Improving the functionality, robustness, and adaptability of myoelectric control for dexterous motion restoration

The development of advanced and effective human–machine interfaces, especially for amputees to control their prostheses, is very high priority and a very active area of research. An intuitive control method should retain an adequate level of functionality for dexterous operation, provide robustness against confounding factors, and supply adaptability for diverse long-term usage, all of which are current problems being tackled by researchers. This paper reviews the state-of-the-art, as well as, the limitations of current myoelectric signal control (MSC) methods. To address the research topic on functionality, we review different approaches to prosthetic hand control (DOF configuration, discrete or simultaneous, etc.), and how well the control is performed (accuracy, response, intuitiveness, etc.). To address the research on robustness, we review the confounding factors (limb positions, electrode shift, force variance, and inadvertent activity) that affect the stability of the control performance. Lastly, to address adaptability, we review the strategies that can automatically adjust the classifier for different individuals and for long-term usage. This review provides a thorough overview of the current MSC methods and helps highlight the current areas of research focus and resulting clinic usability for the MSC methods for upper-limb prostheses.

[1]  Huosheng Hu,et al.  Adaptive myoelectric human-machine interface for video games , 2009, 2009 International Conference on Mechatronics and Automation.

[2]  C. Light,et al.  Establishing a standardized clinical assessment tool of pathologic and prosthetic hand function: normative data, reliability, and validity. , 2002, Archives of physical medicine and rehabilitation.

[3]  Robert D. Lipschutz,et al.  Targeted reinnervation for enhanced prosthetic arm function in a woman with a proximal amputation: a case study , 2007, The Lancet.

[4]  Xinjun Sheng,et al.  User adaptation in long-term, open-loop myoelectric training: implications for EMG pattern recognition in prosthesis control , 2015, Journal of neural engineering.

[5]  Todd A. Kuiken,et al.  An Analysis of Intrinsic and Extrinsic Hand Muscle EMG for Improved Pattern Recognition Control , 2016, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[6]  Manfredo Atzori,et al.  Deep Learning with Convolutional Neural Networks Applied to Electromyography Data: A Resource for the Classification of Movements for Prosthetic Hands , 2016, Front. Neurorobot..

[7]  Todd A. Kuiken,et al.  Dual Window Pattern Recognition Classifier for Improved Partial-Hand Prosthesis Control , 2016, Front. Neurosci..

[8]  P H Veltink,et al.  Intention detection of gait initiation using EMG and kinematic data. , 2013, Gait & posture.

[9]  Hong Liu,et al.  On the development of intrinsically-actuated, multisensory dexterous robotic hands , 2016 .

[10]  José Luis Pons Rovira,et al.  Virtual reality training and EMG control of the MANUS hand prosthesis , 2005, Robotica.

[11]  R. H. Jebsen,et al.  An objective and standardized test of hand function. , 1969, Archives of physical medicine and rehabilitation.

[12]  Guido Bugmann,et al.  Improving the Performance Against Force Variation of EMG Controlled Multifunctional Upper-Limb Prostheses for Transradial Amputees , 2016, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[13]  Ashutosh Saxena,et al.  Robotic Grasping of Novel Objects using Vision , 2008, Int. J. Robotics Res..

[14]  Agnès Roby-Brami,et al.  Intuitive prosthetic control using upper limb inter-joint coordinations and IMU-based shoulder angles measurement: A pilot study , 2016, 2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS).

[15]  Ernest Nlandu Kamavuako,et al.  Biomedical Signal Processing and Control , 2022 .

[16]  Xinjun Sheng,et al.  Reduced Daily Recalibration of Myoelectric Prosthesis Classifiers Based on Domain Adaptation , 2016, IEEE Journal of Biomedical and Health Informatics.

[17]  Xinjun Sheng,et al.  Invariant Surface EMG Feature Against Varying Contraction Level for Myoelectric Control Based on Muscle Coordination , 2015, IEEE Journal of Biomedical and Health Informatics.

