Neural Mechanisms of Selective Attention in Children with Amblyopia

Abstract

Previous studies have indicated that amblyopia might affect children's attention. We recruited amblyopic children and normal children aged 9–11 years as study subjects and compared selective attention between the two groups of children. Chinese characters denoting colors were used in the Stroop task, and the event-related potential (ERP) was analyzed. The results show that the accuracy of both groups in the congruent condition was higher than the incongruent condition, and the reaction time (RT) of amblyopic children was longer. The latency of the occipital P1 in the incongruent condition was shorter than the neutral condition for both groups; the peak of the occipital P1 elicited by the incongruent stimuli in amblyopic children was higher. In both groups, the N1 peak was higher in the occipital region than frontal and central regions. The N1 latency of normal children was shorter in the congruent and neutral conditions and longer in the incongruent condition; the N1 peak of normal children was higher. The N270 latencies of normal children in the congruent and neutral conditions were shorter; the N270 peak was higher in parietal and occipital regions than frontal and central regions for both groups. The N450 latency of normal children was shorter; in both groups, the N450 average amplitude was significantly higher in the parietal region than central and frontal regions. The accuracy was the same for both groups, but the response of amblyopic children was significantly slower. The two groups showed differences in both stages of the Stroop task. Normal children showed advantages in processing speed on both stimulus and response conflict stages.Brain regions activated during the Stroop task were consistent between groups, in line with their age characteristics.

Attention in visually typical and amblyopic children

“…For example, under conditions such as multiple-object tracking or conjunction visual search, differences between observers only become apparent with large sets of distractors (Ho et al, 2006;Neri & Levi, 2006). Delayed or overall slower processing of relevant compound stimuli may explain the increased reaction times found for amblyopic observers in conjunction visual search and Stroop performance (Tsirlin et al, 2018;Zhou et al, 2015). These explanations would support the existence of deficiencies in effectiveness of attentional deployment or perhaps limitations in attentional capacity on complex or high-demand tasks.…”

“…As noted above, older children with unilateral amblyopia show marked performance deficits for both eyes on high-level dynamic attention tasks such as tracking multiple objects at high speeds (Ho et al, 2006). Another study showed that amblyopic children between ages 9 and 11 years, while achieving similar performance accuracy, demonstrated longer latencies on a modified Stroop task when compared to visually typical children (Zhou et al, 2015). This result on the Stroop task, a task assessing selective visual attention by looking at the interference between colors and meaning of the same stimulus, shows that while amblyopic children have similar attention allocation capability as visually typical children, they show slower processing speed on both stimulus and response conflict stages.…”

Does the treatment of amblyopia normalise subfoveal choroidal thickness in amblyopic children?

“…The disease is associated with certain disorders, including strabismus, anisometropia, ptosis and cataract, which cause insufficient visual stimulus and interfere with normal development of the visual pathways during a critical period of visual development. Therefore, amblyopia is considered as a functional deficit of the visual cortex secondary to abnormal early visual input …”

Dichoptic Attentive Motion Tracking is Biased Toward the Nonamblyopic Eye in Strabismic Amblyopia

“…Similarly, another study identified differences in event-related potential waveforms during processing of the Stroop task for children with amblyopia relative to controls. 51 Other studies have used psychophysics to investigate attentive processing in amblyopia under monocular viewing conditions, with mixed results. Impairments have been reported in multiple-object tracking, 52,53 conjunction visual search, 54 and attentional blink tasks, 55 suggesting an attention deficit associated with not just the amblyopic but also the fellow eye, that affects both spatial and temporal components of visual attention.…”