Cognitive Processing of Novel Auditory Stimuli in Children with Acute Disorders of Consciousness

Prognostication of critically ill children appearing acutely comatose remains challenging. Event-related potentials (ERPs) using electroencephalography (EEG) offer a noninvasive method to detect covert consciousness. These include the mismatched negativity (MMN) and P300b responses. We investigated ERPs using the auditory local-global oddball paradigm to assess inattentive or attentive cortical processing in critically ill, clinically unresponsive children.

We prospectively enrolled pediatric intensive care unit (PICU) patients undergoing continuous EEG with Glasgow coma scale scores < 8. Each patient underwent testing with the local-global oddball paradigm. In each trial, five brief tones were delivered; the fifth tone was either identical (local-standard) or different (local-deviant). In total, 80% of trials shared the same local structure (global-standard), and 20% deviated (global-deviant). MMN-like responses were assessed by contrasting local-deviant vs. local-standard trials (100-250 ms post-stimulus) at frontocentral electrodes; P300b-like responses were assessed by contrasting global-deviant vs. global-standard trials (250-700 ms post-stimulus) at centroparietal electrodes. Cluster-based permutation testing identified significant ERPs. Functional outcomes were assessed at 10-12 months using the Glasgow outcome scale extended-Pediatrics (GOSE-Peds), and ERP-outcome associations were analyzed using the Mann-Whitney U test.

Among 29 children, 6 (20.7%) showed reproducible ERPs-2 (6.9%) with MMN-like responses and 4 (13.8%) with P300b-like responses. Presence of either ERP response was associated with lower GOSE-Peds scores (p = 0.029), indicating more favorable outcomes.

ERPs can detect both inattentive and attentive cortical processing in critically ill clinically unresponsive children. The presence of reproducible responses resembling MMN or P300b may be associated with better long-term functional recovery.