Analysis of Brainstem Auditory Evoked Potential Characteristics in Patients with Chronic Disorders of Consciousness: A Cross-Sectional Study

Background Brainstem auditory evoked potentials (BAEP) provide an objective assessment of brainstem functional integrity. However, their characteristic profiles and clinical significance in patients with prolonged disorders of consciousness (pDOC) remain to be fully elucidated, especially in small, well-characterized cohorts. Objective This study aimed to preliminarily characterize BAEP parameters in a small sample of pDOC patients and explore their relationship with consciousness levels. Methods In this cross-sectional study, 29 patients with pDOC (16 with unresponsive wakefulness syndrome [UWS] and 13 in a minimally conscious state [MCS]) were enrolled. BAEP recordings, neurological assessments using the Coma Recovery Scale-Revised (CRS-R), and medical record reviews were performed. BAEP parameters (wave latencies, interpeak latencies [IPLs]) were compared between UWS and MCS groups using Mann-Whitney U tests. Effect sizes (r) were calculated to quantify the magnitude of observed differences. Spearman correlation was used to assess the relationship between BAEP parameters and CRS-R scores. Results No significant differences were observed in the latencies of wave I, wave III, the I–III interpeak interval (IPL), the III–V IPL, or the I–V IPL between the unresponsive wakefulness syndrome (UWS) group and the minimally conscious state (MCS) group (all P > 0.05). However, the study revealed a trend toward prolongation in the latency of wave V and the I–V IPL in the UWS group. Both wave V latency (r = − 0.342) and I–V IPL (r = − 0.354) demonstrated moderate effect sizes, suggesting the presence of substantive differences in these measures between the two groups. Additionally, a moderate negative correlation was observed between the I–V IPL and the total score of the Coma Recovery Scale–Revised (CRS-R) (Spearman’s ρ = − 0.447, p  < 0.001). Conclusion Although no significant differences were observed in the brainstem auditory evoked potential (BAEP) parameters between the two patient groups, the trend of prolonged I–V interpeak interval (IPL) in the unresponsive wakefulness syndrome (UWS) group, along with its moderate correlation with the Coma Recovery Scale–Revised (CRS-R) score, suggests that UWS patients may have more severe brainstem dysfunction. Therefore, BAEP remains a promising electrophysiological marker for assessing brainstem impairment in patients with prolonged disorders of consciousness (pDOC). Although these preliminary findings did not reach statistical significance in intergroup comparisons, they highlight the need for larger sample sizes in future studies to clarify the role of BAEP in the evaluation of consciousness disorders.