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- Wisse, M. (author), Schwab, A.L. (author), Van der Helm, F.C.T. (author) journal article 2004
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Oosterom, R. (author), Van der Pijl, A.J. (author), Bersee, H.E.N. (author), Van der Helm, F.C. (author), Herder, J.L. (author)The invention relates to a joint prosthesis (10), for example, a knee joint or shoulder joint prosthesis comprising a first, socket-holding prosthesis part (11) for attachment to a first bone (12) and a second, ball-holding prosthesis part (13) for attachment to a second bone (14) that intermates with the first prosthesis part, wherein the first...patent 2006
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Hummels, C.C.M. (author), Van der Helm, A.J.C. (author), Hengeveld, B.J. (author), Luxen, R.F. (author), Voort, R. (author), Van Balkom, H. (author), De Moor, J. (author)Very young non- or hardly speaking children with severe disabilities need active guidance to stimulate interaction with their environment in order to develop their communicative and linguistic skills. Augmentative and Alternative Communication (AAC) systems can help this process, provided that they are tuned to this specific user group....journal article 2007
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Van Nierop, O.A. (author), Van der Helm, A. (author), Overbeeke, K.J. (author), Djajadiningrat, T.J.P. (author)We present a skeletal linked model of the human hand that has natural motion. We show how this can be achieved by introducing a new biology-based joint axis that simulates natural joint motion and a set of constraints that reduce an estimated 150 possible motions to twelve. The model is based on observation and literature. To facilitate testing...journal article 2007
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Schouten, A.C. (author), De Vlugt, E. (author), Van Hilten, J.J. (author), Van der Helm, F.C. (author)This study aimed to analyse the dynamic properties of the muscle spindle feedback system of shoulder muscles during a posture task. External continuous force disturbances were applied at the hand while subjects had to minimize their hand displacements. The results were analysed using two frequency response functions (FRFs) from which the model...journal article 2008
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Schouten, A.C. (author), De Vlugt, E. (author), Van der Helm, F.C.T. (author)This study aimed to identify the functional contribution of reflexes to human motor control during posture maintenance. Continuous random force disturbances were applied at the hand while the subjects were instructed to minimize the deviation resulting from the force disturbances. The results were analyzed in the frequency domain with frequency...journal article 2008
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Hengeveld, B. (author), Voort, R. (author), Hummels, C. (author), De Moor, J. (author), Van Balkom, H. (author), Overbeeke, K. (author), Van der Helm, A. (author)Young children with multiple disabilities (e.g., both cognitive and motor disabilities) are confronted with severe limitations in language development from birth and later on. Stimulating the adult-child communication can decrease these limitations. Within LinguaBytes, a three-year research program, we try to stimulate language development by...journal article 2008
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Schutte, S. (author), Polling, J.R. (author), Van der Helm, F.C.T. (author), Simonsz, H.J. (author)Background- Reoperations are frequently necessary in strabismus surgery. The goal of this study was to analyze human-error related factors that introduce variability in the results of strabismus surgery in a systematic fashion. Methods- We identified the primary factors that influence the outcome of strabismus surgery. For each of the human...journal article 2008
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Christiansson, G.A.V. (author), Van der Linde, R.Q. (author), Van der Helm, F.C.T. (author)Human task performance using teleoperator systems depends on the physical and controlled parameters of the system. Two teleoperated grasping tasks—size and stiffness discrimination—were studied to investigate how changes in system parameters influence human capabilities. The device characteristics altered were teleoperator stiffness (size and...journal article 2008
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Schuurmans, J. (author), De Vlugt, E. (author), Schouten, A.C. (author), Meskers, C.G. (author), De Groot, J.H. (author), Van der Helm, F.C.T. (author)Sudden stretch of active muscle typically results in two characteristic electromyographic responses: the short latency M1 and the long latency M2. The M1 response originates from the monosynaptic Ia afferent reflex pathway. The M2 response is less well understood and is likely a compound response to different afferent inputs mediated by spinal...journal article 2009
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Mugge, W. (author), Schuurmans, J. (author), Schouten, A.C. (author), Van der Helm, F.C.T. (author)In daily life humans integrate force and position feedback from mechanoreceptors, proprioception, and vision. With handling relatively soft, elastic objects, force and position are related and can be integrated to improve the accuracy of an estimate of either one. Sensory weighting between different sensory systems (e.g., vision and...journal article 2009
