Working memory and inhibition performance predicts phonological processing in elderly women: Evidence from behavioral and electrophysiological indices
Abstract
To determine how event-related electrical activity in the brain relates to cognitive functioning in a group of 27 normally aging females (68-73 years of age), participants were separated into high and low groups based on their performance on cognitive measures of three domains: Verbal working memory; Immediate auditory recall; and Inhibition. The aim of the study was to expand our understanding of language processing in normal aging, and to characterize how neural indices mediating phonologic processing are related to inhibitory and working memory abilities in healthy, elderly women. Participants were challenged with a visual word pair rhyme judgment task, from which eventrelated brain potentials, reaction time, and accuracy were recorded. Consisting of a prime and target, rhyming word pairs (orthographically congruent: THROWN-OWN and incongruent: CONE-OWN) and non-rhyming word pairs (orthographically congruent: GOWN-OWN, and incongruent: CAKE-OWN) were used. Verbal Working Memory: High performers were distinguished from low performers on both reaction time and accuracy. High performers also distinguished themselves electrophysiologically by an increased amplitude contingent negative variation, a working memory indicator, and by displaying earlier N100 peak latencies, an indicator of early cortical visual processing. Immediate Auditory Recall: Reaction time and accuracy were similar for low and high performers, although high performers displayed an increased N400, the component elicited by the rhyme judgment stimuli. High performers displayed increased rhyme effect mean amplitudes, which are believed to reflect processes underlying the ability to determine whether or not congruent pairs rhyme. Inhibition: High performers displayed faster reaction times and greater accuracy. Additionally, high performers displayed earlier N100 peak latencies under congruent conditions, which was significant over the left hemisphere in incongruent conditions. Lastly, high performers exhibited increased amplitude “later” rhyme effects for incongruent conditions when compared to low performers. In summary, the results of this study clearly demonstrate that differences in behavioral and cognitive abilities mediating verbal working memory, immediate auditory recall, and inhibition predict neural functions for language processing in the elderly, hinting at future opportunities for developing new biomarkers of successful aging.
Degree
Ph.D.
Advisors
Weber-Fox, Purdue University.
Subject Area
Neurosciences|Gerontology
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.