Subjects were seated on a 43 cm high, strait-back chair in front of a 72 cm high table. A hard non-translucent plastic drinking container was used, since glass would reflect the camera flashes and disturb the motion capture. The drinking glass had a 7 cm diameter with a 9. In the start position, the subjects were sitting against the chair back, feet on the floor. Right arm was pronated with the hand resting on the table and wrist line close to the edge of the table. Subjects were asked to find a comfortable sitting position with right upper arm in vertical and adducted position and approximately 90 degrees flexion at elbow.
The subject's left hand was resting on the lap. Drinking movement included reaching and grasping the glass with all fingers no fingers at the bottom , lifting the glass from the table and taking a drink one swallow , placing the glass back on the table inside the marked area and returning to the start position. Subjects were instructed to sit against the chair back during the whole drinking task.
This was also verified by a marker on the thorax, which provided exact kinematic displacements of the trunk during the whole task. The intention was to keep the drinking activity as normal as possible and let the subjects sit close enough to reach the drinking glass without their back leaving the chair support.
The subjects were allowed to try the drinking movement a few times to find a comfortable sitting position. When ready, the test leader announced, "you can start now", and the subject started the drinking task at a comfortable self-paced speed. Every subject was recorded for at least three and at most six trials in one testing session, depending on how well the computer could track the markers automatically. To assess the consistency of the test protocol we performed test-retest on six randomly chosen subjects. Those six subjects were first tested according to the protocol. Then the subject left the measurement area and markers were removed.
After a 5—10 minutes break the markers were replaced and subject was tested a second time. After the recording process, each of the markers were identified in Qualisys Track Manager and reviewed to ensure that the markers were tracked correctly throughout the data capture. In some recordings certain markers were partly hidden or merged with other markers and could not be tracked automatically. While, it was possible to perform a manual analysis of this data, this would demand an excessive amount of work and was considered not feasible according to the goal of this study.
In the final analysis the first three successful recordings from every subject were used and the mean of those were calculated as a final measurement value for each subject. For every recording we calculated and plotted coordinate data showing position, velocity and acceleration. The drinking task was broken down in five logical phases: reaching, forward transport, drinking, back transport, returning. Phase definitions are described in detail under the results. The goal was to find and define parameters that could render us clinically useful information and be comparable for different patient groups in later studies.
After analyzing the graphical plots from the recordings the kinematic data analysis was focused on following variables:. The elbow angle was determined by the angle between the vectors joining elbow and wrist markers and the elbow and shoulder markers.
- Reward Yourself!
- About This Item;
- Star Wars: The New Jedi Order - The Final Prophecy!
- Join Kobo & start eReading today!
- Human Hand Movement Kinematics and Kinesthesia.
Shoulder angle was determined by the angle between the vectors joining the shoulder and elbow markers and the vertical vector from the shoulder marker toward the hip. Joint angles for different movement phases and the range for all movement were calculated. The mean of the three recordings was used in statistical calculations.
The difference between test and retest was analyzed with a paired t -test with alpha level at 0. To check the assumptions of the limits of agreement the differences were plotted against the average of the two measurements for every variable. The drinking task was broken down into five logical phases: reaching includes grasping , forward transport with glass to mouth, drinking, back transport with glass includes release of grasp and returning the hand to the initial position.
The mathematical and dynamical properties of kinematic data were used to determine the start and the end of each phase. Position graphs with coordinate data from each marker were plotted in three different dimensions transverse, sagittal and frontal plane for qualitative visual analysis. Position graphs with coordinate data from five markers, plotted in the three-dimensional graph and separately in transversal plane X-Y , sagittal plane X-Z , frontal plane Y-Z for one subject. X-axis directed anteriorly, Y-axix directed laterally, Z-axis directed upward.
Position graphs for all subjects were rather similar and had a characteristic path pattern. The elbow, wrist and hand markers had distinguished and smooth movement trajectories. The displacement data for the thorax, face and shoulder markers showed that the biggest displacement occurred in sagittal plane. The thorax marker remained relatively motionless with mean displacement Even face mean displacement The wrist, hand and finger markers had rather similar trajectories thus in all presented graphs only the hand marker is plotted representing the endpoint trajectory.
The tangential velocity profiles were calculated and plotted for the hand marker. Those velocity profiles were smooth and bell-shaped with one predominant peak. There were four distinctive velocity peaks for the whole movement task representing different movement phases. The velocity in the reaching and returning phases was approximately double the velocity in the transporting phases when the subject was holding the drinking glass. Hand tangential velocity decreased shortly before the glass was grasped or released. The back transport phase had a longer movement time and the peak velocity occurred earlier compared to the forward transport phase, thus indicating that placing the glass back on the table required more precision.
