New research presented at the European Academy of Neurology (EAN) Congress 2026 indicates that late light-off response (LOR) latency predicts improvements in consciousness seven days later in patients with acute brain injury. The study found this predictive capability after accounting for baseline neurological status, time since injury, sedation, and injury type.

The investigation was carried out by researchers from Copenhagen University Hospital Rigshospitalet and the Danish Technical University. The study included 250 patients who experienced impaired consciousness following traumatic and non-traumatic brain injury, as well as 30 age- and sex-matched healthy controls. Patients underwent daily automated pupillometry and neurological assessments for up to 20 days in the intensive care unit.

Standard pupil measurements, such as the Neurological Pupil Index (NPi) and pupillary light reflex (PLR) latency, did not predict later gains in consciousness in the same way the late LOR latency did. The late LOR latency measure itself was not associated with patients' level of responsiveness on the same day.

Dr. Poul Laigaard, lead author and researcher at Copenhagen University Hospital Rigshospitalet, stated, "Current tests of pupillary function tell us how the brain is responding in the moment, but the late light-off response may provide clues about the brain's potential for recovery." He added that the assessment takes 13 seconds per eye, making it a "fast and practical bedside tool that could potentially be integrated into routine ICU care."

The relationship between late LOR latency and improvements in consciousness appeared strongest among patients not receiving sedative medication. This relationship also seemed particularly strong in patients who had an anoxic–ischaemic brain injury. Researchers noted that these subgroup findings are exploratory and require confirmation through larger studies.

Professor Daniel Kondziella, senior author of the study, said, "We believe this is an important observation that deserves further investigation." Kondziella also stated that "Larger, multicenter studies are needed to determine whether this approach could be used routinely for bedside monitoring and prognosis."