Journal articles on the topic 'Grip pattern'
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Wong, Ming-Horng, Boon-Chin Yeo, Poh-Kiat Ng, and Wei-Jun Choong. "Data Acquisition System and Pattern Image Generations for Hand Grip Device." International Journal on Robotics, Automation and Sciences 3 (November 8, 2021): 13–18. http://dx.doi.org/10.33093/ijoras.2021.3.3.
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Grip pattern is essential to understand how an object being held in hand. One of the solutions is to use the pressure sensing glove to capture the gripping pressure distributed on the surface of the palm. The objective of this project is to develop a data acquisition system for a gripping device that can capture the grip patterns when a person is gripping an object. The design comprises of Velostat sheet, rows, and columns of conductive threads, that are sandwiched and layered to form a glove with pressure sensor grids. Arduino is used to generate the signals for data acquisition and interface with the MATLAB program through serial communication. On the MATLAB, the sensor data are organized and represented in hand pattern color image. Voltage Divider Rule (VDR) was used in an experiment with different resistor values and the effect of the image patterns were observed. Another experiment has been designed to find out the grip consistency. The results show that resistor values 330ohm can cause the image pattern create noises. Meanwhile, 4.7kohm resistance value is sufficient to eliminate most of the noises made in the pattern images. In this paper, different grip images can be obtained from different grip activities, such as holding toothbrush, lifting dumbbell, and pressing syringe. Future works can be done in resolution improvement and grip pattern recognition.
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Ojigho, Efe Jennifer, and Igho Emmanuel Odokuma. "Pencil Grip Patterns of Students and Skilled Workers." Journal of College of Medical Sciences-Nepal 15, no. 1 (March 14, 2019): 53–58. http://dx.doi.org/10.3126/jcmsn.v15i1.19286.
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Background: Pencil grip can be defined via detailed descriptions of the variables constituting the grip and it commences in the preschool years with writing instruments and therefore relevant to graphologists, forensic medicine and anthropology. The purpose of this investigation was to describe the diversity of pencil grip patterns among students and skilled workers in Delta State, Nigeria. The research also aimed at determining the effects of sociodemographic factors, handedness,and handwriting speed on pencil grip patters.
Methods: Stratified random sampling was employed in this cross sectional observational study. Five hundred and fourty three volunteers between the ages of 11-77 years were investigated. Students were observed while writing from their textbooks and skilled workers were observed writing from any available news paper. Photograph of the writing hand was captured with the digital canon camera. The data was analysed using the Statistical Package for Social Sciences (SPSS) 20. Kruska wallis test was used to establish relationship between pencil grip patterns and sociodemographic factors. Handwriting speed was determined by a speed score (letters per minute) and timed for 60 secounds for each participant. A self administered questionnaire was used to obtain data on sociodemographic factors.
Results: This investigation demonstrates that gender had a significant effect on pencil grip patterns among secondary students (p<0.05)(K.W=7.54. df=1. p=0.01). Further observation showed that age and profession had a significant effect on pencil grip patterns among skilled workers at p<0.05 (K.W= 43.09,134.69 ,df=3,3, p=0.00,0.00).
Conclusions: Findings from this investigation present the dynamic tripod grip as the most predominant grip pattern in the studied population.
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Marzke, Mary W. "Tool making, hand morphology and fossil hominins." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1630 (November 19, 2013): 20120414. http://dx.doi.org/10.1098/rstb.2012.0414.
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Was stone tool making a factor in the evolution of human hand morphology? Is it possible to find evidence in fossil hominin hands for this capability? These questions are being addressed with increasingly sophisticated studies that are testing two hypotheses; (i) that humans have unique patterns of grip and hand movement capabilities compatible with effective stone tool making and use of the tools and, if this is the case, (ii) that there exist unique patterns of morphology in human hands that are consistent with these capabilities. Comparative analyses of human stone tool behaviours and chimpanzee feeding behaviours have revealed a distinctive set of forceful pinch grips by humans that are effective in the control of stones by one hand during manufacture and use of the tools. Comparative dissections, kinematic analyses and biomechanical studies indicate that humans do have a unique pattern of muscle architecture and joint surface form and functions consistent with the derived capabilities. A major remaining challenge is to identify skeletal features that reflect the full morphological pattern, and therefore may serve as clues to fossil hominin manipulative capabilities. Hominin fossils are evaluated for evidence of patterns of derived human grip and stress-accommodation features.
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Shang, Xiaoxin. "Grip-pattern verification for a smart gun." Journal of Electronic Imaging 17, no. 1 (January 1, 2008): 011017. http://dx.doi.org/10.1117/1.2892675.
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Seo, Ae-Rim, Mi-Ji Kim, and Ki-Soo Park. "Regional Differences in the Association between Dietary Patterns and Muscle Strength in Korean Older Adults: Data from the Korea National Health and Nutrition Examination Survey 2014–2016." Nutrients 12, no. 5 (May 12, 2020): 1377. http://dx.doi.org/10.3390/nu12051377.
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Objectives: Adequate nutrition is an important factor to prevent sarcopenia in older adults. The purpose of this study was to identify the regional differences in the association between dietary pattern and muscle strength in older Korean adults. Methods: This study was based on data from the Korea National Health and Nutrition Examination Survey (KNHANES) in 2014–2016. Muscle strength was measured by grip strength, and dietary patterns were derived by a cluster analysis using the k-means algorithm. Multiple logistic regression analyses were applied to determine the associations between factors (dietary patterns and residential areas) and grip strength. Results: Most participants in the rural area group (50.4%) had the Cluster Three dietary pattern (diet dominant in white rice and kimchi), while most people in the urban area group (43.8%) and the metropolitan area group (53.2%) had the Cluster One dietary pattern (diet dominant in fruits and fish). Those having poor hand grip strength represented 25.8% of the total in rural, 20.6% in urban, and 17.9% in metropolitan (p = 0.009) areas. Upon adjustment for socio-demographic characteristics, health behaviors, and co-morbidity, the odds ratio of Cluster Two (diet dominant in meat) was 1.601 (95%, CI: 1.001–2.563, p = 0.050) compared to the Cluster Three dietary pattern, but there was no significant difference in residence. Conclusions: Muscle strength in the elderly was more related to dietary pattern than was residence. Education and support for conveying the importance of protein intake in the elderly are required to motivate adequate nutrition. In addition, these actions should lead to prevention of muscle weakness and further prevent frailty.
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Wankhede, Harish A., and Dipti A. Nimje. "Pencil Grip Pattern and Its Effect on Handwriting in Medical Students of Maharashtra." Indian Journal of Anatomy 6, no. 3 (2017): 293–96. http://dx.doi.org/10.21088/ija.2320.0022.6317.7.
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GÜLKE, J., N. J. WACHTER, P. KATZMAIER, T. EBINGER, and M. MENTZEL. "Detecting Submaximal Effort in Power Grip by Observation of the Strength Distribution Pattern." Journal of Hand Surgery (European Volume) 32, no. 6 (December 2007): 677–83. http://dx.doi.org/10.1016/j.jhse.2007.05.020.
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This study examined patterns of grip strength when maximal and submaximal effort are applied. Using a sensor glove, 50 healthy subjects performed two different power grips. Both maximal and submaximal gripping showed characteristic patterns of strength distribution that were independent of the degree of power applied. Significant differences were also noted in the strength distribution patterns, depending on whether the grip was performed at maximal, or submaximal, strength. The small finger plays a decisive role in this. In maximal strength gripping, the total measured strength is distributed relatively evenly over all four fingers, with each finger contributing between 23% and 27% of the total strength. In submaximal strength gripping, the little finger is involved very little and only contributes between 14% and 15% of the total strength, with the remainder of the gripping distributed relatively evenly between the index, middle and ring fingers, each of which contributes between 26% and 32% of the total.
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Lee, Yushin, Joong Hee Lee, Yong Min Kim, Jihwan Lee, Sanghyun Kwon, Hyungmin Sim, and Myung Hwan Yun. "The Effects of Curvature of Edge Screen on Subjective Feelings in Smartphone Usage." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 61, no. 1 (September 2017): 1269–70. http://dx.doi.org/10.1177/1541931213601798.
