Visual search in neurodevelopmental disorders: evidence towards a continuum of impairment

Abstract

Disorders with neurodevelopmental aetiology such as Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD) and Schizophrenia share commonalities at many levels of investigation despite phenotypic differences. Evidence of genetic overlap has led to the concept of a continuum of neurodevelopmental impairment along which these disorders can be positioned in aetiological, pathophysiological and developmental features. This concept requires their simultaneous comparison at different levels, which has not been accomplished so far. Given that cognitive impairments are core to the pathophysiology of these disorders, we provide for the first time differentiated head-to-head comparisons in a complex cognitive function, visual search, decomposing the task with eye movement-based process analyses. N = 103 late-adolescents with schizophrenia, ADHD, ASD and healthy controls took a serial visual search task, while their eye movements were recorded. Patients with schizophrenia presented the greatest level of impairment across different phases of search, followed by patients with ADHD, who shared with patients with schizophrenia elevated intra-subject variability in the pre-search stage. ASD was the least impaired group, but similar to schizophrenia in post-search processes and to schizophrenia and ADHD in pre-search processes and fixation duration while scanning the items. Importantly, the profiles of deviancy from controls were highly correlated between all three clinical groups, in line with the continuum idea. Findings suggest the existence of one common neurodevelopmental continuum of performance for the three disorders, while quantitative differences appear in the level of impairment. Given the relevance of cognitive impairments in these three disorders, we argue in favour of overlapping pathophysiological mechanisms.

Attention for Emotion—How Young Adults With Neurodevelopmental Disorders Look at Facial Expressions of Affect

“…Pending replication in larger samples, such different fixation patterns would suggest that attention for emotion does not tap into pathophysiological mechanism that are common to ASD, ADHD, and SCZ. Here, other processes unrelated to emotion processing may show opposite results, as recently shown by Canu et al ( 134 ).…”

“…Thapar et al ( 2 ) also describe the overlap of the three disorders in many areas of cognitive functioning, but still heterogeneous in terms of clinical characteristics. Accordingly, emotion processing is not equally impaired in all these disorders, but is an aspect that differentiates between them, along with similar deviations of other cognitive functions [see Canu et al ( 134 )]. In general, the concept of continuum should encourage to not use clinical categories too rigidly and to not assign them exclusively based on cut-off values of diagnostic instruments ( 2 ).…”

Evidence towards a continuum of impairment across neurodevelopmental disorders from basic ocular-motor tasks

“…Current conclusions replicate and strengthen the ones presented in another study from our group 85 based visual search, confirming the continuum idea with schizophrenia as the group with the most deficient performance and acknowledging the location’s interchangeability of ADHD and ASD along such continuum based on group-specific strengths (e.g., ASD in search).…”

Gaze-Contingent Eye-Tracking Training in Brain Disorders: A Systematic Review

“…Moreover, altered affective experiences, such as those observed in psychiatric (e.g., mood and psychotic disorders) [ 13 , 14 , 15 , 16 ] and neurodevelopmental conditions (e.g., autism spectrum disorders (ASD) and attention deficit hyperactivity disorder (ADHD)) [ 17 , 18 ], have been shown to be related to abnormal eye movement patterns, concerning both implicit aspects (i.e., smooth pursuit and saccadic eye movements) and more explicit, cognitive components (e.g., exploratory patterns and visual search). In psychiatric and neurodevelopmental disorders, attentional biases regarding emotional information have also been observed, e.g., in major depression [ 19 ], social anxiety [ 20 , 21 ], and ASD [ 22 ].…”