Randomized, controlled trial of an intervention for toddlers with autism: the Early Start Denver Model.

Abstract

To conduct a randomized, controlled trial to evaluate the efficacy of the Early Start Denver Model (ESDM), a comprehensive developmental behavioral intervention, for improving outcomes of toddlers diagnosed with autism spectrum disorder (ASD).
Forty-eight children diagnosed with ASD between 18 and 30 months of age were randomly assigned to 1 of 2 groups: (1) ESDM intervention, which is based on developmental and applied behavioral analytic principles and delivered by trained therapists and parents for 2 years; or (2) referral to community providers for intervention commonly available in the community.
Compared with children who received community-intervention, children who received ESDM showed significant improvements in IQ, adaptive behavior, and autism diagnosis. Two years after entering intervention, the ESDM group on average improved 17.6 standard score points (1 SD: 15 points) compared with 7.0 points in the comparison group relative to baseline scores. The ESDM group maintained its rate of growth in adaptive behavior compared with a normative sample of typically developing children. In contrast, over the 2-year span, the comparison group showed greater delays in adaptive behavior. Children who received ESDM also were more likely to experience a change in diagnosis from autism to pervasive developmental disorder, not otherwise specified, than the comparison group.
This is the first randomized, controlled trial to demonstrate the efficacy of a comprehensive developmental behavioral intervention for toddlers with ASD for improving cognitive and adaptive behavior and reducing severity of ASD diagnosis. Results of this study underscore the importance of early detection of and intervention in autism.

Full text

Page 1

DOI: 10.1542/peds.2009-0958
published online Nov 30, 2009;
Pediatrics
Jessica Greenson, Amy Donaldson and Jennifer Varley
Geraldine Dawson, Sally Rogers, Jeffrey Munson, Milani Smith, Jamie Winter,

