SLEEP SCIENCE:

SLEEP, SLEEPINESS, AND SLEEPLESSNESS

Kenneth Lichstein, Ph.D.Professor EmeritusDepartment of PsychologyThe University of Alabama

questions?

comments?

individual differences

Biological characteristics are normally distributed.

The average American male is 5’10” tall.Someone 5’8” does not have a height disease.

SLEEP IS A BIOLOGICAL CHARACTERISTIC

Course Outline

1 & 2. sleep: normal sleep overview

3 & 4. sleepiness: why do we get sleepy

5 & 6. sleeplessness: sleep disorders

bias: behavioral sleep medicine

Sleep

you are busy when you are asleep

sleep research:

an overview

citation counts for the key word 'sleep'

year

1960 1970 1980 1990 2000 2010 2020

count

0

1000

2000

3000

4000

5000

6000

7000

PsycINFO

PubMed

types of sleep research

• animal

• genetics

• measurement

• epidemiology

• characteristics of normal

sleep

• characteristics of sleep

disorders

• treatment of sleep disorders

• sleep affects on functioning

• children vs adults vs elderly

• men vs women

• sleep in different races

0

500

1000

1500

2000

2500

3000

197719791981198319851987198919911993199519971999200120032005200720092011Ac

cre

dit

ed

Ce

nte

rs

Year

Growth of AASM-Accredited Sleep Disorders Centers

As of June 2012

Source: American Academy of Sleep Medicine

sleep societies

American Academy of Sleep Medicine

Sleep Research Society

Society of Behavioral Sleep Medicine

Many others▪ dentists

▪ sleep techs

▪ states

▪ countries

7 sleep journals

year started

Journal

1978 Sleep

1992 Journal of Sleep Research

1997 Sleep Medicine Reviews

2000 Sleep Medicine

2003 Behavioral Sleep Medicine

2005 Journal of Clinical Sleep Medicine

2015 Sleep Health

sleep measurement

sleep terms

sleep stages❑ N1, nonREM stage 1

❑ N2, nonREM stage 2

❑ N3, nonREM stage 3

❑ REM, rapid eye movement

sleep parameters❑ SOL, sleep onset latency

❑WASO, wake time after sleep onset

❑ NWAK, number of awakenings

❑ TWAK, terminal wake time

❑ TST, total sleep time

❑ TIB, time in bed

❑ SE, sleep efficiency percent

Assessment Methods

polysomnography (PSG)❑ all night

❑MSLT

❑MWT

actigraphy

sleep diary

19

20

21

Amplitude measured in V

Frequency measured in cycles/second or Hz

This is a single EEG wave, sometimes called a cycle. A cycle

begins at the midline, departs upward then downward, and then

returns to the midline to complete one cycle.

Cycles are characterized by their frequency or how many occur

within a second, also called Hz. High frequency waves appear

narrow and low frequency waves wide. A second characteristic

is the height of the wave from peak to trough termed amplitude.

Awake

Drowsy

Stage 1

Stage 2

Stage

REM

Stage

3 & 4

hypnogram: normal middle-aged adult

N1

1

10

9

8

7

6

5

4

3

2

11

12

13

14

15

multiple sleep latency test:go to sleep

4-6 nap opportunities reclined in street clothes commence 2 hours after morning

awakening repeat at 2 hour intervals 20 min limit if no sleep

▪ 15 min of sleep monitoring after sleep onset▪ REM?▪ SOL > 10 min: normal▪ SOL < 8 min: EDS

maintenance of wakefulness test:stay awake

4 nap opportunities

comfortably seated in street clothes

commence 2 hours after morning awakening

repeat at 2 hour intervals

40 min if no sleep▪ terminated with sleep onset

▪ SOL > 30 min: normal

▪ SOL < 8 min: EDS

what is actigraphy

motion sensor▪ piezoelectric accelerometer

▪ converts movement to electricity

▪ wrist movement is proxy for sleep/wake▪ objective assessment▪ long-term monitoring▪ does not restrict activity

features▪ small, light "wristwatch"▪ light sensor▪ event marker▪ alarm▪ collect self-report data

incompetent, uncooperative, unreliable subject▪ nursing home▪ intensive care unit▪ infants▪ teens▪ suspect insomnia reports

Actigraphy in insomnia patient and healthy control subject

Insomnia patient (68 yr. F) Control subject (78 yr. F)

Actigraphy in insomnia patient and healthy control subject

Control subject (78 yr. F)Insomnia patient (68 yr. F)

•Lower level of overall activity

•Irregularity of sleep “window”

•Inactive periods in day

•Higher level of overall activity

•Regular sleep “window”

•Few inactive periods in day

consensus sleep

diary

Acronym Description Computation

SOL sleep onset latency #3

NWAK number awakenings #4

WASO wake time after sleep onset #5

TWAK terminal wake time #7 − #6

SQR sleep quality rating #8 [1 to 5]

TIB time in bed #7 − #2

TST total sleep time TIB − SOL, WASO, TWAK

SE sleep efficiency % TST TIB 100

NAP nap time #9

sleep diary measures

Just under 50 million wearable devices were shipped in 2015 and over 125 million units are expected to ship in 2019.

Forbes

normal sleep

normal adult sleep [highly variable]

7.5 hr TST SOL < 15 min, WASO < 15 min, SE > 90% sleep stage distribution

▪ N1: 5%▪ N2: 50%▪ N3: 20%▪ REM: 25%

sleep stage pattern▪ N3 congregates in the first third of night▪ REM congregates in the second half of night▪ sleep cycle (4 stages) is 90 min

REM characteristics▪ REM emerges from N1 or N2▪ EEG of N1 but as deeply asleep as N3▪ cognitive activity▪ body immobilization▪ sexual arousal

Carskadon & Dement, 2011

normal middle-aged adult

N1

N2

N3

R

to be continued