhythms cannot be reversed. Even if you have been working nightshifts for many years, your body will still be programmed to sleep at night.

Sleep Debt The human body requires a certain amount of sleep each night to function effectively. The average amount of sleep a person needs is 8 hours. When we reduce the number of hours we sleep at night we start to accumulate what is called a ‘sleep debt’.

Sleep debt is defined as the difference between the hours of sleep a person needs and the hours of sleep a person actually gets.

For example, if a person needs 8 hours of sleep per night but only gets 6 hours of sleep one night, they have a sleep debt of two hours. These lost hours of sleep need to be replaced.

When we have sleep debt, our tendency to fall asleep the next day increases. The larger the sleep debt, the stronger the tendency to fall asleep. 2

Sleep debt does not go away by itself. Sleeping is the only way to reduce your sleep debt.

Sleep Inertia Sleep inertia is the feeling of grogginess after awakening and temporarily reduces your ability to perform even simple tasks.

Sleep inertia can last from 1 minute to 4 hours, but typically lasts 15-30 minutes.

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The severity of sleep inertia is dependent on how long you have been asleep and the stage of sleep at awakening.3 Effects can be severe if a person is very sleep deprived or has been woken from a deep sleep stage. However, sleep inertia can usually be reversed within 15 minutes by activity and noise.

Notes Sleep inertia can cause impairment of motor and cognitive functions and can affect a person’s ability to drive safely. Sleep inertia can be very dangerous for people who drive in the early morning hours and shortly after waking up from a sleep.

Microsleeps Microsleeps are brief, unintended episodes of loss of attention associated with events such as blank stare, head snapping, prolonged eye closure, etc., which may occur when a person is fatigued but trying to stay awake to perform a monotonous task like driving a car or watching a computer screen.4

Microsleep episodes last from a few seconds to several minutes, and often the person is not aware that a microsleep has occurred. In fact, microsleeps often occur when a person’s eyes are open.

While in a microsleep, a person fails to respond to outside information. A person will not see a red signal light or notice that the road has taken a curve.

Microsleeps are most likely to occur at certain times of the day, such as pre-dawn hours and mid-afternoon hours when the body is “programmed” to sleep.

Microsleeps increase with cumulative sleep debt. In other words, the more sleep deprived a person is, the greater the chance a microsleep episode will occur.

In one study of microsleep, participants were asked to press a button when a strobe light was flashed directly in their eyes every few seconds. During a microsleep they did not notice the light and were not even aware that they had been asleep.5

Following are links to the television commercial from the latest driver fatigue public education campaign featuring Dr. Kart Kruszelnicki discussing the dangers of having a microsleep while driving. This campaign was launched in December 2001.

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1. Moore-Ede, Martin. ‘Circadian Rhythms and the Biological Clock’. http://www.circadian.com/learning_center/biological_clock.htm 2. Loughborough Sleep Research Centre Dement, William C. ‘Sleep Debt’ 2000. http://www.sleepquest.com/d_column_archive6.html. 3. Tassi, P., Muzet, A. ‘Sleep Inertia’. Sleep Medicine Reviews, Vol.4, No. 4, 341-353. August, 2000. Notes 4. Moore-Ede, Martin. ‘Alertness and Fatigue: Microsleeps’. http://www.circadian.com/learning_center/biological_clock.htm 5. Dement, W.C. ‘Some must watch while some must sleep’. San Francisco, CA: W.H. Freeman. 1974

The Morning Battleground: Why Bipolar Kids Can’t Get Up and Get Going

Does this sound familiar?

Yesterday morning it took an hour-and-a-half attempting to get him up. We kept shaking him, beseeching, threatening, beseeching anxiously. We even called his cell phone thinking he might pick it up for a friend’s call. He simply growled, muttered something we would have preferred not to hear, and turned over and went back to sleep.

We finally did see him rise from the bed and we ran the shower thinking that might wake him up. Ten minutes later we found him in the bathroom curled up on the bath mat, sound asleep.

A father detailed his family’s three-stage morning routine with their six- year-old daughter:

I carry her downstairs to the living room sofa. I leave the room and my wife pulls off her pajamas and dresses her while she’s still asleep (that’s stage one). Stage two: We help her into the kitchen, although she’s still very groggy, sit her in a chair, and give her an “injection of breakfast” by shooting a GoGurt (yogurt in a squeezable tube) in her mouth. Stage 3: We carry her to the bathroom and help her brush her teeth, etc. Then we put on her coat and go outside and wait for the bus (or shall we say, the bus waits for us). Sometimes.

Every morning, in America and abroad, many parents of bipolar children wake up and experience dread as they prepare to get their children up for school. Contrary to cheery television commercials where families gather around quaffing fresh-squeezed orange juice, these parents often forgo that fantasy and mount a siege simply to get their children out of bed.

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It’s a tall order. While it may seem as if the child or adolescent is behaving in an oppositional manner, a great many of these youngsters actually suffer from something called sleep inertia.

What Is Sleep Inertia? Notes Sleep inertia is a transitional state of lowered arousal occurring immediately after awakening from sleep and producing a temporary decrement in any subsequent performance. Studies show that sleep inertia can last from a few minutes to four hours. Youngsters with bipolar disorder are far closer to the latter than the former. One 17-year- old girl described her attempts to get up in the morning this way: I feel as though my insides are whining. I will do anything not to get up. Sleep is more important than anything in the world. I could sleep until 4:00 in the afternoon.

I never think about it from my mother’s point-of-view. I don’t think anything. When I do get to school (after much yelling by my mother and me back at her), I have my head on the desk until somewhere around 11:00 in the morning. Right before lunch I seem to truly get up.

Several factors are involved in sleep inertia. A child may be depressed and chronically tired, or the thought of facing the school day may produce waves of anxiety or panic, forcing the child to choose sleep or somatic complaints over the trial of going into the school environment. In many cases, the medications may be causing an early-morning sleepiness.

We do know that children with bipolar disorder have disturbances in the architecture of their sleep—they have sleep/wake reversals and are activated at night and slowed-down in the morning. There is considerable evidence in the adult literature to suggest that several elements of the sleep/wake cycle are altered in people suffering with mood disorders.

The Typical Architecture of Sleep Normally throughout the night a person experiences two kinds of sleep that alternate rhythmically. One is called rapid eye movement (REM) sleep, during which most dreaming takes place; the other (not surprisingly) is called non-REM.

Non-REM sleep has a four-stage development plan as revealed by electroencephalogram (EEG) sleep studies. Sleep typically begins the night with a light stage 1 sleep where the brain waves are small and fast. After approximately 30 minutes, the sleeper slips deeper into sleep as Stages 2, 3, and 4 of non-REM sleep progress. EEGs of Stage 3 reveal

14 Sleep Inertia, Naps, and Memory larger and slower brain waves. Stage 4 brain waves are large, slow, and regular and this is the deepest period of sleep.

After approximately 90 minutes, a brief period of REM sleep appears. This is the dreaming state and the eyeballs can be observed moving rapidly beneath the eyelids. A 90-minute oscillating pattern develops with REM sleep asserting itself for longer periods of time. The first 90-minute Notes cycle might consist of 85 minutes of non-REM sleep and 5 minutes of REM, but by the time the fourth cycle rolls around, it might consist of 60 minutes of non-REM and 30 minutes of REM.

But all is not so regular. As Drs. Mark W. Mahowald and Carlos H. Schenck of the Minnesota Regional Sleep Disorders Center at the University of Minnesota Medical School have written: The rapid oscillation of states or the inappropriate intrusion of elements of one state into another may result in the appearance of parasomnias (night terrors, restless leg syndrome, teeth grinding, sleep walking, and confused arousals). Given the large number of neural networks, neurotransmitters, and other state-determining substances that must be recruited synchronously, and given the frequent transition among the three states of being, it is surprising that parasomnias do not occur more often.

A significant number of children with bipolar disorder do seem to be suffering several of these parasomnias, especially night terrors and confused arousals.

It may be that children and adolescents are being asked to get up and go to school when they are in the deepest, slow-wave pattern of sleep. Sleep research has shown that abrupt awakenings during a slow wave sleep episode produce more sleep inertia than awakening in stage 1 or 2 when the brain waves are small and fast. Awakenings during a REM episode produces some sleep inertia, but not as much as awakenings during slow- wave sleep.