Early Start Denver Model
Randomized, Controlled Trial of an Intervention for Toddlers With Autism: The
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Randomized, Controlled Trial of an Intervention for
Toddlers With Autism: The Early Start Denver Model
WHAT’S KNOWN ON THIS SUBJECT: Previous studies on the
efficacy of early behavioral intervention for improving outcomes
for preschool-aged children with autism have yielded promising
results. However, no randomized clinical trials of early
developmental behavioral intervention designed for toddlers with
autism have been conducted to date.
WHAT THIS STUDY ADDS: This study assessed the efficacy of the
Early Start Denver Model, a comprehensive developmental
behavioral intervention, for improving outcomes of toddlers with
ASD. The intervention, which was initiated when children were
less than 21⁄2 years, resulted in significant improvements in IQ,
language, adaptive behavior, and autism diagnosis.
abstract
OBJECTIVE: To conduct a randomized, controlled trial to evaluate the
efficacy of the Early Start Denver Model (ESDM), a comprehensive de-
velopmental behavioral intervention, for improving outcomes of tod-
dlers diagnosed with autism spectrum disorder (ASD).
METHODS: Forty-eight children diagnosed with ASD between 18 and 30
months of age were randomly assigned to 1 of 2 groups: (1) ESDM inter-
vention,whichisbasedondevelopmentalandappliedbehavioralanalytic
principlesanddeliveredbytrainedtherapistsandparentsfor2years;or
(2)referraltocommunityprovidersforinterventioncommonlyavailablein
thecommunity.
RESULTS: Comparedwithchildrenwhoreceivedcommunity-intervention,
childrenwhoreceivedESDMshowedsignificantimprovementsinIQ,adap-
tivebehavior,andautismdiagnosis.Twoyearsafterenteringintervention,
theESDMgrouponaverageimproved17.6standardscorepoints(1SD:15
points)comparedwith7.0pointsinthecomparisongrouprelativetobase-
linescores.TheESDMgroupmaintaineditsrateofgrowthinadaptivebehav-
iorcomparedwithanormativesampleoftypicallydevelopingchildren.Incon-
trast, over the 2-year span, the comparison group showed greater delays in
adaptivebehavior.ChildrenwhoreceivedESDMalsoweremorelikelytoexpe-
rienceachangeindiagnosisfromautismtopervasivedevelopmentaldisor-
der,nototherwisespecified,thanthecomparisongroup.
CONCLUSIONS: This is the first randomized, controlled trial to demon-
stratetheefficacyofacomprehensivedevelopmentalbehavioralinter-
vention for toddlers with ASD for improving cognitive and adaptive
behavior and reducing severity of ASD diagnosis. Results of this study
underscore the importance of early detection of and intervention in
autism. Pediatrics 2010;125:e17–e23
AUTHORS: Geraldine Dawson, PhD,a,b,cSally Rogers,
PhD,dJeffrey Munson, PhD,e,fMilani Smith, PhD,eJamie
Winter, PhD,eJessica Greenson, PhD,eAmy Donaldson,
PhD,gand Jennifer Varley, MSe
aAutism Speaks;bDepartment of Psychiatry, University of North
Carolina, Chapel Hill, North Carolina;cDepartment of Psychology,
eUniversity of Washington Autism Center, Center on Human
Development and Disability, andfDepartment of Psychiatry and
Behavioral Sciences, University of Washington, Seattle,
Washington;dMIND Institute, Department of Psychiatry,
University of California Davis, Sacramento, California; and
gDepartment of Speech and Hearing Science, Portland State
University, Portland, Oregon
KEY WORDS
autism, behavioral intervention, cognitive function,
developmental outcomes, early intervention
ABBREVIATIONS
ASD—autism spectrum disorder
ESDM—Early Start Denver Model
ABA—applied behavior analysis
A/M—assess and monitor
PDD—pervasive developmental disorder
NOS—not otherwise specified
MSEL—Mullen Scales of Early Learning
ADOS—Autism Diagnostic Observation Schedule
VABS—Vineland Adaptive Behavior Scales
RBS—Repetitive Behavior Scale
This trial has been registered at www.clinicaltrials.gov
(identifier NCT00090415).
www.pediatrics.org/cgi/doi/10.1542/peds.2009-0958
doi:10.1542/peds.2009-0958
Accepted for publication Jul 17, 2009
Address correspondence to Geraldine Dawson, PhD, Autism
Speaks, 4120 Bioinformatics Building, University of North
Carolina, Chapel Hill, North Carolina. E-mail: gdawson@
autismspeaks.org
PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).
Copyright © 2009 by the American Academy of Pediatrics
FINANCIAL DISCLOSURE: Sally Rogers and Geraldine Dawson
