The Prognostic Role of Candidate Serum Biomarkers in the Post-Acute and Chronic Phases of Disorder of Consciousness: A Preliminary Study

Abstract

Introduction: Serum biomarkers, such as Neurofilament Light (NF-L), Glial Fibrillary Acidic Protein (GFAP), Ubiquitin C-terminal Hydrolase (UCH-L1), and Total-tau (T-Tau) have been proposed for outcome prediction in the acute phase of severe traumatic brain injury, but they have been less investigated in patients with prolonged DoC (p-DoC).

Methods: We enrolled 25 p-DoC patients according to the Coma Recovery Scale-Revised (CRS-R). We identified different time points: injury onset (t₀), first blood sampling at admission in Neurorehabilitation (t₁), and second blood sampling at discharge (t₂). Patients were split into improved (improved level of consciousness from t₁ to t₂) and not-improved (unchanged or worsened level of consciousness from t₁ to t₂).

Results: All biomarker levels decreased over time, even though each biomarker reveals typical features. Serum GFAP showed a weak correlation between t₁ and t₂ (p = 0.001), while no correlation was observed for serum NF-L (p = 0.955), UCH-L1 (p = 0.693), and T-Tau (p = 0.535) between t₁ and t₂. Improved patients showed a significant decrease in the level of NF-L (p = 0.0001), UCH-L1 (p = 0.001), and T-Tau (p = 0.002), but not for serum GFAP (p = 0.283). No significant statistical differences were observed in the not-improved group.

Conclusions: A significant correlation was found between the level of consciousness improvement and decreased NF-L, UCH-L1, and T-Tau levels. Future studies on the association of serum biomarkers with neurophysiological and neuroimaging prognostic indicators are recommended.

Keywords: acquired brain injury; prolonged disorders of consciousness; serum biomarkers.

Figure 1

Biomarker levels (in log pg/mL) showed by patients at t₁ and t₂.

Figure 2

Biomarker levels (in standardized values) by t₁ and t₂ and groups (improved/not improved).