Introduction
A clinical diagnosis of Pervasive Developmental Disorder (PDD; DSM-IV-TR, American Psychiatric Association
2000) or Autism Spectrum Disorder (ASD) requires a detailed developmental interview with the parents, and a direct examination of the child. Additionally, for screening and/or research purposes, specific parent-based questionnaires may be used to get a description of the number and type of currently present ASD problems (Constantino and Todd
2005). One such parent questionnaire is the Children’s Social Behavior Questionnaire (CSBQ; Hartman et al.
2006,
2008; Luteijn et al.
2000a,
2002).
The CSBQ has specifically been developed for assessing social behavior problems within the whole autism spectrum. Development of the CSBQ was based on the idea that existing instruments did not suffice for children with PDD-not otherwise specified (NOS), because items were directly extracted from the DSM-criteria for autistic disorder (AD). With that, the more subtle social problems of children with PDD-NOS are not represented in these instruments. The CSBQ aims to be sufficiently sensitive with respect to the milder end of the autism spectrum, based on the dimensional view of ASDs. This perspective has led to a pool of items representing both core symptoms of AD and more subtle symptoms associated with ASDs, thus trying to capture the behavioral variety from normality to a full diagnosis of AD. The psychometric qualities of the CSBQ were reported to be good (Hartman et al.
2006; Luteijn et al.
2000a) and the CSBQ has been shown to be valuable in measuring (subtreshold) autistic symptomatology in children with normal intelligence and with mental retardation (MR) or intellectual disability (ID; Hartman et al.
2006; de Bildt et al.
2005a; Luteijn et al.
2000a,
b).
A revision of the original CSBQ resulted in more refined subscales with good psychometric properties (Hartman et al.
2006,
2008).The CSBQ has now 49 items, composing 6 subscales all with good internal consistency (α = .76–.94), inter-rater reliability (ICC = .75–.89), and test-retest reliability (
r = .80–.90). Convergent, divergent, and criterion-related validity were also reported as good. So far, however, criterion related validity has only been investigated in relation to clinical A(S)D classifications, and not to standardized instruments for A(S)D such as the Autism Diagnostic Interview-Revised (ADI-R; Rutter et al.
2003) and Autism Diagnostic Observation Schedule (ADOS; Lord et al.
1999).
The current paper aims to further investigate the criterion-related validity of the CSBQ in children with mild and moderate ID. ID occurs very frequently in children with autism (estimates between 70 and 90%; DeMyer et al.
1974; Steffenburg and Gillberg
1986; Fombonne
2005), but also when the whole spectrum is taken into account, still one in every four children is reported to have ID (26% reported by Chakrabarti and Fombonne
2001). Not only does the group with such dual diagnosis differ from children with ASD with normal intelligence in behavior (e.g., more self-injurious behavior, stereotyped behavior, deviant social responses, delayed social development, fears, etc.; de Bildt et al.
2005b), yet also in outcome, and amount, duration and specificity of needed care (Kraijer
1997). The presentation of ASDs in children with ID, however, is not merely characterized by more severe social, communicative, or flexibility problems indicative of the presence of AD. Rather, the whole spectrum of ASDs is present amongst children with ID, and the differentiation between AD and PDD-NOS is even more complicated than in children with normal intelligence (Kraijer
1997). The validation of the CSBQ in specifically this population aims to add to identifying ASD in children with ID and to describing ASD related problem behavior currently present.
The study is conducted by comparing the CSBQ to the ADI-R and ADOS classifications, the current standards for instrumental classification of A(S)D, and to the clinical DSM-IV-TR-based ASD classifications.
Results
As presented in Table
2, correlations of the various subscales of the CSBQ were higher with the ADI-R than with the ADOS, and higher when related to current behavior on the ADI-R than to behavior at age 4 through 5.
Table 2
Pearson r correlations between CSBQ subscale and total scores and ADI-R and ADOS domain and total scores
ADOS |
Communication | .02 | .39** | .13 | −.07 | .41** | .07 | .21* |
Social | −.04 | .38** | .10 | −.09 | .33** | .03 | .15 |
Imagination | .02 | .31** | .15 | −.12 | .21* | −.04 | .13 |
Repetitive restricted | −.09 | .13 | .13 | −.08 | .27** | −.03 | .06 |
Total | −.02 | .42** | .12 | −.09 | .38** | .05 | .19* |
ADI-R age 4–5 |
Communication | .08 | .29** | .12 | .30** | .21* | .28** | .27** |
Social | .07 | .48** | .22** | .28** | .29** | .23** | .35** |
Repetitive restricted | .20* | .36** | .23** | .34** | .48** | .35** | .42** |
Total behavioral domains | .11 | .43** | .21* | .33** | .33** | .30** | .37** |
ADI-R current |
Communication | .26** | .46** | .26** | .31** | .38** | .43** | .45** |
Social | .17* | .60** | .30** | .20* | .35** | .33** | .43** |
Repetitive restricted | .27** | .39** | .30** | .42** | .52** | .41** | .50** |
Total behavioral domains | .26** | .59** | .33** | .32** | .45** | .43** | .52** |
The subscales ‘contact’ and ‘stereotyped’ were most clearly correlated to the ADOS domains and totals. With respect to the ADI-R age 4–5 almost all subscales (except ‘not tuned’) and the total CSBQ score showed significant correlations. With current behavior, the subscale ‘not tuned’ was also significantly correlated to the ADI-R, like all other subscales and the CSBQ total score. The correlations between CSBQ and ADI-R were all higher for ADI-R current behavior, except for the subscale ‘understanding’ in relation to the social domain as well as the total of the three behavioral domains of the ADI-R.