are authors of Early Start Denver Model for Young Children with
Autism from which they receive royalties.
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Autism spectrum disorder (ASD) is
characterized by impairments in so-
cial reciprocity and communication,
and stereotyped and repetitive behav-
iors, with onset during early child-
hood. Intellectual disability is present
in a large proportion of individuals.1
Withaprevalenceof1per150,2autism
costs the United States $35 billion per
year.3The lifetime per-capita societal
cost of autism is $3.2 million, with lost
productivity and adult care among the
largest costs.4Thus, early-intervention
methods that can improve outcome
for individuals with ASD are of high
importance.
The 1987 report by Lovaas5of an early
behavioral intervention that resulted
in 49% of children in the study being
mainstreamed into regular class-
rooms and showing significant IQ
gains created a groundswell of inter-
est among parents and professionals
in early intervention and raised ques-
tions about early plasticity in children
with autism.6Although subsequent in-
tervention studies, including a ran-
domized, controlled trial,7have docu-
mented improvements in IQ for a
subgroup of children, questions re-
garding the efficacy of early interven-
tion have remained. Many of the stud-
ieslackedmethodologicrigor.Authors
of a recent meta-analysis of the effi-
cacy of early behavioral intervention
argued that stronger evidence that
early behavioral intervention results
inbetteroutcomesthanstandardcare
is still needed.8
Our study was a randomized, con-
trolled trial of early intensive behav-
ioral intervention for young children
with ASD that was funded by the Na-
tional Institute of Mental Health (Dr
Dawson, principal investigator). It was
hypothesized that the early interven-
tion would result in significant im-
provements in cognitive abilities of
youngchildrenwithASD.Thestudydif-
fered from previous ones in several
ways. First, we maintained a high level
of methodologic rigor, including gold-
standard diagnostic criteria, random-
ization, comprehensive outcome mea-
sures conducted by naive examiners,
high retention rates, and measures of
fidelityofimplementationofamanual-
ized intervention.
Second,toourknowledge,ourstudyis
thefirstrandomized,controlledtrialof
intervention for toddlers with autism;
all children were younger than 30
months at entry. Given the recent rec-
ommendation by the American Acad-
emy of Pediatrics that 18-month-old
children be screened for ASD,9it is im-
perative that the efficacy of early-
intervention models appropriate for
toddlers with ASD be demonstrated.
Third, the intervention, the Early Start
DenverModel(ESDM),10isacomprehen-
sive early behavioral intervention for in-
fants to preschool-aged children with
ASD that integrates applied behavior
analysis (ABA) with developmental and
relationship-based
ESDM was designed to address the
needs of toddlers with ASD as young as
12 months. The intervention is provided
in a toddler’s natural environment (the
home)andisdeliveredbytrainedthera-
pists and parents. In our study, children
received structured intervention at high
intensity, consistent with the National
ResearchCouncil’srecommendation.11
approaches.The
PATIENTS AND METHODS
Study Procedures
Forty-eightchildrenbetween18and30
months of age diagnosed with autistic
disorder or pervasive developmental
disorder (PDD), not otherwise speci-
fied (NOS), were randomly assigned to
1 of 2 groups: (1) the ESDM group re-
ceived yearly assessments, 20 hours/
week of the ESDM intervention from
University of Washington clinicians,
parent training, and parent delivery
for 5 or more hours/week of ESDM, in
addition to whatever community ser-
vices the parents chose; and (2) the
assess-and-monitor (A/M) group re-
ceived yearly assessments with inter-
vention recommendations and refer-
rals for intervention from commonly
available community providers in the
greater Seattle region.
Children were evaluated by experi-
enced examiners naive to intervention
status at baseline (preintervention), 1
year after onset of the intervention,
and at either 2 years after onset of the
intervention or at 48 months of age,
whicheveryieldedalongertimeframe.
Participants
Participants were recruited through
pediatricpractices,BirthtoThreecen-
ters, preschools, hospitals, and state
and local autism organizations. Exclu-
