Executive Functioning in High-Functioning Autism Spectrum Disorders Assessed by Neuropsychological Tests and Parent's Reports: Its Relationships with Adaptive Functioning

Background: Some previous studies in high-functioning austim spectrum disorders (HF-ASD) have showed impairments in executive functions, as in planning, inhibitory control, flexibility and working memory (Ozonoff, et al. 2004; Robinson, et al., 2009). However, no conclusive results have been obtained (Hill et al., 2004) and the study of executive dysfunction in these children has been amply critized for its excessive reliance in laboratory measures (Gilotty, et al., 2002). Others measures have been used for evaluating executive functioning, as parent’s rated questionnaires which assess the child's daily functioning. By using these questionnaires, it have been founded great impairments in executive functioning, especially in flexibility (Gioia, et al., 2002) and it have been reported that the areas most associated with adaptive functioning were initiative and working memory (Gilotty, et al., 2002; Janusz, et al., 2002). Preliminary results of a large cognitive study in HF-ASD children are presented.

Objectives: The aims of the present study is to analyze the executive functioning of children with HF-ASD with both, neuropsychological tests and parent’s rated questionnaires, and to determine which areas of the executive functioning are related with the adaptive functioning.

Methods:  11 male children with HF-ASD and 10 healthy comparison children were assessed. Both groups did not differ in age, which ranged between 7 and 12 years (ASD mean= 10.08, SD= 1.95; HC mean= 9.86, SD= 1.68). All patients fulfilled ASD criteria on DSM-IV and ICD-10 and ASD diagnosis were confirmed with the Autism Disorder Interview (ADI-R). Inclusion criteria included an IQ above 70 in all participants. All subjects were evaluated with a neuropsychological battery administered by a blind psychologist. Two parent reports were also administered, the Behaviour Rating Inventory of Executive Function (BRIEF), which evaluates the child's executive functioning in daily life, and the Vineland Adaptative Behavior Scale (VABS), which evaluates the child’s adaptive functioning in all areas of daily life.

Results: Children with HF-ASD made significantly more errors than comparison children in flexibility when assessed with neuropsychological tests (p= 0.04) but it was not significantly associated with adaptive functioning. Parents’ questionnaires results showed that HF-ASD children have important difficulties in all areas of executive functioning (BRIEF) (t > 2.59, p < 0.019) and in several areas of adaptive functioning (VABS)  (t > -2.15, p < 0.046). When we correlated the results of both questionnaires administered to parents with each other, impairments in BRIEF inhibitory control emerged as the executive function most associated with VABS social (r= -0.845, p= ≤0.01) and communication difficulties (r= -0.676, p= ≤0.05). Working memory was associated with impairment in academic tasks (r= -0.709, p= ≤0.05). 

Conclusions: In this sample, HF-ASD children showed generalized deficits in everyday life executive functioning when parents inform and in flexibility when assessed with neuropsychological tests. The association between deficits in parents’ reported inhibitory control and working memory with adaptive difficulties, showed the importance of intervention in the executive deficits in these children and that parental information is clinically useful for assessing everyday life, executive and adaptive deficits in HF-ASD.