To evaluate the utility of the electrophysiological blink reflex in prognostication of coma.

Current models in acute brain injury (ABI) use age, basic neurological assessments, and radiological findings as predictors of recovery with unsatisfactory accuracy. The blink reflex is a quantitative electrophysiologic version of the corneal reflex which may enhance prognostication.

A total of 34 ABI patients were recruited prospectively in the Neuroscience ICU. Demographics and injury-related variables were collected. The electrophysiological blink reflex and clinical corneal reflex were performed at bedside. Presence of clinical blink as well as ipsilateral (R1 and R2) and contralateral (R2) responses of the orbicularis oculi were recorded. The Glasgow Outcome Scale-Extended was used to assess the level of recovery at 3-, 6-, and 12-month after injury; a score of 4 or more was considered functional independence.

The median age of patients was 54 (IQR 33, 63) years, predominantly male (83%) of which 18% identified as Black and 44% identified as Hispanic. Traumatic brain injury accounted for 65% of injuries, spontaneous intracerebral hemorrhage for 29%, and spontaneous subarachnoid hemorrhage for 6%. Of the 21 patients who had bilateral R1 responses, 7 (33%) achieved functional recovery, whereas among the 13 patients with either unilateral or absent R1 responses, 1 (8%) achieved functional recovery. Of the 13 patients with an efferent R2 response to bilateral afferent stimuli, 5 (38%) achieved functional recovery; among the remaining 21 patients missing an R2 response to stimulation from at least one side, 3 (14%) achieved functional recovery. A total of 29% of electrophysiologic blink responses did not exhibit a clinical corneal reflex response.

This pilot data demonstrates a promising potential for the use of the blink reflex in the prognostication of coma after acute brain injury. Recruitment is ongoing to further investigate this electrical pathway as a biomarker of functional recovery.