sioncriteriaincluded(1)aneurodevel-
opmental disorder of known etiology
(eg,fragileXsyndrome),(2)significant
sensory or motor impairment, (3) ma-
jor physical problems such as a
chronic serious health condition, (4)
seizuresattimeofentry,(5)useofpsy-
choactive medications, (6) history of a
serious head injury and/or neurologic
disease, (7) alcohol or drug exposure
during the prenatal period, and (8) ra-
tio IQ below 35 as measured by mean
age equivalence score/chronological
age on the visual reception and fine
motor subscales of the Mullen Scales
of Early Learning (MSEL).12Children
who developed seizures during the
courseofthestudywerenotexcluded.
Inclusion criteria included age below
30 months at entry, meeting criteria
forautisticdisorderontheToddlerAu-
tism Diagnostic Interview,13meeting
criteria for autism or ASD on the Au-
tism Diagnostic Observation Sched-
ule,14andaclinicaldiagnosisbasedon
Diagnostic and Statistical Manual of
Mental Disorders,
(DSM-IV) criteria15using all available
information, residing within 30 min-
utes of the University of Washington,
Fourth Edition
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and willingness to participate in a ?2-
year intervention. At baseline, 18 chil-
dren in the A/M group and 21 in the
ESDM group received a DSM-IV diagno-
sis of autistic disorder. Six children in
theA/Mgroupand3intheESDMgroup
received a diagnosis of PDD NOS. This
differencewasnotsignificant(Fisher’s
exact test, P ? .231). The ethnicities
involved were Asian (12.5%), white
(72.9%), Latino (12.5%), and multira-
cial (14.6%). The male-to-female ratio
reflected the expected ratio in ASD of
3.5:1.
Retention rates were 100% (1-year)
and 100% (2-year) for the ESDM group
and 96% (1-year) and 88% (2-year) for
theA/Mgroup,whichyieldedasample
sizeof24intheESDMand21intheA/M
group at outcome. Figure 1 shows the
participant flowchart.
Measures
Autism Diagnostic Interview–Revised
ThetoddlerversionoftheAutismDiag-
nostic Interview–Revised13is a semi-
structured parent interview that as-
sesses autism symptoms across 3
domains: social relatedness; commu-
nication; and repetitive, restricted
behaviors.
Autism Diagnostic Observation
Schedule
The Autism Diagnostic Observation
Schedule (ADOS), WPS version,14is a
semistructuredstandardizedobserva-
tion that measures autism symptoms
in social relatedness, communication,
play, and repetitive behaviors. A stan-
dardized severity score based on
codeswithinthesedomainscanbecal-
culated to compare autism symptoms
across modules.16
Mullen Scales of Early Learning
(MSEL)
The MSEL12are a standardized develop-
mentaltestforchildrenfrombirthto68
months of age. Four of the 5 subscales
wereadministered:finemotor,visualre-
ception,expressivelanguage,andrecep-
tive language. T scores for subscales
have a mean of 50 (SD: 10). The early-
learning composite score is a standard
scorewithmeanof100(SD:15).
Vineland Adaptive Behavior Scales
The Vineland Adaptive Behavior Scales
(VABS)17areaparentinterviewthatas-
sesses social, communication, motor,
anddailylivingskills.Theyprovideage-
equivalent and standard scores for
several subscales, including expres-
siveandreceptivelanguageandsocial
adaptive functioning.
Repetitive Behavior Scale
The Repetitive Behavior Scale (RBS)18
is a parent questionnaire that charac-
terizestheseverityofrepetitivebehav-
iors, yielding 6 subdomain scores (eg,
sameness,
and a total score.
self-injurious behavior)
Randomization
Participants were stratified into 2
groups on the basis of composite IQ at
entry (?55 and 55) and gender to en-
sure comparable IQ and gender ratios
between groups. Within each of these
strata, randomization was conducted
byusingrandompermutedblocksof4.
The intervention groups did not differ
at baseline in severity of autism symp-
toms based on ADOS scores, chrono-
logical age, IQ, gender, or adaptive be-
haviors (see Table 1).
Intervention Groups
ESDM Group
The ESDM group was provided with in-
tervention by trained therapists for
Assessed for eligibility
(n = 96)
Excluded (n = 45)
Did not meet diagnostic
criteria (n = 38)
Met diagnostic criteria but
declined to participate in
randomization because of
demands of intervention
(n = 7)
Randomly assigned (n = 51)
Allocated to ESDM
group (n = 24)
Allocated to A/M
group (n = 24)
Time 1 assessment
(n = 23)
Followed (n = 23)
Lost to follow-up
(n = 1)

