title: Retinal thinning is uniquely associated with medial temporal lobe atrophy in neurologically normal older adults.
abstract: Given the converging pathologic and epidemiologic data indicating a relationship between retinal integrity and neurodegeneration, including Alzheimer's disease (AD), we aimed to determine if retinal structure correlates with medial temporal lobe (MTL) structure and function in neurologically normal older adults. Spectral-domain optical coherence tomography, verbal and visual memory testing, and 3T-magnetic resonance imaging of the brain were performed in 79 neurologically normal adults enrolled in a healthy aging cohort study. Retinal nerve fiber thinning and reduced total macular and macular ganglion cell volumes were each associated with smaller MTL volumes (ps < 0.04). Notably, these markers of retinal structure were not associated with primary motor cortex or basal ganglia volumes (regions relatively unaffected in AD) (ps > 0.70), or frontal, precuneus, or temporoparietal volumes (regions affected in later AD Braak staging ps > 0.20). Retinal structure was not significantly associated with verbal or visual memory consolidation performances (ps > 0.14). Retinal structure was associated with MTL volumes, but not memory performances, in otherwise neurologically normal older adults. Given that MTL atrophy is a neuropathological hallmark of AD, retinal integrity may be an early marker of ongoing AD-related brain health.
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA. Electronic address: kaitlin.casaletto@ucsf.edu.
authors.forename: Kaitlin B
authors.initials: KB
authors.lastname: Casaletto
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA; National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Ward
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Baker
authors.affiliation: Department of Neurosurgery, Rocky Mountain Alzheimer's Disease Center, University of Colorado, Denver Anschutz Medical Center, Aurora, CO, USA; Department of Neurology, Rocky Mountain Alzheimer's Disease Center, University of Colorado, Denver Anschutz Medical Center, Auorora, CO, USA.
authors.forename: Brianne M
authors.initials: BM
authors.lastname: Bettcher
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Gelfand
authors.affiliation: Gladstone Institute of Neurological Disease, Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Yaqiao
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Shubir
authors.initials: S
authors.lastname: Dutt
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Miller
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Joel H
authors.initials: JH
authors.lastname: Kramer
authors.affiliation: Department of Neurology, University of California, San Francisco, CA, USA.
authors.forename: Ari J
authors.initials: AJ
authors.lastname: Green
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000473:pathology; D001284:Atrophy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009410:Nerve Degeneration; D012160:Retina / Q000000981:diagnostic imaging / Q000473:pathology*; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology*; D041623:Tomography, Optical Coherence
keywords: Aging; Alzheimer's disease; Dementia; Neurodegenerative disease; Optical coherence tomography; Retinal imaging