Correlation between the repositioning error measured and subjectively assessed by healthy subject during shoulder flexion.

INTRODUCTION

Assessment of proprioception is useful for clinician practice. The feeling is not retained for the proprioceptive assessment while it is used for dyspnoea or perception of effort with visual analogue scale. Proprioception assessment is often complicated and costly, making it unsuitable for clinical practice. The aim of this study is twofold, 1) to evaluate the correlation between the outcomes of a visual analogue scale and a joint position sense error and 2) to validate the use of an affordable inertial measurement unit.

METHODS

Correlation coefficients between angular joint position error and the feeling of error measured with a visual analogue scale were computed. Data were collected using a smartphone's IMU and the Phyphox application. A total of 30 subjects were divided in two groups ("test group" and "error group"). Each subject performed six arm flexion movements for a total of 90 acquisitions per group.

RESULTS

The "error group" had good capabilities in error detection as 100% of them detected two out of three errors (false positioning). Pearson correlation coefficients were 0.85 (p < 0.001), 0.76 (p < 0.005) and 0.91 (p < 0.005) depending on the shoulder flexion angle ranges.

CONCLUSION

The positive correlation between error in perception of joint position and the values of the visual analogue scale shows that the subjects' sensation could be used to assess proprioception, as the perceptive scale is a complementary piece of data to the quantitative assessment in order to have a patient-centred approach.