Patients with Alzheimer’s disease dementia (ADD) are thought to exhibit taste disorders; however, this has not been extensively studied. We investigated gustatory functions and factors affecting taste in patients with ADD or mild cognitive impairment (MCI) and in non-demented controls (NDCs) and evaluated associations between cognitive impairment and gustatory functions. We recruited 29 patients with ADD, 43 with MCI, and 14 with NDCs. We obtained medical and medication history, measured salivary secretion volumes, and performed cognitive function tests, blood tests, whole-mouth gustatory tests, and dietary and gustatory questionnaires. Patients with ADD showed significantly higher recognition threshold values than NDCs (p < 0.05). Many individuals did not recognize umami at the maximum concentration, and this happened more frequently in patients with ADD or MCI than in NDCs. Evaluation items other than cognitive function tests did not show significant differences among the groups, but many individuals had decreased salivation, low serum zinc levels, and were on multiple medications. We found a significant correlation between recognition threshold and age (r = 0.229, p < 0.05) and cognitive function test score (r = 0.268, p < 0.05). Patients with ADD showed impairment of gustatory function. Gustatory impairment in patients with MCI could not be confirmed. However, many individuals with MCI did not recognize umami, either. Our results suggest that taste disorders in elderly people with cognitive decline occur independently of factors affecting taste such as salivation, zinc levels, or prescription drugs. The study was registered in the UMIN Clinical Trials Registry on February 10, 2017, with reference number UMIN000026087.

中文翻译：

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轻度认知障碍和阿尔茨海默氏病痴呆患者五种基本口味的检测和识别阈值。

阿尔茨海默氏病痴呆症（ADD）患者被认为表现出味觉障碍；但是，这尚未得到广泛研究。我们调查了ADD或轻度认知障碍（MCI）和非痴呆对照（NDC）患者的味觉功能和影响味觉的因素，并评估了认知障碍和味觉功能之间的关联。我们招募了29例ADD，43例MCI和14例NDC。我们获得了医学和用药史，测量了唾液分泌量，并进行了认知功能测试，血液测试，全口味觉测试以及饮食和味觉问卷。ADD患者的识别阈值明显高于NDC（p <0.05）。许多人没有意识到最大浓度的鲜味，与NDCs相比，ADD或MCI患者中这种情况的发生频率更高。除认知功能测试以外的评估项目在各组之间没有显着差异，但是许多人的唾液分泌减少，血清锌水平低并且正在接受多种药物治疗。我们发现识别阈值和年龄（r = 0.229，p <0.05）与认知功能测试得分（r = 0.268，p <0.05）之间存在显着相关性。ADD患者表现出味觉功能受损。无法确认MCI患者的味觉障碍。但是，许多患有MCI的人也无法识别鲜味。我们的结果表明，具有认知能力下降的老年人的味觉障碍独立于影响味觉的因素（例如流涎，锌水平或处方药）而发生。