Sleep Across the Lifespan

Lecture 3

Sleep trends are highly _____ and change throughout _____.

1. variable

2. life

Typically, sleep _____ and _____ decreases as you age.

1. quality

2. quantity

According to guidelines, how much sleep should the average adult be getting?

7-8 hours

Sleep Latency

how long it takes to fall asleep

TST

Total Sleep Time

Sleep Efficiency

time asleep divided by time in bed

WASO

wake after sleep onset

REM sleep is _____ in infancy, followed by a later _____, and then it stays fairly consistent through the lifespan.

1. higher

2. decrease

Sleep architecture changes over the lifespan. This is exemplified by more _____ _____ _____ in children and more _____ in the elderly.

1. slow wave sleep

2. fragmentation

In healthy people, REM stays about the same after the _____ year.

second

Describe hours of sleep need in infants aged 0-2 months? 2-12 months?

1. 10.5-18

2. 14-15

Describe hours of sleep need in toddlers aged 1-1.5 years? 1.5-3 years?

1. 13-15

2. 12-14

Describe hours of sleep need for children aged 3-5 years? 5-12 years?

1. 11-13

2. 9-11

Describe hours of sleep need in adolescents?

8.5-9.5

Describe hours of sleep need in adults?

7-9

Naps

can help pick you up and make you work more efficiently; if too long or too close to bedtime, they can interfere with regular sleep

Describe the typical infant sleep pattern.

fragmented sleep because they are homeostatic sleepers; 1-3 hours spent awake at a time; sleep lasts minutes to hours at a time

What does it mean to say infant sleep is homeostatic?

their sleep is related to their need to be fed, changed, and nurtured

When do circadian rhythms develop in infants?

around 6 weeks; regular sleep-wake cycle by 3-6 months

Why doe 6 month infants typically develop more regular sleep-wake cycles?

nighttime feedings are no longer necessary and they may start sleeping through the night

When do most infants start consistently sleeping through the night?

at 9 months

Infants enter sleep through “_____ _____”, which is analogous to REM sleep.

active sleep

Infants spend about __% in active sleep and __% in “_____ _____”, which is analogous to SWS.

1. 50

2. 50

3. passive sleep

Premature babies exhibit more _____ _____.

active sleep

Infants have __ - __ min cycle between passive and active sleep.

50-60

The NREM _____ develops between 2-6 months in infants, because the brain needs to mature to support high _____ low _____ activity.

1. EEG

2. voltage

3. frequency

By 6 months old, REM sleep is about __% of sleep.

30

3 possibilities for having so much REM sleep in infancy?

1. may be important in the maturation of the cerebral cortex and the oculomotor system

2. may assist in the programming of developing neuronal circuits

3. involvement in plasticity

What did Francis Crick propose about REM sleep? Is this true?

1. that REM might prune synapses

2. unlikely, but it did introduce the idea of REM in neural plasticity

Describe the sleep patterns of children.

typically 1 nap of 1-3 hours; maximal SWS; higher arousal threshold during 1st SWS cycle

2 common issues with sleep in children?

1. NREM parasomnias

2. bed wetting

2 common NREM parasomnias in children?

1. night terrors

2. sleep walking

What is the arousal threshold for children during the 1st SWS cycle?

123 dB

Describe sleep patterns in teens.

many are sleep deprived due to school and extracurriculars; biological sleep patterns shift towards later times for both sleeping and waking

Schools with later start times for teens found better _____ and _____.

1. attendance

2. grades

What is pathological aging?

aging impeded by disorders such as dementia or Parkinson’s

Subjective measures of sleep and aging?

self reports that depend on patients personal expectation regarding aging

Objective measures of sleep and aging?

examines physiological underpinnings of sleep changes (involves direct observation)

5 changes in sleep architecture in the elderly?

1. reduction in N3 sleep

2. increased N1 and N2 sleep (lighter stages)

3. drop in REM (proportional to TST)

4. sleep efficiency and TST drop

5. more daytime sleepiness

_____ sleep may be totally absent by __ years of age.

1. N3

2. 90

Each decade, TST is reduced by about __min/decade.

