Coude

Résumé

Le coude est le segment du membre supérieur situé entre la bras et l'avant-bras. C'est la zone de flexion - extension de l'avant-bras sur le bras. Le terme coude peut désigner la région cubitale anatomique en tant que telle ou désigner le système articulaire du coude. La région est divisée en deux parties :

une région cubitale postérieure,
une région cubitale antérieure formant le pli du coude ou fosse cubitale.

Notes et références Liens externes * * * * * * Catégorie:Articulation du membre supérieur

Source officielle

https://fr.wikipedia.org/wiki/Coude

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Background: Exoskeletons for lower and upper extremities have been introduced in neurorehabilitation because they can guide the patient's limb following its anatomy, covering many degrees of freedom and most of its natural workspace, and allowing the control of the articular joints. The aims of this study were to evaluate the possible use of a novel exoskeleton, the Arm Light Exoskeleton (ALEx), for robot-aided neurorehabilitation and to investigate the effects of some rehabilitative strategies adopted in robot-assisted training. Methods: We studied movement execution and muscle activities of 16 upper limb muscles in six healthy subjects, focusing on end-effector and joint kinematics, muscle synergies, and spinal maps. The subjects performed three dimensional point-to-point reaching movements, without and with the exoskeleton in different assistive modalities and control strategies. Results: The results showed that ALEx supported the upper limb in all modalities and control strategies: it reduced the muscular activity of the shoulder's abductors and it increased the activity of the elbow flexors. The different assistive modalities favored kinematics and muscle coordination similar to natural movements, but the muscle activity during the movements assisted by the exoskeleton was reduced with respect to the movements actively performed by the subjects. Moreover, natural trajectories recorded from the movements actively performed by the subjects seemed to promote an activity of muscles and spinal circuitries more similar to the natural one. Conclusions: The preliminary analysis on healthy subjects supported the use of ALEx for post-stroke upper limb robotic assisted rehabilitation, and it provided clues on the effects of different rehabilitative strategies on movement and muscle coordination.

Biomed Central Ltd2016

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Combining proprioception and touch to compute spatial information

Elisa Canzoneri

Localising a tactile stimulus in egocentric space involves integrating information from skin receptors with proprioceptive inputs about body posture. We investigated whether body posture automatically influences tactile spatial judgements, even when it is irrelevant to the task. In Experiment 1, participants received two successive tactile stimuli on the forearm and were asked to indicate whether the first or second touch of the pair was closer to an anatomical body landmark, either the wrist or the elbow. The task was administered in three experimental conditions involving different body postures: canonical body posture with extended forearm and hand pointing distally; a non-canonical body posture with forearm and hand pointing vertically up at 90A degrees and a 'reversed' body posture with the elbow fully flexed at 180A degrees, so that the hand pointed proximally. Thus, our task required localising touch on the skin and then relating skin locations to anatomical body landmarks. Critically, both functions are independent of the posture of the body in space. We nevertheless found reliable effects of body posture: judgement errors increased when the canonical forearm posture was rotated through 180A degrees. These results were further confirmed in Experiment 2, in which stimuli were delivered to the finger. However, additionally reversing the canonical posture of the finger, as well as that of the forearm, so that the finger was restored to its canonical orientation in egocentric space, restored performance to normal levels. Our results confirm an automatic process of localising the body in external space underlying the process of tactile perception. This process appears to involve a combination of proprioceptive and tactile information.

Springer2014

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Human-Robot Synchrony: Flexible Assistance Using Adaptive Oscillators

Auke Ijspeert, Renaud Ronsse, Jesse van den Kieboom

We propose a novel method for movement assistance that is based on adaptive oscillators, i. e., mathematical tools that are capable of extracting the high-level features (amplitude, frequency, and offset) of a periodic signal. Such an oscillator acts like a filter on these features, but keeps its output in phase with respect to the input signal. Using a simple inverse model, we predicted the torque produced by human participants during rhythmic flexion-extension of the elbow. Feeding back a fraction of this estimated torque to the participant through an elbow exoskeleton, we were able to prove the assistance efficiency through a marked decrease of the biceps and triceps electromyography. Importantly, since the oscillator adapted to the movement imposed by the user, the method flexibly allowed us to change the movement pattern and was still efficient during the nonstationary epochs. This method holds promise for the development of new robot-assisted rehabilitation protocols because it does not require prespecifying a reference trajectory and does not require complex signal sensing or single-user calibration: the only signal that is measured is the position of the augmented joint. In this paper, we further demonstrate that this assistance was very intuitive for the participants who adapted almost instantaneously.

2011

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