Time 2 assessment
(n = 24)
Followed (n = 24)
Lost to follow-up
(n = 0)

Time 2 assessment
(n = 21)
Followed (n = 21)
Lost to follow-up
(n = 3)

Time 1 assessment
(n = 24)
Followed (n = 24)
Lost to follow-up
(n = 0)

Analyzed (n = 21) Analyzed (n = 24)
Excluded (n = 3)
Declined ESDM because of
intervention requirements
(n = 2)
Subsequently diagnosed
with Rett syndrome (n = 1)
Enrollment
Allocation
Follow-up
Analysis
FIGURE 1
Participant flowchart.
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2-hoursessions,twiceperday,5days/
week, for 2 years. A detailed interven-
tion manual and curriculum were
used.19One or both parents were pro-
videdwithparenttrainingfromthepri-
mary therapist during semimonthly
meetings, during which the principles
and specific techniques of ESDM were
taught. Parents were asked to use
ESDM strategies during daily activities
and to keep track of the number of
hours during which they used these
strategies.ESDMusesteachingstrate-
gies that involve interpersonal ex-
change and positive affect, shared en-
gagement with real-life materials and
activities,adultresponsivityandsensi-
tivitytochildcues,andfocusonverbal
and nonverbal communication, based
on a developmentally informed curric-
ulumthataddressesalldevelopmental
domains. Teaching strategies are con-
sistentwiththeprinciplesofABA,such
as the use of operant conditioning,
shaping, and chaining. Each child’s
planisindividualized.Thereisastrong
parent-family role responsive to each
family’s unique characteristics. Par-
ents are taught the basic ESDM strate-
gies and asked to use them during ev-
eryday activities such as feeding, bath
time,andplay.Parentschoseteaching
objectives from the curriculum that
they viewed as high priority.
Intervention programs were super-
vised by a graduate-level, trained lead
therapist who had a minimum of 5
years’ experience providing early in-
tervention to young children with au-
tism,withongoingconsultationfroma
clinical psychologist, speech-language
pathologist,anddevelopmentalbehav-
ioral pediatrician. An occupational
therapist provided consultation as
needed. Intervention objectives and
strategies were reviewed, and the in-
tervention was observed at least bi-
weekly by the lead therapist and every
3 months by the speech-language pa-
thologist. Intervention was delivered
by therapists who typically held a bac-
calaureate degree, received 2 months
of training by the lead therapist, and
met weekly with the lead therapist.
Therapists were trained to compe-
tence, defined as completing course-
work, passing tests, mastering the in-
tervention, demonstrating fidelity of
85%ofmaximumscoresonthefidelity
instrument, and maintaining ongoing
fidelity.20
ESDM intervention hours were sys-
tematically recorded. Although 20
therapist-delivered intervention hours
per week were made available, the ac-
tual mean was 15.2 hours (SD: 1.4) be-
cause of illnesses, vacations, and so
on. Parents reported spending an av-
erage of 16.3 hours/week (SD: 6.2) us-
ing ESDM strategies. The ESDM group
reportedanaverageof5.2hours/week
(SD:2.1)inothertherapies(eg,speech
therapy, developmental preschool)
over the study enrollment period.
Other therapies were documented by
usinganinterventionhistoryinterview
administered every 6 months.
A/M Group
Childrenwhowererandomlyassigned
totheA/Mgroupreceivedcomprehen-
sive diagnostic evaluations, interven-
tion recommendations, and commu-
nity referrals at baseline and again at
each of the 2 follow-up assessments.
Familiesweregivenresourcemanuals
and reading materials at baseline and
twice yearly throughout the study. The
A/M group reported an average of 9.1
hours of individual therapy and an
averageof9.3hours/weekofgroupin-
terventions (eg, developmental pre-
school) across the 2-year period dur-
ing which the intervention study was
conducted.InthegreaterSeattlearea,
there are a number of Birth to Three
centers that provide interventions,
speech and language therapy, and
occupational therapy. Developmen-
tal preschool programs vary but typ-
ically include special education and
related services. There are a number
of private ABA providers in the
community.
Data Analysis
TheeffectofESDMinterventionwasas-
sessed by using repeated-measures
analysis of variance, with a priori con-
trasts that compared baseline scores
with1-and2-yearoutcomescores.The
primary outcome measures were the
MSEL composite standard score and
the VABS composite standard score.
TABLE 1 Baseline Measures for ESDM and A/M Groups
A/M GroupESDM GroupFMS
P
MeanSD
N
MeanSD
N
Age at study entry, mo
MSEL
Early-learning compositea
Receptive languageb
Expressive languageb
Visual receptionb
Fine motorb
VABS
Adaptive behavior compositea
Communicationa
Socializationa
Daily living skillsa
Motor skillsa
ADOS severity score
RBS total
23.13.924 23.94.0 240.48 7.52.490
59.4
21.2
26.0
30.8
30.6
8.6
3.8
8.6
8.9
10.7
24
24
24
24
24
61.0
21.1
24.5
33.2
33.9
9.2
4.7
7.2
11.0
11.9
24
24
24
24
24
0.40
0.01
0.48
0.70
1.02
31.69
0.19
30.08
70.08
130.02
.530
.920
.492
.406
.318
69.9
69.6
72.4
86.8
72.5
6.9
21.5
7.3
7.3
9.4
10.0
6.5
1.7
19.2
24
24
24
24
24
24
24
69.5
68.4
73.8
