Evaluation of the effect of aging on brain asymmetry with functional near infrared spectroscopy

Abstract

Cognitive aging is a natural and lifelong process which may lead to the neurological diseases as dementia and Alzheimer’s. Investigation of the aging process on the cerebral hemodynamics of subjects would lead to the prevention of neurological diseases which are the last stages of cognitive aging process. The aim of this study was to investigate the prefrontal cortex (PFC) oxygenation increase as working memory load is increased, to determine the effect of cognitive aging on PFC hemoglobin oxygenation and to analyze the lateralization index of young and middle aged adults. The study included measurement of hemodynamic changes with Functional Near-Infrared Spectroscopy (fNIRS) during a mental arithmetic task. The study demonstrated that during the mental arithmetic study, prefrontal cortex (PFC) hemoglobin oxygenation increased with the increasing working memory load for both groups; there was no significant hemoglobin oxygenation difference between both groups; young subjects used right PFC regions, while the middle aged subjects used left PFC regions during the mental arithmetic task and lastly the lateralization index of two groups increased with the increasing memory load.|Keywords: Functional Near-Infrared Spectroscopy (fNIRS), local oxygen consumption, working memory, prefrontal cortex (PFC), mental arithmetic task (MA), lateralization index (LI).