Visual and Proprioceptive Influences on Tactile Spatial Processing in Adults with Autism Spectrum Disorders

Abstract

Children with autism spectrum disorders (ASDs) often exhibit altered representations of the external world. Consistently, when localizing touch, children with ASDs were less influenced than their peers by changes of the stimulated limb's location in external space [Wada et al., Scientific Reports 2015, 4(1), 5985]. However, given the protracted development of an external‐spatial dominance in tactile processing in typically developing children, this difference might reflect a developmental delay rather than a set suppression of external space in ASDs. Here, adults with ASDs and matched control‐participants completed (a) the tactile temporal order judgment (TOJ) task previously used to test external‐spatial representation of touch in children with ASDs and (b) a tactile‐visual cross‐modal congruency (CC) task which assesses benefits of task‐irrelevant visual stimuli on tactile localization in external space. In both experiments, participants localized tactile stimuli to the fingers of each hand, while holding their hands either crossed or uncrossed. Performance differences between hand postures reflect the influence of external‐spatial codes. In both groups, tactile TOJ‐performance markedly decreased when participants crossed their hands and CC‐effects were especially large if the visual stimulus was presented at the same side of external space as the task‐relevant touch. The absence of group differences was statistically confirmed using Bayesian statistical modeling: adults with ASDs weighted external‐spatial codes comparable to typically developed adults during tactile and visual‐tactile spatio‐temporal tasks. Thus, atypicalities in the spatial coding of touch for children with ASDs appear to reflect a developmental delay rather than a stable characteristic of ASD. Autism Res 2019, 12: 1745–1757. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary A touched limb's location can be described twofold, with respect to the body (right hand) or the external world (right side). Children and adolescents with autism spectrum disorder (ASD) reportedly rely less than their peers on the external world. Here, adults with and without ASDs completed two tactile localization tasks. Both groups relied to the same degree on external world locations. This opens the possibility that the tendency to relate touch to the external world is typical in individuals with ASDs but emerges with a delay.

Beyond Prior and Volatility: The Distinct Iterative Updating Account of ASD

“…This may well explain the mixed reports of predictive coding in autism. Individuals with ASD can acquire appropriate priors from one-shot learning [29], prior trials [30], or statistically global settings [31,32,34,36]. That the priors are typically intact is also evidenced by the present finding that the ASD group of participants did not differ in their local prior updating from the TD group.…”

“…Our finding that individuals with ASD show intact short-term updating but slow updating of the longer-term prior may well be consistent with the mixed reports of predictive coding in autism. Individuals with ASD can acquire appropriate priors from one-shot learning [32], prior trials [33], or statistically global settings [34,35,41]. In those studies, however, the volatility of the environment and the prior were often fixed throughout the test.…”

“…It should be noted, though, that not all types of prior, or learning of priors, are compromised in ASD. In fact, priors based on experience or top-down knowledge are often preserved in ASD, such as in one-shot learning (e.g., perception of a Dalmatian dog hidden in an image composed of black patches) [32], the influence of gaze cues from previous trials [33,34], and reliance on external-world coordinates in tactile spatial processing [35]. Those mixed findings of usage of priors led Palmer et al [17] argue that the simple Baysian model has a crucial limitation in assuming an unchanging world; instead, they speculated that the atypicalities in ASD may lie in the differential expectation about the uncertainty of changes in hidden states in a hierarchical inference.…”

The development of body representations: an associative learning account

“…For example, a recent longitudinal study that investigated midline crossing behaviours showed that at 10 months of age (but not at five and 14 months), infants at risk of ASD or ADHD produced fewer manual actions that involved their hand crossing the body midline into the contralateral side of space compared to low-risk infants [86]. This reduced level of midline crossing may play a role in the recently demonstrated delay in the ability to represent touch across body postures in children with ASD [87,88]. Individuals with ASD also demonstrate hypoand/or hypersensitivity to individual sensory channels [89] and show disrupted multisensory integration processes [90].…”

Cutaneous tactile sensation and standing balance in children with autism: A Preliminary Report

“…These children may show little or no response to sensory stimulation (Randell et al, 2019) or show heightened response to touch (Espenhahn et al, 2021). In addition, they have an impaired ability to localize or discriminate tactile stimulation problems (He et al, 2021;Hense et al, 2019), especially when in presence of another sensory stimulation such as visual distractors (Poole, 2018). Despite significant deficits in processing tactile information, there is a considerable lack of research understanding the contribution of impaired tactile sensation especially in the foot to balance deficits in ASD.…”