Research is also revealing that sleep inertia is more intense when awakening occurs near the trough—the low point—of the core body temperature as compared to its peak. Sleep/wake irregularities, as well as irregularities of the thermoregulatory system, contribute to sleep inertia.

Thermoregulatory Disturbances Children with bipolar disorder often have irregularities in their thermoregulatory systems. They are hot all the time—even when the ambient temperature feels cold (often very cold) to everyone else. Parents

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struggle constantly to get them to wear jackets in winter. In addition, it is not uncommon to see their ears turn beet red.

Scientists have found that the rapid onset of sleep occurs when the blood vessels in the skin of the hands and feet dilate and cause heat loss at the

extremities. This causes the core body temperature to lower. A group of Notes researchers, Drs. Kurt Krauchi, Christian Cajochen, and Anna Wirz- Justice, noted this functional relationship between core body temperature and sleepiness, and hypothesized that the opposite would also be true: the constriction of blood vessels would raise the core body temperature and the human being would come to a state of wakefulness. (Think colder at night and the onset of sleepiness; and warmer in the morning and the onset of wakefulness.)

The authors write: The circadian clock prepares the thermoregulatory system for vasodilation to begin in the early evening as sleepiness increases, followed by a drop in core body temperature. Even lying down increases sleepiness by redistributing heat in the body from the core to the periphery. Turning out the light is a complex cognitive and physiological signal that also leads to vasodilation. There is a tight correlation between the timing of the endogenous increase in melatonin in the evening and vasodilation, an effect that is mimicked by pharmacological doses of melatonin. Before bedtime, then, many overlapping events orchestrate the thermoregulatory overture.

Could irregularities in the timing of melatonin release—a peptide known to reduce core body temperature and induce sleep—be a factor in the increased activity level seen at night and the marked sleep inertia seen in the morning? Melatonin, produced in the pineal gland, is secreted into the cerebral spinal fluid at dusk and diminishes its effect at dawn.

The pineal gland is a small reddish-gray structure that sits near the center of the brain. Its name is derived from the Latin word for “pine cone” because early viewers glimpsed a resemblance. The pineal gland has a story of its own.

The Pineal Gland All vertebrates possess a pineal gland, and in certain reptiles and birds the gland is situated close enough to the top of the skull to monitor the intensity of sunlight. This “third eye” appears to help animals adjust to changes in the day-light cycles of the yearly seasons. Seventeenth-century

16 Sleep Inertia, Naps, and Memory philosopher Rene Descartes, thought the human pineal to be the seat of the rational soul; early 20th-century scientists felt that the buried-down- under human pineal had been abandoned by the roadside of human evolution.

Not so. In the mid-sixties, researchers discovered that the pineal gland secretes an important hormone called melatonin. As we mentioned Notes above, it is a sleep-inducing hormone thought to have a part in the synchronization of circadian (daily) rhythms. In animals, melatonin influences seasonal breeding patterns. Its secretion is at the highest levels in winter.

Today scientists accept that a kind of biological clock in the human organism establishes a fundamental daily rhythm for bodily functions such as temperature, the release of cortisol, rest/activity cycles, and the secretion of melatonin. But nature has built some flexibility into a human being so that the body can adjust to the ever-changing environmental rhythms-such as longer and shorter days in the summer and winter.

Apparently some people do not adjust so easily. Dr. Alfred Lewy, director of the Sleep and Mood Disorders Laboratory at Oregon Health and Science University, hypothesized that certain depressed people have a desynchronization in their 24-hour internal clock rhythms. For instance, their sleep, temperature, and cortisol cycles may be in synchrony with each other, but be out of step with other 24-hour rhythms, thus causing their internal rhythms to run a few hours behind or ahead of schedule. They either start and stop releasing melatonin earlier than usual (leading to evening sleepiness and early-morning awakening), or start and stop releasing melatonin later than usual (leading to difficulty sleeping at night as well as difficulty getting up in the morning). Exactly what is seen so often in children with bipolar disorder.

What Can Be Done About Sleep Inertia?

A good plan of attack would be to discuss the timing of medications with the treating physician. If one or more of the meds is contributing to morning grogginess, than it might help to administer the drug at an earlier time the day before. If anxiety is causing school refusal, the doctor or therapist may ease the fears of the child by helping him or her deal with the anxiety. Cognitive therapy may be particularly helpful.

It is important that parents and teachers recognize that many children with bipolar disorder have co-occurring learning disabilities and executive function deficits, and that these deficits make school embarrassing and dispiriting. Rather than get up and go to school and fail, the youngster

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may prefer to sleep. Neuropsychological testing will reveal these problems, and the IEP of the student can accommodate these disabilities and make the child or adolescent less anxious.

Phototherapy, or light treatment, may entrain the rhythms and phase

shift the dysregulation many of these children have. Some parents have Notes reported that a dawn simulator is helpful in getting their children out of bed.

If the prescribing doctor thinks a trial of melatonin is a good idea, he or she will discuss the timing and dosage. In a pilot study, one of the authors of this newsletter (D.F.P.), found that 3-6 mg of melatonin given approximately 20 minutes before bedtime, not only enhanced the earlier onset of sleep, but in a number of cases abolished sleep-arousal disorders such as night terrors. A more restorative sleep ensued. Since melatonin is known to lower core body temperature, this may explain one of its effects on the regulation of the sleep/wake cycle.

Remember the parents who had to squirt GoGurt in their daughter’s mouth each morning? They told us that they began to give her melatonin each night and she can now get up, get dressed, and eat without the aid of her parents (and Gogurt is no longer the only staple of her morning menu).

Melatonin requires more study, and no one is certain of its long-term effects, nor will it work for everyone. Naturally, much depends on the causes of the sleep inertia.

Until the sleep/wake cycle is regulated (and your child may always be more of an owl than a lark), an accommodation in the school day may have to be made. It might help if the student is allowed a later start, and it would be wise to schedule all academics later in the morning and in the afternoon when he or she would be more cognitively available for learning.

During the writing of this newsletter, a mother emailed us her philosophy and mantra. She speaks of her “during the school-year child” and her “summer vacation child.” Because her son has learning disabilities, as well as sleep inertia, he feels anxiety, and even has small panic attacks upon arriving at school. She wrote: Each school morning for me, as a mother, is an adventure. I try not to worry in advance because I never know what each morning will bring me from my son. Is it a good morning for him, or a bad morning? I only find out when HE finds out.

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I try not to get anxious or too pushy, but of course sometimes I lose control, especially if there’s a meeting I absolutely can’t miss, or if I have a doctor’s appointment.

I need to be aware of myself, my attitude, my temper, even my breathing. I do my best to slow down, speak Notes reasonably, and gently, and offer whatever alternatives work. I have even been known to offer bribes because I know that once he gets to school, his anxiety usually evaporates and I receive reports later about “what a good day he had.” I need to look at a bad morning as not necessarily a permanent all-day condition.

She concluded by saying: So my Mom mantra for a school day morning is: 1. Greet each day as a new day. 2. Prepare for different contingencies. 3. Maintain my calm, no matter what. 4. The more agitated my son gets, the calmer, slower, and gentler I get. 5. Take my time: it is more important for him to get to school, than it is important that he get to school on time. 6. Learn to cut my losses, and give up on the day if necessary. (If my son gets too agitated, I have to learn that it’s not the end of the world if he doesn’t get to school that day.)

In my opinion, it’s hard to give consequences for behavior that is brain-induced or slowed down by meds. We just try to impress upon him what we expect from him, what the school expects from him. It can be a moment-to-moment experience.

In Conclusion From all of the above, it is easy to surmise that morning alertness is dependent upon a complex set of factors: side effects of medications; chemical cascades that affect sleep architecture, thermoregulation, and mood; as well as the subjective feelings of the child when that morning alarm rings—anxiety, depression, or stress. No one can predict any one factor, several may be contributing, and all must be examined in order to find a solution for the child. The school administration and IEP team must understand the biological and psychological factors at play and

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accommodate the morning difficulties which, after all, are not volitional or oppositional on the part of the child.

We hope the above discussion helps parents who dread the split-second timing of a school morning, realize that they are not alone, and that they

are not inadequate if the morning is tumultuous. For a while, at least, it is Notes going to have to be okay if the child goes to school without breakfast, or leaves looking like he or she has just rolled out of bed (which he or she probably has).

Hopefully one of the suggestions above, and an understanding of what may be happening for the child at reveille, will result in a less gut- wrenching start to the day.

