Value and mechanisms of EEG reactivity in the prognosis of patients with impaired consciousness: a systematic review

Abstract

[...]EEGs merely exhibiting stimuli-induced rhythmic, periodic, or ictal discharges [36] or muscle activity or eye blink artifacts are not considered as reactive by many authors [1, 5–7]. Because visual analysis of reactivity is prone to subjectivity [40–42], automated quantitative approaches have been proposed [37]. Higher-power values are shown in warm colors, and cool colors depict lower power Methods We systematically searched the literature in the PubMed database for published reports pertaining to the use of EEG-R in outcome prediction in patients with impaired consciousness, from inception until March 2018, using the following search terms: (EEG reactivity OR electroencephalogram reactivity OR reactive EEG) AND (coma OR anoxic OR cerebral anoxia OR hypoxia OR post anoxic coma OR resuscitation OR cardiac arrest OR traumatic brain injury OR TBI OR encephalopathy OR unconscious OR vegetative state OR unresponsive wakefulness syndrome OR minimally conscious state) AND (outcome OR prognosis OR prognostication OR prediction OR predictive value OR mortality OR survival OR awakening). [50] analyzed EEG predictors of outcome in 106 patients with disorders of consciousness admitted for intensive rehabilitation and found that mean Coma Recovery Scale–Revised (CRS-R) scores were lower in patients without EEG-R than in patients with EEG-R, at admission and after 3 months. [...]patients without EEG-R had less CRS-R score improvement after 3 months than patients with EEG-R [50]. [...]the same EEG pattern may have a different prognostic value, depending on the presence or lack of EEG-R [44, 46, 125].