scholarly journals A Quality Control Check to Ensure Comparability of Stereophotogrammetric Data between Session and Systems

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8223
Author(s):  
Kirsty Scott ◽  
Tecla Bonci ◽  
Lisa Alcock ◽  
Ellen Buckley ◽  
Clint Hansen ◽  
...  
Keyword(s):  
Quality Control ◽  
Repeated Measures ◽  
Human Movement ◽  
Systematic Errors ◽  
Clinical Diagnostics ◽  
Multicentric Study ◽  
Alternative Technologies ◽  
Additional Equipment ◽  
Quality Control Check ◽  
Short Timeframe

Optoelectronic stereophotogrammetric (SP) systems are widely used in human movement research for clinical diagnostics, interventional applications, and as a reference system for validating alternative technologies. Regardless of the application, SP systems exhibit different random and systematic errors depending on camera specifications, system setup and laboratory environment, which hinders comparing SP data between sessions and across different systems. While many methods have been proposed to quantify and report the errors of SP systems, they are rarely utilized due to their complexity and need for additional equipment. In response, an easy-to-use quality control (QC) check has been designed that can be completed immediately prior to a data collection. This QC check requires minimal training for the operator and no additional equipment. In addition, a custom graphical user interface ensures automatic processing of the errors in an easy-to-read format for immediate interpretation. On initial deployment in a multicentric study, the check (i) proved to be feasible to perform in a short timeframe with minimal burden to the operator, and (ii) quantified the level of random and systematic errors between sessions and systems, ensuring comparability of data in a variety of protocol setups, including repeated measures, longitudinal studies and multicentric studies.

Fig. 9 Freeze fracture electron micrograph of ELimixed phosphoinositides (4:1) liposomes after 10 passes through a0.1 pirn polycarbonate filter. growth, particularly during storage, would be undesirable in most products. Fortunately the tendency of liposomes to aggregate and fuse can be controlled by the inclusion of small amounts of negatively charged lipids such as PS or PG or positively charged amphiphiles such as stearylamine in the formulation. Knowing the number and the sign of charged groups added and the valency and concentration of electrolytes in the me-dium, the magnitude of the electrostatic forces generated by these charged groups can be closely approximated by using the double layer theory. These results can then be correlated with physical stability of liposomes and used to guide formulation efforts. The amount of charged component and ionic conditions in a particular liposome dos-age form can be adjusted to produce a high-enough zeta potential to inhibit close ap-proach of vesicles and prevent their aggregation. In practice it is usually necessary to determine empirically the magnitude of the zeta potential required to prevent aggrega-tion in a particular system. However, once this has been done, it is possible to use the zeta potential as a quality control check to insure that each batch of liposomes contains sufficient charged groups to avoid aggregation during storage.

1998 ◽  
pp. 84-108
Keyword(s):  
Quality Control ◽  
Zeta Potential ◽  
Physical Stability ◽  
Freeze Fracture ◽  
Electron Micrograph ◽  
Electrostatic Forces ◽  
Quality Control Check ◽  
Charged Component ◽  
Fracture Electron ◽  
Positively Charged

scholarly journals Video-based quantification of human movement frequency using pose estimation

2021 ◽  
Author(s):  
Hannah L. Cornman ◽  
Jan Stenum ◽  
Ryan T. Roemmich
Keyword(s):  
Pose Estimation ◽  
Repeated Measures ◽  
Quantitative Assessment ◽  
Human Movement ◽  
Whole Body ◽  
Finger Tapping ◽  
Manual Measurement ◽  
Significant Difference ◽  
Repetitive Movements ◽  
Movement Frequency

ABSTRACTAssessment of repetitive movements (e.g., finger tapping) is a hallmark of motor examinations in several neurologic populations. These assessments are traditionally performed by a human rater via visual inspection; however, advances in computer vision offer potential for remote, quantitative assessment using simple video recordings. Here, we evaluated a pose estimation approach for measurement of human movement frequency from smartphone videos. Ten healthy young participants provided videos of themselves performing five repetitive movement tasks (finger tapping, hand open/close, hand pronation/supination, toe tapping, leg agility) at four target frequencies (1-4 Hz). We assessed the ability of a workflow that incorporated OpenPose (a freely available whole-body pose estimation algorithm) to estimate movement frequencies by comparing against manual frame-by-frame (i.e., ground-truth) measurements for all tasks and target frequencies using repeated measures ANOVA, Pearson’s correlations, and intraclass correlations. Our workflow produced largely accurate estimates of movement frequencies; only the hand open/close task showed a significant difference in the frequencies estimated by pose estimation and manual measurement (while statistically significant, these differences were small in magnitude). All other tasks and frequencies showed no significant differences between pose estimation and manual measurement. Pose estimation-based detections of individual events (e.g., finger taps, hand closures) showed strong correlations with manual detections for all tasks and frequencies. In summary, our pose estimation-based workflow accurately tracked repetitive movements in healthy adults across a range of tasks and movement frequencies. Future work will test this approach as a fast, low-cost, accessible approach to quantitative assessment of repetitive movements in clinical populations.

