Relationships Between Stereotyped Movements and Sensory Processing Disorders In Children with HFASD Versus Children with ASD and Intellectual Disability

Background:  Stereotyped movements (SM) are a defining characteristic of autism spectrum disorders (ASD), but are also present in children with a range of sensory and developmental disorders. SM may be an adaptive response in children whose sensory processing disorders (SPD) cause them to experience environments as over or under-stimulating.

Objectives:  The main aim of this study was to examine relationships between SPD and SM in children with and without developmental or sensory disorders to discover whether SPD accounted for differences in the prevalence and severity of SM. A second aim was to assess whether intellectual disability makes an independent contribution to SM, and if so, whether it also interacts with SPD to exacerbate SM in children with ASD.  

Methods:  

Instrumentation The Short Sensory Profile (SSP) (McIntosh et al., 1999) is a caregiver Likert-style rating scale that reports behavioral sensory processing difficulties in children aged 3 to 10 years. In the context of persons with disabilities, the profile is used with persons up to age 21 years. The SSP was designed for screening and research use and includes 38 items.

The Stereotyped and Self-Injurious Movement Interview (SSIMI), a 32-item clinician-administered questionnaire designed to assess stereotyped body movements, manipulation of objects, and self-injurious behavior (Gal et al., 2002, 2009).

Participants SSP and Stereotyped and Self-Injurious Movements Interview were administered to 221 children (129 boys, 92 girls) aged 6 to 13 years (mean= 9.40, SD=1.81) children with HFASD (n=28), Low functioning ASD (n=28), intellectual disability (no ASD) (n=29), visual impairment (n=50), hearing impairment (n=51), and typical children (n=30).

Data analysis Pearson correlations were calculated to assess the strength of any linear relationship between SSP scores and SM within and across samples. A series of stepwise multiple regression analyses was conducted to discover which linear combination of SSP section scores best predicted SM within and across samples. An analysis of covariance was conducted with disorder type and intellectual disability as the main factors and Short Sensory Profile summary scores as the covariate, to define whether group differences in sensory processing anomalies account for differences in SM.

Results:  The results indicate significant and sometimes strong relationships between the SSP summary score and SM in each sample. The results suggest that children who have both intellectual handicaps and ASD show much more SM than children with HFASD, children with intellectual handicaps who do not have ASD, or children who have sensory loss with or without intellectual handicaps. When group differences related to sensory profile are taken into account (SSP scores serve as a covariate), those who have HFASD show the relatively highest amount of SM.

Conclusions:  Sensory processing disorder may be a source of SM. For children with HFASD the relationship between sensory profile and stereotyped movements are of specific importance. Clinicians should use the individuals’ stereotyped movements as indicators for their sensory systems and accordingly define the focus of intervention.