27

3 results of keeping elderly rats awake for 2 days when compared to young rats?

1. rebound SWS normal

2. less TST

3. less REM rebound

3 results of keeping elderly people awake for 64 hours compared to young?

1. recovery to baseline normal

2. suggests homeostatic mechanisms may be functioning properly

3. even with insomnia can show normal sleep duration after deprivation

Is poor sleep in the elderly due to deterioration of sleep regulation system? How do we know?

1. unlikely

2. rebound sleep studies

What is the main idea behind why sleep in the elderly is so poor?

circadian rhythm changes

4 circadian rhythm changes in the elderly?

1. less consolidation of sleep and wake

2. faster clock

3. impaired adjustment to time zone changes

4. flattening and phase advance of various rhythms

How does delta activity change in the elderly?

delta waves exhibit a serious decreases in amplitude

What are the 3 main categories of neuroendocrine mechanisms impacting sleep?

1. somatotropic

2. gonadotropic

3. HPA axis

Insulin-like Growth factor 1 is correlated with _____ in elderly men.

delta

_____ __ is elevated in elderly poor sleeps and not in young poor sleepers.

interleukin 6

3 types of animal evidence suggesting possible neurochemical changes to sleep? Is this consistent with human findings?

1. changes in receptor levels for hypocretin and serotonin

2. hypothalamic cells activated by sleep deprivation more in young than old animals (cfos expression)

3. higher adenosine levels in older animals (possibly compensating for lower receptor expression)

4. no, human evidence is weak

About 1 in 3 elderly exhibit _____, with complaints being greater in women.

insomnia

How does the rate of insomnia in the elderly change when controlling for co-morbidities?

sharply decreases

Insomnia typically involves sleep _____ rather than sleep _____.

1. maintenance

2. latency

Restless Leg Syndrome (RLS)

urge to move legs; aggravated by rest; common in elderly and higher in females (10-30%)

Periodic Leg Movement Syndrome (PLMS)

stereotypic repetitive movements (myoclonic leg twitches); up to 45% of those over 65 years with a male predominance

RLS and PLMS are possibly related to changes in _____ and _____.

1. dopamine

2. iron

Sleep Apnea

breathing compromised during sleep due to obstruction of upper airway; patient stops breathing for 10s or more; leads to frequent brief arousals and prevents a good night sleep

Prevalence of sleep apnea between 30-60 years old?

5% of men and 2% of women

There are higher rates of sleep apnea among _____ adults.

obsese

Complaints associated with sleep apnea?

snoring, daytime sleepiness, restlessness, nighttime choking, headaches, etc.

4 problems associated with sleep apnea?

1. absence of airflow

2. increased effort to breathe

3. decrease in oxygen levels and heart rate

4. burst in EEG, EMG, and heart rate

How long do sleep apnea episodes last? How many times do they occur per night?

1. 2-3 minutes

2. 40 times

Why do sleep apnea episodes end with bursts in EEG, EMG, and heart rate?

breathing resumes, making oxygen levels climb

4 effects of sleep apnea on sleep?

1. sleep is disturbed

2. N1 increases to about 30-50% (up from 5-10%)

3. N3 may disappear (almost completely)

4. MSLT down to 2-3 min (normally 10-15 min)

2 types of sleep apnea?

1. obstructive

2. central

Obstructive Sleep Apnea

increased fatty tissue in airway structures increases pressure on the pharynx; need higher muscle tone to maintain airway

Pharynx

collapsible segment of airway; feature permits normal breathing, swallowing, and speech

2 aspects of holding open the pharynx?

1. inward pressure during inspiration

2. outward force of airway muscles

Central Sleep Apnea

brainstem control of respiration is compromised; low response from sensors and motor pattern generators; may be due to heart failure, opiates, or high altitude

4 ways respiration is controlled by the brainstem?

1. oxygen chemoreceptor

2. pressure receptors in chest and lungs

3. central pattern generators

4. output to muscles

Can obstructive and central sleep apnea co-occur?

yes; mixed type apnea

2 treatments for sleep apnea?

1. positive pressure device

2. mandibular advancement