Assessing multiple muscle activation during squat movements with different loading conditions – an EMG study

2018 ◽  
Vol 63 (4) ◽  
pp. 413-420
Author(s):  
Amir Pourmoghaddam ◽  
Marius Dettmer ◽  
Stefany J.K. Malanka ◽  
Mitchell Veverka ◽  
Daniel P. O’Connor ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Muscle Activation ◽  
Linear Analysis ◽  
Clinical Diagnostics ◽  
Analysis Tool ◽  
Loading Conditions ◽  
Motor Tasks ◽  
Cyclic Movements ◽  
Non Linear ◽  
Clinical Environments

Abstract Surface electromyography (EMG) is a valuable tool in clinical diagnostics and research related to human neuromotor control. Non-linear analysis of EMG data can help with detection of subtle changes of control due to changes of external or internal constraints during motor tasks. However, non-linear analysis is complex and results may be difficult to interpret, particularly in clinical environments. We developed a non-linear analysis tool (SYNERGOS) that evaluates multiple muscle activation (MMA) features and provides a single value for description of activation characteristics. To investigate the responsiveness of SYNERGOS to kinetic changes during cyclic movements, 13 healthy young adults performed squat movements under different loading conditions (100%–120% of body weight). We processed EMG data to generate SYNERGOS indices and used two-way repeated measures ANOVA to determine changes of MMA in response to loading conditions during movement. SYNERGOS values were significantly different for each loading condition. We concluded that the algorithm is sensitive to kinetic changes during cyclic movements, which may have implications for applications in a variety of experimental and diagnostic settings.

scholarly journals Multi-class classification of biomechanical data: A functional LDA approach based on multi-class penalized functional PLS

2019 ◽  
pp. 1471082X1787115
Author(s):  
M. Carmen Aguilera-Morillo ◽  
Ana M. Aguilera
Keyword(s):  
Discriminant Analysis ◽  
Linear Discriminant Analysis ◽  
Functional Data ◽  
Repeated Measures ◽  
Linear Acceleration ◽  
Human Movement ◽  
Angular Rotation ◽  
Kinematic Data ◽  
Linear Discriminant ◽  
Multi Class Classification

A functional linear discriminant analysis approach to classify a set of kinematic data (human movement curves of individuals performing different physical activities) is performed. Kinematic data, usually collected in linear acceleration or angular rotation format, can be identified with functions in a continuous domain (time, percentage of gait cycle, etc.). Since kinematic curves are measured in the same sample of individuals performing different activities, they are a clear example of functional data with repeated measures. On the other hand, the sample curves are observed with noise. Then, a roughness penalty might be necessary in order to provide a smooth estimation of the discriminant functions, which would make them more interpretable. Moreover, because of the infinite dimension of functional data, a reduction dimension technique should be considered. To solve these problems, we propose a multi-class approach for penalized functional partial least squares (FPLS) regression. Then linear discriminant analysis (LDA) will be performed on the estimated FPLS components. This methodology is motivated by two case studies. The first study considers the linear acceleration recorded every two seconds in 30 subjects, related to three different activities (walking, climbing stairs and down stairs). The second study works with the triaxial angular rotation, for each joint, in 51 children when they completed a cycle walking under three conditions (walking, carrying a backpack and pulling a trolley). A simulation study is also developed for comparing the performance of the proposed functional LDA with respect to the corresponding multivariate and non-penalized approaches.

Consistency of Myocardial Mass Computations as a Quality Control Check on Rest and Stress Left Ventricular Ejection Fractions Computed From 82Rb PET Data

2014 ◽  
Vol 39 (7) ◽  
pp. 593-597 ◽  
Author(s):  
Andrew Van Tosh ◽  
Nathaniel Reichek ◽  
Barbara Phippen-Nater ◽  
Christopher J. Palestro ◽  
Kenneth J. Nichols
Keyword(s):  
Quality Control ◽  
Left Ventricular ◽  
Ventricular Ejection ◽  
Left Ventricular Ejection ◽  
Myocardial Mass ◽  
Quality Control Check

scholarly journals Video-based quantification of human movement frequency using pose estimation: A pilot study

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261450
Author(s):  
Hannah L. Cornman ◽  
Jan Stenum ◽  
Ryan T. Roemmich
Keyword(s):  
Pose Estimation ◽  
Repeated Measures ◽  
Human Movement ◽  
Whole Body ◽  
Finger Tapping ◽  
Repetitive Movement ◽  
Manual Measurement ◽  
Significant Difference ◽  
Repetitive Movements ◽  
Movement Frequency