[18]  K. Englehart,et al.  Resolving the Limb Position Effect in Myoelectric Pattern Recognition , 2011, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[19]  Manfredo Atzori,et al.  Control Capabilities of Myoelectric Robotic Prostheses by Hand Amputees: A Scientific Research and Market Overview , 2015, Front. Syst. Neurosci..

[20]  Honghai Liu,et al.  Multi-Modal Sensing Techniques for Interfacing Hand Prostheses: A Review , 2015, IEEE Sensors Journal.

[21]  Yue Zhang,et al.  Comparison of online adaptive learning algorithms for myoelectric hand control , 2016, 2016 9th International Conference on Human System Interactions (HSI).

[22]  Maja J. Mataric,et al.  Deriving action and behavior primitives from human motion data , 2002, IEEE/RSJ International Conference on Intelligent Robots and Systems.

[23]  James Yang,et al.  Control of Hand Prostheses: A Literature Review , 2013 .

[24]  Roberto Merletti,et al.  Advances in surface EMG: recent progress in clinical research applications. , 2010, Critical reviews in biomedical engineering.

[25]  I. Scott MacKenzie,et al.  Fitts' Law as a Research and Design Tool in Human-Computer Interaction , 1992, Hum. Comput. Interact..

[26]  Aaron M. Dollar,et al.  The Yale human grasping dataset: Grasp, object, and task data in household and machine shop environments , 2015, Int. J. Robotics Res..

[27]  Levi J. Hargrove,et al.  A training strategy to reduce classification degradation due to electrode displacements in pattern recognition based myoelectric control , 2008, Biomed. Signal Process. Control..

[28]  Nitish V. Thakor,et al.  Limb Position Tolerant Pattern Recognition for Myoelectric Prosthesis Control with Adaptive Sparse Representations From Extreme Learning , 2018, IEEE Transactions on Biomedical Engineering.

[29]  Om Prakash Sahu An Integrated Approach of Sensors to Detect Grasping Point for Unstructured 3-D Parts , 2017 .

[30]  Xinjun Sheng,et al.  Mechanical Implementation of Postural Synergies of an Underactuated Prosthetic Hand , 2013, ICIRA.

[31]  Dario Farina,et al.  Proportional estimation of finger movements from high-density surface electromyography , 2016, Journal of NeuroEngineering and Rehabilitation.

[32]  Jaime Valls Miró,et al.  Towards limb position invariant myoelectric pattern recognition using time-dependent spectral features , 2014, Neural Networks.

[33]  Patrick van der Smagt,et al.  Surface EMG in advanced hand prosthetics , 2008, Biological Cybernetics.

[34]  Fan Zhang,et al.  Design of a robust EMG sensing interface for pattern classification , 2010, Journal of neural engineering.

[35]  Dario Farina,et al.  Myoelectric Control of Artificial Limbs¿Is There a Need to Change Focus? [In the Spotlight] , 2012, IEEE Signal Process. Mag..

[36]  Levi J. Hargrove,et al.  Comparison of surface and intramuscular EMG pattern recognition for simultaneous wrist/hand motion classification , 2013, 2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC).

[37]  Gabriel Baud-Bovy,et al.  Neural bases of hand synergies , 2013, Front. Comput. Neurosci..

[38]  J. Fischer,et al.  The Prehensile Movements of the Human Hand , 2014 .

[39]  Jacob L. Segil,et al.  Mechanical design and performance specifications of anthropomorphic prosthetic hands: a review. , 2013, Journal of rehabilitation research and development.

[40]  T. Kuiken,et al.  Quantifying Pattern Recognition—Based Myoelectric Control of Multifunctional Transradial Prostheses , 2010, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[41]  R. Ellis,et al.  The potentiation of grasp types during visual object categorization , 2001 .

[42]  Yu Liu,et al.  A 3-DOF hemi-constrained wrist motion/force detection device for deploying simultaneous myoelectric control , 2018, Medical & Biological Engineering & Computing.

[43]  Kevin B. Englehart,et al.  A robust, real-time control scheme for multifunction myoelectric control , 2003, IEEE Transactions on Biomedical Engineering.

