RESUMO
Introduction: The occurrence of age-related vision changes is inevitable. However, some of these changes can become pathological. Research indicates that vision and hearing loss is correlated with age-related cognitive decline, and with a higher risk of developing dementia due to Alzheimer's disease. Low vision rehabilitation could possibly be a protective factor against cognitive decline, as it provides the clients with compensatory strategies to overcome their visual deficits. Objectives and hypothesis: The aim of this pilot study was to assess correlations between visual and cognitive functions in older adults referred for low vision rehabilitation. We hypothesized that more severe impairment of visual acuity and contrast sensitivity would be correlated with more advanced levels of cognitive impairment. The second objective was to examine which of these correlations would remain significant once established variables that influence cognition are statistically removed (e.g., age, education). Methods: Thirty-eight older adults (age range: 66-97 years old) with a visual impairment (acuity <20/70) were recruited before the onset of their low vision rehabilitation. They underwent vision (reading acuity, reading speed, contrast sensitivity), hearing (audiogram, speech-in-noise perception) and cognitive (global cognition, memory, executive functions) testing, and demographic information was obtained. Results and discussion: Correlations among global cognition and visual aid use, memory and reading speed, memory and contrast sensitivity, memory, and visual aid use, and between executive functions and contrast sensitivity were significant. Correlations between contrast sensitivity and memory, as well as between global cognition and visual aid use remained significant after controlling for age and education. The present study is relevant to clinicians who are assessing the cognitive status of older adults, such as neuropsychologists, because it highlights the importance of considering low vision when administering neuropsychological tests, especially to persons who have not yet received rehabilitation for their visual impairment.
RESUMO
The human brain is highly cross-modal, and sensory information may affect a wide range of behaviors. In particular, there is evidence that auditory functions are implicated in oculomotor behaviors. Considering this apparent auditory-oculomotor link, one might wonder how the loss of auditory input from birth might have an influence on these motor behaviors. Eye movement tracking enables to extract several components, including saccades and smooth pursuit. One study suggested that deafness can alter saccades processing. Oculomotor behaviors have not been examined further in the deaf. The main goal of this study was to examine smooth pursuit following deafness. A pursuit task paradigm was used in this experiment. Participants were instructed to move their eyes to follow a target as it moved. The target movements have a possibility of four different trajectories (horizontal, vertical, elliptic clockwise, and elliptic counter-clockwise). Results indicate a significant reduction in the ability to track a target in both elliptical conditions showing that more complex motion processing differs in deaf individuals. The data also revealed significantly more saccades per trial in the vertical, anti-clockwise, and, to a lesser extent, the clockwise elliptic condition. This suggests that auditory deprivation from birth leads to altered overt oculomotor behaviors.
