Understanding responses to gait instability from plantar pressure measurement and the relationship to balance and mobility in lower-limb amputees

- Center of pressure measures discern between gait conditions for lower-limb amputees.
- Temporal and center of pressure measures discriminate between gait conditions.
- Center of pressure measures relate to clinical balance and mobility measures.
- Intact limb measures are highly relevant to balance and mobility.

BackgroundMeasuring responses to a more unstable walking environment at the point-of-care may reveal clinically relevant strategies, particularly for rehabilitation. This study determined if temporal measures, center of pressure-derived measures, and force impulse measures can quantify responses to surface instability and correlate with clinical balance and mobility measures.MethodsThirty-one unilateral amputees, 11 transfemoral and 20 transtibial, walked on level and soft ground while wearing pressure-sensing insoles. Foot-strike and foot-off center of pressure, center of pressure path, temporal, and force impulse variables were derived from F-Scan pressure-sensing insoles.FindingsSignificant differences (P < 0.05) between level and soft ground were found for temporal and center of pressure path measures. Twenty regression models (R2 ≤ 0.840), which related plantar-pressure-derived measures with clinical scores, consisted of nine variables. Stride time was in eight models; posterior deviations per stride in six models; mean CoP path velocity in five models; and anterior-posterior center of pressure path coefficient of variation, percent double-support time, and percent stance in four models.InterpretationCenter of pressure-derived parameters, particularly temporal and center of pressure path measures, can differentiate between level and soft ground walking for transfemoral and transtibial amputees. Center of pressure-derived parameters correlated with clinical measures of mobility and balance, explaining up to 84.0% of the variability. The number of posterior deviations per stride, mean CoP path velocity stride time, anterior-posterior center of pressure path coefficient of variation, percent double-support time, and percent stance were frequently related to clinical balance and mobility measures.