[44]  Levi J. Hargrove,et al.  The effect of wrist position and hand-grasp pattern on virtual prosthesis task performance , 2016, 2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics (BioRob).

[45]  Danica Kragic,et al.  The GRASP Taxonomy of Human Grasp Types , 2016, IEEE Transactions on Human-Machine Systems.

[46]  O. Stavdahl,et al.  Control of Upper Limb Prostheses: Terminology and Proportional Myoelectric Control—A Review , 2012, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[47]  Robert P. W. Duin,et al.  Data domain description using support vectors , 1999, ESANN.

[48]  Kianoush Nazarpour,et al.  Combined influence of forearm orientation and muscular contraction on EMG pattern recognition , 2016, Expert Syst. Appl..

[49]  Dapeng Yang,et al.  Noise cancellation for electrotactile sensory feedback of myoelectric forearm prostheses , 2014, 2014 IEEE International Conference on Information and Automation (ICIA).

[50]  Hiroki Tamura,et al.  Online learning method using support vector machine for surface-electromyogram recognition , 2009, Artificial Life and Robotics.

[51]  Todd A. Kuiken,et al.  The Effects of Electrode Size and Orientation on the Sensitivity of Myoelectric Pattern Recognition Systems to Electrode Shift , 2011, IEEE Transactions on Biomedical Engineering.

[52]  Blair A. Lock,et al.  A Real-Time Pattern Recognition Based Myoelectric Control Usability Study Implemented in a Virtual Environment , 2007, 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[53]  Panagiotis Artemiadis,et al.  A hybrid BMI-based exoskeleton for paresis: EMG control for assisting arm movements , 2017, Journal of neural engineering.

[54]  Dario Farina,et al.  Decoding the neural drive to muscles from the surface electromyogram , 2010, Clinical Neurophysiology.

[55]  Huosheng Hu,et al.  Support Vector Machine-Based Classification Scheme for Myoelectric Control Applied to Upper Limb , 2008, IEEE Transactions on Biomedical Engineering.

[56]  Christian Cipriani,et al.  Is it Finger or Wrist Dexterity That is Missing in Current Hand Prostheses? , 2015, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[57]  Erik J. Scheme,et al.  Selective Classification for Improved Robustness of Myoelectric Control Under Nonideal Conditions , 2011, IEEE Transactions on Biomedical Engineering.

[58]  Kevin Englehart,et al.  High density electromyography data of normally limbed and transradial amputee subjects for multifunction prosthetic control. , 2012, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[59]  Nitish V. Thakor,et al.  Radio frequency identification — An innovative solution to guide dexterous prosthetic hands , 2011, 2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[60]  D. Farina,et al.  Analysis of motor units with high-density surface electromyography. , 2008, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[61]  Robert D. Lipschutz,et al.  Targeted muscle reinnervation for real-time myoelectric control of multifunction artificial arms. , 2009, JAMA.

[62]  Nitish V. Thakor,et al.  Demonstration of a Semi-Autonomous Hybrid Brain–Machine Interface Using Human Intracranial EEG, Eye Tracking, and Computer Vision to Control a Robotic Upper Limb Prosthetic , 2014, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[63]  Blair A. Lock,et al.  Adaptive Pattern Recognition of Myoelectric Signals: Exploration of Conceptual Framework and Practical Algorithms , 2009, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[64]  H. Harry Asada,et al.  Inter-finger coordination and postural synergies in robot hands via mechanical implementation of principal components analysis , 2007, 2007 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[65]  Nitish V. Thakor,et al.  Decoding of Individuated Finger Movements Using Surface Electromyography , 2009, IEEE Transactions on Biomedical Engineering.

[66]  Erik Scheme,et al.  Electromyogram pattern recognition for control of powered upper-limb prostheses: state of the art and challenges for clinical use. , 2011, Journal of rehabilitation research and development.

[67]  Xinjun Sheng,et al.  Quantification and solutions of arm movements effect on sEMG pattern recognition , 2014, Biomed. Signal Process. Control..

