Saxton J, Snitz B E, Lopez O L, Ives D G, Dunn L O, Fitzpatrick A, Carlson M C, Dekosky S T
Department of Neurology, University of Pittsburgh, 3471 Fifth Avenue, Suite 811, Pittsburgh, PA 15213, USA.
J Neurol Neurosurg Psychiatry. 2009 Jul;80(7):737-43. doi: 10.1136/jnnp.2008.160705. Epub 2009 Mar 11.
To compare rates of mild cognitive impairment (MCI) and rates of progression to dementia using different MCI diagnostic systems.
MCI was investigated at baseline in 3063 community dwelling non-demented elderly in the Ginkgo Evaluation of Memory (GEM) study who were evaluated every 6 months to identify the presence of dementia. Overall MCI frequency was determined using (1) a Clinical Dementia Rating (CDR) score of 0.5 and (2) neuropsychological (NP) criteria, defined by impairment on standard cognitive tests.
40.2% of participants met CDR MCI criteria and 28.2% met NP MCI criteria (amnestic MCI = 16.6%). 15.7% were classified as MCI by both criteria and 47.4% as normal by both. Discordant diagnoses were observed in 24.5% who met NP normal/CDR MCI and in 12.4% who met NP MCI/CDR normal. Factors associated with CDR MCI among NP normal included lower education, lower NP scores, more instrumental activities of daily living impairment, greater symptoms of depression and subjective health problems. Individuals meeting NP MCI/CDR normal were significantly more likely to develop dementia over the median follow-up of 6.1 years than those meeting NP normal/CDR MCI.
Different criteria produce different MCI rates and different conversion rates to dementia. Although a higher percentage of MCI was identified by CDR than NP, a higher percentage of NP MCI progressed to dementia. These findings suggest that the CDR is sensitive to subtle changes in cognition not identified by the NP algorithm but is also sensitive to demographic and clinical factors probably leading to a greater number of false positives. These results suggest that identifying all individuals with CDR scores of 0.5 as Alzheimer's disease is not advisable.
使用不同的轻度认知障碍（MCI）诊断系统比较MCI发生率以及进展为痴呆症的发生率。
在银杏记忆评估（GEM）研究中，对3063名居住在社区的非痴呆老年人进行了基线时的MCI调查，每6个月对他们进行评估以确定是否存在痴呆症。总体MCI频率通过以下方式确定：（1）临床痴呆评定量表（CDR）评分为0.5；（2）神经心理学（NP）标准，即通过标准认知测试中的损伤来定义。
40.2%的参与者符合CDR MCI标准，28.2%的参与者符合NP MCI标准（遗忘型MCI = 16.6%）。15.7%的参与者两种标准均判定为MCI，47.4%的参与者两种标准均判定为正常。在符合NP正常/CDR MCI标准的参与者中，24.5%存在诊断不一致情况；在符合NP MCI/CDR正常标准的参与者中，12.4%存在诊断不一致情况。在NP正常的参与者中，与CDR MCI相关的因素包括受教育程度较低、NP得分较低、日常生活工具性活动受损更多、抑郁症状更严重以及主观健康问题更多。在6.1年的中位随访期内，符合NP MCI/CDR正常标准的个体比符合NP正常/CDR MCI标准的个体更有可能发展为痴呆症。
不同的标准会产生不同的MCI发生率以及不同的痴呆症转化率。尽管通过CDR识别出的MCI比例高于NP，但NP MCI进展为痴呆症的比例更高。这些发现表明，CDR对NP算法未识别出的认知细微变化敏感，但对人口统计学和临床因素也敏感，这可能导致更多的假阳性。这些结果表明，将所有CDR评分为0.5的个体都诊断为阿尔茨海默病是不可取的。
