Oulhaj Abderrahim, Wilcock Gordon K, Smith A David, de Jager Celeste A
OPTIMA, Level 4, John Radcliffe Hospital, Oxford OX3 9DU, UK.
Neurology. 2009 Nov 3;73(18):1436-42. doi: 10.1212/WNL.0b013e3181c0665f. Epub 2009 Sep 30.
Increasing awareness that minimal or mild cognitive impairment (MCI) in the elderly may be a precursor of dementia has led to an increase in the number of people attending memory clinics. We aimed to develop a way of predicting the period of time before cognitive impairment occurs in community-dwelling elderly. The method is illustrated by the use of simple tests of different cognitive domains.
A cohort of 241 normal elderly volunteers was followed for up to 20 years with regular assessments of cognitive abilities using the Cambridge Cognitive Examination (CAMCOG); 91 participants developed MCI. We used interval-censored survival analysis statistical methods to model which baseline cognitive tests best predicted the time to convert to MCI.
Out of several baseline variables, only age and CAMCOG subscores for expression and learning/memory were predictors of the time to conversion. The time to conversion was 14% shorter for each 5 years of age, 17% shorter for each point lower in the expression score, and 15% shorter for each point lower in the learning score. We present in tabular form the probability of converting to MCI over intervals between 2 and 10 years for different combinations of expression and learning scores.
In apparently normal elderly people, subtle measurable cognitive deficits that occur within the normal range on standard testing protocols reliably predict the time to clinically relevant cognitive impairment long before clinical symptoms are reported.
人们越来越意识到老年人的轻度认知障碍（MCI）可能是痴呆症的先兆，这导致前往记忆诊所就诊的人数有所增加。我们旨在开发一种方法来预测社区居住老年人出现认知障碍之前的时间段。通过对不同认知领域进行简单测试来说明该方法。
对241名正常老年志愿者组成的队列进行了长达20年的随访，使用剑桥认知检查（CAMCOG）定期评估认知能力；91名参与者发展为MCI。我们使用区间删失生存分析统计方法来建模哪些基线认知测试最能预测转变为MCI的时间。
在几个基线变量中，只有年龄以及CAMCOG中表达和学习/记忆的子分数是转变时间的预测因素。每增长5岁，转变时间缩短14%；表达分数每降低1分，转变时间缩短17%；学习分数每降低1分，转变时间缩短15%。我们以表格形式呈现了不同表达分数和学习分数组合在2至10年期间转变为MCI的概率。
在明显正常的老年人中，在标准测试方案的正常范围内出现的细微可测量认知缺陷，早在临床症状出现之前就能可靠地预测出现临床相关认知障碍的时间。
