Gustatory function and cognitive impairment in the Korean elderly

A decline in chemosensing is commonly observed in the aging process including neurodegenerative disease, however studies regarding taste sensitivity and cognitive impairment are in lacked. This study examined whether cognitive impairment is associated with gustatory dysfunction in elderly Koreans. A total of 310 Koreans from Korean Genome and Epidemiology Study - Cardiovascular Disease Association Study were analyzed to assess their cognitive function and gustatory function. The participants' cognitive level was classified into three categories: normal, mild cognitive impairment (MCI), and dementia, using the Korean version of the mini mental state examination-second edition: standard version. To evaluate gustatory function, the participants were tested with five tastants: sweet, bitter, salty, sour, and umami, using the whole-mouth technique. A total of 44 subjects (14.2 %) were defined for MCI, and 29 subjects (9.4 %) were defined for dementia. There was no significant association found between the distribution of gustatory dysfunction (10 %) and cognitive impairment. However, subjects with dementia had significantly lower detection sensitivity for sourness compared to those with normal cognition and MCI. While no significant association was observed between cognitive impairment and overall gustatory dysfunction, dementia was associated with a decline in sensitivity to sourness, compared to individuals with normal cognition and those with MCI. The reduced sensitivity to sourness may serve as a potential screening marker for cognitive decline, warranting further research in this area.