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Sleep in Infancy

• Development of sleep

• Cross cultural differences in sleep behavior

• Infant Apnea and Sudden Infant Death Syndrome (SIDS)

• Congenital Central Hypoventilation Syndrome

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0

2

4

6

8

10

12

14

16

18

20

1 6 12 18 24 36 48 60

Age (Months)

Ho

urs

of

Sle

ep

/da

y

98th Percentile Mean 2nd Percentile

How much do Infants Sleep?

Iglowstein et al, Pediatrics, 2003

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Total Daytime Sleep (Napping)

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1

2

3

4

5

6

7

0.5 0.75 1 1.5 2 3 4Years

Ho

urs

/da

y

98th Percentile Mean 2nd Percentile

Iglowstein et al, Pediatrics, 2003

Naps per day 2 1 - 2 1 0 - 1

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Night Awakenings

0

1

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3

4

5

3 6 9 12

Age (Months)

# A

wak

enin

gs/

nig

ht

Goodlin-Jones et al, J Dev Behav Pediatr, 2001

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Determinants of Infant Sleep Behavior

• Biological• Homeostasis

• Circadian factors

• Cultural • Parental values

• Societal norms

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Variations in Sleep Behavior

• Sleeping arrangements

• Bedtime routines

• Transitional objects

• Naps

• Sleep problems

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Sleeping Arrangements:Co-sleeping

• Co-sleeping includes: • Room sharing (sharing a room with a parent, another

adult or sibling) and/or bed sharing

• Co-sleeping is prevalent in many cultures• Tribal (e.g. Samoa, Mayan, Bali)

• Eastern (e.g. Korea, China, Japan, India)

• Southern Europe (e.g. Italy, Portugal)

• Scandinavia (e.g. Sweden)

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Co-sleeping in the United States

• Prevalence of co-sleeping varies with ethnicity, race and socioeconomic class. • African Americans were reported to co-sleep

more often than Caucasians (57% vs. 17%).

• Among Caucasian families only, co-sleeping was associated with lower socioeconomic class.

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Sleeping ArrangementsIndependent Sleeping

• Definition: infants and children sleep in their bed in their own rooms

• Rationale: promotes autonomy

• Independent sleeping is prevalent in western societies such as:• Northern Europe: Germany, Holland,

Switzerland, France

• United States

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Bed Sharing

Bed sharing is prevalent in many cultures:

• It is more common with breast feeding

• It is more common among certain racial and ethnic groups

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Bed Sharing

Most Western health care providers advocate against bed sharing in infancy

• Safety risks for SIDS

• No long term psychosocial consequences

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Prevalence of Bed Sharing (>1 times/week) Among Swiss Children

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5

10

15

20

25

30

35

40

45

50

3 mos 9 mos 1 yr 2 yrs 3 yrs 4 yrs 5yrs 6 yrs

Age

% o

f C

hild

ren

Jenni et al, Pediatrics, 2005

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• Infants should sleep in a crib or bassinet conforming with standards of Consumer Product Safety Commission.

• Infants may be brought to bed for nursing or comforting but should not bed share for sleep.

• The crib or bassinet should be placed in parents’ room close to their bed.

American Academy of Pediatrics Task Force on Sudden Infant Death

Syndrome

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Bedtime

• Many tribal societies have no formalized “bedtime.”

• Infants and children in Southern European countries often have unstructured bedtime routines and later bedtimes.

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Bedtime Routine (Northern European/American)

In child’s own bedroom…

• Ritual: bath, dressing in pajamas, story/lullaby

• Child is placed in own bed with goodnight kisses and left alone for the night.

• Frequent use of nightlight and transitional objects

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Transitional Objects

• Industrialized societies - frequent use of sleep aids e.g. pacifier, teddy etc• American Academy of Pediatrics Task Force (11/05)

recommends pacifiers be used for infants when they are put down to sleep to reduce the incidence of SIDS.

• Non-industrialized cultures - low prevalence of transitional objects

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Naps

• Naps are common in Southern Europe, South America, Africa and Asia, but are disappearing with globalization and 24/7 societies.

• American children typically stop naps by age 4 - 5 yrs.

• African American children nap until older ages than Caucasian children.

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Racial Differences in Napping

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20

40

60

80

100

2 3 4 5 6 7 8

Age (years)

% o

f C

hild

ren

BlackWhite

Crosby et al, Pediatrics, 2005

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International Pediatric Sleep Education Task Force

Across cultures:• Parenting practices, cultural values and lifestyles vary and

influence sleep behavior.

• Sleep problems (e.g. bedtime resistance, nighttime wakings) are universally present.

• Prevalence of sleep problems is similar (20 - 25%) but differs for individual issues.

