Impacts of Motor and Sensory Impairment on Language in Young Children with Autism

Children with autism spectrum disorder (ASD) present with varying degrees of deficit in the broader areas of social communication and stereotyped behaviors, but emerging research proposes delayed motor skill and atypical sensory processing as additional factors worth closer examination. In the current study, I sought to investigate the impacts of visual motor skills and sensory differences on language ability in young children with autism. I hypothesized that young children with autism, atypical sensory processing (Short Sensory Profile, 2 Edition), and impaired visual motor integration (Beery VMI, 6 Edition) would have the most impacted language ability scores (Differential Ability Scales, 2 Edition). A total of 22 children, eight with autism (25% female; M age = 66 months or 5.5 years) and 14 with typical development (50% female; M age = 73 months or 6 years) between the ages of 3:0 and 9:6 and their parents completed measures for this study. Findings were significant for the relations of status (i.e., TD vs. ASD) on language ability [t(20) = 2.66, p = . 015], status on visual motor integration [t(20) = 2.27, p = . 035], and for status on sensory processing [t(20) = -5.35, p < . 001]. Results of the three-way interaction indicated that 72% of the variance in language ability was accounted for by the key variables in this model, but this hypothesis was not supported: p = . 09, B = . 15, CI95 = . 031 to . 33. Related hypotheses of visual motor integration on status and language, sensory processing on status and language, and between visual motor integration and sensory were also not supported. Ancillary analyses of individual moderation indicated significant status group (TD vs. ASD) differences for children with visual motor integration full form standard scores of 119 and below (p < .05) and for children with total sensory scores of 25 to 36 (p < .05). These post MOTOR AND SENSORY IN ASD 6 hoc findings are consistent with previous literature and demonstrate promise for replication in future research with a larger and more heterogeneous sample. Further research on these constructs is encouraged as it could inform meaningful pathways for early intervention. MOTOR AND SENSORY IN ASD 7 CHAPTER I: Introduction and Literature Review Autism spectrum disorder (ASD) is an early onset, pervasive neurodevelopmental disorder distinguished by core impairment in the broader domain of social communication, along with varying degrees of co-occurring restrictive and repetitive behaviors and stereotyped interests (American Psychological Association, 2013). Deficits in these areas yield highly varied, but meaningful adverse outcomes across the lifespan (Bellini, 2006; Humphrey & Symes, 2011). The latest revision of The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition was released in 2013 (DSM-5; American Psychological Association, 2013), with diagnostic criteria now including sensory abnormalities (Ben-Sasson et al., 2009) and disruptions in motor functioning (i.e., atypical and delayed motor skill development; Shoener et al., 2008). There is a growing body of literature which proposes that the presence of long-recognized stereotyped behaviors in ASD (i.e., the adoption of atypical sensory or motor behaviors) may in part be a product of impaired processing of sensory input. Specifically, stereotypic behaviors may ultimately be an individual’s attempt to make sense of and regulate a behavioral response elicited by sensory information (Baker et al., 2008). Moreover, retrospective studies like those performed by Heathcock and colleagues stress the importance of monitoring early motor development for individuals at increased risk for autism (Heathcock et al., 2015), as it could provide a critical pathway for intervention. Despite the wealth of existing literature on language, motor, and sensory impairments in ASD, these constructs have been exclusively explored as separate contributing constructs and in samples of children either very young (i.e., before 36 months) or in older elementary school years (i.e., ages 7 and older). For example, the one discovered study to explore these constructs together sought to investigate the impact of vestibular sensory responsivity and motor integration MOTOR AND SENSORY IN ASD 8 on social communication challenges in children ages 7 to 16 years with autism (Hannant et al., 2016). Research of these early and later lifespan timepoints provide meaningful information— the former examines disruptions at birth through early infancy during Piaget’s sensorimotor stage of cognitive development and the latter addresses outcomes on social and academic performance and beyond during the concrete and formal operations stages (Piaget, 1976). However, the time frame between ages 3 to 7, commonly referred to as the preoperational stage (Piaget, 1976), is critical to connecting these early delays with their later operational outcomes. Thus, there remains a distinct gap in the literature regarding the combined effects of these constructs and specifically as examined within this underrepresented age range, both of which the current study sought to address (see Figure 1). Figure 1. The proposed moderated multiple regression model of the effects of developmental status on language ability through visual motor integration and sensory processing. Autism Spectrum Disorder