Transient Global Amnesia (TGA): Is It Really Benign? A Pilot Study on Blood Biomarkers

Abstract

We aimed to determine whether transient global amnesia (TGA) is associated with alterations in central nervous system (CNS) injury biomarkers-serum neurofilament light chain (sNfL) and serum glial fibrillary acidic protein (sGFAP). In a prospective cohort of TGA patients, blood samples were obtained within 24-48 h of TGA onset (t0) and 6 weeks thereafter (t1). We assessed sNfL and sGFAP levels using the highly sensitive single-molecule array assay and calculated Z-scores adjusted for age, gender, and body mass index (BMI). Demographics, electroencephalography (EEG), and cerebral magnetic resonance imaging (cMRI) findings were also collected. A total of 20 patients were included (median age: 66 years, 70% women). No significant changes in sNfL or sGFAP levels associated with TGA at t0 and t1 were observed. Median sNfL Z-scores were 0.45 (interquartile range [IQR] -0.09, 1.19) at t0 and 0.60 (IQR -0.61, 1.19) at t1. Median sGFAP Z-scores were 0.27 (IQR -0.45, 0.76) at t0 and 0.44 (IQR -0.27, 0.75) at t1. Similarly, in the subgroup of patients with diffusion-weighted imaging (DWI)-positive hippocampal lesions (n = 5/20[25%]), no elevations in blood biomarkers were detected. Our pilot study on neurological blood biomarkers supports the benign nature of TGA, indicating that no CNS tissue damage occurs.

Keywords: Simoa; TGA; central nervous system; glial fibrillary acidic protein; memory disorders; neurofilament light chain; prognosis.

Figure 1

Serum neurofilament (sNfL, Panel A) and serum glial fibrillary acidic protein (sGFAP, Panel B) levels in 20 patients with emergent TGA, measured within 24 to 48 h of symptom onset (t0) and at 6 weeks (t1).