Mismatch Negativity and P300 in the Diagnosis and Prognostic Assessment of Coma and Other Disorders of Consciousness

The objective of this study was to investigate the value of mismatch negativity (MMN) and P300 event-related potentials for discriminating the consciousness state and predicting improvement of consciousness at 6 months in patients with coma and other disorders of consciousness (DOC).

We performed MMN and P300 on 42 patients with DOC with a mean onset time of 40.21 ± 19.43 days. These patients with DOC were categorized into coma, unresponsive wakefulness syndrome (UWS), minimal consciousness minus (MCS-), and minimal consciousness plus (MCS +) groups according to neurobehavioral assessment and the Coma Recovery Scale-Revised score. The primary outcome was the improvement of consciousness at 6 months in patients with DOC. We assessed the efficacy of MMN and P300 in quantitatively predicting the prognosis at 6 months and the capability of MMN and P300 parameters to differentiate between DOC.

At least one significant difference in either MMN or P300 parameters was displayed among the DOC groups, but not between the MCS- and MCS+ groups (significance level: 0.05). Both MMN and P300 amplitudes showed desirable predictive accuracy at 6 months, with areas under the curve (AUCs) of 0.859 and 0.856, respectively. The optimal thresholds for MMN and P300 amplitudes were 2.044 and 1.095 μV. However, the combined MMN-P300 amplitude showed better 6-month predictive accuracy (AUC 0.934, 95% confidence interval 0.860-1.000), with a sensitivity of 85% and a specificity of 90.9%.

MMN and P300 may help discriminate among coma, UWS, and MCS, but not between patients with MCS- and patients with MCS+ . The MMN amplitude, P300 amplitude, and especially combined MMN-P300 amplitude at 6 months may be interesting predictors of consciousness improvement at 6 months in patients with DOC.

Chinese Clinical Trial Registry identifier ChiCTR2400083798.