[68]  Erik J. Scheme,et al.  Confidence-Based Rejection for Improved Pattern Recognition Myoelectric Control , 2013, IEEE Transactions on Biomedical Engineering.

[69]  Kevin Warwick,et al.  Case Studies to Demonstrate the Range of Applications of the Southampton Hand Assessment Procedure , 2009 .

[70]  Honghai Liu,et al.  Robust sEMG electrodes configuration for pattern recognition based prosthesis control , 2014, 2014 IEEE International Conference on Systems, Man, and Cybernetics (SMC).

[71]  Reza Langari,et al.  Myoelectric pattern recognition using dynamic motions with limb position changes , 2016, 2016 American Control Conference (ACC).

[72]  D. Farina,et al.  Linear and Nonlinear Regression Techniques for Simultaneous and Proportional Myoelectric Control , 2014, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[73]  Dapeng Yang,et al.  Experimental Study of an EMG-Controlled 5-DOF Anthropomorphic Prosthetic Hand for Motion Restoration , 2014, J. Intell. Robotic Syst..

[74]  R.F. Weir,et al.  The Optimal Controller Delay for Myoelectric Prostheses , 2007, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[75]  Khairul Anam,et al.  Evaluation of extreme learning machine for classification of individual and combined finger movements using electromyography on amputees and non-amputees , 2017, Neural Networks.

[76]  Weidong Geng,et al.  Gesture recognition by instantaneous surface EMG images , 2016, Scientific Reports.

[77]  Daniela Rus Fine motion planning for dexterous manipulation , 1992 .

[78]  Hans Dietl,et al.  User demands for sensory feedback in upper extremity prostheses , 2012, 2012 IEEE International Symposium on Medical Measurements and Applications Proceedings.

[79]  Huosheng Hu,et al.  Myoelectric control systems - A survey , 2007, Biomed. Signal Process. Control..

[80]  Manuel G. Catalano,et al.  Adaptive synergies for the design and control of the Pisa/IIT SoftHand , 2014, Int. J. Robotics Res..

[81]  Panagiotis K. Artemiadis,et al.  Proceedings of the first workshop on Peripheral Machine Interfaces: going beyond traditional surface electromyography , 2014, Front. Neurorobot..

[82]  Bruno Siciliano,et al.  Experimental evaluation of postural synergies during reach to grasp with the UB hand IV , 2011, 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[83]  Levi J Hargrove,et al.  A real-time comparison between direct control, sequential pattern recognition control and simultaneous pattern recognition control using a Fitts’ law style assessment procedure , 2014, Journal of NeuroEngineering and Rehabilitation.

[84]  T. Kuiken,et al.  A Comparison of Pattern Recognition Control and Direct Control of a Multiple Degree-of-Freedom Transradial Prosthesis , 2016, IEEE Journal of Translational Engineering in Health and Medicine.

[85]  Giulio Sandini,et al.  Multi-subject/daily-life activity EMG-based control of mechanical hands , 2009, Journal of NeuroEngineering and Rehabilitation.

[86]  Todd A. Kuiken,et al.  Improving Myoelectric Pattern Recognition Robustness to Electrode Shift by Changing Interelectrode Distance and Electrode Configuration , 2012, IEEE Transactions on Biomedical Engineering.

[87]  Todd A Kuiken,et al.  Real-time simultaneous and proportional myoelectric control using intramuscular EMG , 2014, Journal of neural engineering.

[88]  E. Biddiss,et al.  Upper-Limb Prosthetics: Critical Factors in Device Abandonment , 2007, American journal of physical medicine & rehabilitation.

[89]  Erik Scheme,et al.  Training Strategies for Mitigating the Effect of Proportional Control on Classification in Pattern Recognition–Based Myoelectric Control , 2013, Journal of prosthetics and orthotics : JPO.

[90]  Kiyoshi Kotani,et al.  A Novel Unsupervised Adaptive Learning Method for Long-Term Electromyography (EMG) Pattern Recognition , 2017, Sensors.