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Verdaasdonk, B.W. (author), Koopman, H.F.J.M. (author), Van der Helm, F.C.T. (author)Like human walking, passive dynamic walking—i.e. walking down a slope with no actuation except gravity—is energy efficient by exploiting the natural dynamics. In the animal world, neural oscillators termed central pattern generators (CPGs) provide the basic rhythm for muscular activity in locomotion. We present a CPG model, which automatically...journal article 2009
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Meskers, C.G.M. (author), Schouten, A.C. (author), De Groot, J.H. (author), De Vlugt, E. (author), Van Hilten, B.J.J. (author), Van der Helm, F.C.T. (author), Arendzen, H.J.H. (author)Background Instead of hyper-reflexia as sole paradigm, post-stroke movement disorders are currently considered the result of a complex interplay between neuronal and muscular properties, modified by level of activity. We used a closed loop system identification technique to quantify individual contributors to wrist joint stiffness during an...journal article 2009
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Meskers, C.G.M. (author), Schouten, A.C. (author), De Groot, J. (author), De Vlugt, E. (author), Van Hilten, B.J.J. (author), Van der Helm, F.C.T. (author), Arendzen, H.J.H. (author)Instead of hyper-reflexia as sole paradigm, post-stroke movement disorders are currently considered the result of a complex interplay between neuronal and muscular properties, modified by level of activity. We used a closed loop system identification technique to quantify individual contributors to wrist joint stiffness during an active posture...journal article 2009
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Mugge, W. (author), Abbink, D.A. (author), Schouten, A.C. (author), Dewald, J.P.A. (author), Van der Helm, F.C.T. (author)This study aims to quantify the separate contributions of muscle force feedback, muscle spindle activity and co-contraction to the performance of voluntary tasks (‘‘reduce the influence of perturbations on maintained force or position’’). Most human motion control studies either isolate only one contributor, or assume that relevant reflexive...journal article 2009
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Van der Meer, J.N. (author), Schouten, A.C. (author), Bour, L.J. (author), De Vlugt, E. (author), Van Rootselaar, A.F. (author), Van der Helm, F.C.T. (author), Tijssen, M.A.J. (author)In dystonia, both sensory malfunctioning and an abnormal intermuscular low-frequency drive of 3–7 Hz have been found, although cause and eVect are unknown. It is hypothesized that sensory processing is primarily disturbed and induces this drive. Accordingly, experimenter-controlled sensory input should be able to inXuence the frequency of the...journal article 2010
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Mulder, M. (author), Abbink, D. (author), Van Paassen, R. (author), Mulder, M. (author), Van der Helm, F. (author), Boer, E.R. (author), Takada, Y. (author)A target-travel-path generating circuit calculates a target travel path along which the controlled object can travel in the future from the current controlled object position, an ideal-control-signal calculating circuit calculates a control profile S to travel along the target travel path P, and a difference calculating circuit calculates a...patent 2010
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De Vlugt, E. (author), De Groot, J.H. (author), Schenkeveld, K.E. (author), Arendzen, J.H. (author), Van der Helm, F.C.T. (author), Meskers, C.G.M. (author)Quantifying increased joint resistance into its contributing factors i.e. stiffness and viscosity ("hypertonia") and stretch reflexes ("hyperreflexia") is important in stroke rehabilitation. Existing clinical tests, such as the Ashworth Score, do not permit discrimination between underlying tissue and reflexive (neural) properties. We propose an...journal article 2010
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Damveld, H.J. (author), Abbink, D.A. (author), Mulder, M. (author), Mulder, Mark (author), Van Paassen, M.M. (author), Van der Helm, F.C.T. (author), Hosman, R.J.A.W. (author)This goal of this study is to understand which parts of the the neuromuscular system contribute during a pitch control task. A novel method developed at the Delft University of Technology allows us to determine the contribution of the neuromuscular feedback system by identifying the admittance, which is the frequency response function of the...conference paper 2010
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Schuurmans, J. (author), Van der Helm, F.C.T. (author), Schouten, A.C. (author)During posture control, reflexive feedback allows humans to efficiently compensate for unpredictable mechanical disturbances. Although reflexes are involuntary, humans can adapt their reflexive settings to the characteristics of the disturbances. Reflex modulation is commonly studied by determining reflex gains: a set of parameters that quantify...journal article 2010