A new valid Walking Aid Scale better predicts distance walked by prosthesis users than Prosthetic Mobility Questionnaire 2.0 and Activities-Specific Balance Confidence Scale

The availability of psychometrically-sound and parsimonious outcome measures is key for optimizing decision-making about prosthetic fitting and rehabilitation in lower limb prosthesis users. Despite the increasing clinical use of observational and self-reported scales for assessing mobility and balance, there is currently no scale that accounts for the use of assistive devices while walking under conditions of increasing difficulty. Therefore, the purpose of this study was to develop and validate a Walking Aid Scale (WAS) in a cross-sectional sample of 144 prosthesis users. Specifically, we examined internal consistency and concurrent validity of WAS against two commonly used self-report measures of prosthetic mobility and balance confidence - the Prosthetic Mobility Questionnaire 2.0 (PMQ 2.0) and Activities-Specific Balance Confidence Scale (ABC-5). The predictive value of WAS, in comparison to PMQ 2.0 and ABC-5, was assessed using a 6-Minute Walk Test (6MWT) and participants' characteristics. The WAS showed significant moderate-to-good correlations with PMQ 2.0 and ABC-5, and all scales correlated well with age and 6MWT. Participants who relied less on walking aids reported higher mobility levels, greater balance confidence, and walked longer distances. Age was associated with greater use of walking aids and lower mobility and balance confidence. In the stepwise linear regression analysis, age, amputation level, time since amputation, and WAS predicted about two-thirds of the variability in 6MWT with no significant contribution of PMQ 2.0 and ABC-5. These findings indicate that WAS is a valid instrument and a better predictor of walking distance than PMQ 2.0 and ABC-5 in the lower limb prosthesis users.