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As the penetration rate of Smartphone grows high and the market gets saturated, the technological and aesthetic progress for manufacturers are heavily demanded to sustain their market share. To meet such demands, manufacturers continuously improve the design of their products. As the design of smartphone varies by manufacturers, there have been many existing researches to identify the relationships between various physical dimensions of smartphones and how users feel (Chowdhury, A., & Kanetkar, M., 2017; Lee, S., Kyung, G., Lee, J., Moon, S. K., & Park, K. J., 2016; Pereira, A., Miller, T., Huang, Y. M., Odell, D., & Rempel, D., 2013; Sung, K., Cho, J., & Freivalds, A., 2016). Recently, in accordance with the development and improvement of flexible displays, curved displays have been applied on smartphones with various curvatures. The popular one among them is the “edge screen” on smartphones, which refers to curved display implemented either on one single side or both sides. Considering that physical dimensions such as shape and size are the important features for customer satisfaction (Hwang, 2012; Ling, C., Hwang, W., and Salvendy, G., 2007), curvature of edge screen can influence on user comfort when the users carry out their tasks on their smartphones. However, such issue hasn’t been dealt in previous studies. Therefore, as a preliminary study, this study aimed to identify the relationships between curvatures of edge screens and subjective feelings in smartphone usage with various usage patterns using subjective evaluation experiment. In this laboratory study, 47 subjects assessed their subjective feelings (grip comfort, control comfort, stability, front visibility, side visibility) towards given samples with four different kinds of usage patterns. The samples were designed with a 5.5-inch flat display of 16:9 ratio (Samsung Galaxy Note 2) as a main screen along with a curved display of different radii of curvatures (R, unit: mm) on the right edge as an edge screen: 4R, 6R, 8R, and 10R. The usage patterns were defined according to which hands were used for grip and control: Grip with right hand and control with right thumb (usage pattern (a)), Grip with left hand and control with right index finger (usage pattern (b)), Grip with both hands and control with both thumbs (usage pattern (c)), and Grip with right hand without control (usage pattern (d)). The statistically significant results of one-way analysis of variance (ANOVA) and post hoc analysis (Duncan’s test) showed that the sample with 4R curvature belonged to the third homogeneous subset (in descending order) for the front visibility while it belonged to the second homogeneous subset for the control comfort in usage pattern (b) and (c). Whereas the sample with 6R curvature belonged to the second homogeneous subset for the front visibility and the second homogeneous subset for the control comfort in usage pattern (b) and (c). In case of the sample with 8R curvature, it was within the first homogeneous subset throughout all analyses conducted. Lastly, the sample with 10R curvature was within the second homogeneous subset for the grip comfort in usage pattern (d). Therefore, it is concluded that the optimal radius of curvature for edge screens is 8R. Although there were some samples evaluated better than the 8R sample in descriptive manner, however, such results were not statistically significant. This study is expected to contribute towards the design of smartphones with edge screens in terms of better subjective feeling by various usage patterns. However, this study is yet a preliminary study which is based on a subjective evaluation. In the future research, more criteria of subjective feeling are needed to be evaluated to decide more precise optimal curvature. In addition, objective evaluation method such as analysis of muscle activity, motion tracking analysis, or behavior analysis could be applied to verify the reliability and validity of the result of this study.
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Liang, Chen, Haowen Li, Hoda Mousavi, Guolin Wang, and Kangying Yu. "Evaluation and improvement of tire rolling resistance and grip performance based on test and simulation." Advances in Mechanical Engineering 12, no. 12 (December 2020): 168781402098117. http://dx.doi.org/10.1177/1687814020981173.
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In order to clarify the contradictory mechanism between tire rolling resistance and grip performance, ten (10) 205/55 R16 radial tires with different tread patterns were selected as the research objects. Using VIC-3D non-contact strain measurement system, the pattern deformation in the contact area under vertical load was tested and the relevant deformation parameters of the contact area were extracted. Correlation analysis was used to establish the relationship between the identified deformation parameters and tire performance indicators. Then the contradiction mechanism between tire rolling resistance and grip performance was identified. The mechanism is such that, in order to improve the grip performance of the tire, it is necessary to reduce the transverse tensile strain of the tread in the contact area and increase the longitudinal tensile strain of the tread, but with the increase of the longitudinal tensile strain, the rolling resistance of the tire will also increase, which leads to the contradiction between tire rolling resistance and grip performance. In order to better understand and solve this contradiction, a finite element model of 205/55R16 tire with complex pattern was established. The influence of the number and width of transverse grooves in outer shoulder area on tire rolling resistance and grip performance was analyzed by numerical simulation, where it was identified that, the longitudinal tensile deformation of the tread is the main cause of contradiction between the two performances. An optimized design of concave transverse groove with narrow groove in the middle and wide groove at both ends was proposed in the outer shoulder area to resolve the contradiction. Compared with the original scheme, the rolling resistance of the optimized scheme was reduced by 2.112 N, and the grip force saw an increase of 10.196 N, and thus delivering a cooperative improvement of tire rolling resistance and grip performance.
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Yun, Myung Hwan, and Andris Freivalds. "Analysis of Hand Tool Grips." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 39, no. 10 (October 1995): 553–57. http://dx.doi.org/10.1177/154193129503901003.
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An efficient measurement and evaluation system for hand tool tasks can provide a practical solution to the problem of designing and evaluating manual tool tasks in the workplace. Such a prototype system, termed the data glove, was developed by overlaying twelve Force Sensitive Resistors on an posture-measuring glove (Cyberglove™, Virtual Technologies, 1992) with eighteen joint angle sensors. To validate the data glove, hand posture and grip force was measured on sixteen different cylindrical grip tasks for six subjects. A factor analysis of the grip force distributions on the hand indicated that three major areas of force concentration occurred: 1) an area of high force levels termed the ‘active’ area, 2) an area of intermediate force levels termed the ‘support’ area, and 3) an area of low force levels termed the ‘inactive’ area. The different grips were also classified and ranked for levels of radian/ulnar deviation torques and flexion/extension torques, and then combined with the force information to yield a pattern of grip degradation with increasing levels of grip stress. A validation experiment comparing the data glove force output with the muscle surface EMG measurement yielded a significant, high correlation between the two measures.
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Murao, Kazuya, Hayami Tobise, Tsutomu Terada, Toshiki Iso, Masahiko Tsukamoto, and Tsutomu Horikoshi. "Mobile phone user authentication with grip gestures using pressure sensors." International Journal of Pervasive Computing and Communications 11, no. 3 (September 7, 2015): 288–301. http://dx.doi.org/10.1108/ijpcc-03-2015-0017.
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Purpose – User authentication is generally used to protect personal information such as phone numbers, photos and account information stored in a mobile device by limiting the user to a specific person, e.g. the owner of the device. Authentication methods with password, PIN, face recognition and fingerprint identification have been widely used; however, these methods have problems of difficulty in one-handed operation, vulnerability to shoulder hacking and illegal access using fingerprint with either super glue or facial portrait. From viewpoints of usability and safety, strong and uncomplicated method is required. Design/methodology/approach – In this paper, a user authentication method is proposed based on grip gestures using pressure sensors mounted on the lateral and back sides of a mobile phone. Grip gesture is an operation of grasping a mobile phone, which is assumed to be done instead of conventional unlock procedure. Grip gesture can be performed with one hand. Moreover, it is hard to imitate grip gestures, as finger movements and grip force during a grip gesture are hardly seen by the others. Findings – The feature values of grip force are experimentally investigated and the proposed method from viewpoint of error rate is evaluated. From the result, this method achieved 0.02 of equal error rate, which is equivalent to face recognition. Originality/value – Many researches using pressure sensors to recognize grip pattern have been proposed thus far; however, the conventional works just recognize grip patterns and do not identify users, or need long pressure data to finish confident authentication. This proposed method authenticates users with a short grip gesture.
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TALSANIA, J. S., and S. H. KOZIN. "Normal Digital Contribution to Grip Strength Assessed by a Computerized Digital Dynamometer." Journal of Hand Surgery 23, no. 2 (April 1998): 162–66. http://dx.doi.org/10.1016/s0266-7681(98)80165-4.
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A computerized digital dynamometer was used to assess the contribution of individual fingers to total grip strength in 100 hands from 50 randomly selected healthy subjects. The dynamometer simultaneously recorded force data from each digit (index, long, ring, and small) and cumulative grip directly to a laptop computer. The percentage contribution of each finger force to total grip force was calculated at three successive handle sizes for dominant and non-dominant hands. Individual digital contributions to total grip strength were approximately 25%, 35%, 26% and 15% for the index, long, ring, and small fingers respectively. This pattern was consistent irrespective of handle size, hand dominance, and grip strength.
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Löwer, Jan, Paul Wagner, Hans-Joachim Unrau, Burkhard Wies, and Frank Gauterin. "Model for the Pattern-Dependent Wet Grip Prediction of Tires." Vehicles 3, no. 1 (February 21, 2021): 84–110. http://dx.doi.org/10.3390/vehicles3010006.
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The most important task of the tire is to ensure driving safety by optimally transmitting the required longitudinal and lateral driving forces. Although great progress has been made in the past in the development of new materials and patterns, many questions remain unanswered in the field of elastomer friction on rough surfaces. This is particularly true when an additional intermediate medium is introduced into the contact, as for braking on wet roads in the form of water. To better understand this process, a model of a single-tread block on a rough road surface is developed. The influence of the fluid is represented by a physical meaningful friction law. The model is validated with results of tire wet-braking tests on an internal drum test rig. The model can map the interaction between tire tread, rough road surface and fluid film and the simulation results show a good agreement with the measurement results. Based on the investigation of individual tread blocks, a new approach to the description of the wet-braking behavior of passenger car tires was thus demonstrated, which can be extended to more complex tread geometries in the future.
