The association between pupil reactivity and cognitive measures among community-dwelling middle-aged and older adults

Title : The association between pupil reactivity and cognitive measures among community-dwelling middle-aged and older adults

Abstract:

Aims: The pupillary light reflex (PLR) has been widely used to reflect visual function and brain activities, making it a potential biomarker for central nervous system (CNS) neurodegeneration. In this cross-sectional study, we evaluated the association between the PLRs and cognition in community-dwelling middle-aged and older individuals.

Methods: Pupil reactivity was recorded using a binocular infrared pupillometer (Neur-Optics, Inc., Irvine, CA) in 403 participants (mean age 60.7 years, 57.3% females) from the Beaver Dam Offspring Study, an epidemiologic cohort study of aging. Thirteen pupil parameters were calculated to describe the PLRs. Cognitive testing consisted of Trail Making Test A and B, Rey Auditory Verbal Learning Test, Digit Symbol Substitution Test, and Verbal Fluency Test. Principal component analysis (PCA) was used to calculate an overall cognitive function score. Linear regression was used to assess the association between pupil parameters and PCA scores, adjusting for age, sex, education, medications, health-related quality of life, and systemic and ocular comorbidities.

Results: Cognitive scores decreased by 0.039 (95% CI [-0.050, -0.028]) per year increase in age and were lower in males than females by 0.76 (95% CI [-0.96, -0.55]) (p < 0.001). Pupil constriction amplitude in millimeters, the duration from stimulus onset to maximal constriction velocity, and the post-illumination pupil response were significantly associated with cognition after adjusting for (1) age and sex and (2) age, sex, and multiple covariates (p < 0.05). 

Conclusions: In this study, we found an association between multiple PLR measures and cognitive function in middle-aged and older adults. The findings suggest the potential of pupil reactivity to serve as a biomarker of brain aging. Future longitudinal research needs to assess if changes in the PLR can predict cognitive decline over time. 

Audience Take Away

• The anatomy and physiology of the PLRs pathway
• How brain aging may affect the neuronal substrates of the PLRs pathway
• The PLRs are associated with neuropsychological cognitive measures
• The potential of the PLRs to serve as a biomarker of brain aging and neurodegeneration

Biography:

Dr. Chen received her MD at Beijing Medical University, China, in 1994 and a PhD at the State University of New York, U.S.A., in 2004. She completed a neurology residency at Saint Louis University and a neuro-ophthalmology fellowship at the University of Iowa before joining the faculty in the Department of Ophthalmology and Visual Sciences at the University of Wisconsin Madison in 2011. As a Neuro-ophthalmology, Dr. Chen’s research focuses on using the pupil as a biomarker for brain aging and neurodegeneration. She has published about 30 research articles in SCI(E) journals.