Accelerated Brain Atrophy, Microstructural Decline and Connectopathy in Age-Related Macular Degeneration

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Age-related macular degeneration (AMD) is increasingly associated with cognitive impairment.
• The precise impact of AMD on brain aging trajectories remains incompletely understood.

Purpose of the Study:

• To investigate the location, extent, and temporal dynamics of brain changes in individuals with AMD using longitudinal diffusion MRI.
• To explore the relationship between retinal health and brain structure/function in AMD.

Main Methods:

• Longitudinal diffusion MRI study with 40 participants (20 AMD, 20 controls) over 2 years.
• Voxel-based morphometry and diffusion tensor imaging analyses to assess brain volume and white matter integrity (Fractional Anisotropy - FA).
• Bundle analysis to examine specific white matter tracts, including inter-lingual and lingual-cerebellar connections.

Main Results:

• AMD participants showed reduced gray matter volume in the cuneate, temporal, and cingulate gyri at baseline.
• Over 2 years, AMD participants exhibited accelerated volume reduction in the temporal cortex and decreased FA in the occipital lobe and superior frontal cortex.
• Lingual gyrus streamline length was reduced in AMD at baseline, with FA differences in related bundles observed at follow-up, indicating downstream effects of vision loss.

Conclusions:

• AMD is associated with widespread brain structural changes, affecting cognitive and visual processing networks.
• These findings suggest AMD accelerates brain aging and impacts neural pathways beyond primary visual processing areas.
• The study highlights a significant connection between retinal health and brain integrity, with vision loss having downstream neurological consequences.