Evaluating associations of RNFL thickness and multifocal VEP with cognitive assessment and brain MRI volumes in older adults: Optic nerve decline and cognitive change (ONDCC) initiative

Abstract

To examine the relationships of retinal structural (optical coherence tomography) and visual functional (multifocal visual evoked potentials, mfVEP) indices with neuropsychological and brain structural measurements in healthy older subjects. 95 participants (mean (SD) age 68.1 (9.0)) years were recruited in the Optic Nerve Decline and Cognitive Change (ONDCC) study in this observational clinical investigation. OCT was conducted for retinal nerve fibre layer (RNFL) and mfVEP for amplitude and latency measurements. Participants undertook neuropsychological tests for cognitive performance and MRI for volumetric evaluation of various brain regions. Generalised estimating equation models were used for association analysis (p < 0.05). The brain volumetric measures including total grey matter (GM), cortex, thalamus, hippocampal and fourth ventricular volumes were significantly associated with global and sectoral RNFL. RNFL thickness correlated with delayed recalls of California verbal learning test (CVLT) and Rey complex figure test (RCFT). The mfVEP amplitudes associated with cerebral white matter (WM) and cingulate GM volumes in MRI and CVLT, RCFT and trail making test outcomes. A significant association of mfVEP latency with logical memory delayed recall and thalamus volume was also observed. Our results suggested significant association of specific RNFL and mfVEP measures with distinctive brain region volumes and cognitive tests reflecting performance in memory, visuospatial and executive functional domains. These findings indicate that the mfVEP and RNFL measurements may parallel brain structural and neuropsychological measures in the older population.