http://www.jneuroengrehab.com/content/10/1/79/abstract
Abstract (provisional)
Background
Functional integration of motor activity patterns enables the production of coordinated
movements, such as walking. The activation of muscles by weightened summation of activation
signals has been demonstrated to represent the spatiotemporal components that determine
motor behavior during walking. Exoskeleton robotic devices are now often used in the
rehabilitation practice to assist physical therapy of individuals with neurological
disorders. These devices are used to promote motor recovery by providing guidance
force to the patients. The guidance should in principle lead to a muscle coordination
similar to physiological human walking. However, the influence of robotic devices
on locomotor patterns needs still to be characterized. The aim of this study was to
analyze the effect of force guidance and gait speed on the modular organization of
walking in a group of eight healthy subjects.
Method
A group of healthy subjects walked on a treadmill with and without robotic aiding
at speeds of 1.5, 2.0 and 2.5 Km/h. The guidance force was varied between 20%, 40%,
70% and 100% level of assistance. EMG recordings were obtained from seven leg muscles
of the dominant leg and kinematic and kinetic features of the knee and hip joints
were extracted.
Results
Four motor modules were sufficient to represent the variety of behavioral goals demanded
during robotic guidance, with similar relationships between muscle patterns and biomechanical
parameters across subjects, confirming that the low-dimensional and impulsive control
of human walking is maintained using robotic force guidance. The conditions of guidance
force and speed that maintained correct and incorrect (not natural) modular control
were identified.
Conclusion
In neurologically intact subjects robotic-guided walking at various force guidance
and speed levels does not alter the basic locomotor control and timing. This allows
the design of robotic-aided rehabilitation strategies aimed at the modulation of motor
modules, which are altered in stroke.
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