Article

Kinesthetic sensibility.

Physiological Reviews (Impact Factor: 29.04). 11/1978; 58(4):763-820.
Source: PubMed
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    ABSTRACT: Background After a limb is lost a prosthesis can restore function. For maximum utility, prosthetic limbs should accept movement commands and provide force and motion feedback, which can be conveyed with vibrotactile feedback (VIBF). While prior studies have shown that force-based VIBF benefits control, the merits of motion-based VIBF are unclear. Our goal was to clarify the effectiveness of position- and velocity-based VIBF for prosthetic arm control. Methods Healthy adults with normal limb function practiced a goal-directed task with a virtual myoelectric prosthetic arm. A linear resonant actuator on the wrist provided VIBF. Two groups with nine subjects each received amplitude modulated VIBF in addition to visual feedback while practicing the task. In one group, the VIBF was proportional to the virtual arm’s position, and in the other group, velocity. A control group of nine subjects received only visual feedback. Subjects practiced for 240 trials, followed by 180 trials with feedback manipulations for the VIBF groups. Performance was characterized by end-point error, movement time, and a composite skill measure that combined these quantities. A second experiment with a new group of five subjects assessed discrimination capabilities between different position- and velocity-based VIBF profiles. Results With practice all groups improved their skill in controlling the virtual prosthetic arm. Subjects who received additional position- and velocity-based VIBF learned at the same rate as the control group, who received only visual feedback (learning rate time constant: about 40 trials). When visual feedback was subsequently removed leaving only VIBF, performance was no better than with no feedback at all. When VIBF was removed leaving only visual feedback, about half of the participants performed better, instead of worse. The VIBF discrimination tests showed that subjects could detect virtual arm angular position and velocity differences of about 5 deg and 20 deg/s, respectively. Conclusions Kinematic VIBF did not increase the rate of skill acquisition or improve performance when controlling a virtual myoelectric prosthetic arm, whether provided in isolation or coupled with visual feedback. VIBF had a deleterious effect on performance for some individuals, who may have had difficulty integrating kinematic VIBF information into their control strategies.
    Journal of NeuroEngineering and Rehabilitation 03/2015; 12(1). DOI:10.1186/s12984-015-0025-5 · 2.62 Impact Factor
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    ABSTRACT: To control movement, the brain has to integrate proprioceptive information from a variety of mechanoreceptors. The role of proprioception in daily activities, exercise and sport has been extensively investigated, using different techniques, yet the proprioceptive mechanisms underlying human movement control are still unclear. In the current work we have reviewed understanding of proprioception and the three testing methods: threshold to detection of passive motion, joint position reproduction, and active movement extent discrimination, all of which have been used for assessing proprioception. The origin of the methods, the different testing apparatus, and the procedures and protocols used in each approach are compared and discussed. Recommendations are made for choosing an appropriate technique when assessing proprioceptive mechanisms in different contexts.
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    ABSTRACT: Haptic feedbacks are usually used to provide a sensation of interaction with virtual or distant objects. These feedbacks give an access to the physical properties or constraints of these objects in a given environment. In the present study, we wondered if a haptic feedback in the hands can provide an enhanced sensation of whole-body self-motion in virtual worlds. We designed two experiments where subjects were visually immersed in a moving virtual environment and exposed, in parallel, to a force feedback stimulation in hands coherent with the virtual camera motion. In the first experiment, the motion was in a straight line combined with a force feedback acting only on Z-axis (longitudinal) and with an amplitude proportional to the acceleration of the virtual camera. We showed that the visuo-haptic stimulation produces a higher sensation of self-motion compared to the visual feedback alone. In the second experiment, we tested our method with a more complex virtual camera trajectory, inducing an acceleration vector of the virtual camera owning components in each 3D axis. Based on the difference of orientation between the velocity and acceleration vectors of the camera, we showed that the force feedback, providing the most important sensation of self-motion, has the same 3D orientation and is proportional in magnitude to the acceleration of the virtual camera. These results highlight the way visual and haptic cues interact together to provide a self-motion sensation. Taken together our results suggest new applications of force-feedback devices in VR, for the purpose of enhancing self-motion sensations.
    2014 IEEE Haptics Symposium (HAPTICS); 02/2014