Obukhova Tatiana S, Stroganova Tatiana A, Artemenko Ada R, Petrokovskaia Anastasiia V, Orekhova Elena V
Center for Neurocognitive Research (MEG Center), Moscow State University of Psychology and Education, Moscow, Russia.
Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University), Moscow, Russiа.
Invest Ophthalmol Vis Sci. 2025 Apr 1;66(4):24. doi: 10.1167/iovs.66.4.24.
Visual Snow Syndrome (VSS) is characterized by visual perceptual distortions, potentially linked to increased neural excitability and/or decreased inhibition in the visual cortex. If present, these putative physiological abnormalities may alter motion direction sensitivity. Trailing-type palinopsia (TTP), commonly associated with VSS, may further affect motion sensitivity. This study aimed to investigate the sensitivity to direction of motion and its dependence on stimulus size in patients with VSS using the Spatial Suppression paradigm.
We assessed motion duration discrimination thresholds for small (1 degree), medium (2.5 degrees), and large (12 degrees) high-contrast gratings in 23 patients with VSS and 27 healthy control participants. The 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.
Patients with VSS reported higher visual discomfort and perceptual disturbances, but 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 sensitivity to direction of motion.
Our findings indicate that when VSS is regarded as a unified diagnostic category, it is not associated with impaired motion direction sensitivity or abnormal center-surround suppression. However, our preliminary results suggest that an absence or presence of comorbid TTP has a qualitatively different effect on directional sensitivity in patients with VSS. The facilitatory effect of TTP on motion sensitivity provides insight into the functional concomitants of TTP, and warrants further exploration, as it may significantly influence experimental outcomes.
视觉雪综合征（VSS）的特征是视觉感知扭曲，可能与视觉皮层神经兴奋性增加和/或抑制作用降低有关。如果存在这些假定的生理异常，可能会改变运动方向敏感性。与VSS常见相关的拖尾型持续性视觉模糊（TTP）可能会进一步影响运动敏感性。本研究旨在使用空间抑制范式调查VSS患者对运动方向的敏感性及其对刺激大小的依赖性。
我们评估了23例VSS患者和27名健康对照参与者对小（1度）、中（2.5度）和大（12度）高对比度光栅的运动持续时间辨别阈值。空间抑制指数（SSI）量化了持续时间阈值中与大小相关的增加。还收集了视觉不适问卷分数和VSS症状评分，包括TTP、后像、畏光等。
VSS患者报告有更高的视觉不适和感知障碍，但在持续时间阈值或SSI方面未发现组间差异。值得注意的是，较高的TTP评分与较低的持续时间阈值相关，表明TTP对运动方向敏感性有促进作用。
我们的研究结果表明，当VSS被视为一个统一的诊断类别时，它与运动方向敏感性受损或异常的中心-外周抑制无关。然而，我们的初步结果表明，合并或不合并TTP对VSS患者的方向敏感性有质的不同影响。TTP对运动敏感性的促进作用为TTP的功能伴随情况提供了见解，值得进一步探索，因为它可能会显著影响实验结果。
