Sensory Impairments and Autism: A Re-Examination of Causal Modelling

Abstract

Sensory impairments are widely reported in autism, but remain largely unexplained by existing models. This article examines Kanner's causal reasoning and identifies unsupported assumptions implicit in later empirical work. Our analysis supports a heterogeneous causal model for autistic characteristics. We propose that the development of a standardised framework for analysing autistic characteristics would facilitate the identification of sub-groups and the location of biological markers for genetic variation. We also support a neuroconstructivist model proposing that peripheral sensory abnormalities disrupt compilation of complex skills; impact on synaptogenesis, synaptic pruning and myelination; and subsequently manifest themselves as autistic behaviours. This model explains some of the structural and functional brain abnormalities and many of the perceptual, cognitive and attentional features found in autism.

Associating Neural Alterations and Genotype in Autism and Fragile X Syndrome: Incorporating Perceptual Phenotypes in Causal Modeling

“…In addition, arguments regarding how such alterations may be associated to causal poly-(autism) or monogenetic (FXS) origins will also be presented. We further argue that the perceptual signatures approach may provide a very useful tool for defining the relationship between genotype and atypical neural networks mediating low-level information processing across neurodevelopmental disorders where emphasis is placed on perceptual, rather than cognitive endophenotypes (see Gerrard and Rugg 2009). …”

A challenging, unpredictable world for people with Autism Spectrum Disorder

“…However, hypo-reactivity to sensory stimuli has also been extensively reported in all sensory modes (Ben-Sasson et al, 2009;Reynolds and Lane, 2008). These paradoxical responses to sensory stimuli often observed in the same individual with ASD, lead to a lack of consensus on the exact nature of the underlying sensory dysfunction, but could explain many of the characteristic autistic behaviours, such as stereotyped behaviour and quest for sameness (see Gerrard and Rugg (2009) for a comprehensive review). Sensitivity to any change occurring in the environment is also a fundamental feature of ASD that appears to be a durable treatment-resistant symptom, which prevents the individual from adapting.…”

Electrophysiological evidence of atypical visual change detection in adults with autism

“…Moreover, several behavioral studies and results from questionnaires have revealed unusual sensory responses such as hyper-reactivity or hypo-reactivity in all sensory modalities (Khalfa et al, 2004; Leekam et al, 2007; Reynolds and Lane, 2008; Ashwin et al, 2009; Ben-Sasson et al, 2009), both sometimes occurring in the same subject. Such paradoxical responses to sensory stimuli have led to a lack of consensus on the exact nature of the underlying sensory dysfunction, but have been hypothesized to contribute to stereotyped behaviors and quest for sameness (Gerrard and Rugg, 2009). Moreover, study of relationships between clinical and electrophysiological findings has demonstrated that atypical brain reactivity in response to sensory changes occurring in stimulus sequence is related to the degree of behavioral intolerance of change as assessed by the Behavioral Summarized Evaluation (BSE-R, Barthelemy et al, 1997) (Gomot et al, 2011).…”