A new technique to measure implicit line orientation discrimination using fast periodic visual stimulation (FPVS).

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Oliver Hermann¹ (oph30@bath.ac.uk), Carla Leonardi^2,3, Karin Petrini¹, Elizabeth Coulthard⁴, George Stothart¹; ¹University of Bath, ²IRCCS Fondazione Santa Lucia, Rome, ³University of Rome Tor Vergata, ⁴University of Bristol

FPVS is an electroencephalography marker of discrimination between two classes of frequency tagged stimuli (standards and oddballs). The technique can detect neurodegeneration-related impairment in recognition memory without active response or task comprehension. Here, we develop FPVS as a probe of low-level visual function, with a view to its future use as a sensitive diagnostic marker of visuospatial cognitive impairment. Thirty subjects (21 (±5) years, 7 males) completed five FPVS conditions that implicitly measured their ability to discriminate an oddball line orientation (1°,5°,10°,30°,80°), from a standard vertical line, as well as an equiprobable control condition. Twenty-four subjects (24 (±5) years, 5 males) completed a retest session one month later. Following 100s of recording, activity at the oddball presentation frequency, a neural signal of discrimination between standard and oddball stimuli was observed in response to lines of 5° and above. The magnitude of this oddball response increased as oddball lines deviated more from vertical. Demonstrating consistency in individual subjects, oddball responses were present in 30/30 subjects in response to a deviation of 30° and 29/30 in response to a deviation of 80°. At larger deviations, oddball responses showed high test-retest reliability, measured using intraclass correlations. Overall, these findings demonstrate that FPVS can consistently and reliably measure line orientation discrimination. The stability of these implicit tasks in the cognitively healthy, demonstrates that they hold great potential as a functional biomarker, that could be capable of capturing low-level visual processing impairments in dementia-causing diseases, e.g., Dementia with Lewy bodies.

Topic Area: PERCEPTION & ACTION: Vision