Autism Spectrum Disorders (ASD’s) are diagnosed based on deficits in social reciprocity, repetitive or restricted behavioural routines and impaired communication. Although these three subcomponents are used to diagnose ASD’s a number of other features are often found, including sensory abnormalities. Research focussing on somatosensory processing in individuals with ASD has led to the inclusion of “hyper- or hypo- reactivity to sensory input or unusual interests in sensory aspects of the environment” in the recent revision of the DSM (5th edition).
The first of two PhD projects draws on our group’s expertise in the study of C-tactile afferents and their hypothesised role in signalling the rewarding value of affiliative touch. By combining behavioural, physiological and neuroimaging techniques we aim to characterise the subjective responses of children and adults with ASD to CT stimulating touch and compare them to age matched controls. Parental touch is recognised as a key regulator of physiological and behavioural arousal in infants, yet aversion to light touch is a commonly reported feature of ASD. We propose that finding affiliative touch aversive would have significant consequences, during early critical periods, in the subsequent development of neural structures and circuits underpinning emotional and social development. A greater understanding of how CT mediated touch is processed in ASD and how this ultimately relates to parent-infant interaction could aid in the identification of early biomarkers and development of targeted early interventions.
The second project focuses on the pain experience of individuals with ASD. As with CTs, it is a population of c-fibres (c-nociceptors) that convey the emotional properties of pain, and of specific interest to this project is the fact that the ASD population has a greater prevalence of co-morbid conditions associated with pain, or painful procedures, than the general population. In particular, children diagnosed with an ASD are more than twice as likely as their neuro-typically developing peers to have accidents requiring medical treatment and thus may be undergoing as yet not fully recognised distress during such procedures. Quantifying the relationship between stimuli, sensation and perception, through the utilisation of psychophysical tests (Quantitative Sensory Testing) will provide clearer empirical evidence of differences in pain perception in ASD, as well as insight into their sensory, cognitive and emotional basis. Furthermore, the project will investigate pain in clinical settings, in order to characterise behavioural responses to pain in ASD. We will not only measure typical expressions of pain, but scrutinise additional behaviours displayed during and after painful procedures, coding these to identify commonalities, not typically seen in the general population. In developing understanding in this area it will be possible to limit sensory overload; an occurrence which can significantly hinder an individual’s daily life.