The Effect of Reading Rehabilitation for Age-Related Vision Impairment on Cognitive Functioning: A non-randomized pre-post intervention study protocol (Preprint)

BACKGROUND Age-related vision impairment and dementia both become more prevalent with increasing age. Research into the mechanisms of these conditions has proposed that some of their causes (e.g., macular degeneration/glaucoma and Alzheimer’s disease) could be symptoms of an underlying common cause, or may be equally linked to a multifactorial context in frailty and aging. Research into sensory-cognitive aging has provided preliminary data that sensory decline may be linked to the progression of dementia through the concept of sensory deprivation. Preliminary data in hearing loss rehabilitation support the idea that improved hearing may have a beneficial effect on cognitive functioning; however, there are to date no data available to examine whether low vision rehabilitation, specifically for reading, could have an equally protective or beneficial effect on cognitive health. The present proposal aims to fill this gap. OBJECTIVE The research questions are the following: 1. Does low vision rehabilitation reduce reading effort? 2. If so, does reduced reading effort increase reading activity, and 3. If so, does increased reading activity improve cognitive (memory) functioning? The objectives are to evaluate cognitive functioning and memory before, and 6 and 12 months after low vision reading rehabilitation using magnification in patients with age-related macular degeneration or glaucoma, compared to age-matched healthy controls, and to correlate participant characteristics with all cognitive outcome variables in order to identify potential mediators, moderators or confounders. METHODS We will employ a quasi-experimental approach (non-randomized, pre-post intervention study), an approach frequently used during the evaluation of health interventions. A 3x3 design (3 groups x 3 time points) will allow us to examine whether cognitive performance will change before and after 6 and 12 months of a low vision reading intervention, when comparing low vision and dual sensory impaired (vision & hearing) patients to age-matched controls with age-normal vision and hearing. We will recruit 150 newly referred clients, as well as 50 age-matched controls. The study includes outcomes measures of vision (e.g., reading acuity and speed), cognition (e.g., short-term and long-term memory, processing speed), as well as potential descriptors, demographics, clinical data and co-variants (e.g., speech perception in noise, depression, anxiety, stress). RESULTS To analyze these data, we will examine change in cognitive test scores from baseline over time using mixed-effects regression models, adjusting for level of vision and hearing impairment as fixed or random effects, and compare across sensory groups. Additional analyses will include latent factor analysis to explore whether specific clusters of variables are specifically associated with improvements in cognitive functioning and/or improved reading ability. CONCLUSIONS We anticipate that evidence of protective effects caused by reading rehabilitation will have a considerable impact on the vision rehabilitation community and their clients as well as all professionals involved in the care of older adults with or without dementia. If we can demonstrate that reading rehabilitation has a beneficial effect on cognition, the demand for such rehabilitation services will likely increase at an accelerated rate, potentially preventing cognitive decline across multiple groups of older adults, including those at risk or already affected by early signs of macular degeneration. CLINICALTRIAL ClinicalTrials.gov ID: NCT04276610; Unique Protocol ID: CRIR-1284-1217; https://clinicaltrials.gov/ct2/show/NCT04276610