Eye and Brain (Jul 2022)
Association Between Vision and Brain Cortical Thickness in a Community-Dwelling Elderly Cohort
Abstract
Chloé Chamard,1,2 Jerome J Maller,3,4 Nicolas Menjot,5 Eloi Debourdeau,1 Virginie Nael,6 Karen Ritchie,2,7 Isabelle Carriere,2,* Vincent Daien1,2,8,* 1Department of Ophthalmology, Gui de Chauliac Hospital, Montpellier, F-34000, France; 2Institute for Neurosciences of Montpellier INM, University Montpellier, INSERM, Montpellier, F-34091, France; 3General Electric Healthcare, Melbourne, VIC, Australia; 4Monash Alfred Psychiatry Research Centre, Melbourne, VIC, Australia; 5Department of Neuroradiology, Gui de Chauliac Hospital, Montpellier, F-34000, France; 6Bordeaux Population Health Research Center, UMR 1219, University Bordeaux, INSERM, Bordeaux, F-33000, France; 7Department of Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; 8The Save Sight Institute, Sydney Medical School, the University of Sydney, Sydney, NSW, Australia*These authors contributed equally to this workCorrespondence: Chloé Chamard, Department of Ophthalmology, Gui de Chauliac Hospital, 80 avenue Augustin Fliche, Montpellier, F-34000, France, Tel +33 6 33 55 65 06, Email [email protected]: Visual impairment is a major cause of disability and impairment of cognitive function in older people. Brain structural changes associated with visual function impairment are not well understood. The objective of this study was to assess the association between visual function and cortical thickness in older adults.Methods: Participants were selected from the French population-based ESPRIT cohort of 2259 community-dwelling adults ≥ 65 years old enrolled between 1999 and 2001. We considered visual function and brain MRI images at the 12-year follow-up in participants who were right-handed and free of dementia and/or stroke, randomly selected from the whole cohort. High-resolution structural T1-weighted brain scans acquired with a 3-Tesla scanner. Regional reconstruction and segmentation involved using the FreeSurfer image-analysis suite.Results: A total of 215 participants were included (mean [SD] age 81.8 [3.7] years; 53.0% women): 30 (14.0%) had central vision loss and 185 (86.0%) normal central vision. Vision loss was associated with thinner cortical thickness in the right insula (within the lateral sulcus of the brain) as compared with the control group (mean thickness 2.38 [0.04] vs 2.50 [0.03] mm, 4.8% thinning, pcorrected= 0.04) after adjustment for age, sex, lifetime depression and cardiovascular disease.Conclusion: The present study describes a significant thinning of the right insular cortex in older adults with vision loss. The insula subserves a wide variety of functions in humans ranging from sensory and affective processing to high-level cognitive processing. Reduced insula thickness associated with vision loss may increase cognitive burden in the ageing brain.Keywords: visual function, vision, cortical thickness, brain, morphometry, MRI