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Dunwoody, Lynn, Heinz G. Tittmar, and Winston S. McClean. "Grip Strength and Intertrial Rest." Perceptual and Motor Skills 83, no. 1 (August 1996): 275–78. http://dx.doi.org/10.2466/pms.1996.83.1.275.
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This experiment illustrates that the 1991 Montazer and Thomas conclusion that grip strength declines over time is incomplete. 15 men performed 4 grip-strength trials with imertrial rests of 120 sec. Analysis showed that performance did not decrease over the 4 trials, on the contrary, the pattern was that of a learning curve, with a significant difference across the 4 trials, i.e., on Trial 1 grip strength was lower than on successive trials. Such a result points to the importance of ‘warming-up’ the muscle to obtain optimum functioning. Also, subjects should be familiar with the task and the equipment to reduce the chance of a Type I error. Implications for research are discussed.
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Angel, Bárbara, Olesya Ajnakina, Cecilia Albala, Lydia Lera, Carlos Márquez, Leona Leipold, Avri Bilovich, Richard Dobson, and Rebecca Bendayan. "Grip Strength Trajectories and Cognition in English and Chilean Older Adults: A Cross-Cohort Study." Journal of Personalized Medicine 12, no. 8 (July 27, 2022): 1230. http://dx.doi.org/10.3390/jpm12081230.
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Growing evidence about the link between cognitive and physical decline suggests the early changes in physical functioning as a potential biomarker for cognitive impairment. Thus, we compared grip-strength trajectories over 12–16 years in three groups classified according to their cognitive status (two stable patterns, normal and impaired cognitive performance, and a declining pattern) in two representative UK and Chilean older adult samples. The samples consisted of 7069 UK (ELSA) and 1363 Chilean participants (ALEXANDROS). Linear Mixed models were performed. Adjustments included socio-demographics and health variables. The Declined and Impaired group had significantly lower grip-strength at baseline when compared to the Non-Impaired. In ELSA, the Declined and Impaired showed a faster decline in their grip strength compared to the Non-Impaired group but differences disappeared in the fully adjusted models. In ALEXANDROS, the differences were only found between the Declined and Non-Impaired and they were partially attenuated by covariates. Our study provides robust evidence of the association between grip strength and cognitive performance and how socio-economic factors might be key to understanding this association and their variability across countries. This has implications for future epidemiological research, as hand-grip strength measurements have the potential to be used as an indicator of cognitive performance.
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Logue, Rachel, Elana Goldenkoff, Michael Vesia, and Susan Brown. "Measuring Hand Function in Older Adults: The Need for Better Assessment Tools." Innovation in Aging 4, Supplement_1 (December 1, 2020): 202. http://dx.doi.org/10.1093/geroni/igaa057.653.
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Abstract Aging is associated with a decline in hand muscle strength, dexterity, and tactile perception, leading to difficulties in activities of daily living and reduced independence (Millan-Calenti et al., 2010). However, current assessments do not adequately capture sensorimotor skills that underlie everyday activities such as dressing and food preparation. This study examined the ability of two novel assessment devices to detect age-related changes in hand force control and tactile pattern discrimination. Sensorimotor function was assessed in 13 healthy older adults (mean age 72.2 +/- 5.5y) and 13 young adults (mean age 20 +/- 1.4y). Maximum grip force (MVC), tactile sensation, and hand dexterity were measured using standard clinical techniques. Novel assessments consisted of submaximal (5-20% MVC) grip force tracking and computer-controlled tactile pattern recognition. Monofilament testing of tactile sensation was normal in the older group. In contrast, both the accuracy and speed associated with identifying tactile patterns was significantly worse in older (p<0.001) compared to young adults for both hands. While maximum grip force was similar in both groups, the ability to smoothly produce (p<0.05) and maintain (p<0.02) low grip force levels was compromised in older adults. Manual dexterity (Grooved Pegboard test) was significantly reduced in the older group (p<0.001) regardless of hand. These results indicate that the ability to extract meaningful information from tactile feedback and control low levels of force - aspects of fine hand control associated with activities of daily living – are impaired in older adults and underscore the need for more sensitive measures of hand function.
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TREDGETT, M., L. J. PIMBLE, and T. R. C. DAVIS. "The Detection of Feigned Hand Weakness Using the Five Position Grip Strength Test." Journal of Hand Surgery 24, no. 4 (August 1999): 426–28. http://dx.doi.org/10.1054/jhsb.1999.0205.
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This study assessed the sensitivity and specificity of the five-position grip strength test (5PGST) for detecting feigned hand weakness in healthy volunteers. The 5PGST reliably detected feigned hand weakness in only 15% of cases. Thirty-three per cent of volunteers demonstrated an entirely normal pattern of grip strength when feigning weakness.
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Fernandes, Luciane Fernanda Rodrigues Martinho, and Ricardo Machado Leite de Barros. "Grip pattern and finger coordination differences between pianists and non-pianists." Journal of Electromyography and Kinesiology 22, no. 3 (June 2012): 412–18. http://dx.doi.org/10.1016/j.jelekin.2012.02.007.
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Ma, C., F. Pan, F. Wu, H. H. Nguyen, L. Laslett, T. Winzenberg, and G. Jones. "SAT0447 CORRELATES OF RADIAL BONE MICROARCHITECTURES IN OLDER ADULTS." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 1180.1–1181. http://dx.doi.org/10.1136/annrheumdis-2020-eular.2262.
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Background:Weight, dietary patterns, vitamin D, physical activity and grip strength have been suggested to be associated with bone loss in older adults. However, studies have yet been performed to investigate the associations between these factors and radial bone microarchitecture.Objectives:This study aimed to describe the associations of weight, dietary patterns, serum 25-hydroxyvitamin D (25(OH)D) concentrations, physical activity and grip strength with bone measures in older adults.Methods:Cross-sectional data on 201 older adults (mean age 72 years, female 46%) from a population-based cohort study were analysed. Weight, dietary patterns, serum 25(OH)D concentrations, physical activity (steps per day), grip strength were collected and analysed from baseline to 10-year follow-up. Areal bone mineral density (aBMD) at spine, hip and whole body were measured by dual-energy X-ray absorptiometry (DXA). Radial cortical and trabecular bone microarchitectures were measured by high-resolution peripheral computed tomography (HRpQCT). Multivariable linear regression was used to analyse associations of study factors with bone measures.Results:Weight was positively associated with radial bone area (total: β=0.18, 95% CI: 0.07, 0.29; cortical: β=0.12, 95% CI: 0.03, 0.21; trabecular: β=0.18, 95% CI: 0.05, 0.32), and was inversely associated with compact cortical volumetric bone mineral density (vBMD) (β= -0.19, 95% CI: -0.37, -0.01) and trabecular thickness (β= -0.25, 95% CI: -0.43, -0.07). Ten-year changes in weight were not significantly associated with bone measures, apart from radial trabecular separation (β= 0.15, 95%CI: 0.009, 0.28). Western dietary pattern scores were inversely associated with radial vBMD (total: β= -0.17, 95% CI: -0.32, -0.01; cortical: β= -0.19, 95% CI: -0.34, -0.04; compact cortical: β= -0.19, 95% CI: -0.34, -0.04; outer transitional zone: β= -0.20, 95% CI: -0.35, -0.06), and were positively associated with cortical porosity (cortical: β= 0.18, 95% CI: 0.03, 0.33; compact cortical: β= 0.19, 95% CI: 0.04, 0.34; outer transitional zone: β= 0.20, 95% CI: 0.06, 0.35). Steps per day were not significantly associated with bone measures, apart from inner transitional zone area and thickness (β= 0.12, 95% CI: 0.003, 0.24; β= 0.19, 95% CI: 0.05, 0.33). Healthy food pattern scores, serum 25(OH)D and grip strength were not significantly associated with radial HRpQCT measures.Conclusion:Higher weight, but not weight change, was beneficial for radial cortical and trabecular bone area but also associated with worse compact cortical vBMD and trabecular thickness. Higher western dietary pattern scores had adverse effects on radial vBMD and cortical porosity while physical activity had inconsistent associations.Disclosure of Interests:None declared
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Weigelt, Matthias, and Thomas Schack. "The Development of End-State Comfort Planning in Preschool Children." Experimental Psychology 57, no. 6 (January 1, 2010): 476–82. http://dx.doi.org/10.1027/1618-3169/a000059.