Alertness Management: Strategic Naps in Operational Settings

Rosekind, M. R., Smith, R. M., Miller, D. L., Co, E. L., Gregory, K. B., Webbon, L. L., Gander, P. H., Lebacqz, J.V. (1995). Alertness Management: Strategic Naps in Operational Settings. J. Sleep Research Society, 4, 62-66.

Introduction Today, 24-hour operations are necessary to meet the demands of society and the requirements of an industrialized global economy. These around- the-clock demands pose unique physiological challenges for the humans who remain central to safe and productive operations. Optimal alertness and performance are critical factors that are increasingly challenged by unusual, extended, or changing work/rest schedules. Technological advancements and automated systems can exacerbate the challenges faced by the human factor in these environments.

Shift work, transportation demands, and continuous operations engender sleep loss and circadian disruption. Both of these physiological factors can lead to increased sleepiness, decreased performance, and a reduced margin of safety. These factors can increase vulnerability to incidents and accidents in operational settings. The consequences can have both societal effects (e.g., major destructive accidents such as Three Mile Island, Exxon Valdez, Bhopal) and personal effects (e.g., an accident driving home after a night shift) (US Congress, Office of Technology Assessment 1991; National Commission on Sleep Disorders Research 1993).

20 Sleep Inertia, Naps, and Memory

Alertness management in operational settings Alertness management strategies can minimize the adverse effects of sleep loss and circadian disruption and promote optimal alertness and performance in operational settings. Sleep and circadian physiology are complex, individuals are different, the task demands of settings are different, and schedules are extremely diverse; therefore, no single strategy will fully address the fatigue, sleepiness and performance Notes vulnerabilities engendered by 24-hour operational demands. Rather than attempt to eliminate fatigue, it may be more useful to consider the critical factors that can promote and optimize alertness management. There are at least six critical factors that can be addressed for their role in managing fatigue in operational settings. These factors include: hours of service, scheduling, education and training, countermeasures, technology, and research. Each of these factors deserves attention to determine how scientific findings on fatigue, sleep, and circadian physiology can be incorporated and addressed in each area.

The application of ‘strategic countermeasures’ involves three components: • understanding the physiological principles related to sleep and circadian rhythms; • determining the specific alertness and performance requirements of a given operation; • taking deliberate actions to apply the physiological principals to meet the operational requirements.

Whenever possible, deliberate actions should be part of a comprehensive plan to manage alertness and performance.

Alertness management strategies can be categorized as preventive and operational strategies (Rosekind et al. 1991). Preventive strategies, which are used before a duty or shift period, can address the underlying physiological mechanisms associated with sleep and circadian factors. For example, some preventive strategies might facilitate circadian adaptation prior to an altered work/rest schedule. These might include the use of bright light or melatonin to promote circadian adaptation before beginning a series of night shifts. Other preventive strategies might promote sleep quantity and quality before a period of sleep loss or disruption. Operational strategies are used during a duty or shift period to maintain performance and alertness. These strategies might include strategic caffeine consumption, physical activity, or social interaction. These strategies are intended to maintain alertness and performance during an operational requirement but may have no, or minimal, effect on underlying physiological mechanisms (i.e., sleep loss and circadian disruption). A combination of strategies may provide the greatest

21 Sleep Inertia, Naps, and Memory

potential to meet the physiological challenges posed by 24-hour operational demands.

Strategic naps as an alertness management strategy Applying the three components outlined for ‘strategic countermeasures’, Notes a ‘strategic nap’ involves : • understanding the physiological principles that relate to napping, including the benefits (e.g. improved performance and alertness) and potential negative effects (e.g. sleep inertia); • determining the operational requirement (e.g. timing of critical phases of operation); • deliberately planning a nap of a specific duration at a specific time to promote performance and alertness during the operation.

Naps are a useful strategy that can be used in both a preventive and an operational manner. As a preventive strategy, naps can be used prophylactically to maintain alertness and performance during a subsequent period of prolonged wakefulness (Dinges et al. 1987; Dinges, et al. 1988). A nap can also be used to reduce the hours of continuous wakefulness before a shift or duty period and the total hours awake at the end of the subsequent work period. For example, a shift worker who awakens at 08.00 hours, reports to a 23.00 hours shift, and finishes the shift at 07.00 hours, is returning home in the 24th hour of wakefulness. An afternoon nap in the 15.00 hours17.00 hours window of sleepiness will decrease the number of continuous hours of wakefulness to 14 (i.e., 17.00 hours-07.00 hours). Naps also can be used as an effective operational strategy. Naps used to interrupt sustained periods of wakefulness during a continuous operation can help to maintain the level of subsequent performance and alertness (Naitoh and Angus 1989; Naitoh et al. 1992). Therefore, a nap can be used as an alertness management strategy during operations, such as in shift work and transportation environments.

Beneficial effects of naps Naps can maintain or improve subsequent performance, physiological and subjective alertness, and mood. Naps can have adverse effects on these factors immediately upon awakening and these will be discussed in a later section on sleep inertia. This initial discussion will focus on nap effects that occur 30 min. or longer after awakening.

Generally, studies have demonstrated that naps maintain performance compared to baseline conditions or improve performance compared to conditions of prolonged wakefulness without naps (e.g. Nonnet et al. 1995; Dinges 1989; Dinges et al. 1988; Gillberg 1984; Nicholson et al.

22 Sleep Inertia, Naps, and Memory

1985; Taub 1977). Orne (Dinges, et al. 1987) has suggested that ‘prophylactic napping,’ which is essentially a preventive strategy taken prior to a period of sustained wakefulness, helps to maintain performance and alertness by reducing or delaying the expected decrement. Others have demonstrated that naps taken during periods of sustained wakefulness (an operational strategy), also can reduce or delay the expected decrement (for review, Niatoh and Angus 1989). Notes Physiological measures of alertness (i.e. MSLT) also have demonstrated improvements following a nap (e.g. Bonnet et al. 1995; Carskadon & Dement 1986; Gillberg 1984). Generally, both subjective alertness and mood ratings are improved following naps (e.g. Dinges et al. 1980; Evens et al. 1977 Taub 1982; Taub et al. 1976).

Experiments have examined naps of varying lengths, from 20 min to 8 hr. (e.g Akerstedt and Gilbert 1986; (Bonnet et al . 1995; Dinges et al 1987; Dinges, et al. 1988; Stampi et al. 1990; Haslam 1984). Generally, there appears to be a relative dose-dependent effect: more sleep is associated with greater improvement. For example, Bonnet et al (1995) recently showed that an 8 hr “nap” showed more improvement in performance and physiological alertness than a 2 or 4 hr. nap . In fact, there was no significant difference in the effects of the 2 and 4 hr. nap conditions and these were combined for analysis. However, some studies suggest that shorter naps can be more effective than longer ones or show no significant differences in performance (e.g., Stampi et al. 1990; Haslam 1984) This issue is made complex in that the length and subsequent effects of a nap are related to the circadian timing of the nap and the infrastructure of sleep stages (to be addressed later).

An important operational consideration is the duration of the beneficial effects obtained from a nap. Studies suggest that a nap can maintain or improve subsequent performance and physiological alertness from 2 to 12 hr. following the nap. For example, Dinges et al. (1988) found a beneficial effect on performance 10 hr. after a 2-hr. nap, while Gillberg (1984) found improvement 10 hr. after a 1-hr. nap. Carskadon and Dement (1986) found improved physiological alertness on the MSLT up to 6 hr. after 45-min. naps.

Potential negative effects of naps There are two potential negative effects of naps that should be considered prior to operational use. The first is sleep inertia, the grogginess, disorientation, and sleepiness that can accompany awakening from deep sleep. Sleep inertia can be associated with an initial performance decrement immediately upon awakening from a nap. Estimates on the duration of sleep inertia effects vary from a few minutes to 35 minutes, though most negative residual effects appear to dissipate

23 Sleep Inertia, Naps, and Memory

in about 10-15 minutes (Akerstedt et al. 1989; Dinges 1989). Sleep inertia is affected by a variety of factors and therefore, specific predictions of its duration or severity can sometimes be difficult. However, two factors seem most related to the severity of effects: duration of deep sleep and circadian time of nap (Akerstedt and Gillberg 1979; Dinges et al. 1987;

Dinges et al. 1985; Langdon and Hartman 1961). Similar to effects found Notes in nocturnal awakenings, the sleep stage (NREM 3 & 4) and duration of SWS will affect subsequent sleep inertia. These can be affected by the circadian timing of the nap and the homeostatic drive.

