Analysis of brain functions in the older adults: A Systematic Review on functional near‐infrared spectroscopy

Abstract

AbstractBackgroundAs the aging phenomenon accelerates worldwide, cognitive health and improvement of the older adults are emerging as important issues. This study was conducted to obtain implications for future clinical and research directions related to elderly cognition by examining studies that identified the brain function of the elderly using brain activation or functional connectivity.MethodThree databases(Web of Science, Scopus, Pubmed) were used to collect literature for a total of five years from January 2018 to December 2022. Using “(“older adult*” OR “elderly”) AND “fNIRS” AND (“functional activation” OR “functional connectivity”)” as the search term, we selected and analyzed the final 8 literature that matched the selection criteria and exclusion criteria of this study.ResultThere were 5 cases targeting healthy older adults and 3 cases for the older adults with mild cognitive impairment, and the most active study in China was shown. In addition, a total of six types of NIRS systems were used to explore brain function in the elderly, and five studies confirmed that the NIRS system produced in Japan was used. In the case of the number of channels used, it had a wide range of 14 to 48, and there were only two studies showing functional connectivity.ConclusionThis study confirmed that it is possible to identify the cognitive function of the older adults using fNIRS, and at the same time, few studies have measured functional connectivity. Since brain regions do not work independently, it is essential to understand functional connectivity that identifies functional integration between brain regions that share similar functions, even if they are located apart. Therefore, based on the results of this study, it is believed that a better understanding of functional brain changes can be achieved if brain activation and functional connectivity are also identified when conducting cognitive‐related research in the elderly using fNIRS in the future.