1. The Ritvo Autism Asperger Diagnostic Scale Revised (RAADS-R)
IMFAR 2010 PHILADELPHIA
The Ritvo Autism Asperger Diagnostic Scale Revised (RAADS-R)
A scale to assist the diagnosis of autistic spectrum disorder in adults- An international validation study with nine participating centers
Ariella Riva Ritvo, Ph.D., Yale Edward R. Ritvo, MD., UCLA Donald Guthrie, Ph.D., UCLA Max Ritvo, Yale University Demetra Hufnagel, Yale University
Daniela Markovic, MS., UCLA
Participating Centers:
Ami Klin, Ph.D., Yale; Latha Soorya, Ph.D. Mt. Sinai; William McMahon, MD, Kim Moody, U of Utah; David Mataix-Cols, Ph.D., King’s Collge; Bruce Tonge, MD, Avril Brereton, PhD, Monash University; Trevor Clark, Ph.D, Vicki Gibbs, Fiona Aldridge, Megan Williams, ASPECT, Sydney; Tony Attwood, Ph.D, J. Eloff, Ph.D. Griffith University; Stephanie Moeser-Warren, Geneva Center, Toronto; Lisa Andersen, Susanne Bejerot, MD, PhD. Karolinska Institute

2. Background
The RAADS-R is a modified version of the Ritvo Autism Asperger Diagnostic Scale. The rationale for its development, its method of construction, and its comparison to other similar scales have been published in JADD in
The first version of the RAADS contained 78 questions. Published data demonstrated it had high validity, reliability, sensitivity, and specificity in a limited number of subjects.
Questions on the initial RAADS assess developmental pathology in three symptom areas: language, social relatedness, and sensory- motor (re. DSM-IV-TR). After critical review and the results of a factor analysis, a revised 80-item version was developed (the RAADS-R) with the addition of a fourth symptom area (circumscribed interests), two questions, and several word clarifications.

3. Objectives
To describe the methods and present the results of the nine university international standardization study of the new 80- item RAADS-R.

4. Methods A uniform protocol was used by all centers
IRB consent was obtained by each center
All subjects signed informed consent
Participating Subject Groups:
Autism Spectrum Disorder Subjects N = 201
66 subjects with a diagnosis of Autistic Disorder
135 subjects with a diagnosis of Asperger’s Disorder
Comparison Subjects N = 578
276 subjects with no DSM-IV-TR diagnosis
302 subjects with other DSM-IV-TR diagnoses

5. Methods ASD Subjects (groups 1 and 2 n = 201)
Uniformly diagnosed by research criteria :
A clinical interview (DSM-IV-TR diagnostic criteria met)
ADI/ADOS Scale (ADOS module IV at least) to establish concurrent validity
Standardized IQ test, (WAIS or WASI) full IQ of =/> 80
Constantino Social Responsiveness Scale-Adult (SRS-A) to assess concurrent validity when available (69 subjects)
Repeat testing to assess reliability
Comparison subjects (groups 3 and 4 n = 578 ):
Volunteers without a DSM-IV-TR diagnosis
Volunteers with current DSM-IV-TR diagnosis other than ASD

6. Methods Administration of RAADS-R:
ASD subjects: Following initial screening, a clinician interviewed each subject to confirm the diagnostic information and IQ data, completed the ADI/ADOS or ADOS module IV, and then introduced the scale and explained how to answer the questions. The clinician remained with each subject as the questions were being answered to offer clarifications when asked, and to make sure answers were entered in the proper columns on the Likert scale. An SRS–A scale was obtained from cooperating accompanying adults when available.
Comparison Subjects: All were given the RAADS-R to complete in the presence of a clinician. All comparison subjects were clinically evaluated to determine that their IQ was 80 or above.
Each of the 9 participating centers was asked to score, review and mail in full packets of ASD subjects. Some of the participating centers contributed data to the comparison group subject pool.

7. Translations
Translations took into account cultural/idiomatic variations. Questions addressed core symptoms regardless of language, which will allow for standardization of results and assessment of validity and reliability. Some studies are well on their way (Swedish and Japanese) while others (French and Hindi) are in early stages. Standard protocol and translation methods are being followed.
Studies are being conducted in:
Swedish: Lisa Andersen, Ph.D, Susanne Bejerot, MD, PhD, Karolinska Institute
Japanese: Prof. Masatsugu Tsujii, Kaori Matsumoto, Kenji Tsuchiya, Nagoya, Japan
Hindhi
French

8. Results: DemographicsN
Males
Females
Mean age
Married %
Highest grade
Mean IQ
High School
College
Graduate
Autistics 66 52
79.1 14
20.9
30.81
13.4
52.2
37.3
10.4
114
Asperger
135 93
68.9 42
31.1
32.01
21.5
37.8
53.3
7.4
122
ASD
201
145
72.1 56
27.9
31.45
18.9
45.0
45.3
8.9
119
No DSM-IV-TR
276
41.3
162
58.7
41.51
39.5
37.7
46.0
16.3
N/A
Other DSM-IV-TR
302
134
44.4
168
55.6
42.04
28.5
40.1 6
All controls
578
248
42.9
330
57.1
41.78
33.7
38.9
49.7
11.2
Total study population
779
394
386
49.5
29.9
39.9
49.4
10.3