Sleep inertia is a consideration when naps are used in an operational setting. This factor should be considered if an operator is likely to have a nap interrupted by an emergency requiring a quick response with a high level of performance. However, the potential for such an emergency response must be weighed in relation to the potential benefits of improved alertness and performance following a nap during regular operations and the related increase in the safety margin.

A second potential negative consequence of naps is the effect on subsequent sleep periods. A long nap, at certain times of the day, can disrupt the quantity and quality of later sleep periods (Akerstedt et al. 1989; Dinges 1989). The disturbance could affect both the duration of the sleep period and its infrastructure. While the nap can improve waking alertness and performance, it might increase subsequent sleep loss by disrupting a later sleep period.

No alertness management strategy will address all of the sleepiness and performance decrements associated with operational sleep loss and circadian disruption. It is also clear that each strategy will present both positive and potentially negative consequences that must be weighed prior to implementation. This reinforces the idea that combining strategies provides the best way to optimize operational performance and alertness.

Strategic naps in an operational setting The following study is described to demonstrate the effectiveness of a planned nap in maintaining alertness and performance during regular operations. Long-haul flight operations can involve multiple time-zone changes, long duty periods, and can engender sleep loss and circadian disruption. Anecdotal reports, logbook studies, and confidential incident reports to the National Aeronautics and Space Administration (NASA) Aviation Safety Reporting System clearly demonstrate that as a consequence, flight crews can experience spontaneous and unplanned sleep episodes. A NASA/Federal Aviation Administration (FAA) study examined the effectiveness of a planned in-flight nap to maintain

24 Sleep Inertia, Naps, and Memory

performance and alertness in long-haul flight operations (Rosekind et al. 1994).

This study involved non-augmented three-person, 747-200 aircraft flying regularly scheduled transpacific flights. The trip schedule involved 8 flight legs in 12 days. Each flight was about 9 hours in duration with an approximately 25-hour layover between flights. The volunteer flight Notes crewmembers were randomly divided into two groups: Rest Group and No-Rest Group. Pilots in the Rest Group were provided a 40-min., planned, in-flight nap opportunity during cruise over water. The 40-min. nap duration was designed to minimize the opportunity for the occurrence of SWS and its duration. One pilot rested while the other two crewmembers maintained the flight. The nap opportunity was spent in the cockpit seat. The No-Rest Group had a 40-minute control period identified during cruise, during which they were instructed to maintain their usual flight activities. Both groups were evaluated with the same measures. Prior to, during, and after the trip schedule, flight crewmembers completed a daily logbook and wore an actigraph to estimate 24-hour rest/activity patterns. Two NASA researchers accompanied the crews during the four middle legs of the trip schedule for intensive monitoring. This involved continuous ambulatory physiological monitoring of brain (EEG) and eye (EOG) activity and vigilance performance during flight.

On 93% of the nap opportunities, Rest Group crewmembers were able to sleep. On average, they fell asleep in 5.6 minutes and slept for 25.8 minutes. To determine the effects of this brief nap, subsequent performance and physiological sleepiness was compared between groups. The No-Rest Group demonstrated reduced performance on night flights compared to days, at the end of flights compared to the beginning, and after multiple flight legs. The Rest Group, however, maintained consistent performance night and day, at the end of flights, and after multiple flight legs.

The Rest Group demonstrated vigilance performance improvements from 16% in median reaction time to 34% in lapses compared to the No- Rest Group. Physiological sleepiness was examined by analyzing changes in EEG (alpha and theta activity) and EOG (SEMs) during the last 90 minutes of flight, through descent and landing (Torsvall and Akerstedt 1988; Torsvall et al. 1989). The total number of microevents associated with physiological sleepiness that occurred in the No-Rest Group (9 Ss) was 120, including 22 during the last 30 min. of flight (descent and landing phase). The total number for the Rest Group (12 Ss) was 34 microevents, with none occurring in the last 30 min. With appropriate statistical transformation, microevents in the No-Rest Group occurred at a rate twice that of the Rest Group (p=0.02). The brief, planned, in-flight

25 Sleep Inertia, Naps, and Memory

nap obtained by the Rest Group was associated with better subsequent performance and physiological alertness compared to the No-Rest Group. Specific procedural and safety guidelines were utilized in the study to facilitate operational implementation. For example, a 20-min. period was allowed after awakening from the nap to examine potential

inertia effects. Partially as a result of this study, the FAA convened an Notes aviation industry/government working group to draft advisory material to sanction controlled rest on the flight deck. Several non-U.S. air carriers have already successfully implemented programs for controlled rest on the flight deck.

This study also emphasizes the need for empirical evaluation of potential alertness management strategies in operational settings. While anecdotal reports suggest that in-flight rest is used to maintain alertness and performance by flight crews, it is not currently sanctioned under Federal Aviation Regulations. It was critical to provide empirical data obtained during usual operations before regulatory action would be considered.

Implementation in operational settings The following factors should be considered before implementing naps or other alertness management strategies in real-world operational settings: • An identifiable benefit: an alertness management strategy should provide a clear and identifiable benefit to the human operator and the operational environment (e.g., increased safety margin). It should minimize some adverse consequence or promote a particular positive outcome; • Opportunity: an appropriate opportunity for implementation should be identified. In some operational circumstances it may not be appropriate to consider a certain strategy (e.g., napping during a shift with high work demand or potential for emergency); • Corporate climate/culture: some strategies may be explicitly or implicitly supported, while others are actively suppressed; • Operational demands: the specific work demands and circumstances of a particular work environment may exclude some potential strategies; • Safeguards: alertness management strategies are intended to promote safety and productivity. Specific safeguards should be employed to ensure that strategies do not negatively affect the safety margin.

Other considerations As attention to issues of work hours, sleepiness, and accidents increases, more approaches to address the issues will emerge. Therefore, it will be

26 Sleep Inertia, Naps, and Memory critical that empirical evaluations be used to demonstrate a quantifiable positive effect of proposed alertness management strategies. Empirical data will support the implementation of approaches that show a worthwhile effect and will expose ineffectual strategies. An important aspect of these evaluations is a demonstration of effectiveness in actual operational settings. This challenges researchers to take significant and provocative laboratory findings and translate them to the complexity of Notes real-world demands. The premature application of strategies that are eventually determined to be ineffective may impede the implementation of future approaches.

Combined strategies should be evaluated to determine the potential emergent effects of combination. For example, a comprehensive alertness management approach might utilize bright light or melatonin to facilitate circadian adaptation, strategic caffeine consumption during a window of circadian sleepiness, and a nap. Guidelines for implementing strategies in a particular environment should be developed and clearly stated.

Defining ‘safety’ and establishing what constitutes a ‘significant performance decrement’ are extremely difficult but important tasks. These delimitations are essential to determining the effects of work hours, sleepiness, and performance degradation on operational incidents and accidents. In turn, evaluating the effectiveness of alertness strategies in attenuating these effects relies on the quantitative definition and assessment of the effects. Clearly, these can change with the specifics of a work setting, but this area remains difficult to quantify.

Finally, education and training programs provide crucial support to all of these activities (e.g. Rosekind et al. 1995) individuals involved in all aspects of 24-hour operations must be informed of the fatigue factors that pose challenges to human physiology . This includes understanding potential strategies to minimize adverse effects and to promote optimal alertness and performance during operations. This information should be provided to operators, schedulers, regulatory agencies, accident investigation personnel, and others.

The physiological and performance capabilities of human operators remain critical to safety, performance, and productivity in 24-hr operational settings.

27 Sleep Inertia, Naps, and Memory

Sleep-Wake State and Memory Function

by Timothy Roehrs

INTRODUCTION Notes Sleep state and level of sleepiness have profound effects on the ability to form new memories and retrieve old memories. However, the memory and sleep literature, while extensive, is complex and somewhat contradictory. Memory consists of several phases or processes: a stimulus registration or acquisition phase of short duration, a consolidation from short-term to long-term memory phase, and the retrieval from long-term memory. Scientists have also postulated a number of different memory systems which elaborate long-term memory. One system developed by Tulving distinguishes perceptual, procedural, episodic, and semantic memory. Perceptual memory, also referred to as implicit, is an unconscious form of memory, procedural memory refers to skilled performance, semantic memory refers to the use and accumulation of factual knowledge, and episodic memory to the recall of personal life experiences. A system described by Squire distinguishes two types of memory: procedural and declarative. Procedural memory is implicit and it includes simple conditioning, perceptual and skills memory. Declarative memory is explicit and is subdivided into semantic and episodic. Squire hypothesizes that declarative memory is specifically organized in the brain at the hippocampus, while procedural memory is more global and non-specific.

