# Diagnostic value of somatosensory evoked potentials for paroxysmal sympathetic hyperactivity: a retrospective cohort study

## TL;DR

This study shows that a specific brain signal (N20-P25 amplitude) can help predict a condition called paroxysmal sympathetic hyperactivity in patients with prolonged disorders of consciousness.

## Contribution

The study identifies reduced N20-P25 amplitude as a novel electrophysiological biomarker for early prediction of paroxysmal sympathetic hyperactivity.

## Key findings

- Reduced N20-P25 amplitude is an independent predictor of paroxysmal sympathetic hyperactivity (PSH).
- Combining reduced N20-P25 amplitude with younger age and male gender improves PSH prediction accuracy.
- The area under the curve for PSH prediction using N20-P25 amplitude is 0.811 with 79.7% sensitivity and 75% specificity.

## Abstract

This study aimed to investigate the diagnostic value of somatosensory evoked potentials (SEPs) in patients with paroxysmal sympathetic hyperactivity (PSH) and to identify independent predictors of the condition.

A retrospective cohort study was conducted on 123 patients with prolonged disorders of consciousness (PDOC) admitted to the Critical Care Rehabilitation Department of Nanjing Jiangning Hospital between August 2022 and August 2024. Patients were classified into PSH-positive (PSH+) and PSH-negative (PSH−) groups according to the Paroxysmal Sympathetic Hyperactivity Assessment Measure (PSH-AM). Demographic, clinical, and SEPs parameters were collected. Univariate and multivariate logistic regression analyses were employed to examine the association between these variables and PSH. The predictive performance was evaluated using receiver operating characteristic (ROC) curve analysis.

A total of 123 patients with prolonged disorders of consciousness were enrolled in the study. Among these, 34 patients (27.64%) were classified into the PSH + group and 89 patients (72.36%) into the PSH − group. Multivariate logistic regression analysis identified younger age (OR = 0.96, 95% CI: 0.92–0.99, p = 0.02), male patient (OR = 0.28, 95% CI: 0.09–0.75, p = 0.02), and reduced N20-P25 amplitude (OR = 0.34, 95% CI: 0.13–0.70, p = 0.01) as independent predictors of PSH. Using a cut-off value of 1.19 μV for the N20-P25 amplitude, the area under the curve (AUC) for discriminating PSH was 0.811 (95% CI: 0.71–0.912), yielding a sensitivity of 79.7% and a specificity of 75%. The combination of these three predictors improved the AUC to 0.846 (95% CI: 0.75–0.942). After adjusting for potential confounders, partial correlation analysis demonstrated a significant negative correlation between N20-P25 amplitude and PSH-AM score (adj. r = −0.30, p = 0.003).

A reduced N20-P25 amplitude may serve as an independent and objective electrophysiological biomarker for the early prediction of PSH. In combination with younger age and male patient, it contributes to the identification of high-risk populations and offers valuable guidance for clinical management.