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Liu, Lizheng Alex

University of British Columbia

Awareness of our body position and movement is for interacting with the world. Proprioception, our physical self perception sense, is vital for daily living tasks like balancing and motor control. Current proprioception tests often assess simple, single-joint movements or require immobilization. These reductionist approaches fail to capture the functional application of proprioception in real-world contexts. This limitation emphasizes the need to develop functionally relevant tests. In this thesis, I propose a novel proprioception test assessing the perception of stance width adjustments during standing balance. The test integrates stance width, a key neuromechanical balance control variable, with the context of free balancing for functional relevance. I investigated three psychophysical methods (2-interval detection, single-interval discrimination and detection at 1 mm) and two stance width displacements (1 mm and 2 mm) in the thesis. Without established standards for this test, these explorations were necessary to identify effective proprioceptive threshold measurement approaches. Detection experiments involved identifying the presence of a stance width change, while discrimination experiments required recognizing the direction of the change. Varying platform movement velocities defined thresholds across all experiments. The experiments were accomplished using custom-developed mechatronic platforms with precise stance width adjustments (errors < 0.1 mm) and minimal vibrations. In a 2-interval detection protocol, participants (N = 19) exhibited lower detection thresholds (1.7 ± 1.3 mm/s) at 2 mm compared to 1 mm (2.6 ± 1.2 mm/s, p < 0.001). Single-interval discrimination (N = 9) resulted in lower thresholds (1.4 ± 1.1 mm/s) compared to the 2-interval detection protocol (2.2 ± 0.8 mm/s, p = 0.030). Conversely, participants in the single-interval detection (N = 10) exhibited higher thresholds (3.0 ± 1.4 mm/s to 4.0 ± 0.9 mm/s, p = 0.006). Thresholds measured in this study were over 10 times lower compared to previous research, highlighting the importance of assessing proprioception during functional tasks. The unexpected lower discrimination thresholds suggests that sway and load-bearing during balance may enhance sensory acuity and influence decision-making, opening avenues for future research. These findings support the potential of my novel proprioception test as a valuable and functionally relevant tool for both laboratory and clinical settings.

Text

2025-03-19

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/90514

Kinesiology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/