Item Details

title

THE NEURAL CORRELATES OF VISUAL CONTRAST SENSITIVITY DYSFUNCTION IN OLDER ADULTS

author

Tanase, Alexis Diana

abstract

Older adults with visual impairment (VI), such as poor contrast sensitivity (CS), are prone to experience many limitations, but the underlying neuro-ophthalmic mechanism remains unclear. CS is an individual’s capacity to detect light and dark shading differences. Poor CS is associated with worse performance on routine tasks, cognition, mobility, and increased risk of falls and car accidents, and injuries which can contribute to lower quality of life. To investigate a neuro-ophthalmic relationship between CS and the brain, functional magnetic resonance imaging (fMRI) data from 192 cognitively-unimpaired older adults ≥70 years old at baseline from the Brain Networks and Mobility (B-NET) study were analyzed. Functional brain networks were divided into interconnected communities, and lower baseline CS was linked to degraded community structures particularly in the sensorimotor network (SMN) during rest, and in the visual network (VN) and default mode network (DMN) during a motor imagery (MI) task. In a longitudinal analysis, worse baseline CS predicted lower community structure integrity at 30-months, notably in the VN, dorsal attention network (DAN), and DMN during the MI task, as well as degraded DMN during rest. Overall, poor CS is associated with decreased functional connectivity and is predictive of future brain network disintegration. Thus, poor CS identifies a subset of older adults at risk of future decrements in brain circuits important for vision and associated activities such as driving or mobility. Further research should explore if decreased CS can be improved and positively influence functional brain health in older adults. In terms of clinical relevance, brain networks associated with CS may also underlie the low physical function observed in people with poor CS.

subject

Aging

Brain networks

Community structure

Contrast sensitivity

fMRI

Vision neuroscience

contributor

Laurienti, Paul J. (advisor)

Laurienti, Paul J. (committee member)

Thompson, Atalie C. (committee member)

Sappington, Rebecca M. (committee member)

date

2024-05-23T08:36:26Z (accessioned)

2025-05-22T08:30:07Z (available)

2024 (issued)

degree

Neuroscience – MS (discipline)

embargo

2025-05-22 (terms)

identifier

http://hdl.handle.net/10339/109454 (uri)

language

en (iso)

publisher

Wake Forest University

type

Thesis