Visual distraction in a patient with abnormal occipital gyration – an eye-tracking study

Abstract

Maintaining focus and resisting distraction is critical for many visual tasks. We investigated these abilities in a patient with congenital abnormal bilateral occipital and parietal gyration, caused by a single gene (LAMC3) mutation. Because of the location and nature of these structural idiosyncrasies as well as compromised performance in several attention-related screening tasks we set out to measure the patient's visual attention in detail. Here, we assessed the patient's ability to maintain focus in the presence of several types of visual distractors. The patient's performance was compared to that of five sex- and education-matched healthy controls. Participants performed four eye-tracking conditions in randomized order in one experimental session: Fixation-only, Fixation with rapid sequential visual perception (RSVP), Fixation with relevant peripheral distractor (RPD), and Fixation with irrelevant peripheral distractors (IPD). Participants were required to fixate at the center and to respond when a target was detected (in RSVP, RPD, IPD). In the RPD condition relevant cues were presented for 100 ms at 8.71 degrees visual angle eccentricity in one of four possible directions, followed by a 200 ms target in the same location. In the IPD condition no cues preceded targets, everything else was as in the RPD condition. Experiments were done in MATLAB using Psychtoolbox and with an ASL Eye-Trac6 D6 Desk Mounted Optics. We measured percent correct in RSVP, RDP and IDP tasks and mean deviation from fixation in horizontal and vertical directions in all experimental conditions. Patient and control group performed comparably in behavioral tasks. Fixation results, however, indicated a decreased fixation quality of the patient in the presence of visual distractors, with deviations from fixation more than doubling (compared to controls) in RDP and IDP conditions. We discuss these results in light of the patient's structural connectivity and morphometry. Meeting abstract presented at VSS 2015. Language: en