Directional motion sensitivity in people with Visual Snow Syndrome is modulated by the presence of trailing-type palinopsia

Using a spatial suppression paradigm, we assessed motion duration discrimination thresholds for small (1°), medium (2.5°), and large (12°) high-contrast gratings in 23 VSS and 27 control participants. Spatial Suppression Index (SSI) quantified size-dependent increases in duration thresholds. Visual Discomfort Questionnaire scores and VSS symptom ratings including TTP, afterimages, photophobia, etc. were also collected. VSS patients reported higher visual discomfort and perceptual disturbances. However, no group differences were found in duration thresholds or SSI. Notably, higher TTP scores were associated with lower duration thresholds, indicating a facilitatory effect of TTP on motion sensitivity.