Post-Anoxic Alpha Coma After Cardiac Arrest

A 58-year-old man is admitted to the ICU after successful resuscitation from out-of-hospital cardiac arrest (VF, 22 minutes downtime). Targeted temperature management is initiated, sedation is stopped at 24 hours post-rewarming. On day 3, he remains in a deep coma (GCS 3) with absent corneal reflexes and extensor posturing. Continuous EEG monitoring shows a monotonous diffuse alpha-frequency rhythm (9–11 Hz) across all brain regions. The feature marked **B** in the diagram—non-reactivity to painful, auditory, and visual stimuli with no attenuation of the alpha rhythm—is documented. Which of the following best describes the prognostic significance of this EEG finding in post-anoxic encephalopathy?