Article

Novel powered prosthetic ankles currently incorporate finite state
control, using kinematic and kinetic sensors to differentiate stance and swing
phases/sub-phases and control joint impedance and position or torque. For more
intuitive control, myoelectric control of the ankle using the remnant residual
limb dorsiflexors and plantarflexors, perhaps in concert with kinetic and
kinematic sensors, may be possible. OBJECTIVE: The specific research objective
was to assess the feasibility of using myoelectric control of future active or
powered prosthetic ankle joints for trans-tibial amputees. STUDY DESIGN: The
project involved human subject trials to determine whether current techniques of
myoelectric control of upper extremity prostheses might be readily adapted for
lower extremity prosthetic control. METHODS: Gait analysis was conducted for
three unilateral trans-tibial amputee subjects during ambulation on an
instrumented split belt treadmill. Data included ankle plantarflexor and
dorsiflexor activity for the residual limb, as well as lower limb kinematics and
ground reaction forces and moments of both the sound and prosthetic limbs.
RESULTS: These data indicate that: 1) trans-tibial amputees retain some
independent ankle plantarflexor and dorsiflexor muscle activity of their residual
limb; 2) it is possible to position surface electromyographic electrodes within a
trans-tibial socket that maintain contact during ambulation; 3) both the
plantarflexors and dorsiflexors of the residual limb are active during gait; 4)
plantarflexor and dorsiflexor activity is consistent during multiple gait cycles;
and 5) with minimal training, trans-tibial amputees may be able to activate their
plantarflexors during push-off. CONCLUSIONS: These observations demonstrate the
potential for future myoelectric control of active prosthetic ankles. Clinical
relevance This study demonstrated the feasibility of applying upper extremity
prosthetic myoelectric signal acquisition, processing and control techniques to
future myoelectric control of active prosthetic ankles for trans-tibial amputees.

Langue : ANGLAIS