Effective Early Interventions for
Biologically Vulnerable Children:
The Importance of Dosage
Sharon Landesman Ramey, Ph.D.
Susan H. Mayer Professor of Child and Family Studies
Director, Georgetown University
Center on Health and Education
Early Childhood Education
Rio de Janeiro December 2009
Scientific Foundations for
the new “Education Science”
• Research on neuroplasticity (animal models)
• Studies of extreme deprivation (orphanages,
maternal deprivation, isolation)
• Demonstration projects
• Naturalistic and longitudinal studies
• Randomized controlled trials (RCTs) to test
the efficacy of educational and “whole child”
interventions to alter the life course
• Traditional and innovative “treatments”
Applied Biosocial Contextual Development (ABCD):
A Framework for Understanding Human Development
Randomized Controlled Trials (RCTs)
we have conducted include:
 The Abecedarian Project (ABC)
 Project CARE
 Infant Health and Development Program (8 sites)
 Romanian Orphanage Studies
 Intensive Pediatric CI Therapy (cerebral palsy)
 National Transition Demonstration Study (31 sites)
 Testing pre-K curricula and coaching models
 System and statewide scale-up studies
Ramey & Ramey
PRINCIPLES OF
EFFECTIVE EARLY INTERVENTION
1.
2.
3.
4.
5.
6.
Timing (onset, duration, offset)
Intensity (per day/wk/mth/yr(s))
Direct learning experiences
Breadth of services/supports
Individual differences
Environmental maintenance
Ramey & Ramey (1998), American Psychologist
1. Principle of Timing
• When the intervention begins and ends
significantly influences magnitude of effects
• Neurodevelopmental theory and research are
central to understanding important features of CNS
that is rapidly developing at certain ages
• Development at earlier stages sets conditions for
later stages (Cumulative Toll Hypothesis)
• Clinical practices shifting to earlier treatments
• Principle is highly similar to that in teratology
Evidence supporting the
principle of timing
• Derives from cross-study comparisons, metaanalyses of > 25 early childhood interventions
• Usually larger and more lasting effects occur when
intervention begins earlier and lasts longer
• Affirmation in animal experiments
Limitation: Inherent confounds in studies related to
this principle, since most RCTs that produced the
largest gains began earlier, continued longer, and
probably were more fully implemented
Synaptogenesis by brain region graph illustrates
plausible biological basis for Principle of Timing
Adapted from
Huttenlocher in
Ramey & Ramey
Right from Birth
(1999)
2. Principle of Dosage
(Intensity)
• Interventions which are more intensive (more
hours per day, days per week, total duration)
tend to produce larger changes
• Exact specification of “optimal doses” has not
occurred, largely due to cost and pragmatic
issues in intervention research
• Some evidence consistent with “threshold
hypothesis” (mostly at lower limits)
• Highly similar to dose-response curve principle
in teratology
Mothers’ Speech and Infant Vocabulary:
Naturalistic evidence consistent with
RCT support for Principle of Dosage
Huttenlocher et al,
Developmental
Psychology, (1991)
3. Principle of Direct Learning
Experiences
• Interventions that directly alter the child’s
experiences (i.e., transactions with others
and environment) have greater child benefits
than indirect interventions (e.g., parenting
and home visiting programs, coordination of
service delivery supports, teacher training)
• Note: majority of early interventions have
focused on indirect effects via parenting
interventions, based on the hope these would
lead to sustainable environmental supports
4. Principle of
Breadth of Services/Supports
• Early interventions that are multi-component and
simultaneously address a child’s needs in health,
cognition, language, and social-emotional
development tend to produce larger and more
enduring benefits
Limitations:
– Research evidence has many confounds, since broader programs also
tend to be more intensive and include direct learning experiences
– most intervention programs tested in RCTs focused on children with
multiple needs and risk conditions (due to natural co-occurrence)
5. Principle of Individual Differences
• Some children benefit more (or less)
• This principle has been affirmed primarily by:
– Findings that children with greater needs for
environmental supports tend to benefit more
– Findings that children with more substantial CNS insult
may not benefit as much from general enrichment
interventions (i.e., not spectrum-specific intervention)
– Analysis of individual growth curves
• Similar to teratology principle of differential genetic
susceptibility or Gene X Environment Interaction
6. Principle of Environmental
Maintenance
• Benefits of early intervention are sustained longer when
children continue to receive strong, appropriate environmental
