The interrater reliability of force measurements using a modified sphygmomanometer in elderly subjects

Background and Purpose. Physical therapists working with elderly people require an instrument that provides reliable force measurements and can be used in a clinical setting. The modified sphygmomanometer has been identified as potentially fulfilling these requirements, yet there is an absence of research on the reliability of measurements taken with this instrument on elderly patients. This study was undertaken to investigate the interrater reliability of force measurements, in a group of elderly subjects, using a modified sphygmomanometer. Subjects. Thirty-six hospitalized subjects (mean age=75.28 years, SD=9.43, range=62-95) participated in the study. Methods. With the modified sphygmamanometer, 3 examiners evaluated the isometric force of the elbow extensors and hip extensors using a break test and a make test, respectively. Results. Intraclass correlation coefficients (2,1) reflecting reliability were .87 for the elbow extensors and .65 for the hip extensors. The estimation of the components of variance for hip extensors revealed that these results were due in part to the raters but that random error contributed to a much larger extent. Conclusion and Discussion. The modified sphygmomanometer appears to be practical to use, and the high correlations found in this study for the elbow extensors suggest that reliable measurements can be obtained with this instrument. Further research is needed, however, to specify the manner in which the modified sphygmomanometer can be used when assessing different muscle groups.