Patients With Better Outcome Have Higher ERP Response to Emotional Auditory Stimuli

Abstract

Purpose: Accuracy of outcome prognosis is one of the most important tasks of coma arousal therapy. Reactions toward sensory stimuli are the most significant predictor of conscience and cognitive functions restoration after a brain injury. A paradigm that includes ERP registration has the advantage of detailed stimuli processing visualization. The authors aimed to investigate perception and distinguishing of emotionally significant sounds (crying and laughter) in coma patients with different consciousness restoration prognosis.

Methods: EEG was recorded in 24 comatose patients with different outcomes (scored with Glasgow Outcome Scale-Extended) and 32 healthy volunteers. The authors presented sounds of crying and laughter. ERPs for sound stimulation were calculated.

Results: An analysis of the correlation of ERP components and Glasgow Outcome Scale-Extended score was performed. P200 (r = 0.6, P = 0.0014) and N200 amplitudes (r = -0.56, P = 0.0037) for emotional sounds correlated with the Glasgow Outcome Scale-Extended score. The significant differences of P300 and N400 amplitudes corresponded to differences of response between sounds of crying and laughter in subjects of the control group. Unlike the control group, comatose participants with good outcome produced similar electrical activity toward pleasant and unpleasant emotional stimuli.

Conclusions: Comatose patients with good outcome produced more prominent ERP for emotional sounds. Even the good outcome participants were unable to distinguish emotional sounds of different moods, which indicate the preservation of solely robust mechanisms of sound processing. N200 and P200 amplitudes for emotional stimuli correlated significantly with outcome prognosis in coma patients.