Highlights
- •Group analysis masks individual variation of amputees in response to modifications.
- •Based on single subject analysis, asymmetric prosthesis improved step length.
- •Asymmetric prosthesis did not improve stability and variability.
Abstract
Background
Group statistical analysis may mask individual differences in response to interaction
with rehabilitative devices such as prostheses. This study sets out to evaluate the
effect of asymmetric prosthesis using a single subject methodology on individuals
with unilateral transfemoral amputation.
Methods
Acceleration data of 17 participants with unilateral transfemoral amputation were
collected using a triaxial accelerometer attached at the L3 level of the spine during
level ground walking under four prosthesis conditions: 1) no added mass; 2) the knee
joint relocated downwards by 18% of the total shank length, shank mass decreased by
68%, thigh mass increased by 7%; 3) the knee joint relocated downwards by 37% of the
total shank length, shank mass decreased by 68%, thigh mass increased by 7%, and 4)
thigh mass increased 17%, shank mass decreased by 38%. Step length, step time, step
length variability, step time variability and Floquet multiplier were statistically
assessed.
Findings
The single subject analysis highlighted that under prosthetic modifications, intact
limb step length was increased and prosthetic step length was deceased in most participants
(n > 9). No significant changes were observed in Floquet multiplier (n > 14), step length (n > 6) and step time variability (n > 9) across all conditions.
Interpretation
Single subject analysis showed that in response to the immediate effect of asymmetric
prosthesis, increase in the intact limb step length and decrease in the prosthetic
limb step length emerged as a dominant strategy for most participants. Regarding Floquet
multiplier, step length, and step time variability, our prosthetic modifications did
not produce the anticipated effects.
Keywords
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Article info
Publication history
Published online: November 10, 2022
Accepted:
November 8,
2022
Received:
July 28,
2022
Identification
Copyright
© 2022 Elsevier Ltd. All rights reserved.
