The rubber hand illusion paradigm transferred to the lower limb: A physiological, behavioral and subjective approach

Biomedical Engineering / Biomedizinische Technik

Preller

et al. 2012

Feelings of unrealistic body parts are related to deficits in human information processing and can occur as a part of phantom sensations after amputation [8]. Experimentally induced sensoric illusions like rubber hand illusion (RHI) [1] may help to understand basic information processing and could give new ideas for treatment or the rehabilitation process. Factors that are related to modulate sensoric illusions during movement may help to develop new intervention strategies in the rehabilitation of illusory symptoms. The goal of this study was to review the factors affecting persistence of the RHI effect during movement. We selected 13 keywords and searched in the following www.dimdi.de data bases (CCTR93, CDAR94, CDSR93, DAHTA, DAHTA, EA08, ED93, EM00, EM47, HG05, KP05, KR03, ME00, ME60, PI67, PY81, TV01, TVPP). A total of 160 articles were found. Duplicates were removed and the remaining list was filtered with the objective to explore the influence of active or passive movement during experimentally induced RHI. Then we identified six articles which experimentally examined persistence of RHI during active or passive movements. Results indicate that RHI are maintained during active or passive movements due to visual and temporal congruency. During active movements the RHI is more stable or global than in passive movements or during tactile stimulation. Factores like visual and temporal congruency are related to maintain RHI and are discussed in the rehabilitation of phantom sensations regarding new innovations in the design of prosthetics IntroductionAfter an amputation, feelings of unrealistic body parts are related to deficits in human information processing and can occur as a part of phantom sensations [8]. Those phantom sensations after an amputation are able to lead to feelings of pain which may be localized in a limb that no longer exists. All of these symptoms suggest disturbances in the experience of the body image/body scheme or in general a potential harm to the body matrix concept [24]. The rubber hand illusionBotvinick and Cohen [2] showed that the body image/scheme can experimentally be manipulated in healthy volunteers. In this standard paradigm a subject sees a visibly rubber hand being brushed while the real hidden hand of the subject is also synchronously brushed. After a certain time (15 seconds to 10 minutes) this process induces the feeling of ownership of an artificial limb (the rubber hand). Studies demonstrated that on average 25% of the participants do not respond to items that indicate this kind of illusory embodiment [10,6,5,4]. The cause and stability of this effect in responding subjects is attributed to multisensory integration between visual, tactile and proprioceptive information (see Image 1).Also a proprioceptive recalibration towards the rubber hand can be measured. This proprioceptive drift is being measured after the evoking of the illusion. The subject is asked to show the position of his/her real hand. In case of a successful illusion, subjects tend to show the po...

Section: Technological Applicationmentioning

confidence: 99%

The rubber hand illusion: Maintaining factors and a new perspective in rehabilitation and biomedical engineering?

Christ

Biomedical Engineering / Biomedizinische Technik

Preller

et al. 2012

“…Experimental investigations of RHI with prosthetic hand [10], show that a manipulation of the body schema is a promising approach to improve prosthetic intervention. First investigations on transferring the RHI to the lower limbs in terms of a Rubber Foot Illusion show significant changes in survey data while results differ regarding the proprioceptive drift [11], [12].…”

Section: Introductionmentioning

confidence: 99%

Implementation, control and user-feedback of the Int<sup>2</sup>Bot for the investigation of lower limb body schema integration

The 23rd IEEE International Symposium on Robot and Human Interactive Communication

Schultje

Wojtusch

et al. 2014

Self Cite

The integration of prostheses or wearable robotics into the body schema of their users is a fundamental requirement for the acceptance and control of such artificial devices. Duration and progress of integration are primarily influenced by visual, tactile, and proprioceptive perception. This paper describes the Int 2 Bot, a robot for the assessment of lower limb body schema integration during postural motion. The robot is designed to imitate human squatting movements to investigate the integration of artificial limbs into the body schema. The psychological and technical concepts as well as the mechatronic implementation and control are presented along with interface extensions comprising human knee position sensing and tactile user-feedback. The performance of the robot is examined by experiments excluding and including the human-robot interface and a human user. Those without interface show that the robot itself can perform considerably fast squats with 0.8 Hz, which comes up to maximum human capabilities. The computed torque control achieves good tracking results and fuzzy-based friction compensation further reduces position errors by up to 50%. Yet, results considering the vision-based part of the human-robot interface show that the setup is mainly limited due to delays in motion acquisition with the RGB-D sensor.

“…These investigations can be performed with a passive rubber hand [6] or with a robotic hand prosthesis [7]. First investigations on transferring the Rubber Hand Illusion to the lower limbs in terms of a Rubber Foot Illusion show significant changes in survey data while results differ regarding the proprioceptive drift [8], [9]. The Int 2 Bot that is subject of this paper represents a robotic concept to perform such experiments during lower limb motion as proposed in [10].…”

Section: Introductionmentioning

confidence: 99%

Comparison of trajectory generation methods for a human-robot interface based on motion tracking in the Int<sup>2</sup>Bot

Schultje

The 23rd IEEE International Symposium on Robot and Human Interactive Communication

Grimmer

et al. 2014

Self Cite

The acceptance of artificial devices like prostheses or other wearable robots requires their integration into the body schemas of the users. Different factors induce, influence and support the integration and acceptance of the device that substitutes or augments a part of the body. Previous studies have shown that the inducing and maintaining factors are visual, tactile and proprioceptive informations as well as their multisensory integration. This paper describes the vision-based part of the human-robot interface in the Int 2 Bot, which is a robot for the investigation of lower limb body schema integration during postural movements. The psychological approach and the technical setup of the robot, which is designed to imitate postural movements in the sagittal plane to imitate the human subject while performing squats, are outlined. To realize the imitation, an RGB-D sensor, in form of a Microsoft Kinect, is used to capture the subjects motions without contact and thereby avoid disturbances of body schema integration. For generation of the desired joint trajectories to be tracked by the control algorithm, different methods like an extended Kalman filter, inverse kinematics, an inverse kinematics algorithm using Jacobian transpose and approaches based on kinematic assumptions are presented, evaluated and compared based on human data. Benchmarking the results with data acquired using a professional motion capturing system shows that best overall joint angle estimations are achieved with the extended Kalman filter. Finally, the practical implementation within the robot is presented and the tracking behavior using the trajectories generated with the extended Kalman filter are analyzed.