Pupil constrictions to subjective brightness as a gateway to probe consciousness in non communicating patients.
Scientific reports July 9, 2025 Aude Sangare, Cécile Eymond, Lise Jodaitis et al. 1 citation
Pupil size is influenced not only by light but also by mental factors like perceived brightness. In healthy people, seeing images that semantically imply brightness (e.g., the sun) causes greater pupil constriction than looking at control images of similar luminance. This study tested whether this effect could detect residual cognition in non-communicating patients with disorders of consciousness. In ten healthy participants and seventeen patients (ten minimally conscious, six in vegetative state/unresponsive wakefulness syndrome, one emerging from minimally conscious state), pupillary responses were measured while viewing photographs of the sun versus matched-luminance controls (moon photos, scrambled sun images, gray squares).