N20-P25 Amplitude can Predict Awakening from Coma.

Background: The objective of this study was to evaluate the relationship between the N20-P25 amplitude of short-latency somatosensory evoked potentials (SSEPs) and neurologic outcomes in patients in a coma state.

Methods: We retrospectively enrolled neurocritical patients who were older than 18 years; were admitted to the Department of Critical Medicine, Xiangya Hospital, Central South University, from January 2017 to January 2021 for 1-3 days; had a Glasgow Coma Scale score ≤ 8; had a body temperature ≥ 35 °C; and had SSEP records. Good outcome was defined as Cerebral Performance Category scores 1-3 at 1 year. The specificity and sensitivity of different SSEP patterns and amplitudes were calculated.

Results: A total of 457 patients were included in this study. The N20-P25 amplitude can be used for predicting awakening for traumatic brain injury (TBI) (area under the curve [AUC] 0.70, p = 0.0077), aneurysmal subarachnoid hemorrhage (SAH) (AUC 0.69, p = 0.005), intracerebral hemorrhage (ICH) (AUC 0.69, p = 0.005), and cardiac arrest (CA) (AUC 0.72, p = 0.0077). An N20-P25 amplitude > 1.6 μV predicted awakening in CA, with a sensitivity of 100% (95% confidence interval [CI] 81.6-100%) and specificity of 46.7% (95% CI 30.9-60.9%). In SAH, an N20-P25 amplitude > 0.74 μV predicted the sensitivity and specificity of awakening were 100% (95% CI 93.8-100%) and 16% (95% CI 8.3-28.5%), respectively. In TBI, an N20-P25 amplitude > 1.20 μV predicted awakening with a sensitivity of 100% (95% CI 86.2-100%) and a specificity of 34.2% (95% CI 21.2-50.1%). An N20-P25 amplitude > 0.65 μV predicted the sensitivity and specificity of awakening in ICH were 100% (95% CI 91.0-100%) and 14.3% (95% CI 5.7-31.5%), respectively.

Conclusions: N20-P25 amplitude can predict awakening in patients in a coma state at 1 year. Different diseases have different cutoff values for predicting awakening.