Repeated Measurements of Arm Joint Passive Range of Motion After Stroke: Interobserver Reliability and Sources of Variation

Lex D. de Jong; Pieter U. Dijkstra; Roy E. Stewart; Klaas Postema

doi:10.2522/ptj.20110280

Figures

Figure 1.

Flow of participants through each stage of the trial from initial screening by physician to follow-up measurement. *If a participant was excluded for more than 1 reason, then all reasons were reported separately. ^†Five participants were assessed by 1 observer only. ^‡One participant missed the 4-week assessment because of poor weather conditions. ^§Four participants were assessed by 1 observer only, and 1 participant was not assessed at 8 weeks because of temporary admission to a hospital. ^∥One participant was assessed by 1 observer only.

Figure 2.

Variance components of shoulder external rotation. Total variance (left circle) comprised participant variance (main effect) and error variance. Several sources contributed to error variance. These sources (right circle) comprised main effects (time and observer), interaction effects (participant × time, participant × observer, and time × observer), and residual variance, all expressed as percentages of error variance.

Tables

Table 1.

Baseline Characteristics of the 48 Participants^{^a}

↵^a IQR=interquartile range, PROM=passive range of motion.
^b A value of 2.5 degrees indicates elbow flexor contracture.

Table 2.

Estimated Variance Components and Their Contributions (in Percentages) to the Error Variance of Repeated Measurements of 7 Arm Movements (n=48)

^a Negative variance components (ranging from −0.027 to −0.517) were set to 0.
^b Error variance expressed as a percentage of total variance. For example, for shoulder external rotation, the calculation would be as follows: total variance (626.4) minus participant variance (385.0) equals error variance (241.3); error variance therefore represents 38.6% of total variance.

Table 3.

Interobserver Reliability Coefficients (and 95% Confidence Intervals), Standard Errors of Measurement (SEMs), and Smallest Detectable Differences (SDDs)^{^a}

↵^a “Overall” refers to the overall reliability, SEM, and SDD for the observers over time; “observers” refers to the SDD and SEM for a single measurement session.