9. Results Diagnostic Accuracy (Sensitivity and Specificity):
Utilizing a cut off RAADS-R score of 65, six ASD subjects from three of the nine centers scored below, and thus were in the non ASD range. They are labeled “false negatives,” yielding sensitivity for the RAADS-R of 97%. None of the comparison subjects scored above 65, so there were no false positives. Thus the specificity for the RAADS-R is 100%.
Pair-wise comparison of each of the 80 questions
Post-hoc unequal variance t-tests were performed for pair-wise comparison of each of the 80 questions. The ASD subjects differed significantly from the comparison groups on all 80 questions (p < for all questions).
The mean RAADS-R scores of the ASD, the Autistic, and the Asperger groups from all nine centers are significantly different (p < ) from the combined mean of the comparison groups, and the mean for each of the nine research centers.
Cronbach Alpha coefficients demonstrate good internal consistency.

10. Cronbach Alpha Coefficients
Circumscribed Interests 9, 13, 24, 30, 32, 40, 41, 50, 52, 56, 63, 70, 75, 78
Alpha = .903
Language 2, 7, 27, 35, 58, 66, 15
Alpha = .789
Sensory Motor 10, 19, 4, 33, 34, 36, 46, 71, 16, 29, 42, 49, 51, 57, 59, 62, 65, 67, 73, 74
Alpha = .905
Social 1, 6, 8, 11, 14, 17, 18, 25, 37, 38, 3, 5, 12, 28, 39, 44, 45, 76, 79, 80, 20, 21, 22, 23, 26, 31, 43, 47, 48, 53, 54, 55, 60, 61, 64, 68, 69, 72, 77
Alpha = .923
© Ariella Riva Ritvo, Ph.D. Yale; Edward R. Ritvo, MD 2010
Slide 10

11. Factor Analysis
Factor Analysis was carried out using both Varimax (orthogonal) and Oblique (non orthogonal) rotation. Results were compared between the two rotational strategies. The Oblique rotational method was chosen because we assume the underlying constructs are interrelated.
We identified four factors. To compare the model derived factors versus the assigned four subdomains (DSM-IV-TR), we computed the Pearson correlation. Factors I and IV correlated most strongly with the social construct (r =.80). Factor II correlated most strongly with circumscribed interests (r =.78), factor III with sensory motor (r =.88).
The language construct was not picked up with the four factor model. However, the factor analysis is a mathematical computation of clusters and picks up on key words, missing the nuances in these questions. For instance, the question: “the phrase ‘I’ve got you under my skin’ makes me feel uncomfortable” is clearly a language construct question and targets concrete language and lack of understanding symbolic language. The factor analysis loaded it as a sensory motor question, most likely because it contained the words “skin” and “uncomfortable”.
We will report the variances accounted for by each factor and the Cronbach alpha coefficients, but upon review of the loadings, we remain confident that the original assignments of questions reflect the clinical picture with more clinical relevance. Either way, the instrument has good internal consistency.

12. Factor Analysis
Factor I accounts for 23.9% of the variance with a Cronbach alpha coefficient of .93
Factor II accounts for 25.0 % of the variance with a Cronbach alpha coefficient of .95
Factor III accounts for 22.4 % of the variance with a Cronbach alpha coefficient of .87
Factor IV accounts for 18.9% of the variance with a Cronbach alpha coefficient of .89

13. Factor Analysis
Factor I: Social, containing questions related to empathy, intimacy and social language Questions: 1, 6, 8, 11, 13, 14, 15, 16, 18, 31, 37, 38, 43, 48, 52, 53, 58, 62, 66, 68, 72, 74, 77.
Alpha= .93
Factor II: Circumscribed Interests, also with questions relating to social blindness Questions: 3, 4, 5, 7, 9, 12, 16, 17, 20, 22, 25, 27, 28, 32, 33, 39, 41, 44, 45, 49, 50, 56, 60, 64, 76, 78, 79, 80.
Alpha = .95
Factor III: Sensory motor Questions: 2, 10, 19, 24, 29, 34, 35, 36, 40, 46, 51, 54, 57, 59, 65, 70, 71, 73.
Alpha= .87
Factor IV: Social Anxiety Questions: 21, 23, 26, 30, 42, 47, 55, 61, 63, 67, 69, 75.
Alpha =.89
This factor is important. Targeting the social anxiety questions within the instrument may help the clinician differentiate social anxiety from ASD. The two are often confused diagnostically.

