Glaucoma-associated abnormalities in cortical activity during a visuocognitive task

To investigate neurophysiological dynamics during a visuocognitive task in glaucoma patients vs. healthy controls.

Fifteen patients with early-stage primary open-angle glaucoma (POAG) and fifteen age-matched healthy participants underwent a "go/no-go" task, monitored with EEG. Participants had to semantically categorize visual objects in central vision, with animal or furniture as targets according to the experimental block.

Early visual processing was delayed by 50 ms in patients with POAG compared to controls. The patients displayed a smaller difference between animal and furniture categorization during higher-level cognitive processing (at 400-600 ms). Regarding behavioral data, the groups differed in accuracy performance and decision criterion. As opposed to the control group, patients did not display facilitation and a higher accuracy rate for animal stimuli. However, patients maintained a consistent decision criterion throughout the experiment, whereas controls displayed a shift towards worse decision criteria in furniture trials, with higher error rate.

The comparative analysis of behavioral and neurophysiological data revealed in POAG patients a delay in early visual processing, and potential high-level cognitive compensation during late, task-dependent activations.

To our knowledge, our findings provide the first evidence of modification in cognitive brain dynamics associated with POAG.