Assessment of repetitive movements (e.g., finger tapping) is a hallmark of motor examinations in several neurologic populations. These assessments are traditionally performed by a human rater via visual inspection; however, advances in computer vision offer potential for remote, quantitative assessment using simple video recordings. Here, we evaluated a pose estimation approach for measurement of human movement frequency from smartphone videos. Ten healthy young participants provided videos of themselves performing five repetitive movement tasks (finger tapping, hand open/close, hand pronation/supination, toe tapping, leg agility) at four target frequencies (1–4 Hz). We assessed the ability of a workflow that incorporated OpenPose (a freely available whole-body pose estimation algorithm) to estimate movement frequencies by comparing against manual frame-by-frame (i.e., ground-truth) measurements for all tasks and target frequencies using repeated measures ANOVA, Pearson’s correlations, and intraclass correlations. Our workflow produced largely accurate estimates of movement frequencies; only the hand open/close task showed a significant difference in the frequencies estimated by pose estimation and manual measurement (while statistically significant, these differences were small in magnitude). All other tasks and frequencies showed no significant differences between pose estimation and manual measurement. Pose estimation-based detections of individual events (e.g., finger taps, hand closures) showed strong correlations (all r>0.99) with manual detections for all tasks and frequencies. In summary, our pose estimation-based workflow accurately tracked repetitive movements in healthy adults across a range of tasks and movement frequencies. Future work will test this approach as a fast, quantitative, video-based approach to assessment of repetitive movements in clinical populations.

scholarly journals Fundamentals of quality assessment of molecular amplification methods in clinical diagnostics

1998 ◽  
Vol 44 (1) ◽  
pp. 12-26 ◽  
Author(s):  
Michael Neumaier ◽  
Andreas Braun ◽  
Christoph Wagener ◽  
Biology Techniques ◽  
Keyword(s):  
Quality Control ◽  
Clinical Diagnostics ◽  
Molecular Diagnostic ◽  
Internal Quality ◽  
Laboratory Practice ◽  
Diagnostic Laboratory ◽  
High Expectations ◽  
Constant Change ◽  
Good Laboratory ◽  
Definition Of

Abstract The increasing interest in molecular biology diagnostics is a result of the tremendous gain of scientific knowledge in genetics, made possible especially since the introduction of amplification techniques. High expectations have been placed on genetic testing, and the number of laboratories now using the relevant technology is rapidly increasing—resulting in an obvious need for standardization and definition of laboratory organization. This communication is an effort towards that end. We address aspects that should be considered when structuring a new molecular diagnostic laboratory, and we discuss individual preanalytical and analytical procedures, from sampling to evaluation of assay results. In addition, different means of controlling contamination are discussed. Because the methodology is in constant change, no general standards can be defined. Accordingly, this publication is intended to serve as a recommendation for good laboratory practice and internal quality control and as a guide to troubleshooting, primarily in amplification techniques.

scholarly journals Pathogenic P0 mutations are blocked at various quality control check points.

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Elisa Tinelli ◽  
Graziana Modica ◽  
Vizzuso Domenica ◽  
Maria Laura Feltri ◽  
Lawrence Wrabetz
Keyword(s):  
Quality Control ◽  
Check Points ◽  
Quality Control Check

Human corticospinal-motoneuronal output is reduced with 5-HT2 receptor antagonism

2021 ◽  
Author(s):  
Jacob R Thorstensen ◽  
Janet Louise Taylor ◽  
Justin J Kavanagh
Keyword(s):  
Repeated Measures ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Silent Period ◽  
Human Movement ◽  
Moderate Intensity ◽  
Response Curves ◽  
Stimulus Response ◽  
Repeated Measures Design ◽  
Double Blinded

Animal models indicate that serotonin (5-HT) release onto motoneurons facilitates motor output, particularly during strong motor activities. However, evidence for 5-HT effects during human movement are limited. This study examined how antagonism of the 5-HT2 receptor, which is a 5-HT receptor that promotes motoneuron excitability, affects human movement. Ten healthy participants (24.2 ± 1.9 yr) ingested 8 mg of cyproheptadine (competitive 5-HT2 antagonist) in a double-blinded, placebo-controlled, repeated-measures design. Transcranial magnetic stimulation (TMS) of the motor cortex was used to elicit motor evoked potentials (MEPs) from biceps brachii. First, stimulus-response curves (90-160% active motor threshold) were obtained during very weak elbow flexions (10% of maximal). Second, to determine if 5-HT effects are scaled to the intensity of muscle contraction, TMS at a fixed intensity was applied during elbow flexions of 20, 40, 60, 80 and 100% of maximal. Cyproheptadine reduced the size of MEPs across the stimulus-response curves (P = 0.045). Notably, MEP amplitude was 22.3% smaller for the cyproheptadine condition for the strongest TMS intensity. In addition, cyproheptadine reduced maximal torque (P = 0.045), lengthened the biceps silent period during maximal elbow flexions (P = 0.037), and reduced superimposed twitch amplitude during moderate-intensity elbow flexions (P = 0.035). This study presents novel evidence that 5-HT2 receptors influence corticospinal-motoneuronal output, which was particularly evident when a large number of descending inputs to motoneurons were active. While it is likely that antagonism of 5-HT2 receptors reduces motoneuron gain to ionotropic inputs, supraspinal mechanisms may have also contributed to the study findings.

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