Whether sleep-wake state and level of sleepiness differentially affect the various memory processes and systems described above is not clear. It is clear that neural processing, and consequently probably also memory function, is reorganized during NREM and REM sleep. Memory neurobiologists locate memory formation in the hippocampus and at the cellular level model it using long-term potentiation. How sleep state gates hippocampal memory functioning is not known. Furthermore, how reorganization occurs during transitions in state (i.e., wake to sleep or sleep to wake) and whether sleepiness itself is a transitional state is intriguing. How memory functions differentially change with state or state transitions may in turn reveal the process by which the transition occurs. We will review and discuss memory functions while sleepy, at transitions of sleep-wake state and during both NREM and REM sleep.

MEMORY IN WAKE AND LEVEL OF SLEEPINESS Sleepiness in the wake state impairs memory formation and retrieval. Sleep loss studies, sedative drug studies, and studies of patients with disorders of excessive sleepiness have all found memory impairment.

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Many of these studies show that the degree of memory impairment is consistent with the degree of waking sleepiness.

Sleep deprivation studies have demonstrated the association of sleepiness with memory impairment. Sleepiness affects stimulus registration. The sleepy state is characterized by microsleeps. Microsleeps are brief episodes of EEG-defined sleep that intrude on the waking EEG during Notes prolonged sleep deprivation. Subjects required to press a switch when a tone or a visual stimulus repeatedly occurs do not respond during microsleeps. Apparently, the presence of the stimulus is not registered during the microsleep. Memory consolidation is also disrupted by sleep loss and the consequent increased sleepiness, as is the retrieval of memories. However, determination of whether or not increased sleepiness due to sleep deprivation or sleep restriction is differentially disruptive of a particular memory system has not been systemically evaluated.

The most extensively studied class of sedating drugs is the benzodiazepine (Bz) receptor agonist. These drugs increase sleepiness as measured by the Multiple Sleep Latency Test (MSLT). Their amnestic effect is also well known. Whether the amnestic effect is due to the sedative activity, rather than direct hippocampal effects, is disputed. The debate goes to the specificity of the amnestic effects with regard to memory system and Bz receptor subtype . Given that Bz1 receptors are not densely distributed in the hippocampus, a Bz1 specific drug by the Squire hypothesis should not alter declarative memory. But, a recent study found amnestic effects for a receptor specific Bz agonist that were comparable to that of a non-specific Bz receptor agonist. Declarative memory, specifically a semantic memory task, was affected; that is the amnesia was system non-specific.

The sleepiness-amnesia association is also seen in sleep disorders patients. Standardized testing of neuropsychological functioning, including memory, in patients with sleep apnea syndrome has shown impairment. The extent of the sleep disturbance and resultant daytime sleepiness related directly to degree of impairment. The range of cognitive functions showing impairment included declarative and procedural tasks (i.e., verbal and visual memory) and both short-term and long-term memory.

MEMORY AT SLEEP-WAKE STATE TRANSITIONS Memory function at the transitions from wake to sleep and from sleep to wake is intriguing both for what might be learned about memory, as well as, state transitions. The transition to sleep is associated with memory loss. Subjects presented stimulus words at 1-minute intervals while falling

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asleep, when awakened 10 minutes later they could not recall those words presented within the immediate 5-min wake interval before EEG signs of sleep. That finding has since been replicated and extended to include both explicit and implicit memory tasks.

This finding is the same for transitions to sleep after an awakening from Notes sleep. Sedative drug studies have found that the rapidity of sleep onset after an awakening from sleep is associated with amnesia the next morning for the material presented during the awakening. The amnesia is also found with barbiturates as well as Bzs and is avoided if wakefulness is enforced for 15-minutes. The same is found in non-drug studies of awakenings from sleep. The morning recall of a stimulus word presented during an awakening improves if a brief motor task also is performed, which delays the return to sleep.

In the opposite state transition, from sleep to wake, there also is memory impairment. This modest and short-lived impairment has been called “sleep inertia”. Any number of motor and cognitive functions, including memory, have shown the impairment. Determinants of the sleep inertia are the extent of prior sleep loss and the sleep stage from which the awakening occurred. Differential sensitivity of memory systems and processes has not been explored.

MEMORY DURING SLEEP Discussion about memory during sleep must begin with a differentiation of memory function during REM and NREM sleep. The data are quite consistent regarding NREM sleep, but very inconsistent and controversial regarding REM sleep. New memories are not formed during NREM sleep, at least not declarative memories. To the extent that declarative memories are formed during NREM sleep the remembered stimuli are associated temporally with a waking EEG and the longer the duration of the waking EEG, the stronger the memory. This NREM amnesia is probably due to a failure to consolidate material from short to long-term memory. As indicated below stimuli are registered and retrieved during sleep.

There is some suggestion that procedural memories in the form of classical conditioning can be formed during NREM sleep. The conditioned response in these studies has been EEG alpha attenuation, EEG K complexes and heart rate. It is reported that sleep stage shifts or an alpha EEG do not occur in response to the stimuli and thus EEG arousal does not account for the conditioning. On the other hand, habituation which is the simplest form of conditioning has not been consistently found. Thus, the extent to which procedural memory during

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NREM sleep is possible, without the confound of EEG arousal, needs further exploration.

Quite controversial is the question of whether memory consolidation occurs during REM. Animal studies have shown that learning during wake is followed by increased paradoxical sleep (PS) and deprivation of PS is followed by memory impairment. Furthermore, new associations Notes can be learned during PS. With regard to specific memory systems, some studies in humans show memory for declarative tasks is not impaired by REM sleep deprivation, but that procedural memory is disrupted by REM deprivation. However, these results directly contradict those discussed earlier regarding memory system function in NREM sleep. The confound may be the extent of EEG arousal, which is a possible result of the REM deprivation. In contrast to these findings is the theory and evidence assembled by Crick that REM sleep is a period of forgetting, or as described by Crick “reverse learning”.

Retrieval of memories formed while awake does occur during sleep, both in NREM and REM sleep (e.g., stimulus information is monitored and processed during sleep). Stimuli presented during sleep evoke responses that subjects have learned during prior wakefulness and subjects also discriminate between stimuli during sleep by responding differentially to them.

To summarize, memory is not consolidated during uninterupted NREM sleep, but may be facilitated during REM sleep. Whether the various memory systems are differentially preserved or facilitated during these sleep states is not clear. At the transitions to and from sleep there is memory impairment that by much evidence is non-specific as to memory system. Finally, sleepiness during wake is also associated with impairment of memory function and again it is non-specific.

In attempting to synthesize this literature, two important factors emerge. The basal state of arousal or activation at the time of memory function, whether it be registration, consolidation, or retrival, seems critical. The sleepy state, state transitions, and NREM sleep may define a continuum of arousal with respect to memory function. But also, the arousing nature of the memory function itself seems important and whether different memory systems involve differing arousal is a question. Finally, there is a clear shift in neurobiology from the NREM to REM state and whole mode of memory function may also change.

About naps and sleep inertia Although many astronauts report feeling fully rested after only six hours of sleep, the fact is, sleeplessness can cause irritability, forgetfulness and

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fatigue - none of which astronauts need to deal with while piloting complicated ‘ships that hurtle through space at tens of thousands of miles per hour.

The solution seems simple: Take a nap.

Notes But naps are a double-edged sword. Sometimes napping can leave you feeling even drowsier than before. If your body enters a deep sleep, trying to wake after only an hour or so can be very unpleasant, and you might remain groggy for some time afterward. This is called “sleep inertia.”

Why do naps sometimes backfire? Researchers don’t yet know the physical causes of sleep inertia, but they would like to be able to predict, at least, when it’s going to strike. This could help doctors prescribe naps of the right time and duration for drowsy people in high-risk professions.

Helping astronauts nap was the goal of a recent series of experiments funded by NASA in cooperation with the National Space Biomedical Research Institute. In those experiments, led by David Dinges, a professor at the University of Pennsylvania School of Medicine, 91 volunteers spent 10 days living on one of 18 different sleep schedules, all in a laboratory setting. The sleep schedules combined various amounts of “anchor sleep,” ranging from about 4 to 8 hours in length, with daily naps of 0 to 2.5 hours.