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We investigated the development of the end-state comfort effect in young children. Fifty-one children from three age-groups (3, 4, and 5 years old) participated in the study. They performed the dowel placing task, which required them to reach for a horizontal dowel and to insert one of its ends into a target disk. Depending on which end was instructed, end-state comfort could be reached by picking up the dowel either with an overhand or with an underhand grip. All children reached for the dowel with an overhand grasp when this resulted in a comfortable end-state (i.e., thumb-up posture). A different pattern emerged when an underhand grip had to be selected. Here, 18% of the 3-year-olds, 45% of the 4-year-olds, and 67% of the 5-year-olds used an underhand grip and finished the action comfortably. For the first time, these results show a distinct pattern of gradual improvement in children’s sensitivity to reach end-state comfort across three age-groups.
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Ganapathy Sankar U and Monisha R. "Evaluation of Hand Strength, Handwriting, and Functional Skills in Children with Developmental Coordination Disorder (DCD)." International Journal of Research in Pharmaceutical Sciences 11, no. 4 (October 13, 2020): 6347–50. http://dx.doi.org/10.26452/ijrps.v11i4.3390.
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Dysgraphia and difficulty in activities of daily living skill are well documented in the research database as impairments affecting children with developmental coordination disorder. Pinch and grip strength has a predominant role in various activities of daily living skills, and a child can fulfil the playing skill only with good pinch and grip strength. To estimate hand strength evolution difference in children with developmental coordination disorder and to analyze the correlations in grip and pinch strength, handwriting and its components, and activities of daily living skills in children with and without developmental coordination disorder. Twenty children were selected and assigned into two groups, typically developing children and children with DCD. Each child was evaluated with pinch and grip strength, handwriting speed and legibility, pencil grip, and levels of performance in functional skills. When considering the strength development pattern, there exists a similar trend in children with and without DCD. Grip strength is having a perfect correlation with pencil control in both children with and without DCD. Handwriting is poor in the children with DCD but not in children without DCD. This study provides evidence that grip and pinch strength are important components when considering therapeutic intervention for enhancing handwriting skill in children with DCD.
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Guillevic, M., L. Bazin, A. Landais, P. Kindler, A. Orsi, V. Masson-Delmotte, T. Blunier, et al. "Spatial gradients of temperature, accumulation and δ<sup>18</sup>O-ice in Greenland over a series of Dansgaard–Oeschger events." Climate of the Past 9, no. 3 (May 7, 2013): 1029–51. http://dx.doi.org/10.5194/cp-9-1029-2013.
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Abstract. Air and water stable isotope measurements from four Greenland deep ice cores (GRIP, GISP2, NGRIP and NEEM) are investigated over a series of Dansgaard–Oeschger events (DO 8, 9 and 10), which are representative of glacial millennial scale variability. Combined with firn modeling, air isotope data allow us to quantify abrupt temperature increases for each drill site (1σ = 0.6 °C for NEEM, GRIP and GISP2, 1.5 °C for NGRIP). Our data show that the magnitude of stadial–interstadial temperature increase is up to 2 °C larger in central and North Greenland than in northwest Greenland: i.e., for DO 8, a magnitude of +8.8 °C is inferred, which is significantly smaller than the +11.1 °C inferred at GISP2. The same spatial pattern is seen for accumulation increases. This pattern is coherent with climate simulations in response to reduced sea-ice extent in the Nordic seas. The temporal water isotope (δ18O)–temperature relationship varies between 0.3 and 0.6 (±0.08) ‰ °C−1 and is systematically larger at NEEM, possibly due to limited changes in precipitation seasonality compared to GISP2, GRIP or NGRIP. The gas age−ice age difference of warming events represented in water and air isotopes can only be modeled when assuming a 26% (NGRIP) to 40% (GRIP) lower accumulation than that derived from a Dansgaard–Johnsen ice flow model.
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Yun, Myung Hwan, Kentaro Kotani, and Darin Ellis. "Using Force Sensitive Resistors to Evaluate Hand Tool Grip Design." Proceedings of the Human Factors Society Annual Meeting 36, no. 10 (October 1992): 806–10. http://dx.doi.org/10.1177/154193129203601036.
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The pressure distribution of the hand is an important element in evaluating hand tool grip. For measuring the pressure distributions of the hand, a portable sensor glove was developed using force sensitive resistors of the conductive polymer type. Pressure distributions of three hand tools for three male subjects were measured. The pressure distribution pattern varied significantly between type of grip, location, and subjective exertion level. Factor analysis was used to identify the relative importance of each area of the hand during grip action. The results showed that there is an ‘active' area involved in gripping the hand tool and a ‘control’ area which supports the hand motion for the given task. Studies about hand tool pressure distributions will provide an important guideline in designing a new tool or improving an existing one. A microcomputer based system is being developed that records data on grip pressure distribution throughout a tool grip task. The digitized data then will be analyzed both graphically and statistically and will be used to evaluate various hand tools for industrial settings.
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Jeannerod, M. "The formation of finger grip during prehension. A cortically mediated visuomotor pattern." Behavioural Brain Research 19, no. 2 (February 1986): 99–116. http://dx.doi.org/10.1016/0166-4328(86)90008-2.
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Wu, Kitty, Romeet Ahluwalia, Shrikant J. Chinchalkar, Joshua I. Vincent, Robert S. Richards, and Nina Suh. "The Effect of Simulated Total Distal Interphalangeal Joint Stiffness on Grip Strength." Plastic Surgery 26, no. 3 (April 23, 2018): 160–64. http://dx.doi.org/10.1177/2292550318767925.
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Purpose: Production of a functional grip pattern requires the concerted action of numerous structures within the hand. This study quantifies the effect of total distal interphalangeal joint (DIPJ) stiffness to grip strength. Methods: Fifty (25 men, 25 women, 100 hands) individuals with a mean age of 38 years (range: 17-69 years) were recruited. Exclusion criteria included history of previous upper limb injury, neuropathies, or systemic disease. Custom thermoplastic orthoses were used to splint participants’ DIPJ in full extension simulating stiffness. Grip strength before and after splinting was measured using a calibrated Jamar dynamometer. Data were analyzed using paired and independent sample t tests and 2 × 2 repeated-measures analysis of variance with hand dominance and configuration (splinted or unsplinted) as within-subject factors. Results: Restriction of DIPJ flexion led to a 20% decrease in grip strength ( P < .001). There was no significant difference in this decrease between dominant and non-dominant hands. Univariate analysis did not demonstrate any interaction between hand dominance and testing configuration. Post hoc analysis revealed no statistical difference in baseline grip strength between the dominant and non-dominant hands. Furthermore, men had significantly stronger grip strength than women in all configurations ( P < .001). Conclusions: Flexion at the DIPJ contributes significantly to grip strength, and stiffness at this joint greatly limits functional capabilities of the hand. This necessitates the need for targeted rehabilitation in DIPJ injuries to minimize adverse effects on grip strength.
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Grant, Katharyn A. "Evaluation of Grip Force Exertions in Dynamic Manual Work." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 38, no. 10 (October 1994): 549–53. http://dx.doi.org/10.1177/154193129403801002.
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An obstacle to the development of guidelines for reducing forceful hand movements is that manual force is not easily measured or estimated at the worksite, especially during highly dynamic activities. Grip force requirements during manual work are dependent not only on object weight, but also on the surface characteristics of the object and the task dynamics. In theory, it is possible to predict grip force requirements for manual tasks using Newtonian laws of physics; however few researchers have attempted to measure grip force during dynamic work, much less to compare actual grip force values to predicted levels. Therefore, a laboratory experiment was conducted to examine grip force exertions during two simulated industrial tasks. In each task, participants repetitively grasped and moved aluminum handles against varying levels of weight or resistance. Grip force was measured using a strain gauge mounted inside the handles. Results indicate that grip force varied continuously throughout each work cycle in response to changes in the motion of the hand/handle. The pattern of variation was consistent between subjects and could be approximated by a sinusoidal model. Greater interindividual variation in grip force exertion was observed when the task allowed greater flexibility in selecting a movement strategy. The results also indicate that subjects are more likely to “overshoot” the necessary grip force (i.e., apply more force than needed) at the initiation of movement, especially at lower weight levels. This study demonstrates that it is possible to predict variations in grip force during dynamic work, although further refinements in the procedure are needed. Use of modelling techniques will enable industrial designers to better estimate grip force requirements and to identify design strategies that will reduce the risk of musculoskeletal injury to the worker.
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Salimi, Iran, Thomas Brochier, and Allan M. Smith. "Neuronal Activity in Somatosensory Cortex of Monkeys Using a Precision Grip. I. Receptive Fields and Discharge Patterns." Journal of Neurophysiology 81, no. 2 (February 1, 1999): 825–34. http://dx.doi.org/10.1152/jn.1999.81.2.825.
