| |
Records |
Links |
|
Author |
Biess, A.; Liebermann, D.G.; Flash, T. |
|
| |
Title |
A computational model for redundant human three-dimensional pointing movements: integration of independent spatial and temporal motor plans simplifies movement dynamics |
Type |
Journal Article |
| |
Year |
2007 |
Publication |
The Journal of Neuroscience : the Official Journal of the Society for Neuroscience |
Abbreviated Journal |
J Neurosci |
|
| |
Volume |
27 |
Issue |
48 |
Pages |
13045-13064 |
|
| |
Keywords |
Analysis of Variance; Arm/physiology; Biomechanics; *Computer Simulation; Humans; *Models, Biological; Movement/*physiology; *Nonlinear Dynamics; Posture/physiology; Psychomotor Performance/*physiology; Range of Motion, Articular/physiology; Reaction Time/physiology; Space Perception/*physiology; Time Factors; Torque |
|
| |
Abstract  |
Few computational models have addressed the spatiotemporal features of unconstrained three-dimensional (3D) arm motion. Empirical observations made on hand paths, speed profiles, and arm postures during point-to-point movements led to the assumption that hand path and arm posture are independent of movement speed, suggesting that the geometric and temporal properties of movements are decoupled. In this study, we present a computational model of 3D movements for an arm with four degrees of freedom based on the assumption that optimization principles are separately applied at the geometric and temporal levels of control. Geometric properties (path and posture) are defined in terms of geodesic paths with respect to the kinetic energy metric in the Riemannian configuration space. Accordingly, a geodesic path can be generated with less muscular effort than on any other, nongeodesic path, because the sum of all configuration-speed-dependent torques vanishes. The temporal properties of the movement (speed) are determined in task space by minimizing the squared jerk along the selected end-effector path. The integration of both planning levels into a single spatiotemporal representation simplifies the control of arm dynamics along geodesic paths and results in movements with near minimal torque change and minimal peak value of kinetic energy. Thus, the application of Riemannian geometry allows for a reconciliation of computational models previously proposed for the description of arm movements. We suggest that geodesics are an emergent property of the motor system through the exploration of dynamical space. Our data validated the predictions for joint trajectories, hand paths, final postures, speed profiles, and driving torques. |
|
| |
Address |
Department of Mathematics, Weizmann Institute of Science, 76100 Rehovot, Israel. armin.biess@weizmann.ac.il |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0270-6474 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
PMID:18045899 |
Approved |
no |
|
| |
Call Number |
|
Serial |
35 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Merdler, T.; Liebermann, D.G.; Levin, M.F.; Berman, S. |
|
| |
Title |
Arm-plane representation of shoulder compensation during pointing movements in patients with stroke |
Type |
Journal Article |
| |
Year |
2013 |
Publication |
Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology |
Abbreviated Journal |
J Electromyogr Kinesiol |
|
| |
Volume |
23 |
Issue |
4 |
Pages |
938–947 |
|
| |
Keywords |
Kinematics; Arm movement; Rehabilitation |
|
| |
Abstract |
Improvements in functional motor activities are often accompanied by motor compensations to overcome persistent motor impairment in the upper limb. Kinematic analysis is used to objectively quantify movement patterns including common motor compensations such as excessive trunk displacement during reaching. However, a common motor compensation to assist reaching, shoulder abduction, is not adequately characterized by current motion analysis approaches. We apply the arm-plane representation that accounts for the co-variation between movements of the whole arm, and investigate its ability to identify and quantify compensatory arm movements in stroke subjects when making forward arm reaches. This method has not been previously applied to the analysis of motion deficits. Sixteen adults with right post-stroke hemiparesis and eight healthy age-matched controls reached in three target directions (14 trials/target; sampling rate: 100Hz). Arm-plane movement was validated against endpoint, joint, and trunk kinematics and compared between groups. In stroke subjects, arm-plane measures were correlated with arm impairment (Fugl-Meyer Assessment) and ability (Box and Blocks) scores and were more sensitive than clinical measures to detect mild motor impairment. Arm-plane motion analysis provides new information about motor compensations involving the co-variation of shoulder and elbow movements that may help to understand the underlying motor deficits in patients with stroke. |
|
| |
Address |
Department of Industrial Engineering and Management, Ben-Gurion University of the Negev, Beer-Sheva, Israel |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1050-6411 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
PMID:23566477 |
Approved |
no |
|
| |
Call Number |
|
Serial |
69 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Issurin, V.B.; Liebermann, D.G.; Tenenbaum, G. |
|
| |
Title |
Effect of vibratory stimulation training on maximal force and flexibility |
Type |
|
| |
Year |
1994 |
Publication |
Journal of Sports Sciences |
Abbreviated Journal |
J Sports Sci |
|
| |
Volume |
12 |
Issue |
6 |
Pages |
561-566 |
|
| |
Keywords |
Adult; Humans; Male; Muscle Contraction/physiology; Muscle, Skeletal/*physiology; *Physical Education and Training; Vibration/*therapeutic use |
|
| |
Abstract |
