HEART RATE VARIABILITY AND LEARNING

IN THE 28-34 WEEK PREMIE

Krueger, C., Behnke, M., Gerhardt, K., DeCasper, A., vanOostrom, H.

Pilot Study funded through the Biobehavioral Research Center

General Clinical Research Center

University of Florida

Premature Infants

• Learning Disabilities

• Delayed Speech and Language

• Neurological Disorders

Survival Rates Have Increased

Incidence of Disabilities has Stagnated

Interventions are preceded by

complete descriptions of normal development

Thus often unreliable and ineffective

RESEARCH QUESTIONS

• What are the developmental changes in HRV?

• What are the developmental changes in the learning capabilities?

• Are there interactions between with HRV as learning occurs?

Heart Rate Variability via Spectral Analysis

• Autonomic Nervous System Development– Chatow

– Karin

– Kotini

• Predict for Later Developmental Delay– DiPietro

– Porges

Learning Capabilities as Indicated by Movement and Cardiac Orienting Response

Time From Stimulus Onset (5-Sec Intervals)

-20 -10 0 10 20 30 40

Mea

n D

iffer

ence

Sco

re in

BP

M-2

-1

0

1Control GroupTarget Group

• Description of Learning Capabilities– Movement

• Lecanuet

• Kiselevsky

– Cardiac Orienting Response

• DeCasper

• Krueger

HF

Interactions Between Learning and HRV

PolyVagal Theory

Time From Stimulus Onset (5-Sec Intervals)

-20 -10 0 10 20 30 40

Mea

n D

iffer

ence

Sco

re in

BP

M

-2

-1

0

1Control GroupTarget Group

PURPOSE

Describe longitudinal changes in HRV and the learning capabilities of

the premature infant (28-34 wk)