To investigate how the scores on the CSBQ are related to a classification of A(S)D on the ADI-R, ADOS, or clinical DSM-IV-TR classification, logistic regressions were applied (Table
3) for all CSBQ subscales and the total score, controlled for age and sex.
Table 3
Contribution of the CSBQ to an AD/ASD-classification on the ADI-R and ADOS and to a clinical DSM-IV-TR ASD classification, controlled for age and sex
CSBQ |
Not tuned | 1.00 (.94–1.16) | 1.05 (.98–1.19) | 1.01 (.96–1.07) |
Contact |
1.18*** (1.08–1.29) |
1.30*** (1.17–1.44) |
1.21*** (1.11–1.32) |
Orientation | 1.04 (.95–1.13) | 1.09 (1.00–1.19) |
1.15** (1.05–1.27) |
Understanding | .98 (.89–1.06) |
1.10* (1.01–1.20) |
1.16** (1.06–1.27) |
Stereotyped |
1.23** (1.08–1.40) |
1.30*** (1.14–1.48) |
1.25*** (1.10–1.42) |
Changes | 1.14 (.94–1.39) |
1.55*** (1.24–1.92) |
1.41** (1.15–1.73) |
Total | 1.02 (1.00–1.04) |
1.05*** (1.02–1.07) |
1.04*** (1.02–1.07) |
The odds ratios express the increase or decrease in the probability of a classification of AD on the ADI-R or ASD (including AD and non-autism ASD) on the ADOS or clinical DSM-IV-TR classification, with increasing scores on the CSBQ subscales or total. For example, with an increase of one point on the total score of the CSBQ, the probability that a child was classified as AD by the ADI-R was elevated with 5% (or was 1.05 times higher).
For the ADOS, only the CSBQ subscales ‘contact’ and ‘stereotyped’ elevated the probability of an ASD-classification, with 18 and 23% respectively for each additional point on the subscale score. For the ADI-R, almost all subscales, except ‘not tuned’ and ‘orientation’ increased the probability of an AD classification with 10–55% (see Table
3). Even more subscales added to the clinical DSM-IV-TR classification of ASD, by 15–41% per point. Only the subscale ‘not tuned’ did not contribute. The CSBQ total score had approximately the same contribution to the clinical DSM-IV-TR classification as to the ADI-R, i.e., 4% per additional point, which is substantially lower than individual subscales. The results in the total group did not differ from the results in the separate levels of ID (data not shown). Additionally, the results did not change when correction for age and sex was eliminated (data not shown).
Discussion
The current paper aimed to investigate the criterion-related validity of the CSBQ in children with mild and moderate ID, by investigating how the CSBQ is related to the ADI-R and ADOS and how the CSBQ contributes to a clinical DSM-IV-TR ASD classification (including AD and non-autism ASD).
The results of our study indicate a satisfactory relationship between the CSBQ and the ADI-R. Specifically, four CSBQ subscales, i.e., ‘contact’, ‘stereotyped’, ‘changes’, and ‘understanding’ are most related and contribute significantly to both ADI-R and clinician-based classifications. A number of important differences between the CSBQ and the ADI-R make a more perfect coherence between both instruments less likely. That is, in contrast to the ADI-R, the CSBQ explicitly tries to capture the behavioral variety from normality to a full diagnosis of AD. Additionally, the CSBQ is a parent questionnaire rather than a clinician based interview, it is dimensional instead of categorical and it reports on the last 2 months without developmental focus. The two CSBQ subscales ‘contact’ and ‘stereotyped’ also compared well with the ADOS. Although the subscales ‘not tuned’ and ‘orientation’ seem less specific for ASD, the latter is important when compared to the clinical DSM-IV-TR classification.
The finding that the CSBQ subscales ‘contact’ and ‘stereotyped’ are the most contributing subscales of the CSBQ with respect to autistic behavior in mild and moderate ID is in line with a former study with regard to the CSBQ in mild and moderate ID that showed a relation between these subscales and autistic symptomatology as measured with the Autism Behavior Checklist (ABC, Krug et al.
1980; de Bildt et al.
2005a,
b). These subscales measure the most salient autistic like behavior.
