scholarly journals Testing the Performance of an Innovative Markerless Technique for Quantitative and Qualitative Gait Analysis

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6654
Author(s):  
Laura Simoni ◽  
Alessandra Scarton ◽  
Filippo Gerli ◽  
Claudio Macchi ◽  
Federico Gori ◽  
...  

Gait abnormalities such as high stride and step frequency/cadence (SF—stride/second, CAD—step/second), stride variability (SV) and low harmony may increase the risk of injuries and be a sentinel of medical conditions. This research aims to present a new markerless video-based technology for quantitative and qualitative gait analysis. 86 healthy individuals (mead age 32 years) performed a 90 s test on treadmill at self-selected walking speed. We measured SF and CAD by a photoelectric sensors system; then, we calculated average ± standard deviation (SD) and within-subject coefficient of variation (CV) of SF as an index of SV. We also recorded a 60 fps video of the patient. With a custom-designed web-based video analysis software, we performed a spectral analysis of the brightness over time for each pixel of the image, that reinstituted the frequency contents of the videos. The two main frequency contents (F1 and F2) from this analysis should reflect the forcing/dominant variables, i.e., SF and CAD. Then, a harmony index (HI) was calculated, that should reflect the proportion of the pixels of the image that move consistently with F1 or its supraharmonics. The higher the HI value, the less variable the gait. The correspondence SF-F1 and CAD-F2 was evaluated with both paired t-Test and correlation and the relationship between SV and HI with correlation. SF and CAD were not significantly different from and highly correlated with F1 (0.893 ± 0.080 Hz vs. 0.895 ± 0.084 Hz, p < 0.001, r2 = 0.99) and F2 (1.787 ± 0.163 Hz vs. 1.791 ± 0.165 Hz, p < 0.001, r2 = 0.97). The SV was 1.84% ± 0.66% and it was significantly and moderately correlated with HI (0.082 ± 0.028, p < 0.001, r2 = 0.13). The innovative video-based technique of global, markerless gait analysis proposed in our study accurately identifies the main frequency contents and the variability of gait in healthy individuals, thus providing a time-efficient, low-cost means to quantitatively and qualitatively study human locomotion.

2015 ◽  
Vol 18 (2) ◽  
pp. 256-276 ◽  
Author(s):  
D. Pumo ◽  
A. Francipane ◽  
F. Lo Conti ◽  
E. Arnone ◽  
P. Bitonto ◽  
...  

The development of Web-based information systems coupled with advanced monitoring systems could prove to be extremely useful in landslide risk management and mitigation. A new frontier in the field of rainfall-triggered landslides (RTLs) lies in the real-time modelling of the relationship between rainfall and slope stability; this requires an intensive monitoring of some key parameters that could be achieved through the use of modern and often low-cost technologies. This work describes an integrated information system for early warning of RTLs that has been deployed and tested, in a prototypal form, for an Italian pilot site. The core of the proposed system is a wireless sensor network collecting meteorological, hydrological and geotechnical data. Data provided by different sensors and transmitted to a Web-based platform are used by an opportunely designed artificial neural network performing a stability analysis in near real-time or in forecast modality. The system is able to predict whether and when landslides could occur, providing early warnings of potential slope failures. System infrastructure, designed on three interacting levels, encompasses a sensing level, integrating different Web-based sensors, a processing level, using Web standard interoperability services and specifically implemented algorithms, and, finally, a warning level, providing warning information through Web technologies.


2020 ◽  
Vol 42 (2) ◽  
pp. 153-160
Author(s):  
Ciarán P. Friel ◽  
Carol Ewing Garber

Wearable physical activity (PA) monitors are widely promoted as a means to motivate people to be more active, but the motivational profile of users has never been assessed. This study’s purpose was to classify adult users by their motivational regulation scores and examine how these profiles were associated with moderate to vigorous PA (MVPA). Current users (N = 320) recruited across the United States completed a Web-based survey. Motivational regulations were measured using the Behavioral Regulation in Exercise Questionnaire, and associations with MVPA were explored using bivariate correlations. MVPA was more highly correlated with autonomous rather than controlling regulations. A cluster analysis was conducted using the respondents’ motivational regulation scores. Five motivational profiles emerged from this analysis, and they differed significantly across motivation and MVPA scores. PA monitor users characterized by more autonomous motives presented with higher MVPA. As technology use increases, assessing the multidimensionality of PA monitor users’ motivation may add value when researching PA behaviors.


