Visser Pieter Jelle, Verhey Frans R J, Scheltens Philip, Cruts Marc, Ponds Rudolf W H M, Van Broeckhoven Christine L, Jolles Jellemer
Department of Psychiatry and Neuropsychology, Institute of Brain and Behaviour, University of Maastricht, The Netherlands.
J Neurol. 2002 Mar;249(3):312-9. doi: 10.1007/s004150200011.
The Preclinical AD Scale (PAS) is a newly developed scale for the diagnosis of preclinical Alzheimer's disease (AD). The PAS combines six markers of preclinical AD, namely age, MMSE score, functional impairment, cognitive test performance, medial temporal lobe atrophy, and the apolipoprotein E (APOE) genotype. The aim of the study was to investigate whether the PAS can accurately identify subjects with preclinical AD who become demented during a 2 or 5 year follow-up from among subjects with mild cognitive impairment for other reasons. We also investigated whether a step-wise scoring of the PAS could reduce the number of elaborate or expensive diagnostic procedures. The PAS was scored retrospectively in two independent samples of non-demented subjects with mild cognitive impairment older than 55 years (average age 65.6 years), who were selected from a memory clinic population. In the first sample, the follow-up was 5 years (5-year follow-up sample; n=69). In the second sample, the follow-up was 2 years (2-year follow-up sample; n=23). The PAS item medial temporal lobe atrophy was not scored in the 5-year follow-up sample. A PAS cut-off score of 4/5 could best identify subjects with AD-type dementia at follow-up (n=25) in the 5-year follow-up sample with a sensitivity of 80% and a positive predictive value of 77%. A PAS cut-off score of 5/6 could best identify subjects with AD-type dementia at follow-up (n=8) in the 2-year follow-up sample with a sensitivity of 88% and a positive predictive value of 70%. The positive predictive value could be increased to 94% in the 5-year follow-up sample and to 80% in the 2-year follow-up sample by using higher cut-off scores, but this reduced the sensitivity. Step-wise scoring of the PAS had the same diagnostic accuracy as the total PAS score and reduced the number of cognitive assessments by 22 to 38%, the number of assessments of medial temporal lobe atrophy by 57 to 74%, and the number of APOE genotypings by 74%. It is concluded that the PAS is a useful scale to identify subjects with preclinical AD who will become demented during the next 2 or 5 years. Step-wise scoring of the PAS can reduce the number of elaborate or expensive diagnostic procedures considerably.
临床前AD量表（PAS）是一种新开发的用于诊断临床前阿尔茨海默病（AD）的量表。PAS结合了临床前AD的六个标志物，即年龄、简易精神状态检查表（MMSE）评分、功能损害、认知测试表现、内侧颞叶萎缩和载脂蛋白E（APOE）基因型。本研究的目的是调查PAS能否从因其他原因患有轻度认知障碍的受试者中，准确识别出在2年或5年随访期间发展为痴呆的临床前AD受试者。我们还研究了PAS的逐步评分是否可以减少复杂或昂贵的诊断程序的数量。PAS是在两个独立的样本中进行回顾性评分的，这些样本来自一家记忆门诊的年龄超过55岁（平均年龄65.6岁）的非痴呆轻度认知障碍受试者。在第一个样本中，随访时间为5年（5年随访样本；n = 69）。在第二个样本中，随访时间为2年（2年随访样本；n = 23）。在5年随访样本中未对PAS项目内侧颞叶萎缩进行评分。PAS临界值为4/5时，在5年随访样本中能够最好地识别随访时患有AD型痴呆的受试者（n = 25），敏感性为80%，阳性预测值为77%。PAS临界值为5/6时，在2年随访样本中能够最好地识别随访时患有AD型痴呆的受试者（n = 8），敏感性为88%，阳性预测值为70%。通过使用更高的临界值，5年随访样本中的阳性预测值可提高到94%，2年随访样本中的阳性预测值可提高到80%，但这会降低敏感性。PAS的逐步评分与PAS总分具有相同的诊断准确性，并且将认知评估的数量减少了22%至38%，内侧颞叶萎缩评估的数量减少了57%至74%，APOE基因分型的数量减少了74%。得出的结论是，PAS是一种有用的量表，可用于识别在未来2年或5年内将发展为痴呆的临床前AD受试者。PAS的逐步评分可以显著减少复杂或昂贵的诊断程序的数量。
