Functional Recovery of Episodic Memory After Bilateral Fornix Infarction: A Longitudinal Tractography Case Report

We present a rare case of bilateral fornix infarction in a 51-year-old woman who developed acute anterograde amnesia despite preserved general cognition. Serial neuropsychological assessments and diffusion tensor imaging-based tractography revealed a correlation between changes in fractional anisotropy (FA) and cognitive recovery, particularly in verbal and visual memory domains. Notably, Wechsler Memory Scale-Revised (WMS-R) delayed recall improved from <50 to 83, and Rey-Osterrieth complex figure test (ROCFT) delayed recall improved from 8 to 23 points during hospitalization. Tractography enabled standardized and reproducible analysis not only of the fornix but also of Papez circuit-related tracts, including the anterior thalamic radiation and cingulum subdivisions. Longitudinal reductions in FA were observed in the fornices, likely reflecting Wallerian degeneration, whereas concurrent cognitive improvement suggested functional reorganization. This case highlights the potential of tractography-derived metrics as biomarkers of structural integrity and cognitive prognosis following focal injury to memory-critical white matter pathways. These findings may inform the development of imaging-guided strategies for monitoring and supporting cognitive rehabilitation in patients with strategic white matter lesions.