A 13-second bedside eye test may help physicians forecast which patients will regain consciousness days after a severe brain injury.
Research unveiled at the European Academy of Neurology Congress 2026 identifies a specific phase of the pupil’s reaction to light, the late light-off response (LOR), as a key indicator. Standard automated pupillometry, already common in ICUs, measures instant brain stem function but says little about long-term recovery.
Investigators from Copenhagen University Hospital Rigshospitalet and the Danish Technical University studied 250 patients with impaired consciousness and 30 healthy controls. Daily assessments for up to 20 days showed that late LOR latency independently predicted a seven-day improvement in awareness. This held true even after adjusting for sedation levels, neurological status, and type of brain injury.
Crucially, standard metrics like the Neurological Pupil Index did not forecast future gains. The late light-off response appeared to expose recovery potential hidden during routine checks. Lead author Dr Poul Laigaard noted that while current tests reflect immediate brain function, the late response hints at the brain’s capacity to heal.
Because the test uses existing handheld devices and takes only 13 seconds per eye, researchers suggest adoption could be practical if validated by larger multicenter trials.