Division of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
J Am Geriatr Soc. 2013 Mar;61(3):429-33. doi: 10.1111/jgs.12122. Epub 2013 Mar 1.
To improve the construct validity of self-reported fatigue by establishing a formal hierarchy of scale items and to determine whether such a hierarchy could be maintained across time (aged 75-80), sex, and nationality.
Cohort study.
Two Nordic urban locations: Jyväskylä, Finland, and Glostrup, Denmark.
Baseline (1989/90) consisted of a random sample of citizens of Finland or Denmark born in 1914 (n = 837). At 5-year follow-up, excluding those lost to follow-up and with baseline disability resulted in a sample of n = 690.
The Mobility-Tiredness (Mob-T) Scale is a six-item scale that requires subjects to self-report on whether they become tired performing mobility-related tasks. Employing item response theory, an attempt was made to enhance construct validity by confirming a hierarchy of mobility-related fatigue.
A formal hierarchy of fatigue tasks, maintained across time, was established using the revised Mob-T Scale. At age 75, the scalability statistics were a homogeneity coefficient (H) of 0.80, Ha T of 3.9% and an H(T) value of 0.66. The corresponding figures at age 80 were 0.75, 6.9% and 0.59. The property of invariant item ordering was maintained across subgroups based on sex and nationality.
Establishing a formal hierarchy at age 75 allowed which tasks were most debilitating to be identified more clearly and the individual's "distance" from these tasks to be gauged. Because it was possible to confirm that the item hierarchy was maintained across time (aged 75-80), researchers or clinicians can be more confident that performance over time is the result of real change and has less to do with measurement error.
通过建立量表项目的正式层次结构来提高自我报告疲劳的结构效度，并确定这种层次结构是否可以跨时间（75-80 岁）、性别和国籍保持不变。
队列研究。
芬兰于韦斯屈莱和丹麦格劳斯特鲁普两个北欧城市。
1989/90 年的基线包括芬兰或丹麦出生于 1914 年的公民的随机样本（n=837）。在 5 年的随访中，排除失访者和因基线残疾导致的样本量为 n=690。
移动疲劳量表（Mob-T）是一个六项目量表，要求受试者自我报告他们在执行与移动相关的任务时是否感到疲劳。运用项目反应理论，试图通过确认与移动相关的疲劳层次结构来提高结构效度。
使用修订后的 Mob-T 量表，在跨时间的基础上建立了一个正式的疲劳任务层次结构。在 75 岁时，可衡量性统计数据为同质系数（H）为 0.80、Ha T 为 3.9%和 H(T) 值为 0.66。80 岁时的相应数据为 0.75、6.9%和 0.59。基于性别和国籍的亚组，不变项目排序的特性得以保持。
在 75 岁时建立正式的层次结构，可以更清楚地确定哪些任务最具致残性，并衡量个体与这些任务的“距离”。由于可以确认项目层次结构在整个时间（75-80 岁）内保持不变，研究人员或临床医生可以更有信心，随着时间的推移，表现是真实变化的结果，而与测量误差的关系较小。
