A novel approach to mechanical foot stimulation during human locomotion under body weight support

Abstract

a b s t r a c tInput from the foot plays an essential part in perceiving support surfaces and determining kinematic events in human walking. To simulate adequate tactile pressure inputs under body weight support (BWS) conditions that represent an effective form of locomotion training, we here developed a new method of phasic mechanical foot stimulation using light-weight pneumatic insoles placed inside the shoes (under the heel and metatarsus). To test the system, we asked healthy participants to walk on a treadmill with different levels of BWS. The pressure under the stimulated areas of the feet and subjective sensations were higher at high levels of BWS and when applied to the ball and toes rather than heels. Foot stimulation did not disturb significantly the normal motor pattern, and in all participants we evoked a reliable step-synchronized triggering of stimuli for each leg separately. This approach has been performed in a general framework looking for ''afferent templates" of human locomotion that could be used for functional sensory stimulation. The proposed technique can be used to imitate or partially restore surrogate contact forces under body weight support conditions.

Changes in Postural Sway According to Surface Stability in Post-stroke Patients

“…The quickly adapting mechanoreceptors provide information about pressure amplitude and changes in pressure exerted on the skin, causing rapid motor changes of posture for postural control 21) . However, this study found that the loss of proprioception due to paralysis 22) and subsequent lowering of proprioception in stroke patients cause an increased span of postural sway compared with that in normal persons. This study measured the postural sway velocity, area, and distance using a forceplate with the aim of exploring the influence of an unstable surface on the postural sway in the standing posture.…”

Development of a body weight support system using pneumatic muscle actuators: Controlling and validation

“…The benefit of gait training using a BWS system is not only simply supporting the subject's body weight during walking but also the improvement of other gait parameters such as ground reaction force, hip, knee, and ankle angle parameters, and the symmetry of gait locus. [5][6][7][8] Recently, the BWS system has been combined with leg robotic orthoses such as Locomat, task activity, which allow patients to initiate gait training activities early after injury. 3 The gait training process for incompletely healed patients normally undergoes many periods, depending on the condition of the patient.…”

Changes of Gait Kinematics in Different Simulators of Reduced Gravity

“…All three major lower limb segments (thigh, shank, foot) contribute to the co-variance of angular motion and to appropriate limb axis length and orientation ('telescopic limb') behavior resulting in a gait-dependent center-ofmass trajectories . Although the force of gravity acts on both the stance and swing limb (Mochon and McMahon 1980;Kuo 2001;Doke et al 2005;Doke and Kuo 2007;Raichlen 2008), most of these studies used reduced gravity simulators that unload the body only during the stance phase Griffin et al 1999;Ivanenko et al 2002;McCrory et al 2002;Gravano et al 2011) under the assumption that the swing limb adapts automatically to the modified gait. However, to what extent is this true?…”