Maher C, Adams R
School of Physiotherapy, Faculty of Health Sciences, University of Sydney, Lidcombe, New South Wales, Australia.
Phys Ther. 1995 Oct;75(10):854-60; discussion 861-4. doi: 10.1093/ptj/75.10.854.
This study investigated whether the poor reliability of judgments of posteroanterior (PA) spinal stiffness is due to rater bias or is a consequence of raters each having individual concepts of PA stiffness.
Three pairs of manipulative physical therapists with a minimum of 5 years of experience took part in the study.
The raters were required to make stiffness judgments of a series of metal springs, and their performance at this task was compared with that obtained when they rated the PA stiffness of patients with low back pain. A range of reliability indices were calculated and evaluated to establish whether rater bias contributed to poor reliability in either task. The relationship between each rater's estimates of the magnitude of the stimuli and the measured stiffness of the springs was also assessed using the Pearson Product-Moment Correlation Coefficient.
The average intraclass correlation coefficient (2, 1) for rating spring stiffness was found to be .60, whereas for human spines it was found to be .19. There was no evidence of rater bias contributing to poor reliability for rating stiffness of human spines. The average correlation between the rater's estimates of the magnitude of the stimuli and the measured stiffness of the stimuli was .80.
Physical therapists demonstrated much better ability to judge spring stiffness than the PA stiffness of human spines. This difference in performance implies that mechanical stiffness is not equivalent to the clinical concept of PA stiffness. Posteroanterior stiffness may have more than one dimension, and individual interpretation of stiffness as a construct may lead to rater disagreement in the clinic. The reliability of judgments of PA spinal stiffness may be enhanced in the future if its dimensions can be identified, defined, and taken into account during clinical procedures.
本研究调查了后前位（PA）脊柱僵硬度判断可靠性差是由于评估者偏差，还是评估者各自对PA僵硬度有不同概念的结果。
三对具有至少5年经验的手法物理治疗师参与了本研究。
要求评估者对一系列金属弹簧的僵硬度进行判断，并将他们在此任务中的表现与对腰痛患者PA僵硬度进行评分时的表现进行比较。计算并评估了一系列可靠性指标，以确定评估者偏差是否导致了任一任务中的可靠性差。还使用Pearson积差相关系数评估了每个评估者对刺激强度的估计与弹簧测量僵硬度之间的关系。
发现评定弹簧僵硬度的平均组内相关系数（2,1）为0.60，而评定人体脊柱僵硬度时为0.19。没有证据表明评估者偏差导致人体脊柱僵硬度评分的可靠性差。评估者对刺激强度的估计与刺激测量僵硬度之间的平均相关性为0.80。
物理治疗师判断弹簧僵硬度的能力远优于判断人体脊柱的PA僵硬度。这种表现上的差异意味着机械僵硬度不等同于PA僵硬度的临床概念。后前位僵硬度可能有多个维度，作为一种结构的僵硬度的个体解释可能导致临床中评估者之间的分歧。如果在临床过程中能够识别、定义并考虑PA脊柱僵硬度的维度，未来对其判断的可靠性可能会提高。
