Predict recovery of consciousness in post-acute severe brain injury: the role of EEG reactivity.

ABSTRACT

OBJECTIVE: This study tested the hypothesis of electroencephalographic reactivity (EEG-R) as a reliable tool for the prognostic evaluation of consciousness recovery in post-acute brain injury. METHODS: EEG was recorded in 50 unconscious patients. All patients had a GCS ≤8 and LCF score ≤2. They suffered from traumatic brain injury, cerebrovascular disease or anoxia. EEG was classified according to Synek classification (1988) as benign, malignant and 'uncertain significance'. EEG-R to painful stimuli was tested. RESULTS: Twenty per cent of patients fulfilled the criteria for benign prognosis, 38% for malignant prognosis, while 42% of them were included in the 'uncertain' category, preventing them from stating a prognosis. EEG-R was detected in 48% of patients classified 'uncertain' and 92% of them recovered consciousness within 5 months from EEG recording. Multivariable analysis indicates that an unconscious patient admitted to the Rehabilitation Unit within 2 months from brain injury, with a LCF score equal to 2 and the presence of EEG-R has a probability of recovery of consciousness higher than 97%. CONCLUSION: EEG-R is a good positive factor for the prognosis of recovery of consciousness in the post-acute phase of brain injury, with a high specificity (88.9%). Nevertheless, its absence is not invariably associated with a poor prognosis.