Hypoxic-ischemic brain injury and the vegetative state: clinical and neuropathologic correlation

We studied 10 patients who survived for 2 to 8 weeks in a vegetative state, including 8 with cardiopulmonary failure and 2 with subarachnoid hemorrhage. Within days of onset, they regained brainstem function and awoke, but none had evidence of cognitive awareness. All patients opened their eyes within 2 weeks, and eight had roving conjugate eye movements. Pupillary and corneal responses were intact within 1 week, and seven patients had tonic oculovestibular responses (OVR) within 24 hours. By the end of 1 day, only three patients failed to move limbs in response to noxious stimuli. At postmortem, all patients had widespread ischemic neuronal damage in the cerebral hemispheres. The brainstems lacked morphologic abnormality, except that one patient had a single microinfarct in the superior colliculus.