背景:随着社会人口的老龄化，阿尔茨海默病作为一种慢性、进行性、不可逆的神经系统退行性疾病，严重威胁着人们的生活质量及生命健康，同时也加重了社会负担。认知检查是临床诊断阿尔茨海默病的客观手段。记忆缺陷通常是阿尔茨海默病和轻度认知障碍最早和最明显的症状，但近年来有研究证据表明注意力改变是认知障碍的最早迹象之一，甚至早于记忆力的改变。目的：以Spinnler 和Tognoni等人提出的数字划消试验为原型，通过数字划消试验发现患者的注意力改变，探究其用于早期诊断阿尔茨海默病的有效性，实现临床工作中对认知障碍疾病的早期筛查。方法：本研究分两部分进行，第一部分探究数字划消试验是否可识别出存在认知障碍的患者，将373位研究对象按临床痴呆评分 （Clinical Dementia Rating，CDR）及简明精神状态检查（Mini-Mental State Examination，MMSE）评分进行认知程度划分，分为认知正常组（Normal Cognition, NC）、轻度认知障碍组（Mild Cognitive Impairment, MCI）及痴呆组（Dementia, D）来比较组间测试结果的差异。第二部分选择阿尔茨海默病神经影像学计划标准招募入组的40位患者，按临床诊断标准分为正常认知水平组（NC）、轻度认知障碍组（MCI）、阿尔茨海默病组（Alzheimer‘s Disease, AD）来进行数字划消试验检查，评价数字划消试验对阿尔茨海默病进行早期筛查的有效性。以Geldmacher等人提出的划消指数作为评估指标，采用多元线性回归分析了人口学特征对数字划消试验的影响，并使用单因素协方差分析比较各组测试结果的差异。分析了数字划消试验与MMSE、MoCA等量表的相关性，通过研究对象工作特征曲线（Receiver Operating Characteristic Curves，ROC）和曲线下面积（Area Under the Curve，AUC）评估数字划消试验区分认知正常老年人及早期认知障碍患者的诊断性能。p<0.05为差异有统计学意义。结果：数字划消试验的结果在不同认知程度组间具有显著性差异(p<0.05)，且与MMSE、MoCA等量表具有相关性。ROC曲线获得其最佳诊断界值为0.098254，曲线下面积AUC为0.823，其对阿尔茨海默病的早期筛查具有良好的诊断性能。结论：数字划消试验可通过注意力评估来区分不同认知障碍程度的患者，并通过其检查所发现的轻度认知障碍患者来进行阿尔茨海默病的早期筛查。
Background: With the aging of the population, Alzheimer‘s disease (AD) is a chronic, progressive and irreversible neurodegenerative disease, which seriously threatens people‘s quality of life and health, and also increases the social burden. Cognitive examination is an objective means of clinical diagnosis of Alzheimer‘s disease. Memory deficits are usually the earliest and most obvious symptoms of Alzheimer‘s disease and mild cognitive impairment, but in recent years, research evidence has shown that attention changes are one of the earliest signs of cognitive impairment, even before memory changes.Objective: Spinnler and Tognoni‘s digital cancellation test was used as a prototype to detect changes in patients‘ attention, and to explore its effectiveness for early diagnosis of Alzheimer‘s disease (AD) and as an early cognitive screening tools be used in clinical work.Methods: The study was conducted in two parts. The first part investigated whether digital cancellation tests could identify people with cognitive impairment. CDR score) and Mini-Mental State Examination (MMSE) score were used to classify the subjects into normal cognitive group (NC), mild cognitive impairment group (MCI) and dementia group (D) to compare the differences among the three groups. In the second part, 40 patients were selected from the Alzheimer‘s Disease Neuroimaging Initiative. According to the clinical diagnostic criteria, they were divided into normal cognitive level (NC) group, mild cognitive impairment (MCI) group and Alzheimer‘s disease (AD) group for digital cancellation test, and the effectiveness of digital cancellation test for early screening of AD was evaluated. Using the cancellation index proposed by Geldmacher et al., as the evaluation index, multiple linear regression was used to analyze the influence of demographic characteristics on the digital cancellation test, and one-way analysis of covariance was used to compare the differences in test results between groups. The correlation among digital cancellation test, MMSE, MoCA and other scales was analyzed. The Receiver Operating Characteristic Curves (ROC) and the Area Under the Curve (AUC) of the subjects were calculated. AUC was used to evaluate the diagnostic performance of digital cancellation test in distinguishing cognitively normal elderly from patients with early cognitive impairment. p<0.05 was considered statistically significant.Results: There were significant differences in the results of digital cancellation test between the groups with different cognitive levels (p<0.05), and the results were correlated with the scores of MMSE and MoCA. The ROC curve obtained its best diagnostic cut-off value was 0.098254, and the area under the curve was 0.823. Digital cancellation test had a good diagnostic performance for early screening of Alzheimer‘s disease.Conclusions: Digit cancellation test can be used to distinguish patients with different degrees of cognitive impairment through attention assessment, and can be used for early screening of Alzheimer‘s disease in patients with mild cognitive impairment found by its examination.