To measure how effective the naps were, the scientists gave the volunteers a battery of tests probing memory, alertness, response time, and other cognitive skills throughout the experiment. They also measured things like core body temperature and hormone levels in blood and saliva, all of which fluctuate in a natural daily cycle known as a person’s “biological clock.”

In general, they found, longer naps were better. No surprise there. But they also found that some cognitive functions benefited more from napping than others:

“To our amazement, working memory performance benefited from the naps, [but] vigilance and basic alertness did not benefit very much,” says Dinges.

“Working memory,” he explains, “involves focusing attention on one task while holding other tasks in memory ... and is a fundamental ability critical to performing complex work [like piloting a spaceship]. A poor working memory could result in errors.”

32 Sleep Inertia, Naps, and Memory

For vigilance and alertness, which involve the ability to maintain sustained attention and to notice important details, they found that the total amount of sleep during 24 hours remained the most important factor.

Another interesting finding was that naps didn’t work as well for volunteers on a nocturnal schedule. Sleep schedules for some of Dinges’ Notes subjects were flipped, so that anchor sleep occurred when their bodies thought it was daytime. The nap, then, fell in the middle of biological nighttime. This simulated what might happen when an astronaut’s biological clock is out of sync with the mission schedule.

These out-of-sync volunteers had a very hard time waking from naps, and the grogginess of sleep inertia lasted for up to an hour. Some sleep inertia did occur after naps on a normal schedule too, notes Dinges, but the inertia after a nighttime nap was much more severe.

The ultimate goal, says Dinges, is to tie all these data together into a mathematical model of naps. Such a model, written as a computer program, could prescribe effective naps compatible with the scheduling demands of a mission. Not only astronauts would benefit from such a program, but also doctors, pilots, firefighters … the list goes on.

Such a program is still in the future. Meanwhile, Dinges notes another finding of their study: Naps are a short-term fix, offering only temporary boosts in mental acuity. “They cannot replace adequate recovery sleep over many days,” he says.

In the end, there’s no substitute for 8 sweet hours of shut-eye.

Rise and shine? That’s not quite how it works, study says

By LEE BOWMAN Scripps Howard News Service

Published: Tuesday, January 10, 2006

(SH) - That trouble getting going in the morning isn’t caused by just laziness. The inertia we feel after waking from a dead sleep is both real and enduring, according to a new study by scientists.

They found that people awakening after eight hours of sleep have more impaired thinking and memory skills than someone kept awake for 24 hours - equivalent to being drunk.

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“This is the first time that anyone has quantified the effects of sleep inertia,” said Kenneth Wright, a researcher at the University of Colorado- Boulder and lead author of the study, published Wednesday in a letter to The Journal of the American Medical Association.

The study, funded mainly by NASA, was carried out in the sleep lab at Notes Boston’s Brigham and Women’s Hospital, where Wright was a staff neuroscientist and instructor at Harvard Medical School before joining the Colorado program.

The findings have implications for medical, safety and transportation workers who are often called upon to perform critical tasks immediately after waking up.

“We found that the cognitive skills of test subjects were worse upon awakening than after extended sleep deprivation,” Wright said. “For a short period, at least, the effects of sleep inertia may be as bad or worse than being legally drunk.”

The study participants were nine paid volunteers, all but one man, ranging in age from 20 to 41, with no medical, psychiatric or sleep disorders.

They stayed in the clinic for six days. Following six nights of monitored sleep lasting eight hours per night, participants were given a performance test that involved adding two randomly generated, two-digit numbers. They’d also been asked to spend several hours doing the task each day they were in the lab. They continued to take the test every two hours while they were kept awake over the next 24 hours.

Each subject did substantially worse on the test than he or she did during any of the later tests.

The results showed the most severe impairment from sleep inertia in the first three minutes after awakening, and that level of grogginess dissipated within another seven minutes, although effects were detectable in some subjects for up to two hours.

“These were very healthy people who had performed the test hundreds of times, making the results even more profound,” Wright said.

Other studies conducted by Dr. Thomas Balkin and his team at Walter Reed Army Institute of Research in Washington have shown that some parts of the brain critical to analysis and complex thinking take longer to come “online” following sleep than other areas of the brain.

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The new findings may be particularly important for medical professionals, such as resident physicians in hospitals who may work 80 hours a week or more and often take “catnaps” at slow times during their shifts, then have to respond to a crisis at a moment’s notice.

Wright said those waking suddenly could be more prone to making Notes simple math mistakes on tasks such as deciding medicine doses.

Sleep inertia also takes a toll on emergency medical technicians and firefighters who may be suddenly awakened and have to drive a vehicle to an emergency scene, and for commercial drivers who pause for quick naps during long hauls.

The study also illustrates the challenges that everyone faces when forced to make judgments when abruptly awakened, whether by a crying child or an alarm.

Wright said that more studies need to be done to measure the effects of nap interruption and “recovery sleep” in people who are on-call and sleep-deprived.

Snooze, You Win

According to new studies, nothing tunes up mind and body like a good nap. But there’s an art to catching the right kind of z’s.

When billionaire adventurer Steve Fossett broke the record for around- the-world solo jet flight last March, he slept just 60 minutes in 67 hours of flight time -- 60 minutes broken into two- and three-minute naps. “I slept when I needed it and awoke refreshed,” he says. Fossett, who holds world records in ballooning, sailing, and flying, adds that none of his feats could have been done without these micro-variety “power naps.”

So what makes a power nap effective? Think of it as an investment with the greatest return in the least amount of time, a kind of super-efficient sleep that fits nicely in a high-pressure schedule: say, between business meetings or in the minutes before a game.

Napping in general benefits heart functioning, hormonal maintenance, and cell repair, says Dr. Sara Mednick, a scientist at the Salk Institute for Biological Studies who is at the forefront of napping research. A power nap, says Mednick, simply maximizes these benefits by getting the sleeper into and out of rejuvenative sleep as fast as possible. No surprise that Lance Armstrong’s coach, Chris Carmichael, says that “naps were critical

35 Sleep Inertia, Naps, and Memory

in his overall training plan.” In Manhattan, napping has become a lucrative business: MetroNaps in the Empire State Building provides darkened cot-like redoubts that attract Broadway actors between shows as well as investment bankers who otherwise would fall asleep at their desks. And in Iraq, U.S. Marine commanders have mandated a power

nap before patrols. Notes Here’s how the power nap works: Sleep comes in five stages that recur cyclically throughout a typical night, and a power nap seeks to include just the first two of them. The initial stage features the sinking into sleep as electrical brain activity, eye and jaw-muscle movement, and respiration slow. The second is a light but restful sleep in which the body gets ready -- lowering temperature, relaxing muscles further -- for the entry into the deep and dreamless “slow-wave sleep,” or SWS, that occurs in stages three and four. Stage five, of course, is REM, when the eyes twitch and dreaming becomes intense.

The five stages repeat every 90 to 120 minutes. Stage one can last up to 10 minutes, stage two until the 20th minute. Extenuating circumstances, like manning the controls of a jet, aside, experts believe that the optimal power nap should roughly coincide with the first 20 minutes in order to give you full access to stage two’s restorative benefits. In addition to generally improving alertness and stamina, stage two is marked by a certain electrical signals in the nervous system that seem to solidify the connection between neurons involved in muscle memory. “It’s like a welding machine,” says Mednick. “When you wake up, your neurons perform the same function as before, but now faster and with more accuracy,” making the 20-minute nap indispensible to the hard-working athlete looking to straighten out his putter or baseline shot.

Mednick’s most recent research also shows that power naps can lift productivity and mood, lower stress, and improve memory and learning. In fact, Mednick has found through MRIs of nappers that brain activity stays high throughout the day with a nap; without one, it declines as the day wears on. Tell that to the boss next time he finds you passed out at your desk.

There is, however, a pitfall in all this sleeping around. You have to carefully time the duration of your nap in order to avoid waking in slow- wave sleep. This can produce what’s known as sleep inertia. That’s when the limbs feel like concrete, the eyes can’t focus, the speech is slurred, the mind is sluggish. Sleep inertia can ruin your day. You must keep the nap to 20 minutes or slightly less, and if you need the extra sleep, wait until the 50-minute mark. This will safely keep you on the power side of your nap.