[91]  Patrick M. Pilarski,et al.  Adaptive artificial limbs: a real-time approach to prediction and anticipation , 2013, IEEE Robotics & Automation Magazine.

[92]  Barbara Caputo,et al.  Improving Control of Dexterous Hand Prostheses Using Adaptive Learning , 2013, IEEE Transactions on Robotics.

[93]  Robert Riener,et al.  Control strategies for active lower extremity prosthetics and orthotics: a review , 2015, Journal of NeuroEngineering and Rehabilitation.

[94]  H. Smith,et al.  Smith hand function evaluation. , 1973, The American journal of occupational therapy : official publication of the American Occupational Therapy Association.

[95]  Peter J Kyberd The influence of control format and hand design in single axis myoelectric hands: assessment of functionality of prosthetic hands using the Southampton Hand Assessment Procedure , 2011, Prosthetics and orthotics international.

[96]  Peter J. Kyberd,et al.  A Critical Review of Functionality Assessment in Natural and Prosthetic Hands , 1999 .

[97]  Dario Farina,et al.  Influence of the training set on the accuracy of surface EMG classification in dynamic contractions for the control of multifunction prostheses , 2011, Journal of NeuroEngineering and Rehabilitation.

[98]  Dario Farina,et al.  Effect of arm position on the prediction of kinematics from EMG in amputees , 2012, Medical & Biological Engineering & Computing.

[99]  Levi J. Hargrove,et al.  A Comparison of Surface and Intramuscular Myoelectric Signal Classification , 2007, IEEE Transactions on Biomedical Engineering.

[100]  Kapil D. Katyal,et al.  Individual finger control of a modular prosthetic limb using high-density electrocorticography in a human subject , 2016, Journal of neural engineering.

[101]  Erik J. Scheme,et al.  Support Vector Regression for Improved Real-Time, Simultaneous Myoelectric Control , 2014, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[102]  J. Elliott,et al.  A CLASSIFICATION OF MANIPULATIVE HAND MOVEMENTS , 1984, Developmental medicine and child neurology.

[103]  M. Goldfarb,et al.  A Method for the Control of Multigrasp Myoelectric Prosthetic Hands , 2012, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[104]  Nareen Karnati,et al.  Electromyogram synergy control of a dexterous artificial hand to unscrew and screw objects , 2013, Journal of NeuroEngineering and Rehabilitation.

[105]  Ernest Nlandu Kamavuako,et al.  Combined surface and intramuscular EMG for improved real-time myoelectric control performance , 2014, Biomed. Signal Process. Control..

[106]  Hong Liu,et al.  Dynamic Hand Motion Recognition Based on Transient and steady-State EMG signals , 2012, Int. J. Humanoid Robotics.

[107]  Hong Liu,et al.  Classification of Multiple Finger Motions During Dynamic Upper Limb Movements , 2017, IEEE Journal of Biomedical and Health Informatics.

[108]  Roberto Merletti,et al.  Advances in surface EMG: recent progress in detection and processing techniques. , 2010, Critical reviews in biomedical engineering.

[109]  Hong Liu,et al.  Dynamic training protocol improves the robustness of PR-based myoelectric control , 2017, Biomed. Signal Process. Control..

[110]  Xinjun Sheng,et al.  Towards Zero Retraining for Myoelectric Control Based on Common Model Component Analysis , 2016, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[111]  Blair A. Lock,et al.  Determining the Optimal Window Length for Pattern Recognition-Based Myoelectric Control: Balancing the Competing Effects of Classification Error and Controller Delay , 2011, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[112]  A. Timmermans,et al.  Technology-assisted training of arm-hand skills in stroke: concepts on reacquisition of motor control and therapist guidelines for rehabilitation technology design , 2009, Journal of NeuroEngineering and Rehabilitation.

[113]  R.N. Scott,et al.  A new strategy for multifunction myoelectric control , 1993, IEEE Transactions on Biomedical Engineering.

