Interhemispheric Communication in Healthy Aging Individuals

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Despite the fact that older adults represent the fastest growing demographic in the United States, there are aspects to healthy aging that remain unclear. Research suggests that the relationship between white matter integrity, specifically the corpus callosum, and resulting interhemispheric communication is only partially understood as it relates to healthy aging. The current study aims to provide a better understanding of the latter—by comparing the well-known bilateral field advantage (BFA) paradigm in a sample of older versus younger adults using a computer-based reaction time (RT) matching task. The BFA refers to the difference in RT when making RT decisions for information (e.g., whether “a” and “b” are the same letter) flashed to bilateral (faster RT) vs. unilateral (slower RT) visual fields. Visual evoked potentials (EP) were recorded while participants performed the task. It was hypothesized that a) older adults would show a significant difference in reaction times compared to younger adults, b) older adults would show a significant difference in accuracy compared to younger adults, and c) there would not be a correlation between the BFA and an average EP-IHTT regardless of age group. The current study found the expected BFA in the entire sample regardless of age. Moreover, age was not a significant contributor to the benefits of bilateral field presentation of the stimulus. Further, the sample showed that age did not significantly impact accuracy on the letter-matching task. Lastly, the study did not find a correlation between an average EP-IHTT and a BFA measure and age.

Degree Name

Doctor of Psychology in Clinical Psychology (PsyD)

First Advisor

Marion, Sarah DeBoard

Document Type





Aging, Corpus callosum




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