87.3
70.9
7.2
15.2
5.7
7.6
7.7
11.4
6.2
1.7
10.8
24
24
24
24
24
24
24
0.04
0.32
0.29
0.03
0.78
0.35
1.93
1.69
17.52
21.33
3.52
31.69
1.02
468.75
.844
.577
.594
.381
.862
.557
.171
No significant differences among baseline measures were found (P ? .10 on all measures).
aStandard score (mean: 100 ?SD: 15?).
bT score (mean: 50 ?SD: 10?).
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Secondary outcome measures were
the ADOS severity score,16the RBS,18
MSEL, and VABS subscale scores, and
changes in diagnostic status (autistic
disorder, PDD NOS, and no diagnosis).
RESULTS
No serious adverse effects related to
the intervention were reported during
the 2-year period.
1-Year Outcome
Table 2 displays statistics for 1- and
2-year outcomes, change scores rela-
tive to baseline, and group compari-
sons for primary and secondary mea-
sures. Significant intervention effects
were found for cognitive ability after 1
year on the MSEL composite standard
scores.TheESDMgroupdemonstrated
an average IQ increase of 15.4 points
(?1SD)comparedwithanincreaseof
4.4 points in the A/M group. The visual
reception subscale was the only indi-
vidual subscale on the MSEL on
which the groups significantly dif-
fered at the 1-year outcome. The
ESDM group gained 5.6 T-score
points, whereas the A/M group de-
clined1.7points.TheESDMgroupim-
proved 17.8 points on receptive lan-
guage compared with a 9.8-point
improvement in the A/M group, a dif-
ference that fell just short of statis-
tical significance.
As a whole, children gained raw
score points in the daily living skills
subscale of the VABS; however,
progress was much slower in rela-
tion to the VABS normative sample
between baseline and 1 year. The
groups did not differ in terms of
adaptive behavior, measured by the
VABS composite standard score, af-
ter 1 year (the ESDM group showed a
3.8-point decline, and the A/M group
showed a 6.3-point decline). The
groupsdidnotdifferintermsoftheir
ADOS severity scores or RBS total
score after 1 year of intervention.
2-Year Outcome
Two years after the baseline assess-
ment, the ESDM group showed signif-
icantly improved cognitive ability,
measured by MSEL composite stan-
dard scores, which increased 17.6
points compared with 7.0 points in
the A/M group. The bulk of this
change seems to have been a result
of receptive and expressive lan-
guage, which showed increases of
18.9 and 12.1 points, respectively, for
the ESDM group, whereas the A/M
group improved 10.2 and 4.0 points,
respectively.
The ESDM and A/M groups signifi-
cantly differed in terms of their
adaptive behavior as measured by
the VABS composite standard scores
at the 2-year outcome (see Fig 2). The
ESDM group showed similar stan-
dard scores at the 1- and 2-year out-
comes,indicatingasteadyrateofde-
velopment, whereas the A/M group,
on average, showed an 11.2-point av-
erage decline. Thus, the A/M group’s
delays in overall adaptive behavior
became greater when compared
with the normative sample. The A/M
group showed average declines in
standard scores that were twice as
great as those in the ESDM group in
thedomainsofsocialization,dailyliv-
ing skills, and motor skills. The
groupsdidnotdifferintermsoftheir
ADOS severity scores or RBS total
score after 2 years of intervention.
Diagnosis
At baseline, the diagnoses in each
group were not significantly differ-
ent (Fisher’s exact test, P ? .461)
and were distributed as follows:
TABLE 2 Child Outcomes After 1 and 2 Years of Study Participation
1-y Outcome 2-y Outcome Group ? Time
(Baseline vs
1-y)
Group ? Time
(Baseline vs 2-y)
A/M (N ? 23) ESDM (N ? 24) A/M (N ? 21)ESDM (N ? 24)
Mean SD
?
MeanSD
?
MeanSD
?
MeanSD
?
FMS
P
FMS
P
Chronological age, mo
MSEL
Early-learning
composite
Receptive language
Expressive language
Visual reception
Fine motor
VABS
Communication
Socialization
Daily living skills
Motor skills
ADOS severity score
RBS total
38.13.8 15.338.84.414.9 52.14.3 29.352.4 3.428.50.95 2.18.334 1.276.91.266
64.0 13.84.476.423.415.466.3 15.37.0 78.624.2 17.65.99 1416.90.0184.311264.38.044
31.1
33.0
29.0
26.1
63.7
71.0
68.9
65.3
70.7
7.3
23.3
11.1
11.5
10.7
8.6
8.8
13.0
12.1
7.1
12.2
2.1
17.5
9.8
6.7
38.9
36.1
38.8
32.7
65.7
73.5
70.0
65.6
75.1
6.5
15.5
15.4
14.2
16.4
11.7
9.8
11.7
9.9
8.6
14.4
1.5
12.3
17.8
11.6
5.6
?1.3
?3.8
5.0
?3.8
?5.3
?12.2
?0.7
31.5
30.0
34.5
28.5
59.1
69.4
63.1
58.0
64.1
7.3
22.0
10.6
9.2
13.0
9.5
8.8
15.8
9.3
8.1
12.3
1.8
16.3
10.2
4.0
4.5
?2.8
?11.2
?0.7
?8.9
?14.5
?23.1
40.0
36.6
41.0
33.5
68.7
82.1
69.2
64.7
77.4
7.0
16.7
16.3
13.6
17.9
12.2
15.9
21.8
11.6
12.4
19.8
1.9
13.1
18.9
12.1
7.8
?0.4
?0.8
13.7
?4.6
?6.2
?9.9
?0.2
2.5
4.00
1.99
4.22
1.32
0.85
1.38
0.01
0.89
0.99
3.38
0.001
745.21
290.43
621.97
161.35
71.61
175.69
1.15
51.78
157.43
13.15
0.19
.051
.165
.046
.256
.360
.246
.934
.350
.326
.072
.976
4.14
4.88
0.63
0.46
7.05
6.38
1.29
6.73
7.40
0.66
0.37
843.56
748.07
126.23
63.81
1181.82
2300.98
204.57
773.34
1881.65
3.29
92.50
.048
.033
.433
.503
.011
.015
.263
.013
.009
.422
.545
?1.7
?5.0
?6.3
1.2
?3.5
?7.4
?15.9
0.4
1.0
0.3
0.9
?0.6
? indicates mean change from baseline.
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Page 7