Joint angles were calculated for the elbow extension-flexion and also for the shoulder in sagittal plane flexion-extension and in frontal plane abduction and adduction. Joint angles for elbow extension-downward, flexion-upward and for shoulder in sagittal plane flexion-up, extension-down and in frontal plane abduction-up, adduction-down. The elbow angle graph demonstrated a characteristic smooth movement pattern with the maximal elbow extension during grasping and releasing the glass.
The maximal elbow flexion occurred during the drinking phase. Shoulder flexion approached the maximal angle in the end of the reaching phase, and peaked shortly thereafter second time during the drinking phase. Shoulder abduction approach a small peak in the middle of reaching, indicating a slight half-circular arm movement in the reaching phase.
The maximal adduction was achieved in the end of reaching phase and followed up by a maximal abduction during drinking phase. The second part of the movement was almost identical with the first part in all graphs. The movement patterns were fairly similar for all subjects. Some stylistic differences were noticed with slightly different drinking styles. For example some subjects had their elbow near to the body adducted and others away from body more abducted in the drinking phase. For example the joint angle in abduction in drinking phase ranged from Interjoint coordination between the shoulder and elbow joint excursions during reaching phase showed a high correlation.
Correlation coefficients r ranged from 0. Trajectory for interjoint coordination was smooth and continuous, forming an almost linear correlation between elbow and shoulder joint excursions.
Interjoint coordination for the shoulder and elbow joint movements in reaching phase for one subject. Reaching movement starts from the right lower corner of the graph.
What is Kobo Super Points?
Test-retest consistency for kinematic variables. The present study provides a detailed three-dimensional kinematic analysis of the drinking task in control subjects. A standardized test protocol for the drinking task was developed, including the set-up of cameras, measurement volume, location of markers and position of the subjects. The test protocol demonstrated a good consistency in test-retest and provided clear and accurate results.
The phase analysis which divided the drinking task into five sequential phases was unique for the present study. Kinematic data are presented for the movement times, marker positions, velocities and joint angles for the control subjects. The drinking activity is a complex task in terms of kinematics. It contains several different movements as reaching, grasping, transporting the glass and drinking. In the present study, five sequential phases were identified: reaching, forward transport, drinking, back transport and returning.
This phase analysis gives a logical and easy observable structure for the drinking task and provides the possibility to investigate different variables separately in each phase. There are no studies, to our knowledge, which have presented the phase definitions for the whole drinking movement; hence the phase analysis applied for the drinking task in this study is unique.
The concept of three-dimensional joint movements and joint angles is a quite unusual for clinicians. It is common to think of two-dimensional movement in different planes. One limitation of this study, for example, is that we have not analyzed the rotations in shoulder and elbow joints or joint angles in the wrist joint. Wrist joint motion and forearm rotations could provide additional information of different drinking strategies. Although the system has the potential to provide this information, a much more complex set-up and analysis would be required. The goal of this study was not to measure the joint angles in all joints and in all degrees of freedom.
Our intention was to collect informational and clinically useful data for the drinking task with the existing camera system and according to the current stage of software development. We have used surface markers and computed the joint angles as the angles between the corresponding vectors joining the adjacent markers or vertical vector.
It must be understood that those joint angles do not pass through the centers of rotation of the joints, thus they are not the true joint angles. However, placing the markers on the well-defined superficial bony prominences increases the reproducibility of data on different occasions. This was confirmed by the good consistency in test-retest in this study as well in other studies using surface markers [ 21 ].
Kinematics of the Brain Activities : Volume III - cyxasyvyqe.gq
Earlier studies of reaching movements have reported that trunk movement is acting both as stabilizer and as an integral component in positioning the hand close to the target [ 24 ]. Several studies have also shown that when reaching within arm's length, healthy subjects use minimal trunk displacement in contrast to hemiparetic subjects who use a compensatory strategy involving trunk recruitment [ 24 - 26 ].
- Customer Reviews.
- British 2-Pack: Vampire Assassin League.
- WiMAX/MobileFi: Advanced Research and Technology!
- Human Hand Movement Kinematics and Kinesthesia | SpringerLink.
- Bucharest-Vienna Delayed.
- Exploring representations of human grasping in neural, muscle and kinematic signals!
In the present study the object was placed within an arm's length and the subject could reach the glass while sitting against the chair back during the whole task. Any unintentional trunk displacement was also measured using a marker on the thorax. The intention was to keep the drinking movement as natural as possible but allow some trunk displacement during the task.
Interjoint coordination for the elbow and shoulder joint excursions during a reaching movement is shown to be highly coupled in normal subjects, but has a significant decrease in stroke subjects with hemiparetic arm [ 11 , 12 ]. Levin et al suggested that a measure of interjoint coordination can give us clinically beneficial information about the subject's motor function. In the present study we found a high correlation between the shoulder and elbow joint excursions in reaching phase indicating a good interjoint coordination.