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Neuronal activity in somatosensory cortex of monkeys using a precision grip. I. Receptive fields and discharge patterns. Three adolescent Macaca fascicularis monkeys weighing between 3.5 and 4 kg were trained to use a precision grip to grasp a metal tab mounted on a low friction vertical track and to lift and hold it in a 12- to 25-mm position window for 1 s. The surface texture of the metal tab in contact with the fingers and the weight of the object could be varied. The activity of 386 single cells with cutaneous receptive fields contacting the metal tab were recorded in Brodmann’s areas 3b, 1, 2, 5, and 7 of the somatosensory cortex. In this first of a series of papers, we describe three types of discharge pattern, the receptive-field properties, and the anatomic distribution of the neurons. The majority of the receptive fields were cutaneous and covered less than one digit, and a χ2 test did not reveal any significant differences in the Brodmann’s areas representing the thumb and index finger. Two broad categories of discharge pattern cells were identified. The first category, dynamic cells, showed a brief increase in activity beginning near grip onset, which quickly subsided despite continued pressure applied to the receptive field. Some of the dynamic neurons responded to both skin indentation and release. The second category, static cells, had higher activity during the stationary holding phase of the task. These static neurons demonstrated varying degrees of sensitivity to rates of pressure change on the skin. The percentage of dynamic versus static cells was about equal for areas 3b, 2, 5, and 7. Only area 1 had a higher proportion of dynamic cells (76%). A third category was identified that contained cells with significant pregrip activity and included cortical cells with both dynamic or static discharge patterns. Cells in this category showed activity increases before movement in the absence of receptive-field stimulation, suggesting that, in addition to peripheral cutaneous input, these cells also receive strong excitation from movement-related regions of the brain.
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Baker, Stuart N., and Roger N. Lemon. "Precise Spatiotemporal Repeating Patterns in Monkey Primary and Supplementary Motor Areas Occur at Chance Levels." Journal of Neurophysiology 84, no. 4 (October 1, 2000): 1770–80. http://dx.doi.org/10.1152/jn.2000.84.4.1770.
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Precise spatiotemporal patterns in neural discharge are a possible mechanism for information encoding in the brain. Previous studies have found that such patterns repeat and appear to relate to key behavioral events. Whether these patterns occur above chance levels remains controversial. To address this question, we have made simultaneous recordings from between two and nine neurons in the primary motor cortex and supplementary motor area of three monkeys while they performed a precision grip task. Out of a total of 67 neurons, 46 were antidromically identified as pyramidal tract neurons. Sections of recordings 60 s long were searched for patterns involving three or more spikes that repeated at least twice. The allowed jitter for pattern repetition was 3 ms, and the pattern length was limited to 192 ms. In all 11 recordings analyzed, large numbers of repeating patterns were found. To assess the expected chance level of patterns, “surrogate” datasets were generated. These had the same moment-by-moment modulation in firing rate as the experimental spike trains, and matched their interspike interval distribution, but did not preserve the precise timing of individual spikes. The number of repeating patterns in 10 randomly generated surrogates was used to form 99% confidence limits on the repeating pattern count expected by chance. There was close agreement between these confidence limits and the number of patterns seen in the experimental data. Analysis of high complexity patterns was carried out in four long recordings (mean duration 23.2 min, mean number of neurons simultaneously recorded 7.5). This analysis logged only patterns composed of a larger number (7–11) of spikes. The number of patterns seen in the surrogate datasets showed a small but significant excess over those seen in the original experimental data; this is discussed in the context of surrogate generation. The occurrence of repeating patterns in the experimental data were strongly associated with particular phases of the precision grip task; however, a similar task dependence was seen for the surrogate data. When a repeating pattern was used as a template to find inexact matches, in which up to half of the component spikes could be missing, similar numbers of matches were found in experimental and surrogate data, and the time of occurrence of such matches showed the same task dependence. We conclude that the existence of precise repeating patterns in our data are not due to cortical mechanisms that favor this form of coding, since as many, if not more, patterns are produced by spike trains constructed only to modulate their firing rate in the same way as the experimental data, and to match the interspike interval histograms. The task dependence of pattern occurrence is explicable as an artifact of the modulation of neural firing rate. The consequences for theories of temporal coding in the cortex are discussed.
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Song, Chang-Ik. "Effects of Muscle Activation to Grip Pattern"s Change in Amateur Tennis Members." Korean Journal of Sports Science 26, no. 2 (April 30, 2017): 1237–47. http://dx.doi.org/10.35159/kjss.2017.04.26.2.1237.
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Jang, Min-Soon, Tea-Min Park, Jung-Kwon Lee, and Bo-Hyeun Wang. "One Grip based Doorpull Shaped Doorlock System using Fingerprint Recognition and Touch Pattern." Journal of Korean Institute of Intelligent Systems 26, no. 1 (February 25, 2016): 30–36. http://dx.doi.org/10.5391/jkiis.2016.26.1.030.
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Seo, Na Jin. "Involuntary contralateral upper extremity muscle activation pattern during unilateral pinch grip following stroke." Journal of Hand Therapy 26, no. 3 (July 2013): 272–78. http://dx.doi.org/10.1016/j.jht.2013.04.006.
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Siggaard-Andersen, M. L., P. D. Ditlevsen, A. Walløe Hansen, and S. J. Johnsen. "Two modes of glacial climate during the late stage 5 identified in Greenland ice core records." Climate of the Past Discussions 3, no. 1 (February 2, 2007): 285–99. http://dx.doi.org/10.5194/cpd-3-285-2007.
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Abstract. From a detailed analysis of marine and terrestrial aerosol tracers in the NGRIP ice core we identified two distinct glacial atmospheric flow patterns. The climate transition from Marine Isotope Stage 5 (MIS 5) to MIS 4, at approximately 75 kyr BP, marks a shift between two different atmospheric flow regimes. Before this transition, during MIS 5d-a, the state of atmospheric flow was alternating between the two modes of different flow patterns, while a more persistent flow pattern was prevailing through the glacial period afterwards. These changes are accompanied by strong changes in an independent Greenland ice core proxy, namely the deuterium excess from the GRIP ice core, reflecting changes in the hydrological cycle and moisture source temperatures as well. The changes in atmospheric flow pattern are correlated with changed extent of ice-rafted detritus (IRD) deposition in the North Atlantic, indicating that the state of the atmospheric flow was highly sensitive to the waxing and waning of the Laurentide ice sheet.
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Bell, Joshua A., Kaitlin H. Wade, Linda M. O’Keeffe, David Carslake, Emma E. Vincent, Michael V. Holmes, Nicholas J. Timpson, and George Davey Smith. "Body muscle gain and markers of cardiovascular disease susceptibility in young adulthood: A cohort study." PLOS Medicine 18, no. 9 (September 9, 2021): e1003751. http://dx.doi.org/10.1371/journal.pmed.1003751.
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Background The potential benefits of gaining body muscle for cardiovascular disease (CVD) susceptibility, and how these compare with the potential harms of gaining body fat, are unknown. We compared associations of early life changes in body lean mass and handgrip strength versus body fat mass with atherogenic traits measured in young adulthood. Methods and findings Data were from 3,227 offspring of the Avon Longitudinal Study of Parents and Children (39% male; recruited in 1991–1992). Limb lean and total fat mass indices (kg/m2) were measured using dual-energy X-ray absorptiometry scans performed at age 10, 13, 18, and 25 y (across clinics occurring from 2001–2003 to 2015–2017). Handgrip strength was measured at 12 and 25 y, expressed as maximum grip (kg or lb/in2) and relative grip (maximum grip/weight in kilograms). Linear regression models were used to examine associations of change in standardised measures of these exposures across different stages of body development with 228 cardiometabolic traits measured at age 25 y including blood pressure, fasting insulin, and metabolomics-derived apolipoprotein B lipids. SD-unit gain in limb lean mass index from 10 to 25 y was positively associated with atherogenic traits including very-low-density lipoprotein (VLDL) triglycerides. This pattern was limited to lean gain in legs, whereas lean gain in arms was inversely associated with traits including VLDL triglycerides, insulin, and glycoprotein acetyls, and was also positively associated with creatinine (a muscle product and positive control). Furthermore, this pattern for arm lean mass index was specific to SD-unit gains occurring between 13 and 18 y, e.g., −0.13 SD (95% CI −0.22, −0.04) for VLDL triglycerides. Changes in maximum and relative grip from 12 to 25 y were both positively associated with creatinine, but only change in relative grip was also inversely associated with atherogenic traits, e.g., −0.12 SD (95% CI −0.18, −0.06) for VLDL triglycerides per SD-unit gain. Change in fat mass index from 10 to 25 y was more strongly associated with atherogenic traits including VLDL triglycerides, at 0.45 SD (95% CI 0.39, 0.52); these estimates were directionally consistent across sub-periods, with larger effect sizes with more recent gains. Associations of lean, grip, and fat measures with traits were more pronounced among males. Study limitations include potential residual confounding of observational estimates, including by ectopic fat within muscle, and the absence of grip measures in adolescence for estimates of grip change over sub-periods. Conclusions In this study, we found that muscle strengthening, as indicated by grip strength gain, was weakly associated with lower atherogenic trait levels in young adulthood, at a smaller magnitude than unfavourable associations of fat mass gain. Associations of muscle mass gain with such traits appear to be smaller and limited to gains occurring in adolescence. These results suggest that body muscle is less robustly associated with markers of CVD susceptibility than body fat and may therefore be a lower-priority intervention target.
