Test–retest reliability of the lower limb proprioception measures in individuals with stroke

This study investigated the test-retest reliability of simplified proprioception measures based on quantitative metrics using an image capture technique in individuals with stroke.

This study included 19 individuals (mean age 80.05 ± 6.84 years) with acute stroke with no signs of unilateral spatial neglect, agnosia, or aphasia and no history of lower limb conditions. The proprioception measure included the threshold to detect passive motion (TDPM) for six movement directions: hip external and internal rotation, knee flexion and extension, and ankle dorsiflexion and plantarflexion. The average TDPM values for each direction were combined to define the lower limb flexion pattern (hip external rotation, knee flexion, and ankle dorsiflexion) and extension pattern (hip internal rotation, knee extension, and ankle plantarflexion) that resulted in a multi–joint TDPM. The participants were initially positioned in a seated posture with the knee joint flexed at 90° and soles lifted off the floor. The vision was occluded using an eye mask. The TDPM was performed by capturing photographs using a smartphone paired with a Bluetooth remote controller at the moment when participants first perceived movement, which was guided by the examiner at 5.00°/s. The difference between the joint angle acquired from the image data using ImageJ and starting angle was considered the TDPM value. The TDPM was randomly performed thrice. These measurements were repeated within 48 h, using an average of 2.85 days after stroke as the baseline in conjunction with risk management. Statistical analyses were performed using intraclass correlation coefficients (ICC 3.1), standard error of the mean (SEM), minimal detectable change (MDC), and 95% confidence intervals for limits of agreement (LoA) based on Bland–Altman plots.

The multi–joint TDPM and TDPM showed moderate to high reliability across all tested movement directions, with no fixed errors identified (multi–joint TDPM: ICC 3.1 0.62–0.95, SEM 5.78°–16.03°, MDC 16.03°–44.43°, and LoA −13.57° to 8.65°; TDPM: ICC 3.1 0.52–0.86, SEM 3.47°–6.96°, MDC 9.61°–19.30°, and LoA −4.40° to 4.43°). Proportional errors were observed in the multi–joint TDPM for the extension pattern and in TDPM for hip internal rotation and ankle plantarflexion that comprise this pattern.

The multi–joint TDPM and TDPM using the image capture technique are reliable measures for evaluating proprioception in individuals with stroke. Furthermore, proprioceptive functions associated with extension patterns in individuals with stroke might exhibit specific changes over time.

The findings contribute to introduce quantitative proprioception measures into clinical practice and investigate effect of proprioceptive deficits on motor function and their recovery trajectory.