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Makayla McCoskey, Victoria Addis, PRITHVI SANKAR, Jin Sha, Maureen G Maguire, Eydie G Miller-Ellis, Amanda Lehman, Rebecca Janet Salowe, Laura O'Keefe, Joan M O'Brien; Association between Cognitive Impairment and Primary Open-Angle Glaucoma Using the Montreal Cognitive Assessment. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2834.
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It has been hypothesized that primary open-angle glaucoma (POAG) may be associated with cognitive impairment and/or dementia because both are age-related neurodegenerative processes. Neuropathy in POAG extends throughout the visual pathway, from the optic nerve to visual cortex. It is unclear whether glaucoma affects other neurological functions, such as cognition, in addition to vision. This study examined the potential association between POAG and cognitive impairment.
The Montreal Cognitive Assessment (MoCA) was administered to patients enrolled in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study at the Scheie Eye Institute. This was an initial pilot study. Patients were categorized into two groups: POAG cases and non-POAG controls. A single investigator, masked to patient diagnostic status, administered the MoCA to all patients. Patients received a total score (out of 30 possible points), as well as sub-scores evaluating visuospatial/executive function, naming, memory, attention, language, abstraction, and orientation. Scores were compared between diagnostic categories. Cases were further assessed by retinal nerve fiber layer (RNFL) thickness measurements. Adjustments were made for age, sex, and educational level.
The MoCA was administered to 88 patients in total: 49 cases (average age=70.2, age range=44-88) and 39 controls (average age=64.9, age range=39-87). Before adjustment, the mean difference between cases and controls was -1.40 (95% CI=-3.08-0.28, p=0.09). After adjustment for age, sex, and educational level, however, the mean difference was not statistically significant, at -0.63 (95% CI=-1.92-0.67, p=0.34). There was no statistically significant association between RNFL thickness and MoCA score in POAG cases (95% CI=-0.21-0.03, p=0.17).
These data do not demonstrate large differences between POAG cases and controls in cognitive function as measured by the MoCA. Neurodegeneration associated with glaucoma may be limited to the visual pathway, and may not extend more globally in the brain to affect neural pathways involved in cognition. Alternatively, the MoCA may not be a sensitive enough test to evaluate subtle differences in cognitive ability in POAG patients. Finally, it is possible that only a subset of patients manifest a cognitive impairment associated with POAG, so a larger, better-powered study is planned.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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