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Van Mechelen, M., S. Hayer, K. Van Laere, R. Lories, and B. Neerinckx. "AB0106 THE PATTERN OF JOINT INFLAMMATION IN THE CAIA MOUSE MODEL OF ARTHRITIS." Annals of the Rheumatic Diseases 81, Suppl 1 (May 23, 2022): 1184.1–1184. http://dx.doi.org/10.1136/annrheumdis-2022-eular.2233.
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BackgroundAnimal models of inflammatory arthritis such as the collagen-antibody induced arthritis (CAIA) have a variable disease incidence in hind paw arthritis, complicating experimental design.ObjectivesTo investigate the use of 18FDG µPET/CT as a guide for inflammation in joints otherwise inaccessible for clinical scoring, enabling the use of additional joints for histological analysis.MethodsCAIA was induced in 8 male DBA/1 mice using the ArthritoMab Antibody cocktail (4 mg/mouse on day 0), followed by 100 µg LPS at day 3. Body weight, clinical signs of arthritis such as paw swelling and grip strength loss were recorded 3 times per week in both front and hind paws. Whole body 18FDG µPET/CT was performed at day 11, the estimated time of peak inflammation, and inflammation was scored visually on images scaled to the same standardised uptake value. At day 28, animals were euthanized and peripheral joints were collected for histological analysis.ResultsCumulative disease incidence based on paw swelling dropped from 100% to 87.5% when looking only at hind paws, and to 75% when taking into account only the region suitable for histological analysis, namely the ankle and midfoot of the hind paws. Symmetrical, bilateral hind paw arthritis was not observed. While hind paw arthritis showed a tendency to be less severe in comparison to front paw arthritis, grip strength was equally affected, indicating possible involvement of other hind limb joints. µPET/CT images detected inflammation in the hind paws (at least unilateral involvement in 62.5% of the mice, bilateral involvement in 0%), knee joints (at least unilateral in 75%, bilateral in 50%), hip joints (at least unilateral in 50%, bilateral in 0%), elbow joints (at least unilateral in 50%, bilateral in 37.5%) and shoulder joints (at least unilateral in 25%, bilateral in 25%). Histology could confirm this inflammation with the presence of inflammatory infiltrates and bone erosions. Grip strength loss in hind limbs without paw swelling correlated only weakly with knee inflammation detected by µPET/CT.ConclusionIn the CAIA model, inflammatory arthritis can develop in all peripheral joints, in particular with a high incidence in knee joints, which are highly suitable for subsequent histological analysis. Since clinical scoring seems insufficient for detecting these affected joints, implementation of in vivo imaging modalities such as µPET/CT, offers a substantial benefit in disease monitoring and assessment.Disclosure of InterestsNone declared
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Lin, Hai Bo, Zhe Guang Hu, and Wen Hui Zhao. "Study on Construction of Tyre Tread Pattern Mold and its Machining with 3-Axis Numerical Control." Advanced Materials Research 215 (March 2011): 212–16. http://dx.doi.org/10.4028/www.scientific.net/amr.215.212.
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Tyre tread pattern mainly accounts for tyre performance and its endurance. In tyre mold processing, pattern block processing is technologically disturbing, of which the tread pattern is the most challenging. This article first analyses the function conversion of the points from point to plane to space along the tyre tread curve. Aided by GRIP language, it continues to make tread section with spatial curve, and then with the help of UG scanning order, it produces a three-dimensional diorama of accurate tyre pattern. To solve the problem of large errors arising in tyre mold processing with 3 axis numerical control technology, the article proposes a new method to produce tyre tread pattern with 3 axis technology and validates the method. The research contributes to dividing processing of tyre tread pattern, and reducing errors theoretically. Experiments had been done to illustrate that the method can achieve high quality and efficient processing.
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Trossman, Patricia B., and Ping-Wu Li. "The Effect of the Duration of Intertrial Rest Periods on Isometric Grip Strength Performance in Young Adults." Occupational Therapy Journal of Research 9, no. 6 (November 1989): 362–78. http://dx.doi.org/10.1177/153944928900900604.
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This study examined the effect of the duration of intertrial rest periods on isometric grip strength scores in successive trials with the use of the power grip attachment of the Baltimore Therapeutic Equipment work simulator. Male and female subjects, 19 to 41 years of age, were randomly assigned to one of three groups, categorized by 15-, 30-, or 60-sec rest periods between five consecutive isometric grip tests. No significant differences were found between the groups in the pattern of decline in torque across trials. However, the group with the longest intertrial rest period had a significantly smaller percentage of decline in torque from the first to the last trial and the highest intraclass correlation coefficient between the five trials for both hands. In addition, the same group of subjects demonstrated significantly smaller differences in torque from the first to the second pretrial, which had a 2-min rest period, than from the first to the second experimental trial, which had shorter intertrial rest periods of 15, 30, or 60 sec.
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Bennett, K. M., and R. N. Lemon. "Corticomotoneuronal contribution to the fractionation of muscle activity during precision grip in the monkey." Journal of Neurophysiology 75, no. 5 (May 1, 1996): 1826–42. http://dx.doi.org/10.1152/jn.1996.75.5.1826.
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1. During independent finger movements, the intrinsic muscles of the hand show a fractionated pattern of activity in which the timing and amplitude of electromyographic (EMG) activity varies considerably from one muscle to another. It has been suggested that, in the macaque monkey, corticomotoneuronal (CM) cells that produce postspike facilitation (PSF) of EMG in these muscles contribute to this fractionation. To test this hypothesis, we have investigated the relationship between the pattern of PSF exerted by a CM cell and the pattern of activity shown by the cell and by its target muscles. 2. The activity of 15 identified CM cells was recorded from two monkeys that performed a precision grip task. Spike-triggered averaging of rectified EMG during the hold period of this task showed that each cell produced PSF in at least two intrinsic hand muscles. 3. Segments of data were selected from the initial movement period of the task in which the EMG activity in one target muscle was substantially greater than that of the other, and the mean firing rate of each CM cell was determined for these periods. 4. CM cells showed bursts of activity in the movement period. Most of them (13/15) had a significantly (P < 0.001) higher firing rate when one of its target muscles was more active than the other. For nine of these cells (identified as set A), this muscle was the one receiving the larger PSF. In four cases (set B), the reverse was true. Two cells (set C), which produced PSF of equal size in their target muscles, showed no change in firing rate across the periods of fractionated EMG activity. 5. All set A and set B cells fired at significantly (P < 0.001) higher rates during the movement period, in association with fractionation of EMG activity, than in the hold period, in which a cocontracted pattern of muscle activity was observed. 6. There were pronounced differences in the strength of PSF exerted by the CM cells on their target muscles during the fractionation periods. One CM cell exerted PSF of a muscle during one period of fractionation, but postspike suppression of the same muscle during the other period. 7. It is suggested that changes in the firing rate of a CM cell and in the degree of facilitation it exerts could both contribute to the fractionation of activity in its target muscles. Cells of set A appear to be specifically recruited in a manner that directly reflects the pattern of facilitation they exert on the sampled target muscles. These results may explain why the CM system is so important for the performance of relatively independent finger movements.
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HAHN, P., J. BREDERLAU, H. KRIMMER, and U. LANZ. "Explosion Injuries of the Hand." Journal of Hand Surgery 21, no. 6 (December 1996): 785–87. http://dx.doi.org/10.1016/s0266-7681(96)80191-4.
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Twenty-six hands in 25 male patients were treated for peace-time explosion injuries of the palmar aspect. All patients were examined after a mean interval of 7 (1–17) years. In order to establish a regional pattern for each injury the palmar surface of the hand was divided in 21 fields. For each field a score depending on the extent of injury was calculated. Comparing this regional score with the spatial relation between hand and exploding object resulted in six typical patterns depending on the grip during explosion. With knowledge of the three-dimensional relation between the hand and exploding object, the hand surgeon is prepared for potential problems during operation.
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Kinoshita, Hiroshi, Lars Bäckström, J. Randall Flanagan, and Roland S. Johansson. "Tangential Torque Effects on the Control of Grip Forces When Holding Objects With a Precision Grip." Journal of Neurophysiology 78, no. 3 (September 1, 1997): 1619–30. http://dx.doi.org/10.1152/jn.1997.78.3.1619.
