Unreactive EEG: Pattern in Locked-In Syndrome

Abstract

Locked-in syndrome (LIS) is a state of complete paralysis except for ocular movements in a conscious individual, normally resulting from brainstem lesions. We report three patients with acute brainstem strokes and LIS whose repeated EEG recordings exhibited an "alpha coma" pattern including an unreactive alpha rhythm to multimodal stimuli. This finding is of importance since preservation of consciousness is often difficult to ascertain in LIS and presence of unreactive alpha on unresponsive patients is normally equated with vegetative states and discards LIS. Failure to diagnose LIS results in abandonment of communication efforts with these tragically affected individuals. Alpha reactivity cannot define consciousness.