ESDM, 21 with autistic disorder and 3
with PDD NOS; A/M, 18 with autistic
disorder and 6 with PDD NOS. At the
2-year outcome, 15 (62.5%) children
in the ESDM group had the same di-
agnosis (14 with autistic disorder, 1
with PDD NOS) and 15 (71.4%) chil-
dren in the A/M group had the same
diagnosis (all 15 with autistic disor-
der). Diagnosis improved (baseline
autistic disorder to PDD NOS at year
2) for 7 (29.2%) children in the ESDM
group but for only 1 (4.8%) child in
the A/M group. However, the diagno-
sis changed from PDD NOS at base-
line to autistic disorder at year 2 for
2 (8.3%) children in the ESDM group
and 5 (23.8%) children in the A/M
group. Thus, children who received
ESDM were significantly more likely
to have improved diagnostic status
atthe2-yearoutcomecomparedwith
children in the A/M group, as as-
sessed by using Fisher’s exact test 2
(intervention groups) ? 2 (improved
versus worsened diagnosis) contin-
gency table (P ? .041). Fisher’s exact
test for the 2 (intervention groups)
? 3 (diagnostic change: no change
versus improved versus worsened
diagnosis) contingency table was
just short of significance (P ? .060).
DISCUSSION
Recommendations by the American
Academy of Pediatrics9that all chil-
dren be screened for autism at 18
months of age oblige the develop-
mentofinterventionsthatareappro-
priate for toddlers with ASD. To our
knowledge, this study is the first to
demonstrate the efficacy of an inten-
sive intervention designed for tod-
dlers with ASD as young as 12
months of age. After 2 years of inter-
vention, children provided with the
ESDM19showed significant improve-
ments in IQ, adaptive behavior, and
diagnostic status compared with
children who received community in-
terventions. Consistent evidence of
improvement in communicative abil-
itiesintheESDMgroupwasfound,as
demonstrated by gains in receptive
and expressive language scores on
the MSEL subscales and the VABS
communication subscale. Significant
improvement for the ESDM group
was found for overall adaptive be-
havior, communication, daily living
skills, and motor skills. Specifically,
the ESDM group, although still signif-
icantly delayed in adaptive behavior,
was able to keep pace with the rate
of change of the VABS normative
sample, whereas the community-
based intervention group continued
to fall farther behind in adaptive be-
havior. Given the importance of
adaptive behavior for everyday func-
tioning at home and school, the fact
that the ESDM group did not continue
to fall farther behind is likely to af-
fect ability to function in less-
restrictive environments. This dem-
onstrates that the ESDM intervention
accelerates overall development and
is generalizing to everyday life.
Whereas 71% of the children in the
group that received community-
based intervention retained their di-
agnosis of autistic disorder over the
2-year period, only 56% of children in
theESDMgroupdidso.Thediagnosis
of 7 children (30%) in the ESDM
group changed from autistic dis-
order to PDD NOS, whereas this
only occurred for 1 child (5%) in
the community-intervention group.
These diagnostic assessments were
conducted by experienced clinicians
who were naive with respect to
intervention-group status. However,
this change in diagnostic severity
was not reflected in significant dif-
ferences in the ADOS severity scores.
This lack of correspondence be-
tween measures is difficult to inter-
pret, because the child’s perfor-
mance in the ADOS contributes to
clinical diagnosis. However, other
behaviors,includingparentalreport,
also contribute to overall clinical
diagnosis. The repetitive-behavior
scores also did not change over time
in either group.
CONCLUSIONS
The outcomes of this study, which in-
volve an increase in IQ scores of 17
points(?1SD)andsignificantgainsin
language and adaptive behavior, com-
pare favorably with other controlled
studies of intensive early intervention
(eg, Smith et al [2000],7which deliv-
ered discrete trial intervention for ?2
FIGURE 2
Mean scores on the MSEL (left) and the VABS composite (right) for children in the ESDM and A/M
groups 1 and 2 years after entering study. Error bars indicate ?1 SD.
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DAWSON et al
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Page 8

