Access Type

Open Access Thesis

Date of Award

January 2013

Degree Type

Thesis

Degree Name

M.A.

Department

Psychology

First Advisor

John L. Woodard

Abstract

Two theories predominate to explain the covariation of cognitive and sensory functions across the lifespan: The Common Cause hypothesis and the Sensory Deprivation hypothesis. It was hypothesized that the Common Cause hypothesis better accounted for the these relationships. This hypothesis was assessed by examining the associations between sensory functioning, cognitive functioning, functional status, and motor functioning in samples of octogenarians (n = 80) and centenarians (n = 244) drawn from the Georgia Centenarian Study, Phase 3, Project 3. Special attention was given to cross-sensory-modality associations. Hierarchical regressions were also utilized to determine whether inclusion of either measured or self-reported sensory functioning predictors or motor functioning predictors would result in incremental variance accounted for in late-life outcomes, beyond variance explained by demographic factors alone. The relative predictive value of each sensory indicator was also compared for octogenarians and centenarians to determine whether the covariation of sensory, cognitive, and functional abilities increased across the lifespan. Although age and education were important predictors of late-life cognitive and functional outcomes, sensory functions accounted for significant proportions of variance in several late-life outcomes. In particular, objectively-measured hearing ability consistently predicted variance in cognitive and functional abilities. Furthermore, grip strength and hand-tapping ability were significant predictors of late-life outcomes. The results of the current study provide strong evidence for the common cause hypothesis of cognitive aging.

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