All measurements systems including the kinematic systems, suffer from measurement error. A typical average value for measurement error is estimated to be 2—3 mm in all dimensions in gait analysis [ 8 ]. Turner-Stokes et al found the absolute mean difference differences between two measurements in either direction are treated as positive in joint range to be 2. Replacing the markers produced slightly greater differences than repositioning and recalibration of the whole system [ 21 ]. In this study we tested the consistency regarding the replacing the markers and the repositioning the subject.
The absolute mean difference in test-retest for shoulder abduction was 2. These values are comparable with results in study of Turner-Stokes et al. The analysis of upper extremity tasks requires a measurement set-up and camera system which can track all the necessary markers throughout the whole movement. This has been a challenge in the present study.
This data lost is acceptable considering the biomechanical complexity in the upper extremity movement analysis [ 10 ]. The problem with segmentation and gaps in data have also been reported in other studies, especially when few two to four cameras are used and when the movement is complex in degrees of freedom [ 17 , 20 , 21 ]. As reported in other studies, the set-up of camera systems and data analysis in special software programs required a good collaboration between clinicians and engineers in the present study [ 10 , 21 ].
Results of this study corroborate that that the use of the existing motion capture system, as used in the presented protocol, still has some limitations and requires further refinement to be feasible for clinical use with persons with neurological disorders. The main clinical benefit of this study is the establishment of the phases of an important activity of daily living ADL. The establishment of the phases can simplify the camera measurement system and allow for increased clinical use.
In addition, the phases provide a descriptive methodology to classify strategies of drinking task of healthy persons. Kinematic analysis has great possibilities to be used as an outcome measure in clinical research especially when optoelectronic camera systems become more readily available in clinical settings.
Our approach to investigate and analyze a goal-oriented daily task has a great clinical potential. However a certain degree of standardization is indispensable in order to obtain repeatable and reliable results. Further development of objective and reliable evaluation methods for upper extremity tasks is required, particularly for natural and goal-oriented movements.
Consequently the next step is to use and test this protocol on persons with impairments and disabilities from upper extremities e. MAM contributed to the concept and design, acquisition, analysis and interpretation of data, drafting and completion of the manuscript. KSS contributed to conception and design, subsequent planning of study, analysis and interpretation of data, and revised the manuscript critically. BJ contributed to conception and design, subsequent planning of study, and revised the manuscript. CW contributed to conception and design, subsequent planning of study, analysis and interpretation of data, and revised the manuscript critically.
All authors read and approved the manuscript to be published. This study required a close collaboration between physical therapy and engineering and I would like to thank Nasser Hosseini, PhD for assistance in motion capture sessions and data analysis as well Steve Murphy, PhD for contributing with his excellent technical knowledge.
National Center for Biotechnology Information , U. Journal List J Neuroengineering Rehabil v. J Neuroengineering Rehabil. Published online Aug Margit Alt Murphy 1 Dept. Katharina S Sunnerhagen 1 Dept. Bo Johnels 2 Dept. Author information Article notes Copyright and License information Disclaimer. Corresponding author. Margit Alt Murphy: moc. Received Mar 22; Accepted Aug This article has been cited by other articles in PMC.
Abstract Background Development of reliable and objective evaluation methods is required, particularly for natural and goal-oriented upper-extremity tasks.
Join Kobo & start eReading today
Methods A protocol was developed for the drinking activity including the set-up of cameras and positions of the markers and the subject. Results The test protocol showed good consistency in test-retest. Conclusion This study provides a detailed description of the three-dimensional kinematic analysis of the drinking task. Background The upper extremity has an important role in several daily activities such as eating, drinking, clothing, grooming, writing, as well as in different sports and leisure activities.
The aims of the present study were: 1. To develop a protocol and test the consistency of that protocol for the three-dimensional motion analysis of an daily activity "drinking from a glass", 2. Methods Subjects The study group was based on a sample of convenience and included 20 control subjects 9 male and 11 female.
Free delivery. Arrives by Wednesday, Oct 9. Or get it by Tue, Oct 1 with faster delivery. Pickup not available. Product Highlights Kinematics of the Brain Activities.
What is Kobo Super Points?
About This Item We aim to show you accurate product information. Manufacturers, suppliers and others provide what you see here, and we have not verified it.
See our disclaimer. Customer Reviews. Write a review. See any care plans, options and policies that may be associated with this product. Email address. Please enter a valid email address. Walmart Services. Get to Know Us. Customer Service. In The Spotlight. Shop Our Brands. All Rights Reserved. Cancel Submit.