Background: Electroencephalogram (EEG) is used in evaluating thalamocortical function in comatose patients. EEG reactivity is increasingly being recognized as a potentially important predictor of outcome in comatose patients. There are no existing guidelines or standardized testing for EEG reactivity assessment. We will report the use of a clinically implemented standardized reactivity testing protocol in comatose patients to determine accurate prognosis. Methods: In this retrospective study we report results from standardized reactivity testing from January 2016 to May 2016. Five stimuli (Calling name, clapping, nasal tickle, noxious stimulus, tracheal suctioning) were applied at one minute intervals in comatose patients of all etiologies. The EEG background reactivity will be analyzed by two independent electroencephalographers ad correlated to clinical outcome. Results: The methods for establishing EEG reactivity and the inter-rater reliability in determining EEG reactivity will be reported. Conclusions: EEG background reactivity is likely beneficial in determining prognosis. However, reliable methods for eliciting and determining EEG reactivity in comatose patients are necessary.