Developmental Changes in Sensory Profiles in Autism Spectrum Disorder and Williams Syndrome

Background: Autism spectrum disorder (ASD) and Williams syndrome (WS), a rare genetic neurodevelopmental disorder associated with mild to moderate intellectual disability (ID), can be seen as contrasting disorders in the social interaction domain, with clear deficits present in ASD and hypersociability in WS. Yet, the disorders have many similarities, including sensory atypicalities, which play an important role in the manifestations of both conditions.

Objectives: The aim of this study was to compare the sensory patterns and modalities of children and adolescents with ASD, WS and typically developing individuals, and explore differences in sensory symptoms across different age groups. Comparison of sensory patterns and modalities of individuals with ASD (with and without additional ID), to those presented in WS and in typically developing (TD) children, will allow us to explore syndrome-specific characteristics which are crucial to the formulation of theories of sensory processing.

Methods: Parents of 149 children between 3 and 16 years of age of whom 44 were TD, 73 had an ASD diagnosis (37 had additional ID) and 32 had WS, completed the Sensory Profile (SP; Dunn, 1999) to provide information about their children’s sensory experiences.

Results: Two multivariate analysis of variance (MANOVA) were conducted with the four sensory processing patterns and five sensory modalities as repeated measures, with diagnostic group (WS, ASD with ID, ASD no ID, TD) and age (3 categories: under 6,5 years old; between 6,5–9,5 years old; above 9,5 years old) as between-group factors.

There was a significant sensory processing pattern by group effect (F_{(9, 51)} = 2.76, p = 0.01), indicating that there were significant differences between the participants across different diagnostic groups on sensory processing pattern scores. No significant main effect of age or interaction between group and age was found. In addition a main effect of sensory modality by group (F_{(12, 72)}=7.51, p<.001) was found. Finally a significant interaction was found between sensory modality and age (F_{(8, 72)}=2.40, p=.024).

To test for specific differences, a two-way ANOVA was conducted separately for each of the sensory symptoms and Bonferroni post-hoc tests were applied. For all sensory features the TD group had significantly higher (more typical) scores than the WS, ASD with ID and ASD without ID groups. No significant main effect for age was found for either sensory processing patterns or sensory modalities. Two significant group by age category interactions were found – for auditory (F_{(6, 134)}=4.04, p=.001) and visual (F_{(6, 134)}=2.48, p=.026) modalities.

Conclusions: Children with ASD and WS have very similar sensory profiles that are distinct from those present in TD children. Similar levels of sensory atypicalities in WS and ASD across both sensory processing patterns and sensory modalities across age groups suggests that sensory difficulties remain a persistent characteristic of both disorders in childhood and adolescence. Further investigation is needed to examine whether a decrease in severity of sensory symptoms takes place in adulthood.