Assessing consciousness in acute coma using name-evoked responses

Area of Science:

• Neuroscience
• Clinical Neurology
• Medical Technology

Background:

• Assessing consciousness in unresponsive patients, especially those with acute brain injury, is clinically challenging.
• Existing research primarily focuses on chronic conditions, leaving a gap in understanding acute coma states.
• Electroencephalography (EEG) has shown promise in detecting brain responses in unresponsive individuals.

Purpose of the Study:

• To investigate the potential for detecting residual consciousness in acute coma patients using bedside electroencephalography (EEG) and electromyography (EMG).
• To evaluate the efficacy of an auditory oddball paradigm, incorporating personalized stimuli, in eliciting detectable brain and muscle responses.
• To differentiate between passive and active listening conditions to identify reliable indicators of awareness.

Main Methods:

• Recruited 22 patients with acute brain injury (traumatic brain injury or cardiac arrest) and Glasgow Coma Scale (GCS) scores ≤ 8.
• Utilized bedside EEG and EMG during an auditory oddball paradigm with personalized (own name) and standard names.
• Compared event-related potentials (ERPs) and EMG spectra between conditions: passive listening and active listening (hand movement cue).

Main Results:

• Patients showed enhanced ERP responses to their own names, particularly during active listening.
• Distinct differences in brain network connectivity and increased EMG responses were observed during active listening to personalized stimuli.
• These findings suggest a measurable neural and muscular response to personally relevant auditory cues in acute coma.

Conclusions:

• Bedside EEG and EMG can detect signs of residual consciousness in patients with acute coma.
• Personalized auditory stimuli, especially within an active listening paradigm, can elicit specific responses indicative of awareness.
• This approach offers a promising tool for assessing consciousness in behaviorally unresponsive patients.