supports after early intervention ends
Limitation: Almost impossible to separate effects of subsequent
depriving or harmful environments (which could reverse
benefits of early intervention) from the need for true
“maintenance”
Influenced by the fact that special needs children display
different “issues” that result in “problems” that depend on their
age and setting
Opportunity to apply new learning and skills may vary, thus
enhancing or constraining future development
Examples affirming these principles
from some of our longitudinal RCTs
• Interventions for children from highly
impoverished, often chaotic environments
(Abecedarian Project and Project CARE;
Romanian Orphanage studies)
• Targeted interventions for
– Low birthweight, premature infants (IHDP)
– Children with moderate to severe neuromotor
impairments (Project ACQUIRE)
An example of a highly
intensive, targeted intervention
that challenges “conventional
practices”
Children with Neuromotor
Impairments (Cerebral Palsy)
• Most highly requested and provided intervention is
physical and/or occupational therapy (universal)
• Most popular therapy is described as
Neurodevelopmental Therapy (NDT)
• Typical dosage is 1 or 2 hourly sessions per week
Evidence for 20+ years does not support its efficacy
(e.g., Palmer, Shapiro, Wachtel et al, NEJM, 1988;
Hur, 2005; Barry, 2001)
Intensive CI-Pediatric Therapy for
Children with Cerebral Palsy
• Based on fundamental principles of learning theory,
clinical rehab reports of adults with stroke, and
animal experiments
• First-ever RCT to test a highly intensive form of
therapy targeted for children with hemiparetic CP
• Results demonstrated large and sustained benefits,
plus spillover effects (unanticipated) to other
domains of development
Taub, Ramey, DeLuca, & Echols, Pediatrics, 2002
DeLuca, Echols, & Ramey, Child Neurology, 2006
Key features of Pediatric CI Therapy
(ACQUIREc Therapy)
•Highly intensive (6 hours per day, 21 consecutive days)
•Direct and active engagement of child as learner
•Responsive to child’s interests, initial competence
•Based on learning theory principles
•Designed to promote generalization
•Constraint leads child to “focus” on impaired limb,
overcome “developmental disregard, eliminate
competing responses, create new CNS pathways
DeLuca, Echols, & Ramey (2007)
Basic ACQUIREc Therapy Cycle:
MR3
• MR3 = Movement-ReinforcementRepetition-Refinement
• Movement is encouraged, prompted, and stimulated;
movement of the upper extremity starts the cycle
• Reinforcement is immediate, positive, informative, and
rewarding/motivating for the child
• Repetition occurs immediately, many times, as well as
over extended periods of time (i.e., after other MR3
therapy cycles for different skills and movements)
• Refinement occurs at natural times as skill progresses
The MR3 Cycle in
ACQUIREc Therapy
1
2
Move
Reward
4
3
Refine
Repeat
PMAL: Quality Rating of
Upper Extremity Movement
3.5
3
2.5
2
Pretreatment
Posttreatment
1.5
1
0.5
0
Intensive Movement Traditional Services /
Therapy
Crossover Condition
Pediatric Motor Activity Log –
Frequency of Upper Extremity Use
3.5
3
2.5
2
Pretreatment
Posttreatment
1.5
1
0.5
0
Intensive Movement Traditional Services /
Therapy
Crossover Condition
“Spillover” Effects from
Intensive Pediatric CI Therapy
• Increased positive social-emotional
responsiveness
• Reduced behavioral problems
• Improved communication skills
• Decreased sensory aversion to touch
• Improved gross motor and mobility skills
• Increased self-confidence and independence
DeLuca, Echols, & Ramey, 2007
Individual Differences Principle
in Pediatric CI Therapy Trial
5
4
Pre-Treatment
Post-Treatment
3
2
1
0
CHOP
ORMA
SEIE
KSAN
INEY
ELDY
NSER
AMUS
DEEL
Pediatric Neuromotor Research Clinic
• > 160 children who received standardized full
treatment protocol (with systematic
documentation of treatment fidelity)
• Parents (and children, when appropriate)
granted informed consent (assent) for
participating in clinical study
• Standardized assessments, pre- and posttreatment
Comparison of RCT and Clinical
Research Samples
• Pediatric Motor Activity Log – Quality of
Movement gain scores: 2.0 (RCT) vs 2.4 (CRS)
• Pediatric Motor Activity Log – Frequency of Use
gain scores: 1.9 (RCT) vs 1.9 (CRS)
• Emerging Behaviors Scale, # of new behaviors:
9.3 (RCT) vs 10.93 (CRS)
• Maintenance of benefits at 6 months (and beyond)
in both samples
Recent 3-site RCT designed to
test dosage effects of ACQUIREc
• Children (ages 3 – 6) randomly assigned to receive
3 versus 6 hours per day for 21 days
• Therapists received common training to treatment
protocol standards
• Therapists randomly assigned to children
• RESULTS presented at AACPMD meeting (Sept
2009) support benefits at both levels, but higher
for children receiving 6 hours oer day
• KEY UNANSWERED QUESTION: Are longterm changes related to initial dosage level?
