The Functional Profile of Children with Autism Spectrum Disorders: A Study with the Vineland Adaptive Behavior Scale (VABS) At Different Intellectual Levels Versus Non Autism Population

Background: Autism spectrum disorders (ASD) are severe, life-long neurodevelopmental disorders that compromise functioning across multiple domains, including cognitive functioning and adaptative behavior. The relevance of Intellectual Quotient (IQ) to the symptomatic expression of autism and consequent involvement in the subject’s personal and social autonomy remains unclear. Therefore, the assessment of adaptive skills is an important factor to diagnostic evaluations, treatment planning and progress monitoring.

Objectives: Our aim is to study the influence of the primary diagnosis of ASD versus other neurodevelopmental disorders (OND) on daily living skills (DLS) besides IQ.

Methods: The sample consisted of 147 school-aged children with ASD (N=73) or OND (N=74). All ASD patients had ADI-R and ADOS positive results. The subjects in the OND group did not met the clinical criteria for ASD. These two clinical groups were further subdivided, taking into account the classification of intellectual disability (ID) of the CID-9 (ID is present when the IQ<70), and matched by Full-Scale IQ score. In these four clinical subgroups (ASD with no ID–ASD_NID; ASD with ID–ASD_ID; OND with no ID–OND_NID; OND with ID–OND_ID) we compared the functional profile by ID (ASD_NID[N=49] vs OND_NID[N=48]; ASD_ID[N=24] vs OND_ID[N=26]), namely in the communication, DLS, socialization and the adaptative behavior composite-ABC-(assessed with the VABS; mean±SD:100±15) to clarify the impact of primary diagnosis in the everyday adaptative skills besides IQ. Statistic analysis (SPSS17) was performed comparing the standard scores of VABS within the two clinical groups and between the four subgroups with Mann-Whitney U test. Significance level(σ)=0.05.

Results: ASD(N=73) and OND(N=74) groups showed similar results in the communication domain of the VABS (p=.860), but statistically significant differences in the other domains: DLS , socialization and the ABC (p<.05). When we analyzed the four clinical subgroups paired by ID we found a differential profile of standard scores of VABS in DLS (ASD_NID/OND_NID:p=.028; ASD_ID/OND_ID:p<.001) and socialization (ASD_NID/OND_NID:p=.001; ASD_ID/OND_ID:p=.031) domains. In these two domains, the OND group had higher standard scores (DLS-mean±SD:ASD_NID-75±11; OND_NID-81±11; ASD_ID-58±11; OND_ID-73±15 and socialization-mean±SD:ASD_NID-78±12; OND_NID-86±10; ASD_ID-66±8; OND_ID-73±12). In the communication domain the only statistical difference was found in the subgroup ASD_ID/OND_ID:(p=.037). The same happened in the ABC (ASD_NID/OND_NID:p=.084; ASD_ID/OND_ID:p=.002).

Conclusions: These findings demonstrate that the ASD groups differ negatively from OND groups in the competence of DLS and socialization, despite de same IQ and education opportunity. Given the fact that the social interaction difficulties are one of the core symptoms of ASD, this was an expected result. The true novelty of this study is the fact that the level of autonomy is considerably lower in ASD groups, even when we focus on the group NID. Taken together, these results show that IQ in neurodevelopmental disorders is not the determinant factor for developing adaptative DLS. It is possible to presume that the specific cognitive social deficits in autism in the application of knowledge are a factor that limits adaptative competence for DLS. These results have significant clinical implications, enhancing the importance of early intervention targeting personal and social autonomy. These preliminary findings should be replicated in a larger sample.