Sangare Aude, Eymond Cécile, Jodaitis Lise, Demeret Sophie, Rohaut Benjamin, Naccache Lionel
Faculty of Medicine, Sorbonne University, Paris, France.
Department of Neurophysiology, DMU Neurosciences, Assistance Publique - Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Charles Foix, Paris, France.
Sci Rep. 2025 Jul 9;15(1):24619. doi: 10.1038/s41598-025-06941-7.
Retinal illumination primarily determines pupil size, yet extra-retinal factors like subjective brightness also influence pupillary responses. Previous works reported that in healthy individuals, stimuli whose semantic content evokes brightness cause greater pupillary constriction than control stimuli of similar luminance. This study adapted this approach and tested a passive task to assess consciousness levels of non-communicating patients in intensive care unit. In ten healthy participants and seventeen patients with Disorders of Consciousness (10 in a Minimally Conscious State, 6 in Vegetative State also coined Unresponsive Wakefulness Syndrome), 1 in Emergence from Minimally Conscious State), we measured pupillary responses to photographs of the sun and control stimuli of matched luminance (moon photographs, scrambled sun images, uniform gray squares). At the group level, both healthy participants and Minimally Conscious State patients showed greater pupil constriction for the sun photographs compared to control pictures which elicited a pupillary dilatation. In Vegetative State/ Unresponsive Wakefulness Syndrome patients, this subjective brightness effect on pupillary diameter was not significant. Notably, this effect was observed in only one Vegetative State patient, who regained consciousness a few weeks after the evaluation. The results support that pupillary response to subjective brightness could be a novel method to assess residual cognition at the bedside in non-communicating patients.
视网膜光照主要决定瞳孔大小，但视网膜外因素如主观亮度也会影响瞳孔反应。先前的研究报告称，在健康个体中，语义内容能唤起亮度的刺激比类似亮度的对照刺激会引起更大的瞳孔收缩。本研究采用了这种方法，并测试了一项被动任务，以评估重症监护病房中无沟通能力患者的意识水平。在10名健康参与者和17名意识障碍患者（10名处于最低意识状态，6名处于植物状态，也称为无反应觉醒综合征，1名处于从最低意识状态苏醒过程中）中，我们测量了他们对太阳照片以及匹配亮度的对照刺激（月亮照片、打乱的太阳图像、均匀灰色方块）的瞳孔反应。在组水平上，与引起瞳孔扩张的对照图片相比，健康参与者和最低意识状态患者对太阳照片都表现出更大的瞳孔收缩。在植物状态/无反应觉醒综合征患者中，这种主观亮度对瞳孔直径的影响并不显著。值得注意的是，仅在一名植物状态患者中观察到了这种效应，该患者在评估后几周恢复了意识。结果支持，对主观亮度的瞳孔反应可能是一种在床边评估无沟通能力患者残余认知的新方法。