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Kinoshita, Hiroshi, Lars Bäckström, J. Randall Flanagan, and Roland S. Johansson. Tangential torque effects on the control of grip forces when holding objects with a precision grip. J. Neurophysiol. 78: 1619–1630, 1997. When we manipulate small objects, our fingertips are generally subjected to tangential torques about the axis normal to the grasp surface in addition to linear forces tangential to the grasp surface. Tangential torques can arise because the normal force is distributed across the contact area rather than focused at a point. We investigated the effects of tangential torques and tangential forces on the minimum normal forces required to prevent slips (slip force) and on the normal forces actually employed by subjects to hold an object in a stationary position with the use of the tips of the index finger and thumb. By changing the location of the object's center of gravity in relation to the grasp surface, various levels of tangential torque (0–50 N⋅mm) were created while the subject counteracted object rotation. Tangential force (0–3.4 N) was varied by changing the weight of the object. The flat grasp surfaces were covered with rayon, suede, or sandpaper, providing differences in friction in relation to the skin. Under zero tangential force, both the employed normal force and the slip force increased in proportion to tangential torque with a slope that reflected the current frictional condition. Likewise, with pure tangential force, these forces increased in proportion to tangential force. The effects of combined tangential torques and tangential forces on the slip force were primarily additive, but there was a significant interaction of these variables. Specifically, the increase in slip force for a given increment in torque decreases as a function of tangential force. A mathematical model was developed that successfully predicted slip force from tangential torque, tangential force, and an estimate of coefficient of static friction in the digit-surface interface. The effects of combined tangential torques and forces on the employed normal force showed the same pattern as the effects on the slip force. The safety margin against frictional slips, measured as the difference between the employed normal force and the slip force, was relatively small and constant across all tangential force and torque levels except at small torques (<10 N⋅mm). There was no difference in safety margin between the digits. In conclusion, tangential torque strongly influences the normal force required for grasp stability. When controlling normal force, people take into account, in a precise fashion, the slip force reflecting both tangential force and tangential torque and their interaction as well as the current frictional condition in the object-digit interface.
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UMETSU, Tomoki, Takeshi YAMAGUCHI, Kenichi KASUGA, Takayuki ITO, Satoshi ISHIZAWA, and Kazuo HOKKIRIGAWA. "109 Design criteria of High Grip Shoe Sole Pattern for Prevention of Slip Related Falls." Proceedings of Conference of Tohoku Branch 2010.45 (2010): 22–23. http://dx.doi.org/10.1299/jsmeth.2010.45.22.
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Shah, Maulik, Sweety Shah, and Vaibhavi Ved. "A Study to Evaluate Pencil Grip Type, Hand Functions - Dexterity & Grip Strength in Children Using Tech for 2 or More Hours a Day." International Journal of Health Sciences and Research 12, no. 3 (March 16, 2022): 274–84. http://dx.doi.org/10.52403/ijhsr.20220339.
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Background: These days, modern innovative technology plays a crucial part in our life. Touch screens has become the primary interaction method for smart phones due to their ability to combine input and output in a single interface. On the one hand, it has made our lives easier by allowing us to browse the internet, have essential conversations, and have a source of pleasure. Frequent use of technical devices without taking regular rest periods may result in cumulative trauma disorders to the neck, shoulders, hands and wrists. These disorders may occur because Smartphone, iPod etc. use typically requires thumb and finger interactions with the screen. Reports have shown that extended technology use accompanied by awkward wrist posture can lead to collective trauma disorders of the wrist joints, particularly when the wrist, hands, and fingers are overused. Repetitive static motion of the hands may also decrease blood supply and prevent nutrients from being delivered to muscles, thus leading to pain and muscle fatigue may result into poor hand function including reduced grip strength & poor dexterity. Children are attracted to smart phones because these devices can be used anywhere and contain games that are specifically matched to their ages. Numbers of studies have been done on Smartphone usage, hand writing performance & grip strength individually. However, the link between Smartphone addiction and grip strength and upper limb disability has been left unnoticed. Methodology: A cross sectional observational study was conducted to evaluate pencil grip type, hand dexterity & grip strength in children using technological devices for 2 or more hours a day dividing subjects into 2 groups. Group A: Children using technological devices for 2 or more hours a day. Group B: Children not using technological devices. Written consent was taken from the subjects and the subjects were made to understand the purpose of the study. Hand dexterity was evaluated using Functional Dexterity Test, Grip strength with hand held dynamometer & Pencil grip type was evaluated. Results: Data analysis was done using Graph Pad Prism 6. In Group A, Dynamic Tripod grasp was present in 19 subjects (61.29%) Five finger grasp in 0 subjects (0 %,), Thumb Wrap grasp in 1 subject (3.22%), Upright tripod grasp in 11 subject (35.48%).In Group B, Dynamic Tripod grasp was present in 26 subjects (83.87%) Five finger grasp in 0 subjects (0 %,), Thumb Wrap grasp in 1 subject (3.22%), Upright tripod grasp in 4 subjects (12.90%).The result showed significant difference for the functional dexterity test between Group A and Group B (t = 5.725 and p = 0.0001) & grip strength between Group A and Group B (t = 6.449 and p = 0.0001). Conclusion: Increased use of tech devices significantly affects Hand performance like Grip strength, Hand dexterity & Pencil grip pattern amongst children. Key words: Hand Dexterity, Grip Strength, Pencil Grip Type, Smart Phone Use, Functional Dexterity Test, Hand Writing Performance.
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Shafique, Sidra, Hafiza Neelam Muneeb, Naseem Abbas, and Iqra Abdul Ghafoor. "COMPARISON OF MOBILIZATION WITH MOVEMENT AND SOFT TISSUE MOBILIZATION ON PAIN SEVERITY, HAND GRIP STRENGTH AND FUNCTIONAL ACTIVITY IN TENNIS ELBOW PATIENTS." Pakistan Journal of Rehabilitation 11, no. 1 (January 3, 2022): 45–50. http://dx.doi.org/10.36283/pjr.zu.11.1/010.
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BACKGROUND AND AIM Lateral epicondylitis or tennis elbow is a pain pattern most commonly seen in tennis player due to forceful repetitive movements in a wrong way. So, the Objective was to determine the comparison of mobilization with movement and soft tissue mobilization on pain, grip strength and functional activity in patients with tennis elbow. METHODOLOGY In this Randomized Controlled Trial, Non probability sampling technique was used. Thirty tennis players having lateral epicondylitis pain were included in the study. Two interventions were used i.e. Mobilization with movement and soft tissue mobilization. Pain, Muscle power and function activity were 3 outcome measure in both groups. RESULTS In both groups the mean age of the participants was 24.30 ± SD 3.01. There was a significant Mean difference in the pain scores for MWM (5.34) and Soft Tissue Mobilization (3.74) after treatment. P value is significant for both group but there was greater difference with group MWM CONCLUSIONS The present study concluded that Mobilization with movement has greater effect than the Soft Tissue Mobilization in relieving pain and improving Hand grip strength and functional activity in patients with tennis elbow. Key words Movement, soft tissue, pain, grip, hand strength functional status, tennis elbow
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Turella, Luca, Raffaella Rumiati, and Angelika Lingnau. "Hierarchical Action Encoding Within the Human Brain." Cerebral Cortex 30, no. 5 (January 14, 2020): 2924–38. http://dx.doi.org/10.1093/cercor/bhz284.
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Abstract Humans are able to interact with objects with extreme flexibility. To achieve this ability, the brain does not only control specific muscular patterns, but it also needs to represent the abstract goal of an action, irrespective of its implementation. It is debated, however, how abstract action goals are implemented in the brain. To address this question, we used multivariate pattern analysis of functional magnetic resonance imaging data. Human participants performed grasping actions (precision grip, whole hand grip) with two different wrist orientations (canonical, rotated), using either the left or right hand. This design permitted to investigate a hierarchical organization consisting of three levels of abstraction: 1) “concrete action” encoding; 2) “effector-dependent goal” encoding (invariant to wrist orientation); and 3) “effector-independent goal” encoding (invariant to effector and wrist orientation). We found that motor cortices hosted joint encoding of concrete actions and of effector-dependent goals, while the parietal lobe housed a convergence of all three representations, comprising action goals within and across effectors. The left lateral occipito-temporal cortex showed effector-independent goal encoding, but no convergence across the three levels of representation. Our results support a hierarchical organization of action encoding, shedding light on the neural substrates supporting the extraordinary flexibility of human hand behavior.
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Khan, Adil, Manzoor Ahmad, and Abdul Waheed. "Pakistan's Journey to Civilian Rule (1958-70): An Analysis of Ayub Era." Global Legal Studies Review I, no. I (December 30, 2016): 1–8. http://dx.doi.org/10.31703/glsr.2016(i-i).01.