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Infant Apnea and Sudden Infant Death Syndrome (SIDS)

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Sudden Infant Death Syndrome (SIDS)

• The sudden death of any infant under one year of age, which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history.

Willinger et al. Pediatr Pathol 1991;11:677

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Apparent Life-threatening Event (ALTE)

An episode that is frightening to the observer, and that is characterized by some combination of apnea (central or occasionally obstructive), color change, marked change in muscle tone, choking or gagging. In some cases, the observer fears that the infant has died.

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SIDS

• Most common cause of postneonatal infant death

• About 2,300 deaths/year

• SIDS rate: almost 0.6/1,000 live births

• Increased incidence in:• Winter• Males (60%)• Lower socioeconomic groups• Children whose parents smoke

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SIDS Antecedent Risk Factors

NIH Consensus Committee, 1987

Unknown (74% )

Death of Previous Sibling toSIDS (0.7% )

ALTE (7% )

Prematurity (18% )

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Relative Risk for SIDS by Age at Death

MMWR December 14, 1990;39

*first month as reference

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SIDS Postmortem Findings

• Right ventricular hypertrophy

• Periadrenal brown fat

• Extramedullary hematopoiesis

• Astroglial cell proliferation

• Intrathoracic petechiae

• Neurotransmitter deficits in brainstem

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Basis for the SIDS – Apnea Hypothesis

• Population• Three infants with recurrent apnea and cyanosis

• Two siblings of SIDS victims

• Methods• Serial PSG over three to six months

• Findings• “frequent brief, self-limited” apneas during REM

• Two infants died of SIDS approximately three months of age

• Commentary• small sample

• No control group

• Mother later convicted of murderSteinschneider A. Pediatrics 1972;50

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Collaborative Home Infant Monitoring Evaluation

• 1079 infants had PSG and home monitor (RIP, ECG, oximetry, position, expanded memory)

Idiopathic ALTE 152

SIDS sibling 178

Preterm (<34 weeks) 443

Healthy term 306

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CHIME Cardiorespiratory Events

Extreme Events Conventional Events

Group risk ratio p risk ratio p

Preterm

symptomatic 18.0 <.001 4.3 <.001

asymptomatic 10.1 <.001 2.7 <.001

ALTE 7.6 .001 1.5 .16

sibling 5.6 .007 1.2 .56

Term

sibling 2.6 .11 1.4 .07

ALTE 2.5 .18 1.1 .75

healthy 1 1

Only preterm infants had more events than healthy controls

Ramanathan, et al. JAMA 2001

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CHIME Cardiorespiratory Events

The likelihood of experiencing at least one ALTE decreased until about 43 weeks post conception, when all groups were similar.

Ramanathan, et al. JAMA 2001

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Ventilatory Drive

Respiratory control disorders in infants and children. Beckerman RC, Brouillette RT, Hunt CE (eds). Baltimore: Williams & Wilkins, 1992.

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Impaired Arousal Response

McCulloch et al. J Pediatr 1982

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Heart Rate Variability

Schechtman et al. Pediatr Res 1992

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Sleep Position and SIDS

Relative Risk (prone vs. others) = 8.8 (p<.001)

SIDS Control

Prone 62 76

Side 4 32

Supine 1 23

Unknown 0 3

Fleming et al. Br Med J 1990

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Change in SIDS Rate withChange in Sleep Position

Baseline Rate After Campaign

England 3.5 1.7

Netherlands 1.0 0.4

Norway 3.5 1.6

Tasmania 7.6 4.1

Fleming et al. Br Med J 1990

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• “Although prospective randomized clinical trials have not been performed, the weight of evidence implicates the prone position as a significant risk factor for SIDS.”

Sleep Position and SIDS

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Sleep Position and SIDS

• “It should be stressed that, although the relative risk of the prone position may be several times that of the lateral or supine position, the actual risk of SIDS when placing an infant in a prone position is still extremely low.”

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Lateral Positioning

• SIDS risk similar to prone position

• Lateral position unstable• High probability of rolling to prone

• Infants unaccustomed to prone position are at even greater risk when they are prone.

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U.S. SIDS Rate

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Sleep and Infant Position

• Prone positioning results in:• increased sleep

duration• increased quiet

(non-REM) sleep• fewer, shorter

arousals

• Prone positioning results in:• upper airway

occlusion• CO2 rebreathing• hyperthermia

– exacerbated by bundling, inappropriate bedding

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Sleep Position and SIDSScandinavian Questionnaire Study

244 SIDS cases, 869 controls% of SIDS death that could be avoided if:

All infants slept supine 74%

No maternal smoking during pregnancy 47%

Pre-term birth eliminated 16%

Low birth weight eliminated 16%