Lower masticatory function relates to cognitive health and intrinsic brain network in older adults

Abstract

ObjectivesMastication is associated with brain activation at the primary somatosensory cortex (S1) and the primary motor cortex (M1). Masticatory functions differ between patients with cognitive impairment (CI) and cognitively healthy older adults (non‐CI). The association between cognitive health, brain network of functional connectivity, and mastication has remained unknown. The study investigated the association between masticatory performance (MP) and the topological feature of the functional network at the M1 and S1 in the CI and non‐CI groups.Subjects and MethodsForty‐nine non‐CI and 15 CI subjects received resting‐state (rs) fMRI and assessment of MP. The topological feature of the M1 and S1 was quantified by eigenvector centrality (EC), an index that reflects a brain region as a functional “hub” of brain network.ResultsIn the non‐CI group, MP was significantly correlated with EC of the left M1 and the right M1. The correlation was not statistically significant in the CI group. Cognitive status (CI or non‐CI) and EC of the left M1 and the right M1, respectively, were statistically significant predictors to individual MP.ConclusionCognitive status and the topological feature of the M1 in the intrinsic functional network may contribute to the individual difference in masticatory function.

Association of Denture Use and Chewing Ability with Cognitive Function Analysed Using Panel Data from Korea Longitudinal Study of Aging (2006–2018)

“…Further, several previous studies report that difficulty chewing is significantly associated with frailty [ 15 , 16 , 17 ]. Chewing increases activity not only in the hippocampus and prefrontal cortex, which play important roles in cognitive processes, but also in the primary somatosensory cortex (S1) and primary motor cortex (M1), and it has a positive influence on brain functions [ 18 , 19 ]. Therefore, decreased and impaired chewing ability reduces blood flow to the brain, induces chronic stress, inhibits spatial learning ability, and decreases cognitive function due to poor dietary intake [ 20 ].…”