1,720,970 research outputs found
An evaluation of the effects on postural stability of a force feedback rendered by a low-cost haptic device in various tasks
No full textRehabilitation for stroke patients with postural instability or balance disorders can be enhanced using game-based rehabilitative strategies. Our work explored the potential of commercially available haptic devices for a home rehabilitation system. One group of participants used a low-cost device (Falcon) while another group used a high-end device (Omega). Both groups performed various tasks with the haptic device, with the eyes either closed or open. Results showed that participants interacted somewhat differently with the two devices, although the analysis of the center of pressure showed qualitatively similar balance performance for the two groups. Light touch task increased the stability, whereas the force tasks decreased it. This study showed that a low-cost haptic device can affect postural stability in a controllable way. © 2013 IEEE
Ability of low-cost force-feedback device to influence postural stability
No full textLow-cost gaming technology offers promising devices for the rehabilitation of stroke patients at home. While several attempts have been made to use low-cost motion tracking devices (Kinect) or balance boards (Wii Board), the potential of low-cost haptic devices has yet to be explored in this context. The objective of this study was to investigate whether it is possible to influence postural stability with a low-cost device despite its technical limitations, and to explore the most promising modes of haptic interaction to increase and decrease postural stability. Two groups of younger subjects used a high-end (Omega.3) and a low-cost (Falcon) device respectively. A third group of older subjects used the Falcon. We show that light touch contact with the device improves stability, whereas the force tasks decrease it. The effects of the different tasks are consistent in the two age groups. Although there are differences in the participants' interaction with the two devices, the effect of the devices on postural stability is comparable. We conclude that a low-cost haptic device can be used to increase or decrease postural stability of healthy subjects with an age similar to that of typical stroke patients, in a safe and controllable way
AIDA - Advances in Haptic Interfaces Design and Applications: Soft Contact, Multi-point and Multi-modal Integration
No full textIn this paper, the Italian research program AIDA, supported by MIUR (Italian Ministry of Education, University and Research) within the PRIN 2005 action, is presented. The activity, planned for two years, is developed by five Research Units, active at the University of Bologna, University of Siena, University of Verona, PERCRO Lab. (Scuola Superiore S. Anna), San Raffaele University in Milano, and involves, with different modalities, about 40 researchers. The general objective of AIDA is to study and develop innovative haptic interfaces, with particular attention to interfaces with "multi-point" capabilities, to allow for a more natural interaction with virtual objects, and to the interaction with compliant virtual objects. An important part of this proposal consists in the analysis and study of the human perceptual and control abilities in the type of tasks considered in this project. This knowledge will be exploited to optimize the design of new haptic interfaces
Video-games based Neglect rehabilitation using haptics
No full textVideo-games are effective and motivating tools in the rehabilitation of patients. This study presents a video-game based platform controlled by a haptic device for the rehabilitation of Neglect patients. Haptic structure, game engine, game design criteria and example games are presented in detail
Is it possible to perceive the shape of an object without exploring it?
