Atypical attentional filtering of visual information in youth with chromosome 22q11.2 deletion syndrome as indexed by event-related potentials

Abstract

Background: Youth with chromosome 22q11.2 deletion syndrome (22q) face one of the highest genetic risk factors for the development of schizophrenia. Previous research suggests impairments in attentional control and potential interactions with elevated anxiety and reduced adaptive functioning may increase the risk for developing psychosis in this population. Here, we examined how variations in attentional control relate to the presence or severity of psychosis-proneness symptoms in these individuals.

Methods: To achieve this, we measured attentional control in youth (12-18 years) with 22q (N = 35) compared to a typically developing group (N = 45), using a flanker task (the Distractor Target task) while measuring neural activity with event-related potentials.

Results: Similar to previous findings observed in people with schizophrenia, greater attentional capture by, and reduced suppression of, non-target flanker stimuli characterized participants with 22q and was indexed by the N2pc (N2-posterior-contralateral) and P_D (distractor positivity) components. Although we observed no relationships between these components and measures of psychosis-proneness in youth with 22q, these individuals endorsed a relatively low incidence of positive symptoms overall.

Conclusions: Our results provide neural evidence of an attentional control impairment in youth with 22q that suggests these individuals experience sustained attentional focus on irrelevant information and reduced suppression of distracting stimuli in their environment. Impairments in attentional control might be a valid biomarker of the potential to develop attenuated positive symptoms or frank psychosis in high-risk individuals long before the age at which such symptoms typically arise. The evaluation of such a hypothesis, and the preventive potential for the putative biomarker, should be the focus of future studies.

Keywords: 22q11.2 deletion; Attention; Event-related potential; Flanker; Psychosis.

Fig. 1

Experimental design. The DT task. Note. Participants looked for a specific target color in the center of the screen (red, blue, or green), while two colored circles flanked the target circle. Participants pressed one button if the center circle matched the target color they were looking for and pressed another button if the center circle was another color.

Fig. 2

DT Behavior Note. Participants with 22q were less accurate than TD participants across all trial types. ***p < 0.001, **p < 0.01, *p < 0.05.

Fig. 3

DT ERPs. Note. A: Grand average ERP waveforms show the N2pc/P_D balance for participants with 22q and TD participants. B: Grand average difference waves (contralateral minus ipsilateral). The colored region around the difference waves represents 95% bootstrapped confidence intervals. C: Participants with 22q had larger N2pc area amplitudes, D: smaller P_D area amplitudes, and E: more negative mean N2pc/P_D amplitudes than TD participants. The gray shaded regions highlight the time window used to measure the N2pc and P_D effects. **p < 0.01.