Neural Mechanisms of Selective Attention in Children with Amblyopia

Impact of strabismus and binocular dysfunctions in the developmental eye movement test and test of visual perception skills: A multicentric and retrospective study

PURPOSE

To compare the performance in the Developmental Eye Movement test (DEM) and the Test of Visual Perceptual Skills (TVPS) between three groups: individuals with strabismus and amblyopia, patients with binocular and accommodative dysfunctions, and subjects with normal binocular and accommodative function.

METHODS

A multicentric, retrospective study including 110 children aged 6-14 years old was conducted to investigate the potential impact of strabismus, amblyopia, and different binocular conditions in DEM results (adjusted time in vertical and horizontal parts) and TVPS (percentiles in the seven sub-skills).

RESULTS

No significant differences were found in the different subtests of the vertical and horizontal DEM and all the sub-skills in the TVPS between the three groups of the study. We found high variability of performance in the DEM test between participants with strabismus and amblyopia compared with binocular and accommodative problems.

CONCLUSION

DEM and TVPS scores have not been found to be influenced by the presence of strabismus with or without amblyopia, nor by binocular and accommodative dysfunctions. A slightly correlation tendency with horizontal DEM and degree of exotropia deviation was observed.

Neural signature of attention impairment in allergic asthma: an ERP study

Background Cognitive impairments are linked to poor treatment response and disease control in allergic asthma. However, there are no studies exploring attention-related functional brain alterations in allergic asthma. Here, we explore attention deficit and its association with clinical characteristics and common neuropsychiatric disorders in patients with allergic asthma.Methods We recruited 38 participants, equally distributed into healthy and asthma groups. Behavioral, neurophysiological, and lung function assessment tools were used in this study.Results Our behavioral data show that allergic asthma induces attention impairment. Additionally, the event-related potentials (ERP) analysis reveals that this attention deficit is associated with a disruption in cognitive processing capability in frontal brain areas. These behavioral and neurophysiological abnormalities were strongly correlated with disease severity and neuropsychiatric comorbidities of asthmatic patients.Conclusion Together, here we propose that disrupted neurophysiological responses in frontal brain areas might lead to attention impairments in patients with allergic asthma. These findings could help characterizing the neuro-pathophysiology of cognitive disorders in allergic asthma, possibly opening the way for development of novel treatment strategies.

Inhibitory Control of Emotional Interference in Deaf Children: Evidence From Event-Related Potentials and Event-Related Spectral Perturbation Analysis

BACKGROUND

Impairment of interference control ability may reflect a more general deficit in executive functioning, and lead to an increase in internal-externalized problems such as impulsivity, which has been reported in deaf children. However, few researches have examined the neural mechanism of this impairment.

METHODS

This study applied the electroencephalogram (EEG) technique to investigate the interference control ability in 31 deaf children and 28 hearing controls with emotional face-word stroop task.

RESULTS

Results from behavioral task showed that deaf children exhibited lower accuracy compared to hearing controls. As for EEG analysis, reduced activation of ERP components in N1 and enhanced activation of ERP components in N450 have been found in deaf children. Besides, incongruent condition elicited larger N450 than congruent condition. Furthermore, for brain oscillation, alpha band (600-800 ms) revealed a reduced desynchronization in deaf children, while theta band (200-400 ms) revealed an enhanced synchronization in deaf children and incongruent condition, which were in line with ERP components.

CONCLUSION

The present findings seem to indicate that the deficit during emotional interference control ability among deaf children might be due to the impaired attention allocation ability and emotional cognitive monitoring function during emotional conflict detection process. Consequently, reduced N1 and enhanced N450 might be due to early attention impairment causing more effort of deaf children later in emotional cognitive monitoring.

Attention in visually typical and amblyopic children

Amblyopia is a cortical visual disorder caused by unequal visual input to the brain from the two eyes during development. Amblyopes show reduced visual acuity and contrast sensitivity and abnormal binocularity, as well as more “global” perceptual losses, such as figure-ground segregation and global form integration. Currently, there is no consensus on the neural basis for these higher-order perceptual losses. One contributing factor could be that amblyopes have deficiencies in attention, such that the attentional processes that control the selection of information favor the better eye. Previous studies in amblyopic adults are conflicting as to whether attentional deficits exist. However, studies where intact attentional ability has been shown to exist were conducted in adults; it is possible that it was acquired through experience. To test this hypothesis, we studied attentional processing in amblyopic children. We examined covert endogenous attention using a classical spatial cueing paradigm in amblyopic and visually typical 5- to 10-year old children. We found that all children, like adults, independently of visual condition, benefited from attentional cueing: They performed significantly better on trials with an informative (valid) cue than with the uninformative (neutral) cue. Response latencies were also significantly shorter for the valid cue condition. No statistically significant difference was found between the performance of the amblyopic and the visually typical children or between dominant and nondominant eyes of all children. The results showed that covert spatial attention is intact in amblyopic and visually typical children and is therefore not likely to account for higher-order perceptual losses in amblyopic children.

Amblyopic-related frontal changes in an orientation discrimination task: a research of P3a event-related potentials in anisometropic amblyopia

BACKGROUND

Amblyopic deficits in the primary and secondary visual cortex have been demonstrated broadly. However, the cognitive process at late stage originating in higher brain area in amblyopes hasn't been studied yet. The aim of this study was to investigate the late cognitive process at the frontal lobe in anisometropic amblyopes of a distinct degree, using visual event-related potential (ERP) techniques.

METHODS

Thirteen severe anisometropic amblyopes, 14 mild-to-moderate anisometropic amblyopes, and 13 control subjects participated in this study. Oddball paradigm (three stimuli: target, novel, and non-target stimuli) of low spatial frequency (1 cycle per degree, CPD) was used to elicit brain ERP waves. Reaction time, accuracy, latency, and amplitude of P3a waves evoked by novel stimuli at Fz electrode (the central electrode at frontal lobe), were analyzed statistically.

RESULTS

Neither accuracy nor reaction time showed significant difference among the three groups. The latency of N200 wave showed no significant difference. The latency of P3a wave was delayed in the amblyopes compared with healthy controls, but there was no significant difference between severe and mild-to-moderate amblyopes. P3a amplitude in mild-to-moderate amblyopes was significantly higher than in controls and severe amblyopes.

CONCLUSIONS

Our findings indicated that the cognitive process in anisometropic amblyopes was impaired, and the compensative effect of P3a amplitude was shown in mild-to-moderate amblyopes. P3a visual ERP could become a useful tool to investigate cognitive processing in amblyopes. Hippokratia 2016, 20(1): 60-66.