“Biologically vulnerable children”
in Abecedarian Project
• Children born to lowest IQ (<70) mothers
• Children with lower APGAR Scores
• Children with non-optimal Ponderal Index
(birthweight to length ratio)
Analyses confirmed these children showed greater
benefits by ages 3 and 4
ABC Project:
Influences on IQ by Child Age
Regression Coefficients (95% CI)
Age in Months
Educational
Preschool
Maternal IQ<70
Positive Home
Environment
12
+ 7.9
1.0
+ 4.9
24
+ 12.7
- 4.3
+ 5.1
36
+ 18.6
- 8.2
+ 8.6
48
+ 13.2
- 11.7
+ 8.9
Adapted from Martin, Ramey, & Ramey, American Journal of Public Health, 1996
Abecedarian Project: Woodcock-Johnson
Age-referenced Reading Standard Scores at age 8
The Abecedarian (ABC) Project
Longitudinal Effect Sizes for Reading by Treatment Group
Campbell, Ramey,
Pugello, Sparling, &
Miller-Johnson (2001)
Applied
Developmental
Science
Participation Index for Children in
Infant Health and Development
• Composite score generated each year:
– Number of completed weekly or bi-monthly
home visits to family
– Number of monthly parenting information
sessions attended
– Total days child attended special preschool
(only from 12 to 36 months)
Participation Index predicted:
• Children’s Stanford-Binet scores at age 3
• Significant differences in high, medium,
and low participation groups – after
controlling for other variables associated
with levels of participation
• Low participation level similar to
Comparison group (that only received
health and social services) Ramey et al,
Pediatrics, 1992
• Click to edit Master text styles
– Second level
• Third level
– Fourth level
» Fifth level
IHDP: Heavier LBW (2001-2500gm) Intervention
Group had mean IQ scores 14 points > Controls
Infant Health and Development, JAMA, 1990
Ramey, AAAS, 1996
IHDP: Lighter LBW (< 2000 gm) Intervention Group ha
mean IQ scores 6.6 points > Controls
Infant Health and Development, JAMA, 1990 Ramey, AAAS, 1996
Why did the biologically vulnerable
LBW infants benefit less?
• Benefits for lower LBW group (<2000 gm)
disappeared by age 5
• No cognitive benefits for lower LBW children
with cerebral palsy, even at age 3
• In McCormick et al (Pediatrics, 2006) 18 yr
follow-up hypothesized that participation levels of
less than 400 (of 500 possible) days of attendance
may have accounted for this weaker effect. Also,
lower LBW children more likely to enter Special
Education early.
Recent evidence for Dosage Principle for
children from low resource environments
• In Louisiana, a Pre-K program was offered
– Full day, Half year
– Full day, Full year
• In Maryland, a highly similar Pre-K
program was offered:
– Half day
National Percentile Rank
60
50
40
A Comparison of Children’s Academic Progress
in Pre-K Programs that differ in dosage
LA Full day, Full year
LA Full day, Half Year
MD Half day, Full year
50
31
30
30
20
14
10
10
0
Pre
Post
How to think about “dosage” for future
research and planned interventions?
• The most vigorously studied early interventions are for
children from under-stimulating and sometimes
neglectful life situations
• For low resource children, increased dosage and
participation lead to greater realization of benefits
(enrichment dosage)
• For children with major biological conditions affecting
development, more specialized and higher dosage
interventions may be essential to realizing benefits