Reduced visual evoked potential amplitude in autism spectrum disorder, a variability effect?

Klara Kovarski,Raoul K Khanna,Magali Batty,Marianne Latinus,Sophie Arsène,Joëlle Malvy

doi:10.1038/s41398-019-0672-6

Abstract

Atypical sensory behaviours represent a core symptom of autism spectrum disorder (ASD). Investigating early visual processing is crucial to deepen our understanding of higher-level processes. Visual evoked potentials (VEPs) to pattern-reversal checkerboards were recorded in ASD children and age-matched controls. Peak analysis of the P100 component and two types of single-trial analyses were carried out. P100 amplitude was reduced in the ASD group, consistent with previous reports. The analysis of the proportion of trials with a positive activity in the latency range of the P100, measuring inter-trial (in)consistency, allowed identifying two subgroups of ASD participants: the first group, as control children, showed a high inter-trial consistency, whereas the other group showed an inter-trial inconsistency. Analysis of median absolute deviation of single-trial P100 (st-P100) latencies revealed an increased latency variability in the ASD group. Both single-trial analyses revealed increased variability in a subset of children with ASD. To control for this variability, VEPs were reconstructed by including only positive trials or trials with homogeneous st-P100 latencies. These control analyses abolished group differences, confirming that the reduced P100 amplitude results from increased inter-trial variability in ASD. This increased variability in ASD supports the neural noise theory. The existence of subgroups in ASD suggests that the neural response variability is not a genuine characteristic of the entire autistic spectrum, but rather characterized subgroups of children. Exploring the relationship between sensory responsiveness and inter-trial variability could provide more precise bioclinical profiles in children with ASD, and complete the functional diagnostic crucial for the development of individualized therapeutical projects.

Highlights

Autism spectrum disorder (ASD) is characterized by (i) disturbances in the social and communication domain, and by (ii) repetitive and restricted behaviours
Inter-subject variability, measured as the proportion of participants of each group showing a positive activity around the P100 (Fig. 1c), highlighted that all participants of both groups showed a positive deflection on their averaged evoked-related potentials (ERPs) between 90 and 100 ms, suggesting that the differences observed on the P100 are not driven by the absence of a positive response on the ERPs in some participants
P100 amplitudes and latencies evoked by pattern-reversal checkerboards were measured in children with ASD and in typically developing (TD) peers

Summary

Introduction

Autism spectrum disorder (ASD) is characterized by (i) disturbances in the social and communication domain, and by (ii) repetitive and restricted behaviours Within this second group of symptoms, sensory abnormalities, as acknowledged in the Diagnostic and Statistical Manual-5 (DSM-5) are considered a diagnostic feature of ASD1. Atypical brain responses are supported by structural abnormalities in visual regions[10], as revealed by different size and organization of micro-columns in those with ASD compared with controls[11]. Taken together, these findings have been acknowledged by recent reviews, suggesting that investigating early sensory responses might provide crucial information to understand higherlevel disturbances[12,13]

Methods

Results

Conclusion