Andrew Sawers, Brian J. Hafner
Kinesiology, University of Illinois at Chicago, 60612 Chicago, USA. E-mail: asawers@uic.edu
DOI: 10.2340/16501977-2329

Objective: Challenging clinical balance tests are needed to expose balance deficits in lower-limb prost-hesis users. This study examined whether narrowing beam-walking could overcome conceptual and practical limitations identified in fixed-width beam-walking.
Design: Cross-sectional.
Participants: Unilateral lower-limb prosthesis users.
Methods: Participants walked 10 times along a low, narrowing beam. Performance was quantified using the normalized distance walked. Heuristic rules were applied to determine whether the narrowing beam task was “too easy,” “too hard,” or “appropriately challenging” for each participant. Linear regression and Bland-Altman plots were used to determine whether combinations of the first 5 trials could predict participants’ stable beam-walking performance.
Results: Forty unilateral lower-limb prosthesis users participated. Narrowing beam-walking was appropriately challenging for 98% of participants. Performance stabilized for 93% of participants within 5 trials, while 62% were stable across all trials. The mean of trials 3–5 accurately predicted stable performance.
Conclusion: A clinical narrowing beam-walking test is likely to challenge a range of lower-limb prosthesis users, have minimal administrative burden, and exhibit no floor or ceiling effects. Narrowing beam-walking is therefore a clinically viable method to evaluate lower-limb prosthesis users’ balance ability, but requires psychometric testing before it is used to assess fall risk.

Existing clinical balance tests may be too easy, limiting their ability to detect balance deficits in lower-limb prosthesis users. We studied whether narrowing beam-walking was a feasible method for challenging balance control in these subjects. We found that lower-limb prosthesis users could start, but not finish, the narrowing beam-walking task. Their performance stabilized rapidly, and a score could be predicted accurately with as few as 5 trials. These results suggest that narrowing beam-walking is an effective method for measuring balance ability in lower-limb prosthesis users, and may address issues present in many existing balance tests.

Appendix S1