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Reconciling the Co-Occurrence of Impulsivity and Insistence on Sameness in ASD
Objectives: The aim of this study was to investigate impulse control towards interests in ASD. We expected children with ASD would show a greater sensitivity, reflected by increased impulsivity, towards stimuli depicting their interests versus their non-interests.
Methods: 100 children aged 6-12 yrs who were either typically developing (TD) or had ASD performed a novel go/nogo task to cues of their interest versus cues of non-interest on an iPad. Children chose their favorite (interest) and least favorite hobby/activity (non-interest) from 23 options. One category of cues served as the go-stimulus (e.g. interests) to which participants were instructed to touch the image on the iPad-screen as fast as possible and the other category of cues served as the nogo-stimulus (e.g. non-interests) for which participants withheld their response. Go and nogo stimuli were counterbalanced across two runs. False-alarm rate was calculated as the number of erroneous button presses to the nogo cue in each run. D-prime (d’) was calculated as the normalized hit rate (go-accuracy) – normalized false alarm rate. Using Linear Mixed-Effects models differences in hit rate, false alarms and d’ were tested with task condition, diagnostic status and age as fixed factors, and within subject variability as a random factor. Caregivers also completed the Repetitive Behavior Scale - Revised (RBS-R) to provide a measure of the severity of repetitive behaviors and the Strengths and Weaknesses of ADHD symptoms and Normal behavior (SWAN) to measure the children’s inattention and hyperactivity/impulsivity.
Results: Children with ASD were more impulsive towards their interests as shown by an interaction effect between task condition and diagnostic status on d’ (F(1,73) = 5.4, p = .024). This interaction was driven by a lower d’ to interests as compared to non-interests in children with ASD (ß = -0.29, s.e. = 0.11, p = .012, 95% CI = -.52 - -.07), in combination with lower d’ to interests in children with ASD compared to TD children (ß = -0.39, s.e. = 0.18, p = .029, 95% CI = -.74 - -.04)(Figure 1). Interestingly, impulsivity towards interests (d’) was specifically associated with higher caregiver reports of insistence on sameness behaviors on the RBS-R in children with ASD (r = -.39 , p = .016; Figure 2). Furthermore, across TD children and children with ASD, symptoms of ADHD measured by the SWAN specifically correlated with d’ to interests (r = -.46 , p < .001). There were no correlations with d’ to non-interests.
Conclusions: These findings suggest some children with ASD may present with both insistence on sameness behaviors and difficulties with impulsivity, two behaviors that could be perceived as mutually exclusive. As interests negatively influenced self-control in children with ASD, using a child’s personalized interest as a reinforcer during clinical intervention may be challenging.