A New Instrument to Aid in Early Diagnosis for Autism Spectrum Disorder

Presented By Peter D. Marle, M.A.

Coolidge Autistic Symptoms Survey – Toddler Version

A New Instrument to Aid in Early Diagnosis for Autism

Spectrum Disorder


A Brief History of Autism

Anecdotal Accounts of Autism Prior to Scientific DocumentationMartin Luther, 1652Changeling BabiesFeral children (e.g., Victor “wild boy” of Aveyron)

Scientific Investigation the Autism SpectrumEarly 20th Century

De Sanctis, Earl, & PotterMid 20th Century

Leo Kanner and Hans AspergerDifferentiated autistic behaviors from schizophreniaStudied children with mild forms of autismKanner was suspect of autism being derived from “cold parents”

Led to Bettelheim and the term “refrigerator mothers”Bernard Rimland eventually dissuaded this notion



Scientific Investigation the Autism SpectrumLate 20th Century

Wakefield et al. 1998Prompted mass hysteria with study suggesting vaccines cause autismWas it correct?People such as Jenny McCarthy still propagate this notion



Scientific Investigation the Autism SpectrumLate 20th Century

Wakefield et al. 1998Prompted mass hysteria with study suggesting vaccines cause autismWas it correct?People such as Jenny McCarthy still propagate this notion

Current Research Directions for AutismEmphasis on genetics, neuroscienceAlso, there is a movement toward the hope that autism may be recoverable (Ozonoff, 2013)

May be preemptiveMay only be applicable to changing behaviors in milder forms of autismHowever, early interventions in children with an autism spectrum disorder (ASD) can greatly influence the developmental trajectory of a child


Early Identification of ASD

Rationale for the Coolidge Autistic Symptoms Survey – Toddler Version (CASS-T)Changes in DSM Diagnostic Criteria

Forthcoming DSM-5 is expected to combine autistic disorder, Asperger’s disorder, childhood disintegrative disorder, and PDD-NOS into Autism Spectrum Disorder

Changes to the diagnostic criteria ensuedLanguage criteria expected to be removedAddition of 3 Levels of Severity, ranging from mild to severe

APA’s rationale for the changes:Literature regarding the differentiation of these disorders has been unreliableCombination was subject to common diagnosable symptomatology

Current surveys exist, but may soon be outdated due to these changes


Development of the CASS-T

Item DevelopmentA total of 39 items were derived from DSM-5 diagnostic criteria andExtant literature on autism spectrum disordersItems only pertinent to children under the age of 5 were included

Hypotheses1. A 1-component solution (as determined by principal components analysis) would

best fit the structure 39-item CASS-T2. The CASS-T would show good internal reliability (Cronbach’s α ≥ .80)3. The CASS-T would have good test-retest and split-half reliabilities (r ≥ .80).4. The CASS-T would significantly differentiate among children with

a) milder forms of autism (e.g., Asperger’s disorder and high-functioning autism)

b) moderate-to-severe forms of autistic spectrum disordersc) no diagnoses (i.e., a group-matched control group)

5. There would be a strong, positive correlation between the CASS-T and CASS (The CASS has been developed separately as an ASD diagnostic tool

for children over 5 years of age)



Method• Participants• Materials

• Informed Consent Form• Demographic Sheet• 39-item CASS-T (Retrospective)• 83-item CASS

• Procedure• All data were collected with IRB approval• Packets were either

• hand-delivered to parents or • given in an electronic format (via a secure online survey host; i.e.,

PsychData.com)• Packets took approximately 30 min to complete• Participants were given the option of returning the materials via a self-addressed

return envelope, postage paid or returning the materials to the CITI-trained researcher

Table 1Participant Data for Mild ASD, Moderate-to-Severe ASD, Group-Matched Control Group, and Full Dataset n

(% male)* Age

Range* Age

(M, SD)% in

TherapyTherapy Length(Months; M, SD)

* Age Dx(M, SD)

Mild ASD 22 (77%) 6 – 16 (9.6, 2.5) 52% (30.5, 21.8) (6.4, 3.1)M-S ASD 23 (83%) 5 – 16 (9.2, 3.3) 81% (60.1, 37.6) (3.0, 1.6)Control 22 (59%) 5 – 17 (9.6, 3.9) 0% --- ---Full DS (CASS-T) 88 (63%) 5 – 17 (9.9, 3.5) 38% (45.4, 32.6) (4.7, 3.1)Full DS (CASS) 86 (63%) 5 – 17 (9.9, 3.6) 34% (48.2, 33.7) (4.6, 3.0)Note. M-S = Moderate-to-Severe. DS = Dataset. Dx = Diagnosed. * in years.