The items of the subscale ‘changes’ measure behavior when confronted with changes, expressed as fear, panicking, resistance, and freezing. Although not included in DSM-IV-TR diagnostic criteria or the ADI-R algorithm, these behaviors are nonetheless more related to the ADI-R and clinical DSM-IV-TR classification than to the ADOS. This is probably due to the fact that these behaviors are less likely to occur at full in a one-to-one test situation like the ADOS, than can be described by parents over time in the ADI-R or CSBQ. From our previous study with the CSBQ in mild and moderate ID it is known that the subscale ‘changes’ is also related to level of ID, with higher scores for children with mild ID as opposed to moderate ID (de Bildt et al.
2005a,
b).
Children with high scores on the subscale ‘understanding’ have difficulties in understanding the rules of communication and the social use of language. Like with the subscale ‘changes’, these pragmatic language problems are not specifically captured by the ADI-R algorithm nor are they part of the DSM-IV-TR diagnostic criteria, yet they are clearly associated with the clinical DSM-IV-TR classification and the ADI-R. When comparing the communication domain items of the ADOS to this CSBQ subscale, they are found to have a slightly different focus. Again, the setting of the ADOS is very different from the CSBQ, more so than that of the ADI-R.
The remaining subscales of the CSBQ (‘orientation’ and ‘not tuned’) seem to measure behavior beyond the scope of the ADI-R and ADOS. From the comparison between clinical groups (Hartman et al.
2006,
2008) it is already known that these subscales are rather unspecific for ASD. Behaviors from these subscales also occur in children with ADHD and oppositional defiant disorder (ODD). The finding that these subscales do not relate to the ADI-R or ADOS is therefore not surprising. However, the subscale ‘orientation’ contributes to the clinical DSM-IV-TR classification of ASD in the current study, indicating that more subtle behaviors like little overview of activities with respect to time and place have importance for the clinician in classifying ASD. Additionally, this subscale has also shown to be related to level of functioning, with higher scores for children with moderate ID (de Bildt et al.
2005a,
b). The subscale ‘not tuned’ does not contribute to any of the classifications of A(S)D as measured in this study, even though the lack of attuning to a social situation may be viewed as an important component of ASD. However, as mentioned, this subscale is not specific for ASD (Hartman et al.
2006) and therefore may not have a great importance in classifying the disorder. Nevertheless, descriptively, this subscale may be valuable, since the behaviors tapped provide additional information on the nature and severity of problems associated with ASD.
Full interpretation of the current findings is limited by the sample of participants. First of all, the results would have been more clear-cut had the study been conducted in children with normal intelligence, the group for whom the CSBQ originally was developed. Such a study is currently being carried out, however, data are not complete yet. Nevertheless, the currently presented results are important on their own, since the CSBQ is also used for children with ID. Additionally it would have been helpful when more children and adolescents without ASD could have been included, especially with classified other types of behavior problems, e.g., ADHD. Since scores on the CSBQ ‘not tuned’ and ‘orientation’ subscales are reported to be higher in children with PDD-NOS and comorbid ADHD (Hartman et al.
2006), it would have been interesting to further investigate this.
To conclude, the interrelationship between the CSBQ and the ADI-R is stronger than between the CSBQ and the ADOS, even though the ADI-R has a more narrow focus of AD, and takes into consideration a longer time period (developmental history). The ADOS would appear more closely linked to the CSBQ as it includes non-autism ASD, yet its scoring is based on a relatively short time period (i.e., the duration of the assessment only) and a different setting. The source of information seems of great importance in explaining our findings: the CSBQ and ADI-R are based on parent information, the ADOS on the judgment of an external observer. In sum, the contribution of the CSBQ to a classification of ASD in children and adolescents with mild and moderate ID is most specific for the subscales ‘contact’ and ‘stereotyped’ that are correlated to and contribute to the classifications on all three measures. Additionally, the subscales ‘understanding’ and ‘changes’ and the CSBQ total score are valid for predicting an ADI-R or DSM-IV-TR classification in this population. Finally, the subscale ‘orientation’ contributes to a clinical DSM-IV-TR ASD classification only.
The CSBQ can be considered as a helpful tool to describe ASD-related problems of children with mild and moderate ID. The CSBQ subscales add to the clinical DSM-IV-TR classification, and can therefore be valuable in an orienting stage of a diagnostic procedure. Using the score profile of the six subscales, the CSBQ may contribute to identifying whether or not the problem behavior as experienced is suggestive of ASD and whether further diagnostic assessments should be focused on ASD. Additionally, it may be of value in the diagnostic process, clearly not in diagnosing ASD which should be based on a more extensive diagnostic procedure preferably including ADOS and ADI-R, but in complementing other methods by adding unique additional information about the clinical presentation of a child. Even in this group, where differentiating ASD is more complicated, the current study shows that the CSBQ may be used as a signaling, screening, or describing instrument for those with ASD.