CONCEPTUAL MODEL

A Systems Approach to Behavioral Development

Environmental

A Systems Approach to Behavioral Development

Behavioral

Neural

Genetic

Individual Development

Environmental

A Systems Approach to Behavioral Development

Behavioral

Neural

Genetic

MATERNAL VOICE

Environmental

A Systems Approach to Behavioral Development

Behavioral

Neural

Genetic

COR MOVEMENT

MATERNAL VOICE

Environmental

A Systems Approach to Behavioral Development

Behavioral

Neural

Genetic

COR MOVEMENT

HRV

MATERNAL VOICE

Environmental

A Systems Approach to Behavioral Development

Behavioral

Neural

Genetic

COR MOVEMENT

HRV

MATERNAL VOICE

Subjects and Setting

• Convenience sample

• 28 premature infants

• Neonatal Intensive Care Unit– General Clinical Research Center

•Inclusion Criteria

–28 weeks post menstrual age

–English as native language

–Dubowitz confirmation of age

•Exclusion Criteria

–Abnormal head ultrasound

–Cardiac abnormality

–Viral/bacterial infection

–Sensorineural hearing loss

• Independent Variable– Nursery Rhyme

• Dependent Variable– Heart Rate Variability

• Via spectral analysis

– Cardiac Orienting Response– Movement

Group 1

Group 2

28 29 30 31 32 33 34

Gestational Age in Weeks

Nursery Rhyme

• CD Recording of Maternal Recitation– Twice a day– 15 min after meal– Quiet

• CD Recording of Unfamiliar Female– Once a week– 15 min after meal– Quiet

55 + 5 dB

20cm from ear

WEEKLY TEST SESSION

Quiet Rhyme

HRV COR

HRV

Movement

Layout of NICU

4

3

1

2

6

Sink

9

7

8

5

Computer Door Door Sink

General Work Station

Sound Levels Across the Different Monitoring Stations

Sound Monitoring Station

1 2 3 4 5 6 7 8 9

So

un

d L

eve

l in

De

cib

els

40

50

60

70

80

90

100 LeqLmax

Sound Levels Across Time of Day

Time of Day

7am 8am 9am 10am 11am 12am 1pm 2pm

So

un

d L

evel

in D

ecib

els

40

50

60

70

80

90

100

LeqLmax

Auditory Stimulus 57-59 dB

Subject 05

Before During After

0 50 100 150 200 250 300 350 400

He

art

Ra

te in

Bea

ts p

er M

inut

e

60

80

100

120

140

160

180

200

Subject 06

Before During After

0 50 100 150 200 250 300 350 400 450 500

He

art

Ra

te in

Bea

ts p

er

Min

ute

60

80

100

120

140

160

180

200

Subject 03

Before During After

0 50 100 150 200 250 300 350

He

art

Ra

te in

Bea

ts p

er M

inu

te

60

80

100

120

140

160

180

200

Subject 02

Before During After

0 50 100 150 200 250 300 350 400

He

art

Ra

te in

Bea

ts p

er M

inu

te

60

80

100

120

140

160

180

200

28 week

Auditory Stimulus 51-54 dB

#012

Before During After

0 50 100 150 200 250 300 350 400

He

art

Ra

te in

Bea

ts p

er M

inu

te

60

80

100

120

140

160

180

200

011

Before During After

0 50 100 150 200 250 300 350 400

He

art

Ra

te in

Bea

ts p

er M

inu

te

60

80

100

120

140

160

180

200

Subject 010

Before During After

0 50 100 150 200 250 300 350 400

He

art

Ra

te in

Bea

ts p

er M

inut

e

60

80

100

120

140

160

180

200

Subject 09

Before During After

0 50 100 150 200 250 300 350 400

He

art

Ra

te in

Bea

ts p

er M

inut

e

60

80

100

120

140

160

180

200

07

Before During After

0 50 100 150 200 250 300 350 400 450

Hea

rt R

ate

in B

eats

per

Min

ute

60

80

100

120

140

160

180

200

28 weeks

Challenges Encountered

• Technological

• Physiological

• Environmental

Developmental Changes in HRV

Total Power via Spectral Analysis

High Frequency Component of HRV

Developmental Changes

Learning Capabilities

• Cardiac Orienting Response

• Movement

Time From Stimulus Onset (5-Sec Intervals)

-20 -10 0 10 20 30 40

Mea

n D

iffer

ence

Sco

re in

BP

M

-2

-1

0

1Control GroupTarget Group

32 Weeks Post-Menstrual Age

33 Weeks Post-Menstrual Age

34 Weeks Post-Menstrual Age

Arm Movements

Before During After

Maternal 32 weeks: total 9, mean 0.10, range 0-5

Maternal 34 weeks: total 29, mean 0.54, range 2-5

Non-maternal 32 weeks: total 36, mean 0.2, range 2-6

Non-maternal 34 weeks: total 40, mean 0.74, range 3-6

Mouth Movements

Before During After

Maternal 32 weeks: total 6, mean 0.07, range 0-4

Maternal 34 weeks: total 36, mean 0.70, range 2-5

Non-maternal 32 weeks: total 14, mean 0.19, range 0-4

Non-maternal 34 weeks: total 7, mean 0.13, range 0-4

Respiratory Movements

Before During After

Maternal 32 weeks: total 7, mean 0.07, range 0-4

Maternal 34 weeks: total 1, mean 0.02, range 0-1

Non-maternal 32 weeks: total 10, mean 0.14, range 0-3

Non-maternal 34 weeks: total 20, mean 0.37, range 0-4

HF

Interactions Between Learning and HRV

34 Weeks Gestation

Time in Seconds

-15s -10s -5s 5s 10s 15s

Diff

eren

ce S

core

in

BP

M

-6

-4

-2

0

2

4

6

8

10

12

14

Group 1Group 2

Interactions Between Learning and HRV

33 Weeks Gestation

Time in Seconds

-20 -15 -10 -5 0 5 10 15 20

Diffe

rence

Sco

re in B

PM

-6

-4

-2

0

2

4

6

Group 1Group 2

34 Weeks Gestation

Time in Seconds

-20 -15 -10 -5 0 5 10 15 20

Diffe

ren

ce S

core

in

BP

M

-6

-4

-2

0

2

4

6

Group 1Group 2

Program of Research Fetus Premie

34 Weeks Gestation

Time in Seconds

-15s -10s -5s 5s 10s 15s

Diff

eren

ce S

core

in

BP

M

-6

-4

-2

0

2

4

6

8

10

12

14

Group 1Group 2

TENTATIVE CONCLUSIONS

• Experience• Maturation of ANS• Interactions across

levels of analysis• Maternal voice

– Premature Infant

34 Weeks

Timing in Relation to Rhyme

Before During After

Pow

er .

2-.4

0

10

20

30

40

50

Group1 Group 2

34 Weeks Gestation

Time in Seconds

-15s -10s -5s 5s 10s 15s

Diff

eren

ce S

core

in

BP

M

-6

-4

-2

0

2

4

6

8

10

12

14

Group 1Group 2

FUTURE RESEARCH

• 28-40 weeks gestation (R-15)– Memory

• Underlying behavioral process (NSF)