years for 25–40 hours/week). The
group differences reported from our
study are larger than those produced
byothercomparativetrialsofdevelop-
mental behavioral approaches, which
were conducted for briefer periods of
time and with fewer hours of delivery
perweek.21,22Whetherthechildrenwill
sustain their gains over a longer term
is an important question that will re-
quire follow-up study.
The results of this study suggest that
the ESDM model,19an intervention ap-
proach that uses teaching strategies
of ABA that are delivered within an af-
fectivelyrich, relationship-focused
context, can be effective for improving
outcomes of young children with au-
tism. Parents’ use of these strategies
at home during their daily activities
likely was an important ingredient of
its success.
ACKNOWLEDGMENTS
This study was supported by National
Institute of Mental Health grant
U54MH066399 (to Dr Dawson).
We acknowledge the contributions of
the parents and children who took
part in this study and the support and
effortofnumerousundergraduateand
graduate students and staff who are
part of the University of Washington
Autism Center.
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Page 9

DOI: 10.1542/peds.2009-0958
published online Nov 30, 2009;
Pediatrics
Jessica Greenson, Amy Donaldson and Jennifer Varley
Geraldine Dawson, Sally Rogers, Jeffrey Munson, Milani Smith, Jamie Winter,

Early Start Denver Model
Randomized, Controlled Trial of an Intervention for Toddlers With Autism: The

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