14. Test – Retest Reliability
mean interval between tests = 15 months
Subjects N
Mean RAADS-R
1st Test
2nd Test
ASD subjects 15
155
149
Comparison subjects 20 21

15. Test – Retest Data Statistical Analysis
Subject group
Number
Pearson r=
Spearman Rho=
All subjects 30
.987
.956
Autistic 7
1.0
Asperger 8
.939
.952
Comparisons 15
.874
.764

16. Type and number of subjects
Validity Data
Type and number of subjects
Percent agreement
Research center’s clinical criteria (inclusion requirement)
ASD 201
100%
ADI/ADOS or ADOS module 4 (inclusion requirement)
RAADS Sensitivity (6 false negatives) Specificity (0 false positives)
ASD COMPARISON 578
97% 100%
Constantino SRS-A Sensitivity (3 false negatives)
ASD 69
95.69%

17. Validity Data-Constantino Social Responsiveness Scale, Adult (SRS-A)
69 SRS-A were administered to a 3rd party (e.g. parent, spouse).
SRS-A cutoff t score is 59. Three subjects (4.31 percent) scored below the cutoff (55, 57 and 58). This is a 95.59% concordance rate with RAADS-R subjects.

18. Mean RAADS-R Scores and Ranges by Research Center: ASD Subjects
Min
Max
UCLA 53
146 84
222
Yale 31
115 48
178
Mount Sinai 19
123 73
166
University of Utah 7 92 72
109
Monsah University, Australia 13
138 62
172
Aspect, Sydney 14
118 58
193
Griffith University, Australia 42 56
227
Geneva Center, Canada 8
148
107
216
University of London
135 67
205

19. Mean RAADS-R Scores and Ranges – Autism, Asperger and, ASD
Min
Max
All ASD subjects
201
133.8 44
227
All Autistic subjects 66
138.5
All Asperger subjects
135
131.5 52
225

20. Mean RAADS-R Scores and Ranges – Comparison Subjects
Min
Max
No DSM-IV-TR diagnosis
275 22 64
Other DSM-IV-TR diagnoses
302 30 65
Total All Comparison subjects
578 25

21. Characteristics of the only 6 ASD subjects (3%) whose mean RAADS-R scores were below 65 (false negatives) Sorted by RAADS-R scores (mean age = 19.9)
Center
Diagnosis N
Sex
School
SRS IQ
RAADS-R
Yale
Asperger 19 M HS
120 52
Griffith 23 90
117 56
Aspec
Autistic 18
116 58
122 20
COL 59 60

22. Conclusions
No difficulties were reported in administration even though subjects were evaluated at nine medical centers on three continents.
The RAADS-R proved to be highly accurate in discriminating between subjects with ASD and those without a DSM-IV-TR diagnosis and with another DSM-IV-TR diagnosis (Sensitivity = 97%. Specificity = 100).
Mean RAADS-R scores were significantly different (p < ) between ASD and comparison subjects at each of the nine centers and in all centers combined.
All eighty questions significantly differentiated between ASD and comparison subjects. The fact that this was true even when the comparison cases had a variety of DSM-IV- TM diagnoses other than ASD makes the RAADS-R particularly useful in adult clinic clinical settings.
The RAADS-R also demonstrated high test – retest reliability (Pearson Correlation Coefficient = .987, Spearman Correlation Coefficients = .956).
Concurrent validity with ADI/ADOS was 100% and with Constantino SRS-A concordance rate was 95.59%.

23. Conclusions
Cronbach alphas were good for the four DSM-IV-TR domains, suggesting a good internal consistency of the RAADS-R.
Factor analysis with oblique rotation to account for assumed correlation between constructs yielded four factors, also with good internal consistency.
Because ASD is a behaviorally defined syndrome with subtle nuances and factor analysis is mathematically based, picking up key words, we prefer to remain with the original question assignment, which reflects the clinical picture more accurately. That being said, the Cronbach alpha coefficients are good either way, and the original subdomains as well as the factors differentiate ASD from non-ASD subjects in a statistically significant way. The instrument was designed to be used as a whole, and all questions ultimately have one measurement—ASD symptomatology.

24. Summary
The results from nine medical centers, based on 201 ASD subjects and 578 comparison subjects, demonstrated that the RAADS-R is highly valid, highly reliable, and it is easy to administer and to score. Thus we conclude that it can serve as a valuable asset to assist clinicians diagnosing ASD in adults eighteen years and older.

25. Clinical Implications of RAADS Scores
Sensitivity = 97% (6 false negatives) Specificity = 100% (no false positives)
66 OR ABOVE
HIGHLY LIKELY
TO HAVE ASD
65 OR BELOW
HIGHLY UNLIKELY

26. The Ritvo Autism Asperger Diagnostic Scale-R
SENSITIVITY = 97%
SPECIFICITY = 100%
MEAN
134
RAADS SCORES 65
MEAN 22
MEAN 30
ASD N = 201
NO OTHER DX N = 276
OTHER DX N = 302

27. © The Ritvo Autism Asperger Diagnostic Scale Revised (RAADS-R) 2010
Thank you.
© The Ritvo Autism Asperger Diagnostic Scale Revised (RAADS-R) 2010