Sensory Processing in ASD and ADHD: A Multi-Groups Approach

Background: Though the DSM-5 diagnostic criteria for autism spectrum disorder (ASD) and attention/deficit-hyperactivity disorder (ADHD) show little overlap between the two disorders, studies have shown that children with ASD and ADHD have many overlapping issues, including sensory issues. Sensory processing impairments occur in several modalities including touch, taste, smell, and sound and can impact how a child perceives and responds to everyday events. In turn, these impairments have significant implications for a child’s social communication, academic achievement, and quality of interpersonal relationships. Despite this, few researchers have directly compared sensory processing patterns in ASD and ADHD. Thus, while it is known that children with ASD and ADHD both exhibit atypical sensory processing, the extent to which these patterns operate similarly across groups remains unclear.

Objectives:

• To compare sensory processing across ASD and ADHD using the Short Sensory Profile (SSP);
• To evaluate the validity of the current seven-factor model in describing sensory processing patterns in ASD and ADHD using the SSP;
• To compare factor structures between ASD and ADHD.

Methods: Participants included 571 children and young adults (Age range=1.88-21.89 years, Mean age=10.01±3.98), with ASD (n=361) and ADHD (n=210) without any comorbidities. Parents completed a well-established questionnaire assessing sensory processing (SSP). Subscale scores on the SSP were compared across groups. Confirmatory factor analyses were performed using individual items comprising the SSP on each group separately to determine whether a seven-factor model to describe sensory processing holds the same meaning and measurement properties across ASD and ADHD groups. The seven latent variables were defined based on the original creation of the SSP where each item loaded onto the corresponding sensory system to which it belongs.

Results: Direct comparisons across diagnoses revealed that the ASD group showed greater impairment in tactile, taste/smell, movement, low energy, and visual/auditory (all p-values<.001), but not sensory seeking (p=.634) domains and the ADHD group showed greater impairment in the auditory filtering domain (Figure 1). For both ASD and ADHD models, all items on the SSP loaded onto the originally proposed latent variables well (>.40; Table 1), fit indices indicated acceptable overall fit (Table 1), and correlations among latent variables were low (<.85), indicating that these variables are tapping into distinct constructs in describing sensory processing patterns. Thus, despite significant differences in sensory processing between diagnostic groups, the factor structures still capture the same underlying latent variables for both groups.

Conclusions: Our results demonstrate that although there are differences in the way individuals with ASD and ADHD process sensory information, a single inventory of sensory processing can be reliably used to describe sensory processing patterns in both groups. The SSP measures components of basic sensory processing without referencing social or affective responses to sensory events, providing a good measure of sensory processing without tapping into other diagnostic features. These findings provide a useful next step for those interested in understanding the underlying structure of sensory processing in diagnostic groups who exhibit similar sensory processing patterns as those with ASD and ADHD.