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

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.

Looking for Consistency in an Uncertain World: Test-Retest Reliability of Neurophysiological and Behavioral Readouts in Autism

“…Atypicalities in sensory-evoked neural responses and behavioral performance have been widely reported in ASD, including altered responses to visual (2,49,58), auditory (59), and somatosensory stimuli (60)(61)(62). Moreover, in some studies, higher inter-participant (48-50) and within-participant inter-trial (51-53) variability of brain responses to sensory stimuli has been shown.…”

“…This is in line with higher inter-trial behavioral variability that was observed for individuals with ASD, measuring reaction times to executive function (63) and tactile judgment tasks (64), as well as rhythmic tapping tasks (65). The higher variability between trials and between individuals with ASD has, in turn, been interpreted in the context of neuronal processing being "noisy" or "unreliable" (e.g., (49,50,52,(66)(67)(68), but see (69,70) for reports of lower noise in ASD, and (25,26) for evidence of typical levels of noise in ASD). According to this view, high levels of endogenous neural noise in ASD render neural signals unreliable (53,71).…”

Visual Noise Effect on Contour Integration and Gaze Allocation in Autism Spectrum Disorder

“… Weinger et al (2014) reported lower signal-to-noise ratios and deficits in low-contrast responses at the stimulus frequency of 12.5 Hz in the ASD group compared to the TD group. Increased inter-trial variability in ASD that resulted in reduced P100 amplitude was recently described by Kovarski et al (2019) .…”

ReSync: Correcting the trial-to-trial asynchrony of event-related brain potentials to improve neural response representation

“…There are three major descriptive points from Fig 6 that are worth to be stressed: 1) The latency estimation appears to be reliable as shown in the sorted trials (Fig 6a b); 2) The correction of jitter in the specified time window (400 ms to 800 ms) still preserve the jitter features in other time windows (e.g., early ones, see Fig 6c); 3) The correction in the average waveform is also exclusively taking effect in relevant window (Fig 6d). Likewise, the latency jitter issue can occur in the early time window as well, and its functional relevance has been studied (Kovarski et al, 2019;Magnuson, Iarocci, Doesburg, & Moreno, 2019;Milne, 2011). To serve as a demonstration, we can specify the time window 200-400 ms encompassing the early component in the sample data.…”