ResultsHypothesis 1

A 1-component solution would provide the best fit for the CASS-T (accounting for at least 50% of the variance)

• Either a 4-component (total variance explained = 65.5%) or 5-component solution (total variance explained = 69.5%) best fit the data

Table 2Cronbach’s α Computations for the CASS-T 4- and 5-Component Solutions

4-Component Solution 5-Component Solution

Component # Items α # Item Overlap # Items α

1: DSM Dx Criteria 20 .96 14 19 .97

2: Physical Contact 9 .91 6 7 .90

3: Development 6 .83 4 4 .79

4: Sensory Issues 4 .91 4 4 .91

5: Stereotypy/Humor -- -- 0 5 .84

Note. For all analyses, n = 88. # Item Overlap refers to the number of items in the 5-component solution that also appear in the respective 4-component solution component.



ResultsHypothesis 2

The CASS-T would show good internal reliability (Cronbach’s α ≥ .80)

• Cronbach’s α = .97 (n = 88)

Table 3Cronbach’s α Computations for the CASS-T 4- and 5-Component Solutions

4-Component Solution 5-Component Solution

Component # Items α # Item Overlap # Items α

1: DSM Dx Criteria 20 .96 14 19 .97

2: Physical Contact 9 .91 6 7 .90

3: Development 6 .83 4 4 .79

4: Sensory Issues 4 .91 4 4 .91

5: Stereotypy/Humor -- -- 0 5 .84

Note. For all analyses, n = 88. # Item Overlap refers to the number of items in the 5-component solution that also appear in the respective 4-component solution component.



ResultsHypothesis 3

The CASS-T would have good test-retest reliability (r ≥ .80)

• r(90) = .95, p < .001

The CASS-T would have good split-half reliability (r ≥ .80)

• r(38; 1 week) = .80, p < .001



ResultsHypothesis 4

There would be significant differences among the group means for the CASS

a) the moderate-to-severe autism group would have the significantly highest mean,

b) the mild autism group would have the second highest mean, and

c) the group-matched control group would have the significantly lowest mean

F(2, 64) = 199.93,

p < .0005; η2 = .86

Control Mild ASD Moderate-to-Severe ASD1

2

3

4

Pos

sibl

e M

eans

ran

ged

from

1

(Str

ongl

y F

alse

) to

4 (

Str

ongl

y T

rue)

Figure 1. Comparison of CASS-T group means. 95% CIs are given.



ResultsHypothesis 5

There would be a strong, positive correlation between the CASS-T and the CASS means

• Correlation coefficient

r(92) = .89, p < .0005

1 1.5 2 2.5 3 3.5 40

1

2

3

4

Control

Mild ASD

Moderate-to-Severe ASD

CASS Mean

CASS

-T M

ean

Figure 2. Scatterplot of CASS and CASS-T means marked by group.



ResultsHypothesis 5



r(92) = .89, p < .0005

1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 3.20

1

2

3

4

Control

Mild ASD


CASS Mean

CASS

-T M

ean




ResultsHypothesis 5



r(92) = .89, p < .0005

1 1.5 2 2.5 3 3.5 40

1

2

3

4

Control

Mild ASD


CASS Mean

CASS

-T M

ean




DiscussionRelating to the Development of the CASS-T

With the exception of Hypothesis 1, all other hypotheses were confirmedIt appears that the CASS-T can be used to assess ASD in children younger than 5, although current study assessed via retrospective

Limitations and Future ResearchA limitation of the study was the sample size used for PCA

Further research is necessary to determine the component structure of the CASS-T

Current diagnoses for ASD do not typically generate a moderate (Level 2) diagnosis

Once a diagnosis of Level 2 ASD becomes more common, the CASS-T should be re-evaluated for its ability to differentially assess this part of the spectrum

Future research should also assess the sensitivity and specificity of the CASS-T

Thank you!

Questions?

A New Instrument to Aid in Early Diagnosis for Autism Spectrum Disorder

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