Retinal Changes linked With Alzheimer Disease Neuroimaging B
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Retinal biomarkers reflecting in vivo brain Alzheimer disease (AD) pathologic abnormalities could be a useful tool for screening cognitively normal (CN) individuals at the preclinical stage of AD.

A Study was conducted to investigate the association of both functional and structural alterations of the retina with in vivo AD pathologic abnormalities in CN older adults and model a screening tool for detection of preclinical AD.

This cross-sectional study included a total of 49 CN individuals. All participants underwent complete ophthalmic examination, including swept-source optical coherence tomography (SS-OCT) and multifocal electroretinogram as well as amyloid-beta positron emission tomography and magnetic resonance imaging.

For structural parameters of the retina, the thickness of the macula and layer-specific thicknesses, including peripapillary retinal nerve fiber layer and ganglion cell-inner plexiform layer measured by SS-OCT, were used for analysis. For functional parameters of the retina, implicit time and amplitude of rings 1 to 6 measured by multifocal electroretinogram were used.

--Of the 49 participants, 25 were women, mean (SD) age was 70.6 years.

--Compared with 33 CN individuals without Abeta deposition(Abeta - CN), the 16 participants with (Abeta +CN) showed reduced inner nasal macular thickness (mean [SD], 308.9 vs 286.1 microm) and retinal nerve fiber layer thickness, particularly in the inferior quadrant (133.8 vs 103.8 microm).

--In addition, the Abeta+CN group showed prolonged implicit time compared with the Abeta -CN group, particularly in ring 5 (41.3 vs 38.2 milliseconds).

--AD-related neurodegeneration was correlated with the thickness of the ganglion cell-inner plexiform layer only (r=0.41).

--The model to differentiate the Abeta+CN vs Abeta-CN groups derived from the results showed 90% accuracy.

The results of this research, which showed both functional and structural changes in the retina assessed by multifocal electroretinogram and SS-OCT in preclinical AD, indicate that retinal biomarkers may be used to detect in vivo AD pathologic abnormalities in CN older adults.