In this study, we investigated a new method of training for maximal strength and flexibility, which included exertion with superimposed vibration (vibratory stimulation, VS) on target muscles. Twenty-eight male athletes were divided into three groups, and trained three times a week for 3 weeks in one of the following conditions: (A) conventional exercises for strength of the arms and VS stretching exercises for the legs; (B) VS strength exercises for the arms and conventional stretching exercises for the legs; (C) irrelevant training (control group). The vibration was applied at 44 Hz while its amplitude was 3 mm. The effect of training was evaluated by means of isotonic maximal force, heel-to-heel length in the two-leg split across, and flex-and-reach test for body flexion. The VS strength training yielded an average increase in isotonic maximal strength of 49.8%, compared with an average gain of 16% with conventional training, while no gain was observed for the control group. The VS flexibility training resulted in an average gain in the legs split of 14.5 cm compared with 4.1 cm for the conventional training and 2 cm for the control groups, respectively. The ANOVA revealed significant pre-post training effects and an interaction between pre-post training and 'treatment' effects (P < 0.001) for the isotonic maximal force and both flexibility tests. It was concluded that superimposed vibrations applied for short periods allow for increased gains in maximal strength and flexibility. |
|
| |
Address |
Ribstein Centre for Research and Sport Medicine Sciences, Wingate Institute, Wingate Post, Israel |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0264-0414 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
PMID:7853452 |
Approved |
no |
|
| |
Call Number |
|
Serial |
56 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Liebermann, D.G.; Berman, S.; Weingarden H.; Levin, M.F.; Weiss, P.L. |
|
| |
Title |
Kinematic features of arm and trunk movements in stroke patients and age-matched healthy controls during reaching in virtual and physical environments |
Type |
Conference Article |
| |
Year |
2009 |
Publication |
Virtual Rehabilitation International Conference |
Abbreviated Journal |
|
|
| |
Volume |
|
Issue |
|
Pages |
179-184 |
|
| |
Keywords |
|
|
| |
Abstract |
Motor performance of stroke patients and healthy individuals was compared in terms of selected kinematic features of arm and trunk movements while subjects reached for visual targets in virtual (VR) and physical (PH) environments. In PH, the targets were placed at an extended arm distance, while in VR comparably placed virtual targets were presented via GestureTek's IREX system. Our goal was to obtain further insights into research methods related to VR-based rehabilitation. Eight right-hemiparetic stroke patients (age =46-87 years) and 8 healthy adults (age =51-73 years) completed 84 reaching movements in VR and PH environments while seated. The results showed that arm and trunk movements differed in the two environments in patients and to a lesser extent in healthy individuals. Arm motion of patients became jerkier in VR, with larger paths and longer movement durations, and presented greater arm torsion (i.e., larger elbow rotations around the hand-shoulder axis). Interestingly, patients also showed a significant reduction of compensatory trunk movements during VR reaching. The findings indicate that when targets were perceived to be beyond hand reach, stroke patients may be less able to estimate 3D virtual target locations obtained from the 2D TV planar displays. This was not the case for healthy participants. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
|
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
|
Serial |
52 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Frenkel-Toledo, S.; Bentin, S.; Perry, A.; Liebermann, D.G.; Soroker, N. |
|
| |
Title |
Dynamics of the EEG Power in the Frequency and Spatial Domains During Observation and Execution of Manual Movements |
Type |
Journal Article |
| |
Year |
2013 |
Publication |
Brain Research |
Abbreviated Journal |
Brain Res |
|
| |
Volume |
1509 |
Issue |
|
Pages |
43-57 |
|
| |
Keywords |
|
|
| |
Abstract |
Mu suppression is the attenuation of EEG power in the alpha frequency range (8-12Hz) while executing or observing a motor action. Whereas typically observed at central scalp sites, there are diverging reports about the extent of the attenuation over the cortical mantle, its exact frequency range and the specificity of this phenomenon. We investigated the modulation of EEG oscillations in frequency-bands from 4 to 12Hz at frontal, central, parietal and occipital sites during the execution of manual movements and during observation of similar actions from allocentric (i.e., facing the actor) and egocentric (i.e., seeing the actor from behind) viewpoints. Suppression was determined relative to observation of a non-biological movement. Action observation elicited greater suppression in the lower (8-10Hz) compared to the higher mu range (10-12Hz), and greater suppression in the entire 4-12Hz range at frontal and central sites compared to parietal and occipital sites. In addition, suppression tended to be greater during observation of a motor action from allocentric compared to egocentric viewpoints. During execution of movement, suppression of the EEG occurred primarily in the higher alpha range and was absent at occipital sites. In the theta range (4-8Hz), the EEG amplitude was suppressed during action observation and execution. The results suggest a functional distinction between modulation of mu and alpha rhythms, and between the higher and lower ranges of the mu rhythms. The activity of the presumed human mirror neuron system seems primarily evident in the lower mu range and in the theta range. |
|
| |
Address |
Sackler Faculty of Medicine, Tel Aviv University, Israel; Department of Neurological Rehabilitation, Loewenstein Hospital, Raanana, Israel. Electronic address: silvi197@bezeqint.net |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
|
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0006-8993 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
PMID:23500633 |
Approved |
no |
|
| |
Call Number |
|
Serial |
68 |
|
| Permanent link to this record |