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Getting the Perfect Nap Everyone, no matter how high-strung, has the capacity to nap. But the conditions need to be right. Dr. Sara Mednick, who will publish a book on napping in the spring (tentatively titled Take Back the Nap!, Workman Publishing) has some helpful hints: 1. The first consideration is psychological: Recognize that you’re Notes not being lazy; napping will make you more productive and more alert after you wake up. 2. Try to nap in the morning or just after lunch; human circadian rhythms make late afternoons a more likely time to fall into deep (slow-wave) sleep, which will leave you groggy. 3. Avoid consuming large quantities of caffeine as well as foods that are heavy in fat and sugar, which meddle with a person’s ability to fall asleep. 4. Instead, in the hour or two before your nap time, eat foods high in calcium and protein, which promote sleep. 5. Find a clean, quiet place where passersby and phones won’t disturb you. 6. Try to darken your nap zone, or wear an eyeshade. Darkness stimulates melatonin, the sleep- inducing hormone. 7. Remember that body temperature drops when you fall asleep. Raise the room temperature or use a blanket. 8. Once you are relaxed and in position to fall asleep, set your alarm for the desired duration (see below).

How Long Is A Good Nap? THE NANO-NAP: 10 to 20 seconds Sleep studies haven’t yet concluded whether there are benefits to these brief intervals, like when you nod off on someone’s shoulder on the train.

THE MICRO-NAP: two to five minutes Shown to be surprisingly effective at shedding sleepiness.

THE MINI-NAP: five to 20 minutes Increases alertness, stamina, motor learning, and motor performance.

THE ORIGINAL POWER NAP: 20 minutes Includes the benefits of the micro and the mini, but additionally improves muscle memory and clears the brain of useless built-up information, which helps with long- term memory (remembering facts, events, and names).

THE LAZY MAN’S NAP: 50 to 90 minutes Includes slow-wave plus REM sleep; good for improving perceptual processing; also when the system is flooded with human growth hormone, great for repairing bones and muscles.

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Sleepiness and Fatigue

Laura A. Stokowski, RN, MS

Duty calls, and we answer. Often we do so whether or not we have had sufficient sleep. The alarm rings now to wake us up to the fact that Notes working while fatigued or sleep deprived is not a good idea. It’s time to change our collective attitudes toward work so that exhaustion and continued effort in the face of sleep deprivation are seen as posing unacceptable risks to patient safety rather than as signs of dedication. Ann Rogers, PhD, RN, FAAN, Associate Professor, University of Pennsylvania School of Nursing, Philadelphia, is a well-known expert on the topic of sleep loss and sleep deprivation in nurses. Her presentation advanced our understanding about the nature of sleep and fatigue, and how the latter can jeopardize not only patient safety but our own health as well.

Sleep is a basic human need. The busier we are, the more elusive and precious sleep becomes. Few of us are shy about vocalizing our need for more sleep to friends and coworkers, yet we rarely manage to get the sleep we crave. Like most Americans, nurses regularly shortchange themselves on sleep, getting by on an average of 6.8 hours of sleep on their work days instead of the commonly recommended 8 hours per 24- hour period. Ongoing sleep deprivation of as little as an hour a day can lead to a sleep debt over time that is not easily erased. When we have a sleep debt, our inclination to fall asleep the next day increases. The larger the sleep debt, the stronger the tendency to fall asleep. Sleep debt does not go away by itself. Sleeping is the only way to erase sleep debt.

The terms sleepiness and fatigue are often used interchangeably, although they are not precisely the same thing. Sleepiness is the desire or inclination to sleep. Fatigue is the desire or disinclination to continue performing the task at hand. It is a weariness that can be caused by either mental or physical exertion. A person can be fatigued without being sleepy, but often the two go hand in hand, and their effects are very much the same.

Reduced vigilance, reaction time, memory, psychomotor coordination, and decision making are the traits of the sleepy individual. Speed of mental processing slows during the night under conditions of sleep deprivation. In addition, the following signs and symptoms of fatigue are common: • Increased negativity and irritability, bad mood; • Inability to concentrate; • Lack of energy; • Short-term memory loss;

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• Apathy; • Poor communication; and • Perseveration on ineffective solutions.

Fighting the “Body Clock” Notes

Thomas Edison is often blamed for our society’s propensity to stay up late at night. Even the light bulb, though, can’t keep us awake through the wee hours of the morning. The body’s intrinsic circadian rhythm, controlled by the hypothalamus, coordinates daily cycles in such functions as sleep/wake, body temperature regulation, hormone secretion, digestion, performance capabilities, and mood. Its role is to program us on a 24-hour schedule to sleep at night and to be awake during the day.

The circadian rhythm slows to its nadir between 0300 and 0500 and strongly favors sleeping during this time. Body temperature drops to its lowest. The feeling of being cold experienced by many nurses in the predawn hours is a sign of circadian disruption. Alertness and performance capabilities also drift downward. It is not surprising that many nurses report struggling to stay awake and frequently falling asleep at work on the night shift.

Involuntary episodes of sleep lasting 10-20 seconds, known as “microsleeps,” are common. Such brief losses of attention can appear to others as a blank stare, head snapping, prolonged eye closure, or failure to respond to outside stimuli when a fatigued person is trying to stay awake during a monotonous task. Often the person is not aware that a microsleep has occurred. Microsleeps occur most often during the circadian trough early in the morning, and they increase in frequency in persons who are sleep-deprived.

Another sleep-related phenomenon occurring during nighttime work hours is sleep inertia. Nurse practitioners who work 24-hour shifts and sleep in on-call rooms, as well as anyone who has attempted to nap during their break time, will have experienced sleep inertia if they managed to sleep longer than 30 minutes. Sleep inertia is the feeling of grogginess upon awakening from sleep that temporarily impedes one’s ability to perform even the simplest of tasks. It often occurs when an individual awakens suddenly from a very deep sleep, and is more severe in individuals who have been sleep deprived. Sleep inertia typically lasts 15-30 minutes and can be reversed by activity, exercise, and noise.

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Overall, night shift workers tend to get less sleep than their day shift counterparts, and their sleep is qualitatively poorer. Sleep during the day is shorter, lighter, more fragmented, and less restorative than at night; thus, the night nurse arrives at work with a larger sleep deficit than does a day shift nurse. Although some night nurses report that they are “night

people” and have no difficulty sleeping during the day or staying awake at Notes night, in reality, circadian rhythms cannot be reversed. Even those who have been working night shifts for many years are still programmed to sleep at night.

Fatigue and Impairment

Most nurses would never dream of going to work after having a couple of alcoholic drinks. The same nurses, however, might not think twice about pulling a double shift or going without sleep for as long as 24 hours. This is a common practice on the first shift of a night rotation or when a nurse practitioner works a busy 24-hour shift without getting any sleep. Alarmingly, though, studies show that when an individual has been awake for as few as 17 hours straight, their cognitive and psychomotor performance deteriorates to equal that of someone with a blood alcohol level of .05% (about 1-2 alcoholic drinks, depending on body weight and speed of consumption).

After 24 hours of sustained wakefulness, one’s impairment mirrors that of someone who has had 2-3 alcoholic drinks and whose blood alcohol is 0.1%, a level that is considered legally drunk in the United States. The finding that moderate levels of fatigue produce performance decrements that are greater than those induced by alcohol intoxication has been confirmed in other investigations.

In sleep research, adult subjects who were restricted to 4 to 6 hours of sleep for 14 days showed steady declines in cognitive abilities, equivalent to going without sleep for 3 days in a row, as their sleep deficits accumulated. Cognitive performance deficits included reduced abilities to pay attention, think and react quickly, “multitask,” perform simple math problems, and avoid mistakes.

To prevent neurobehavioral deficits from accumulating, the average person needs slightly more than 8 hours of sleep per 24-hour period. There was no evidence that subjects adapted to the accumulating sleep loss, debunking the notion that individuals “get used to” chronic sleep deprivation. It is worrisome that subjects reported feeling only modestly tired during their most cognitively impaired moments, perhaps explaining why many people consistently fail to get enough sleep.

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Fatigue-Related Errors

Although much evidence supports levels of fatigue-induced impairment sufficient to cause errors, little research has been done to document the occurrence of fatigue-related errors by nurses or nurse practitioners. In one study, nurses who worked rotating shifts were more sleep deprived Notes and more likely to fall asleep at work; they were nearly twice as likely to report making a medication error when compared with nurses who predominantly worked day shifts.

