Relationship between mild cognitive decline and oral motor functions in metropolitan community-dwelling older Japanese: The Takashimadaira study.

BACKGROUND

Diminished oral motor function is considered to be a factor influencing cognitive decline, but this association has not been clarified. The aim of the present study was to clarify the association between cognitive and oral motor function in older people with either from normal cognitive function or mild cognitive decline.

METHODS

A cross-sectional study was conducted across 1118 older people (445 men, 673 women) aged ≥70 years (mean age, 77.0 ± 4.7 years) who lived in a city of Tokyo Metropolis, Japan. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Older people who had an MMSE score of 23 points or lower were excluded. To investigate the relationship between cognitive and oral motor function, Pearson's correlation, multiple linear regression, and path analysis were performed.

RESULTS

Pearson's correlation revealed that, among the oral motor functions assessed, masticatory performance, occlusal force, and tongue pressure were correlated with MMSE score. Multiple linear regression showed that tongue pressure and oral diadochokinesis (ODK) were significantly associated with MMSE score. Path analysis revealed that decreases in tongue pressure and in ODK were directly associated with decreases in MMSE score. Decreases in tongue pressure were also indirectly associated with decreases in MMSE score via decreases in ODK.

CONCLUSIONS

Among the oral motor functions assessed, tongue pressure and ODK were associated with cognitive function in older people ranging from those with normal cognitive function to those with mild cognitive decline. Diminished tongue pressure and ODK might thus lead to cognitive decline.