Electroencephalographic differences between waking and sleeping periods in patients with prolonged disorders of consciousness at different levels of consciousness

KeKe Li ¹ Man Li ² Wanqing Liu ^1,3 Yanzhi Wu ¹ Fang Li ¹ Jingwei Xie ¹ Shaolong Zhou ¹ Sen Wang ¹ Yongkun Guo ^1* Jiahui Pan ^4* Xinjun Wang ^1,3*

• ¹ Department of Neurosurgery, The Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
• ² School of Automation Science and Engineering, South China University of Technology, Guangzhou, Guangdong Province, China
• ³ Department of Neurosurgery, The Third Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, China
• ⁴ School of Software, South China Normal University, Guangzhou, China

Objective: This study aims to explore differences in sleep electroencephalogram (EEG) patterns in prolonged disorders of consciousness, utilizing polysomnography to assist in distinguishing between vegetative state (VS) / unresponsive wakefulness syndrome (UWS) and minimally conscious state (MCS), thereby reducing misdiagnosis rates and enhancing the quality of medical treatment.Methods: A total of 40 patients with prolonged disorders of consciousness (27 with VS/UWS and 13 with MCS) underwent polysomnography. We analyzed the differential EEG indices between VS/UWS and MCS and performed correlation analyses between these indices and the Coma Recovery Scale-Revised (CRS-R) scores. The diagnostic accuracy of the differential indices was evaluated using receiver operating characteristic (ROC) curves.Results: 1.The fractal dimension (HFD) of MCS patients tended to be higher than that of VS/UWS in all phases, with a significant difference only in the waking phase (P < 0.05). The HFD in the waking phase was positively correlated with the CRS-R score and had the highest diagnostic accuracy at 88.3%. Teager_kaiser_energy4 (TKEO) also showed higher levels than VS/UWS, significantly in NREM2 (P < 0.05), with a positive correlation with the CRS-R score and a diagnostic accuracy of 75.2%. The δ-band power spectral density (PSD(δ)) of MCS patients was lower than that of VS/UWS, significantly in the waking phase (P < 0.05), and negatively correlated with the CRS-R score, with a diagnostic accuracy of 71.5%.Polysomnography for VS/UWS and MCS reveals significant differences, aiding in distinguishing between the two patient categories and reducing misdiagnosis rates. Notably, the HFD and PSD(δ) excels during wakefulness compared to sleep, while TKEO shines in the NREM2 stage.Notably, HFD boasts a robust correlation with CRS-R scores, the highest diagnostic accuracy, and shows immense promise in the clinical diagnosis of prolonged disorders of consciousness.