Added Value of Late Auditory Evoked Potentials in the Multimodal Prognostication of Patients With Disorders of Consciousness.

Objectives: This study aimed to evaluate the added prognostic value of late auditory evoked potentials (AEPs): mismatch negativity (MMN) and P3, alongside other prognostic markers (electroencephalogram, somatosensory evoked potentials, absent pupillary reflex), in the prognostication of patients with disorders of consciousness. We stratified our analysis based on the type of brain injury: hypoxic-ischemic brain injury (HIBI) vs. non-HIBI.

Design and setting: We performed a single-center retrospective study comparing the prognostic values of late AEPs and other neurophysiologic markers in predicting unfavorable outcomes, defined as a Glasgow Outcome Scale-Extended of 1-2 at 3 months, in both HIBI and non-HIBI groups. We compared the prognostic performance of a model including late AEPs to a model including only well-established markers.

Patients: We included 148 patients from one institution at the subacute phase after coma onset (median, 20.0 d). The main cause of disorder of consciousness was HIBI in 43.9% of cases, followed by stroke in 31.8%.

Interventions: None.

Measurements and main results: The absence of P3 and MMN responses had a positive predictive value (PPV) for unfavorable outcome of 92.9% and 88.4% in HIBI, and 67.9% and 57.4% in non-HIBI, respectively. Predictive values of neurophysiologic markers were generally lower in non-HIBI compared with HIBI patients. Specifically, the PPV for unfavorable outcome of electroencephalogram malignant patterns and absent reactivity was significantly higher in HIBI compared with non-HIBI patients (76.9% vs. 31.3%, and 88.9% vs. 33.3%; p = 0.04, respectively). A model including AEPs significantly reduced the differences between individual predicted probabilities and actual outcome, both in the HIBI and non-HIBI contexts.

Conclusions: Integrating late AEPs into multimodal assessments enhances the model's predictive performance. Their contribution to neuroprognostication may be particularly relevant in the non-HIBI context, where the predictive values of neurophysiologic tools are lower than in the HIBI context. Late AEPs are interesting and cost-effective tools for neuroprognostication in both HIBI and non-HIBI contexts.