No full textThe deformation of the fingerpads along the contact surfaces in a
real grasp provides local information about the shape of the object,
which is crucial for the stability of the grasp. Several experiments
were performed to investigate whether it was possible to transmit
information about the shape of a virtual object grasped via a singlecontact haptic interface, in spite of the fact that thimbles prevent the
deformation of the fingerpads. To that end, we modified the classic god-point algorithm by using a pseudo-ellipsoidal force field
that provides information about the object’s shape by increasing
the compliance along the normal or tangential direction. The position of the god-point was held fixed during the whole contact. The
main finding was that participants could identify the orientation of
the contact surface when the compliance was maximum in the tangential plane by using small exploratory movements allowed by the
contact model
Motor Commands Induce Time Compression for Tactile Stimuli
No full textAbstractThe link between time perception and action has attracted special interest in recent years and it is progressively disclosing a multifaceted nature. A large set of temporal effects variously associated to the execution of actions has been documented (Haggard et al., 2002; Hagura et al., 2012; Tomassini et al., 2012; Yarrow et al., 2001), suggesting that perceived time may directly emerge from sensory-motor processes. Saccadic eye movements have been shown to cause not only compression of the visual space towards the saccadic target, but also a compression of time. Apparent event time is both shifted and compressed so that the temporal separation of two visual stimuli is strongly reduced and even their order of appearance sometimes reversed. The spatial and temporal distortions are thought to be interconnected phenomena that might be related to the problem of maintaining perceptual stability during eye movements (Burr & Morrone, 2012; Cicchini et al., 2013). Interestingly, evidence suggests that similar phenomena may occur around the time of hand movements, when brief tactile stimuli are systematically mislocalized in the direction of the movement. In this study we measured whether hand movements also cause an alteration of the perceived timing of the tactile signals. Participants compared the temporal separation between two pairs of tactile taps while moving their right hand in response to an auditory cue. The first pair of tactile taps was presented at variable times with respect to movement with a fixed onset asynchrony of 150ms. 2 s after test presentation - when the hand was stationary- the second pair of taps was delivered with a variable temporal separation. Tactile stimuli could be delivered either to the right moving or left stationary hand. We found that when the tactile stimuli were presented on the motor effector, their perceived temporal separation was reduced. The compression of time began in stationary conditions, during the motor preparatory period, and persisted during movement. Critically, at the moments around action initiation, time compression was restricted to the motor effector. Duration was misjudged only when tactile stimuli were delivered to the hand that was about to move and not when delivered to the other, stationary hand. That time compression is effector-specific makes highly implausible any explanation based on high-level attentional modulations. Rather, it points to a specific mechanism based on a finely-tuned sensory-motor coupling. To understand better the nature and origin of the temporal distortion accompanying hand movements we tested also an isometric condition. Motor efference, with no associated spatial displacement of any body part, induced comparable compression of perceived time as actual movement. An intention-to-move signal, seems thus to be sufficient to mediate the observed perceptual effects. Our result corroborates recent evidence of a tight link between time perception and action and shows a selective and anticipatory movement-related distortion of time. The changes in apparent time that we observed for tactile stimuli at the moment of hand movements closely resemble the peri-saccadic distortions of visual time. As for vision, the mislocalizations of time and space of touch stimuli may be consequences of a mechanism attempting to achieve perceptual stability, suggesting that different sensorimotor systems may exploit similar strategies during the active exploration of the environment
Method for the estimation of a double hinge kinematic model for the trapeziometacarpal joint using MR imaging
No full textMRI and motion capture to compute of the kinematic parameters of a realistic kinematic model for the trapezio-metacarpal joint
No full textIntelligent Game Engine for Rehabilitation (IGER)
No full textComputer games are a promising tool to support intensive rehabilitation. However, at present, they do not incorporate the supervision provided by a real therapist and do not allow safe and effective use at a patient's home. We show how specifically tailored computational intelligence based techniques allow extending exergames with functionalities that make rehabilitation at home effective and safe. The main function is in monitoring the correctness of motion, which is fundamental in avoiding developing wrong motion patterns, making rehabilitation more harmful than effective. Fuzzy systems enable us to capture the knowledge of the therapist and to provide real-time feedback of the patient's motion quality with a novel informative color coding applied to the patient's avatar. This feedback is complemented with a therapist avatar that, in extreme cases, explains the correct way to carry out the movements required by the exergames. The avatar also welcomes the patient and summarizes the therapy results to him/her. Text to speech and simple animation improve the engagement. Another important element is adaptation. Only the proper level of challenge exercises can be both effective and safe. For this reason exergames can be fully configured by therapists in terms of speed, range of motion, or accuracy. These parameters are then tuned during exercise to the patient's performance through a Bayesian framework that also takes into account input from the therapist. A log of all the interaction data is stored for clinicians to assess and tune the therapy, and to advise patients. All this functionality has been added to a classical game engine that is extended to embody a virtual therapist aimed at supervising the motion, which is the final goal of the exergames for rehabilitation. This approach can be of broad interest in the serious games domain. Preliminary results with patients and therapists suggest that the approach can maintain a proper challenge level while keeping the patient motivated, safe, and supervised
- …
