Patterns of stereotyped muscle coactivation, clinical-ly referred to as synergies, emerge following stroke and impair arm function. Although researchers have fo-cused on cortical contributions, there is growing evidence that altered stretch reflex pathways may also contribute to impairment. However, most previous reflex studies have focused on passive, single-joint move-ments without regard to their coordination during volitional actions. The purpose of this study was to exa-mine the effects of stroke on coordinated activity of stretch reflexes elicited in multiple arm muscles following multijoint perturbations. We hypothesized that cortical injury results in increased stretch ref-lexes of muscles characteristic of the abnormal flexor synergy during active arm conditions. To test this hypothesis, we used a robot to apply position perturbations to impaired arms of 10 stroke survivors and dominant arms of 8 healthy age-matched controls. Corresponding reflexes were assessed during volitional contractions simulating different levels of gravitational support, as well as during voluntary flexion and extension of the elbow and shoulder. Reflexes were quantified by average rectified surface electromyogram, recorded from eight muscles spanning the elbow and shoulder. Reflex coordination was quantified using an independent components analysis. We found stretch reflexes elicited in the stroke group were significantly less sensitive to changes in background muscle activation compared with those in the control group (P 0.05). We also observed significantly increased reflex coupling between elbow flexor and shoulder abduc-tor– extensor muscles in stroke subjects relative to that in control subjects. This increased coupling was present only during volitional tasks that required elbow flexion (P
0.001), shoulder extension (P 0.01), and gravity opposition (P
0.01), but not during the “no load” condition. During volitional contractions, reflex amplitudes scaled with the level of impairment, as assessed by Fugl-Meyer scores (r2  0.63; P 0.05). We conclude that altered reflex coordination is indicative of motor impairment level and may contri-bute to impaired arm function following stroke.

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(EN)Disclosed is a wearable motion assist device (10) provided with a motion assist glove (20) that comprises finger insertion portions (21) into which fingers of a wearer are inserted, drive units (40) that are disposed on the back side of the motion assist glove (20) and drive the finger insertion portions (21), linear members (50) that are disposed along the extension directions of the finger insertion portions (21) so as to transmit the drive force of the drive units (40) to the finger insertion portions (21), a biosignal detection unit (60) that detects a biosignal for operating the fingers of the wearer, and a control unit (70) that outputs a drive control signal to the drive units (40) on the basis of the biosignal generated by the biosignal detection unit (60), the wearable motion assist device (10) being characterized in that the drive units (40) operate the liner members (50) in the extending directions or bending directions of the finger insertion portions (21) on the basis of the drive control signal from the control unit (70).
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System for controlling an exoskeleton haptic device for rehabilitation purposes, and corresponding exoskeleton haptic device.

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A technique for deflecting an actuator belt includes applying a variable deflection force to the actuator belt. The technique may be used to construct actuators for active orthotics, robotics or other applications. Versions with passive clutches may also be used to construct variable-ratio motor gearheads, or may be scaled up to build continuously variable transmissions for automobiles, bicycles, or other vehicles.

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Калифорнийская компания Berkeley Bionics представила публике экзоскелет eLEGS, позволяющий ходить людям с парализованными нижними конечностями.

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