Older patients with cognitive impairment exhibit worse masticatory performance (MP), which may be attributed to poorer abilities of control, learning, and adaptation of oral sensorimotor functions. This study tested the hypothesis that the association between the structural signature of the right premotor cortex (which relates to sensorimotor integration) and masticatory performance would differ between cognitively impaired (CI) and healthy older people. Thirty-one CI and 31 non-CI older participants (aged 60-84 years; male: female = 28: 34) were recruited and between-group matched for the average age and sex ratio. All the participants received T1-weighted magnetic resonance imaging (MRI) and assessments of MP and the number of missing teeth (NMT). Voxel-based morphometry (VBM) was performed to quantify the gray matter volume (GMV). VBM analyses revealed that in the non-CI but not the CI group, MP was positively correlated with regional GMV at the right premotor cortex (PMC) (p = 0.036, corrected for familywise error under small volume correction), controlling for the participants' sex, age, NMT, and total intracranial volume. Multiple linear regression models revealed that in the non-CI group, the right PMC (beta = 0.3, p = 0.049) was a significant predictor of individual MP. In the CI group, only NMT (beta = -0.7, p = 0.001) was a significant predictor of MP. In non-CI older people, both the NMT and the regional GMV of the right PMC contributed to individual MP. In contrast, in CI patients, tooth loss was the dominant factor in MP. An altered association of the brain-stomatognathic system could be linked to cognitive impairment.

中文翻译：

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在认知障碍和未受损的老年人中，区域脑容量与咀嚼功能之间的关联有所不同。

认知障碍的老年患者表现出较差的咀嚼性能（MP），这可能归因于对口感觉运动功能的控制，学习和适应能力较差。这项研究检验了以下假设：认知障碍（CI）和健康老年人之间，右前运动皮层的结构特征（与感觉运动整合有关）与咀嚼性能之间的关联会有所不同。招募了31名CI和31名非CI的较老参与者（年龄在60-84岁；男性：女性= 28:34），并根据平均年龄和性别比对各组进行了匹配。所有参与者均接受了T1加权磁共振成像（MRI）以及MP和牙齿缺失数量（NMT）的评估。进行基于体素的形态测定（VBM）以量化灰质体积（GMV）。VBM分析显示，在非CI组而非CI组中，MP与右前运动皮层（PMC）的区域GMV正相关（p = 0.036，在小量矫正下经家庭误差校正），控制了参与者的体重。性别，年龄，NMT和总颅内体积。多个线性回归模型显示，在非CI组中，正确的PMC（β= 0.3，p = 0.049）是单个MP的重要预测指标。在CI组中，只有NMT（β= -0.7，p = 0.001）是MP的重要预测指标。在非CI老年人中，正确的PMC的NMT和区域GMV都有助于个人MP。相反，在CI患者中，牙齿脱落是MP的主要因素。脑胃蠕动系统改变的关联可能与认知障碍有关。