[114]  Rongqiang Liu,et al.  Dexterous motion recognition for myoelectric control of multifunctional transradial prostheses , 2014, Adv. Robotics.

[115]  Xinjun Sheng,et al.  Improving robustness against electrode shift of high density EMG for myoelectric control through common spatial patterns , 2015, Journal of NeuroEngineering and Rehabilitation.

[116]  Hong Liu,et al.  Analysis of Hand and Wrist Postural Synergies in Tolerance Grasping of Various Objects , 2016, PloS one.

[117]  Dario Farina,et al.  Bionic Limbs: Clinical Reality and Academic Promises , 2014, Science Translational Medicine.

[118]  Dingguo Zhang,et al.  Application of a self-enhancing classification method to electromyography pattern recognition for multifunctional prosthesis control , 2013, Journal of NeuroEngineering and Rehabilitation.

[119]  Guanglin Li,et al.  Toward attenuating the impact of arm positions on electromyography pattern-recognition based motion classification in transradial amputees , 2012, Journal of NeuroEngineering and Rehabilitation.

[120]  Ping Zhou,et al.  High-Density Myoelectric Pattern Recognition Toward Improved Stroke Rehabilitation , 2012, IEEE Transactions on Biomedical Engineering.

[121]  Panagiotis K. Artemiadis,et al.  Learning human reach-to-grasp strategies: Towards EMG-based control of robotic arm-hand systems , 2012, 2012 IEEE International Conference on Robotics and Automation.

[122]  Fumitoshi Matsuno,et al.  Hand and Wrist Movement Control of Myoelectric Prosthesis Based on Synergy , 2015, IEEE Transactions on Human-Machine Systems.

[123]  Dapeng Yang,et al.  An anthropomorphic robot hand developed based on underactuated mechanism and controlled by EMG signals , 2009 .

[124]  Dario Farina,et al.  The Extraction of Neural Information from the Surface EMG for the Control of Upper-Limb Prostheses: Emerging Avenues and Challenges , 2014, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[125]  Y. Matsuoka,et al.  Reinforcement Learning and Synergistic Control of the ACT Hand , 2013, IEEE/ASME Transactions on Mechatronics.

[126]  Christian Cipriani,et al.  Independent Long Fingers are not Essential for a Grasping Hand , 2016, Scientific Reports.

[127]  Stefano Stramigioli,et al.  Myoelectric forearm prostheses: state of the art from a user-centered perspective. , 2011, Journal of rehabilitation research and development.

[128]  P. Dario,et al.  Control of multifunctional prosthetic hands by processing the electromyographic signal. , 2002, Critical reviews in biomedical engineering.

[129]  Gerd Hirzinger,et al.  Synergy level impedance control for multifingered hands , 2011, 2011 IEEE/RSJ International Conference on Intelligent Robots and Systems.

[130]  Ernest Nlandu Kamavuako,et al.  Real-Time, Simultaneous Myoelectric Control Using Force and Position-Based Training Paradigms , 2014, IEEE Transactions on Biomedical Engineering.

[131]  Rongqiang Liu,et al.  Adaptive learning of multi-finger motion recognition based on support vector machine , 2013, 2013 IEEE International Conference on Robotics and Biomimetics (ROBIO).

[132]  S. Shankar Sastry,et al.  On motion planning for dexterous manipulation. I. The problem formulation , 1989, Proceedings, 1989 International Conference on Robotics and Automation.

[133]  Honghai Liu,et al.  Human Hand Motion Analysis With Multisensory Information , 2014, IEEE/ASME Transactions on Mechatronics.

[134]  D. Farina,et al.  Spatial Correlation of High Density EMG Signals Provides Features Robust to Electrode Number and Shift in Pattern Recognition for Myocontrol , 2015, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[135]  Patrick van der Smagt,et al.  Evidence of muscle synergies during human grasping , 2013, Biological Cybernetics.

[136]  J. F. Soechting,et al.  Coordination of arm and wrist motion during a reaching task , 1982, The Journal of neuroscience : the official journal of the Society for Neuroscience.