It is possible that the role of sleepiness as a factor contributing to adverse events and medication errors, particularly those occurring during the night shift, is currently underestimated. For example, root cause analysis of a serious 10-fold medication error taking place at 0400 in a neonatal intensive care unit did not include fatigue among potential contributing factors. There is also some evidence that nurses don’t acknowledge the role that fatigue might play in critical incidents. When intensive care and operating room nurses were questioned about error, stress, and teamwork, approximately 60% of them agreed with the statement that, “Even when I am fatigued, I perform effectively during critical times.”

Despite a lack of research linking fatigue among nurses and nurse practitioners to errors in patient care, there is a substantial body of research concerning fatigue-related performance degradation and error in other industries, such as aviation. For example, 21% of incidents reported to the National Transportation Safety Board are attributed to pilot fatigue. There is no reason to believe that the nursing profession is immune to making fatigue-related errors. Both the Agency for Healthcare Research and Quality and the Institute of Medicine have highlighted fatigue and sleepiness as potential causes of medical and nursing errors in need of systems-based preventive solutions. In their 2004 report, “Keeping Patients Safe: Transforming the Work Environment of Nurses,” the Institute of Medicine makes this recommendation: To reduce error-producing fatigue, state regulatory bodies should prohibit nursing staff from providing patient care in any combination of scheduled shifts, mandatory overtime, or voluntary overtime in excess of 12 hours in any given 24-hour period and in excess of 60 hours in any given 7-day period.

It remains to be seen whether state governments will adopt these recommendations limiting the work hours of nurses in the interest of patient safety. It is undoubtedly a difficult time for hospitals that are also facing a significant nursing shortage, and sometimes it is difficult to determine what is worse -- a tired nurse or no nurse at all? The fact that such recommendations have been made, however, might make it difficult

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for nurses to defend themselves in litigation involving errors that occur while working overtime hours or second jobs. These recommendations raise many questions about institutional and individual responsibility for adequate sleep and avoidance of fatigue.

Notes Drowsy Driving

One of the most insidious aspects of fatigue is the inability of the individual to recognize his or her own level of impairment and to take appropriate action. Teri, a neonatal nurse practitioner, tells this story about driving home one morning after working a typical 24 hour shift:

“I was pulled over by a policeman, who told me that every trucker south of the city had called in to report me as a drunk driver. That’s how badly I was weaving back and forth on the road.”

Teri was lucky that she was stopped before she got into an accident and hurt herself and perhaps someone else. According to the National Highway Traffic Safety Administration, so-called “drowsy driving” causes 100,000 automobile crashes yearly, resulting in 76,000 injuries and 1500 deaths. Individuals who work night shifts have 6 times the risk of being involved in a sleep-related crash. Nearly 95% of nurses working 12-hour night shifts report having had an automobile accident or near-miss accidents while driving home from work in the morning.

Last year, the state of New Jersey passed “Maggie’s Law,” the first in the nation to specifically address drowsy driving. The law defines fatigue as more than 24 hours without sleep and allows prosecution of fatigued driving as recklessness under the state’s existing vehicular homicide statute. Driver fatigue accident litigation could increase sharply, with both personal and corporate liability in cases where nurses and nurse practitioners are driving home after working 12- or 24-hour shifts.

Sleep Loss and Health

Chronic sleep deprivation also has important long-term health consequences for the individual, including an increased incidence of certain types of cancer. Working a rotating night shift at least 3 nights per month for 15 or more years may increase the risk of colorectal cancer in women. The risk of breast cancer is significantly elevated among postmenopausal women who worked for 30 or more years on rotating night shifts, compared with those who never worked rotating night shifts. It is hypothesized that increased nighttime light exposure produces an oncogenic effect through the melatonin pathway. Melatonin, normally

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secreted during the night, and thought to have cancer protective effects, is decreased in women who work the night shift.

There is significant concern that the mismatch of circadian rhythm occurring on the night shift also increases the risk of cardiovascular disease by increasing the risk for metabolic syndrome. The underlying cause of metabolic syndrome is insulin resistance, a lowered sensitivity in Notes muscle, liver, and fat cells to the actions of insulin. Evidence indicates that night shift work is associated with increased insulin resistance. Obesity, high triglycerides, and low concentrations of high-density lipoprotein cholesterol, all suggesting the metabolic syndrome, are seen in night shift workers more often than day workers.

Although it is commonly stressed that 8 hours of sleep is optimal for good health, a recent study has contradicted this belief. Mortality risk was calculated for women in the Nurses’ Health Study who answered a questionnaire about sleep duration in 1986. In this study, mortality was lowest among women who reported sleeping 7 hours per night.

Summary

Sleep is a vital physiological function. Most adults do not get enough sleep, and the consequences of sleep loss can be serious. The delivery of healthcare relies heavily on human cognition and executive functions such as judgment, logic, complex decision-making, detection, memory, vigilance, information management, and communication. These are the processes that are most affected by the fatigue and sleepiness that result from sleep loss.

Where does this leave nurses, who can’t avoid working the shifts that, from time to time, result in sleep deprivation and fatigue? Recent recommendations to limit the work hours of nurses aim to eliminate the threats to patient safety posed by fatigue and sleepiness in the workplace. While nurses do not wish to harm patients, they also don’t want to abandon them when there are no replacement nurses after their shifts are over. Experienced nurses may feel that they are more likely to make mistakes from having to care for too many patients than from being a little bit tired at work. Simple mandates to limit nurses’ working hours will not guarantee patient safety if adequate staffing levels are not simultaneously ensured.

Individual nurses need to protect their own health and safety as well as the safety of their patients. Professional nursing organizations should take the lead in setting the standards that will protect nurses both in and out of the workplace. If we fail to recognize and address sleep

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deprivation as a serious health issue, we may find our nursing shortage to be more acute than we predicted it would be.

Notes

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Examination

Select the best answer to each of the following items. Mark your responses on the Answer Form.

Notes 1. Sleep inertia may sometimes affect the performance of doctors, emergency medical technicians, and firefighters a. True b. False

2. The primary study cited in this course is the first time anyone has quantified the effects of sleep inertia. a. True b. False

3. According to the study, sleep inertia has implications for medical professionals who are often called on to tend patients in crisis on a moment's notice, often at odd hours. Medical residents, for example, who may work 80 hours or more per week and who catnap at times, could be prone to make simple math mistakes when calculating dosages of medicine during bouts of sleep inertia. a. True b. False

4. The present results may have important implications for occupations in which sleep-deprived personnel are expected to perform immediately on awakening from deep sleep, including ______. a. truck drivers b. pilots arising from on-board sleeper berths c. public safety and military personnel d. All of the above

5. Sleep inertia is the feeling of grogginess after awakening and temporarily reduces your ability to perform even simple tasks. a. True b. False

6. Sleep inertia can last from 1 minute to 4 hours, but typically lasts ______. a. 5-10 minutes b. 15-30 minutes c. 30-60 minutes d. about an hour and a half

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7. Sleep inertia is a transitional state of lowered arousal occurring immediately after awakening from sleep and producing a temporary decrement in any subsequent performance. a. True b. False

Notes 8. Sleep research has shown that abrupt awakenings during a slow wave sleep episode produce more sleep inertia than awakening in stage 1 or 2 when the brain waves are small and fast. a. True b. False

9. Research is also revealing that sleep inertia is more intense when awakening occurs near the trough—the low point—of the core body temperature as compared to its peak. a. True b. False

10. Sleep inertia is affected by a variety of factors and therefore, specific predictions of its duration or severity can sometimes be difficult. a. True b. False

11. In one study cited here, out-of-sync volunteers had a very hard time waking from naps, and the grogginess of sleep inertia lasted for up to an hour. Some sleep inertia did occur after naps on a normal schedule too but the inertia after a nighttime nap was much more severe. a. True b. False

12. The severity of sleep inertia is dependent on how long you have been asleep and the stage of sleep at awakening. a. True b. False

13. Sleep debt is defined as the difference between the hours of sleep a person needs and the hours of sleep a person actually gets. a. True b. False

14. Alertness management strategies can minimize the adverse effects of sleep loss and circadian disruption and promote optimal alertness and performance in operational settings. a. True b. False

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15. As attention to issues of work hours, sleepiness, and accidents increases, more approaches to address the issues will emerge. a. True b. False

Notes

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Notes

48