Optical coherence tomography as a potential biomarker for the logopenic variant of primary progressive aphasia: A cross-sectional prospective study.

Optical coherence tomography (OCT) and OCT angiography (OCT-A) have been studied as biomarkers for Alzheimer's disease (AD), with promising results. Nevertheless, their potential in the logopenic variant of primary progressive aphasia (lvPPA), which shares the same amyloid pathology, has not yet been explored. This work aimed to characterize retinal changes in lvPPA compared to healthy controls. Ten participants with lvPPA and eleven controls underwent OCT and OCT-A imaging. Amyloid pathology in lvPPA was confirmed by lumbar puncture. Retinal parameters included retinal nerve fiber layer (RNFL) thickness and foveal avascular zone (FAZ). Compared to controls, lvPPA participants exhibited reduced RNFL thickness in the temporal sector (p = 0.013) and significantly decreased FAZ circularity (p = 0.002). RNFL thinning may reflect trans-synaptic degeneration from cortical atrophy, while reduced FAZ circularity suggests early microvascular changes related to amyloid burden. Our findings support OCT and OCT-A as potential biomarkers for lvPPA. For the first time, OCT and OCT-A are studied as potential biomarkers for lvPPA.Compared to healthy controls, retinal nerve thickness is decreased in lvPPA patients.Retinal vasculature exhibits structural alterations in lvPPA patients.