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Pakistan, since its inception, has passed through several phases of transitions to civilian rule and authoritarian reversals. Similar to the pattern of transition between civilian rule and dictatorship, there is a pattern of change within authoritarian Regimes that could be observed in all the three experiences of transition in Pakistan. This paper identifies the pattern of change from military dictatorship to civilian rule from 1958 to 1970. The key questions addressed in this paper are: firstly, how the military regime consolidated its grip on power after the October 1958 coup? Secondly, how early cracks appeared in the military's control over power and matured with the passage of time, resulting in a national crisis? Thirdly, how failure in crises management led to the transition to civilian rule, as well as, the disintegration of the state.
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Souza, Vitor, Rinaldo Guirro, Heloyse Kuriki, Gabriela de Carvalho, Alexandre Marcolino, and Rafael Barbosa. "Photobiomodulation Decreases Fatigue of the Wrist Extensors: Electromyographic and Dynamometric Analysis." Advanced Science, Engineering and Medicine 12, no. 4 (April 1, 2020): 535–41. http://dx.doi.org/10.1166/asem.2020.2544.
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This study analyzed the effects of photobiomodulation, on wrist extensor muscles when applied before a fatigue protocol. Twenty-eight men participated in a crossover, blinded, and controlled trial. Subjects performed grip dynamometry associated with superficial electromyography of the extensor carpi radialis, extensor carpi ulnaris, and flexor digitorum superficialis, which was used to evaluate muscle recruitment pattern by median frequency. The initial assessment was performed with a onerepetition maximum test. Twenty-four hours later the allocation was performed in two moments, and randomization was initially performed with 28 volunteers, divided between the two groups: control group, and the Low-Level Laser Therapy (30 mW, 0.06 cm2, 20 J/cm2, 1.2 J per point, and total energy of 10.8 J). Median frequency demonstrated Extensor Carpi Ulnaris fatigue in the control group as well as when compared after the fatigue protocol in the laser group. Exhaustion time was greater in the laser group and the fatigue protocol was effective at decreasing grip strength, with significant difference in the control group (p < 0.05). After the fatigue protocol, Low-Level Laser Therapy was effective in maintaining grip strength to increase exhaustion time and does not promote alterations in Median Frequency behavior at wrist extensor muscles.
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Sandykbayeva, Danissa, Zhanat Kappassov, and Bakhtiyar Orazbayev. "VibroTouch: Active Tactile Sensor for Contact Detection and Force Sensing via Vibrations." Sensors 22, no. 17 (August 27, 2022): 6456. http://dx.doi.org/10.3390/s22176456.
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Accurate and fast contact detection between a robot manipulator and objects is crucial for safe robot–object and human–robot interactions. Traditional collision detection techniques relied on force–torque sensors and Columb friction cone estimation. However, the strain gauges used in the conventional force sensors require low-noise and high-precision electronics to deliver the signal to the final user. The Signal-to-Noise Ratio (SNR) in these devices is still an issue in light contact detection. On the other hand, the Eccentric Rotating Mass (ERM) motors are very sensitive to subtle touch as their vibrating resonant state loses immediately. The vibration, in this case, plays a core role in triggering the tactile event. This project’s primary goal is to use generated and received vibrations to establish the scope of object properties that can be obtained through low-frequency generation on one end and Fourier analysis of the accelerometer data on the other end. The main idea behind the system is the phenomenon of change in vibration propagation patterns depending on the grip properties. Moreover, the project’s original aim is to gather enough information on vibration feedback on objects of various properties and compare them. These data sets are further analyzed in terms of frequency and applied grip force correlations in order to prepare the ground for pattern extraction and recognition based on the physical properties of an object.
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Erazo Macias, M. José H., and S. Alejandro Vega. "Electromyographic Pattern Analysis and Classification for a Robotic Prosthetic Arm." Applied Bionics and Biomechanics 3, no. 2 (2006): 113–19. http://dx.doi.org/10.1155/2006/176825.
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This paper deals with the statistical analysis and pattern classification of electromyographic signals from the biceps of a person with amputation below the humerus. Such signals collected from an amputation simulator are synergistically generated to produce discrete elbow movements. The purpose of this study is to utilise these signals to control an electrically driven prosthetic or orthotic elbow with minimum extra mental effort on the part of the subject. The results show very good separability of classes of movements when a learning pattern classification scheme is used, and a superposition of any composite motion to the three basic primitive motions—humeral rotation in and out, flexion and extension, and pronation and supination. Since no synergy was detected for the wrist movement, different inputs have to be provided for a grip. In addition, the method described is not limited by the location of the electrodes. For amputees with shorter stumps, synergistic signals could be obtained from the shoulder muscles. However, the presentation in this paper is limited to biceps signal classification only.
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Rasines, Irati, Miguel Prada, Viacheslav Bobrov, Dhruv Agrawal, Leire Martinez, Pedro Iriondo, Anthony Remazeilles, and Joseph McIntyre. "Regulating Grip Forces through EMG-Controlled Protheses for Transradial Amputees." Applied Sciences 11, no. 23 (November 25, 2021): 11199. http://dx.doi.org/10.3390/app112311199.
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This study aims to evaluate different combinations of features and algorithms to be used in the control of a prosthetic hand wherein both the configuration of the fingers and the gripping forces can be controlled. This requires identifying machine learning algorithms and feature sets to detect both intended force variation and hand gestures in EMG signals recorded from upper-limb amputees. However, despite the decades of research into pattern recognition techniques, each new problem requires researchers to find a suitable classification algorithm, as there is no such thing as a universal ’best’ solution. Consideration of different techniques and data representation represents a fundamental practice in order to achieve maximally effective results. To this end, we employ a publicly-available database recorded from amputees to evaluate different combinations of features and classifiers. Analysis of data from 9 different individuals shows that both for classic features and for time-dependent power spectrum descriptors (TD-PSD) the proposed logarithmically scaled version of the current window plus previous window achieves the highest classification accuracy. Using linear discriminant analysis (LDA) as a classifier and applying a majority-voting strategy to stabilize the individual window classification, we obtain 88% accuracy with classic features and 89% with TD-PSD features.
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Belcher, Henry J. C. R., and Hayley Smith. "Extended dynamometry: reference values." Journal of Hand Surgery (European Volume) 44, no. 2 (November 8, 2018): 196–202. http://dx.doi.org/10.1177/1753193418805959.
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Grip strength is used as a measure of capacity in disability and personal injury claims. Although seemingly an objective measure, it is widely recognized that it is fallible to the effects of sub-maximal effort. We have developed an extended test protocol that uses the five positions of a Jamar dynamometer. The protocol mitigates the effect of inconsistency while retaining the ability to detect sub-maximal effort. Dynamometry was undertaken in 242 volunteers (male:female, 124:118) with a median age of 39 years (range 18–89, interquartile range 29–52). Normative values for consistency, curve deviation and variation from the expected curve pattern are provided. None of these measures were significantly affected by laterality, hand dominance, sex or age despite the effects of these variables on grip strength. The study defines the methodology and reference values to allow assessment of both the capacity of a patient and the reliability of the test for use in medicolegal practice. Level of evidence: II
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Rich, Tonya L., Jeremiah S. Menk, Kyle D. Rudser, Timothy Feyma, and Bernadette T. Gillick. "Less-Affected Hand Function in Children With Hemiparetic Unilateral Cerebral Palsy: A Comparison Study With Typically Developing Peers." Neurorehabilitation and Neural Repair 31, no. 10-11 (October 2017): 965–76. http://dx.doi.org/10.1177/1545968317739997.
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Background. Neurorehabilitation interventions in children with unilateral cerebral palsy (UCP) target motor abilities in daily life yet deficits in hand skills persist. Limitations in the less-affected hand may affect overall bimanual hand skills. Objective. To compare hand function, by timed motor performance on the Jebsen-Taylor Test of Hand Function (JTTHF) and grip strength of children with UCP to children with typical development (CTD), aged 8 to 18 years old. Exploratory analyses compared hand function measures with regard to neurophysiological outcomes measured by transcranial magnetic stimulation and between group comparisons of hemispheric motor threshold. Methods. Baseline hand skills were evaluated in 47 children (21 UCP; 26 CTD). Single-pulse transcranial magnetic stimulation testing assessed corticospinal tract and motor threshold. Results. The mean difference of the less-affected hand of children with UCP to the dominant hand of CTD on the JTTHF was 21.4 seconds (95% CI = 9.32-33.46, P = .001). The mean difference in grip strength was −30.8 N (95% CI = −61.9 to 0.31, P = .052). Resting motor thresholds between groups were not significant, but age was significantly associated with resting motor threshold ( P < .001; P = .001). Children with UCP ipsilateral pattern of motor representation demonstrated greater mean differences between hands than children with contralateral pattern of motor representation ( P < .001). All results were adjusted for age and sex. Conclusions. The less-affected hand in children with UCP underperformed the dominant hand of CTD. Limitations were greater in children with UCP ipsilateral motor pattern. Rehabilitation in the less-affected hand may be warranted. Bilateral hand function in future studies may help identify the optimal rehabilitation and neuromodulatory intervention.