Examining the Impacted of the Severity of Attention Deficit/ Hyperactivity Disorder Symptoms on the Cognitive Flexibility in Children and Adolescents with Autism Spectrum Disorders.

Background: Autism spectrum disorder (ASD) is a lifelong neurodevelopmental disorder. Symptoms of the manifest ASD as impairments in cognitive flexibility, the ability to adaptive switch among multiple representations as a function of changing relevant cues in the environment.

One of the most commonly used of cognitive flexibility is the Wisconsin Card Sorting Test (WCST), but the previous studies on ASD have yielded mixed results, some studies showed impairments in cognitive flexibility in ASD than typical development (TD), but some argued that there are no differences between two groups.

Previous studies have described that children with ASD (30-50%) suffer from comorbid with Attention deficit/ hyperactivity disorder (ADHD) symptoms, and several studies showed children with ADHD had poor performance in WCST. To date, only few studies examine the severity of comorbid ADHD symptoms, whether would influence the performance of cognitive flexibility in ASD.

Objectives: Thus, previous studies argued the inconsistencies might be due to differences in participant characteristics like age, IQ, and co-occurring ADHD symptoms.

The aim of this study was: (1) to investigate whether children and adolescents (7-17 years old) with ASD group shows cognitive flexibility impairments than matched TD group on WCST performance, (2) to investigate the influence of comorbid ADHD symptoms on WCST performance.

Methods: A total of 141 ASD and 94 TD were matched by sex (ASD vs TD, male/ female: 126/15 vs 79/15), age (12.22 ± 2.20 vs 12.49 ± 2.08) and Wechsler full-scale intelligence (FIQ) (106.26 ± 11.91 vs 108.57 ± 10.73).

The computerized version of WCST was selected as cognitive flexibility measures. Symptoms in ASD were assessed by Autism Diagnostic Interview-Revise (ADI-R), and in ADHD were assessed by Swanson, Nolan, and Pelham rating scale version IV (SNAP-IV).

For the analysis, firstly, group comparisons of demographic data were used independent t-tests. Secondly, Cohen's d was calculated to quantify the magnitudes of group effects in the differences of WCST performance. Lastly, the differences of WCST performance were examined through analysis of covariance (ANCOVA), whereby the analyses were controlled for the effects of the age FIQ and comorbid ADHD symptoms covariates.

Results: A statistical comparison of Demographic revealed no significant difference between ASD and TD group (Table 1).

The independent t-tests showed the ASD group performed significantly worse with the TD group on the WCST index (Figure1), including the trials administered (p<.0001), total correct (p<.0001), total errors (p= 0.062), % perseverative response (p= 0.0011), % perseverative errors (p= 0.0026), and the medium effect size was found (Table 2).

The analysis of ANCOVA revealed the significant differences between the groups in the trials administered, total correct, total errors, %perseverative response, %perseverative errors, and no main and interactive effects of age-FIQ and age-FIQ-comorbid ADHD symptoms of WCST performance (Table 2).

Conclusions: In the present study, we have replicated previous results reporting impairment of the ASD group in cognitive flexibility (WCST performance), and confirmed the deficits of cognitive flexibility were associated with ASD diagnosis, rather than the severity of the comorbid of ADHD symptoms.