1988 ◽  
Vol 59 (02) ◽  
pp. 273-276 ◽  
Author(s):  
J Dawes ◽  
D A Pratt ◽  
M S Dewar ◽  
F E Preston

SummaryThrombospondin, a trimeric glycoprotein contained in the platelet α-granules, has been proposed as a marker of in vivo platelet activation. However, it is also synthesised by a range of other cells. The extraplatelet contribution to plasma levels of thrombospondin was therefore estimated by investigating the relationship between plasma thrombospondin levels and platelet count in samples from profoundly thrombocytopenic patients with marrow hypoplasia, using the platelet-specific α-granule protein β-thromboglobulin as control. Serum concentrations of both proteins were highly correlated with platelet count, but while plasma β-thromboglobulin levels and platelet count also correlated, there was no relationship between the number of platelets and thrombospondin concentrations in plasma. Serial sampling of patients recovering from bone marrow depression indicated that the plasma thrombospondin contributed by platelets is superimposed on a background concentration of at least 50 ng/ml probably derived from a non-platelet source, and plasma thrombospondin levels do not simply reflect platelet release.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 789
Author(s):  
David Kreuzer ◽  
Michael Munz

With an ageing society comes the increased prevalence of gait disorders. The restriction of mobility leads to a considerable reduction in the quality of life, because associated falls increase morbidity and mortality. Consideration of gait analysis data often alters surgical recommendations. For that reason, the early and systematic diagnostic treatment of gait disorders can spare a lot of suffering. As modern gait analysis systems are, in most cases, still very costly, many patients are not privileged enough to have access to comparable therapies. Low-cost systems such as inertial measurement units (IMUs) still pose major challenges, but offer possibilities for automatic real-time motion analysis. In this paper, we present a new approach to reliably detect human gait phases, using IMUs and machine learning methods. This approach should form the foundation of a new medical device to be used for gait analysis. A model is presented combining deep 2D-convolutional and LSTM networks to perform a classification task; it predicts the current gait phase with an accuracy of over 92% on an unseen subject, differentiating between five different phases. In the course of the paper, different approaches to optimize the performance of the model are presented and evaluated.


Agronomy ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 616
Author(s):  
Virginia Birlanga ◽  
José Ramón Acosta-Motos ◽  
José Manuel Pérez-Pérez

Cultivated lettuce (Lactuca sativa L.) is one of the most important leafy vegetables in the world, and most of the production is concentrated in the Mediterranean Basin. Hydroponics has been successfully utilized for lettuce cultivation, which could contribute to the diversification of production methods and the reduction of water consumption and excessive fertilization. We devised a low-cost procedure for closed hydroponic cultivation and easy phenotyping of root and shoot attributes of lettuce. We studied 12 lettuce genotypes of the crisphead and oak-leaf subtypes, which differed on their tipburn resistance, for three growing seasons (Fall, Winter, and Spring). We found interesting genotype × environment (G × E) interactions for some of the studied traits during early growth. By analyzing tipburn incidence and leaf nutrient content, we were able to identify a number of nutrient traits that were highly correlated with cultivar- and genotype-dependent tipburn. Our experimental setup will allow evaluating different lettuce genotypes in defined nutrient solutions to select for tipburn-tolerant and highly productive genotypes that are suitable for hydroponics.


Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 912
Author(s):  
Mai Matsumoto ◽  
Hiroyuki Suganuma ◽  
Naoki Ozato ◽  
Sunao Shimizu ◽  
Mitsuhiro Katashima ◽  
...  

Consumption of fruits and vegetables rich in carotenoids has been widely reported to prevent cardiovascular diseases. However, the relationship between serum carotenoid concentrations and visceral fat area (VFA), which is considered a better predictor of cardiovascular diseases than the body-mass index (BMI) and waist circumference, remains unclear. Therefore, we examined the relationship in healthy individuals in their 20s or older, stratified by sex and age, to compare the relationship between serum carotenoid concentrations and VFA and BMI. The study was conducted on 805 people, the residents in Hirosaki city, Aomori prefecture, who underwent a health checkup. An inverse relationship between serum carotenoid concentrations and VFA and BMI was observed only in women. In addition, the results were independent of the intake of dietary fiber, which is mainly supplied from vegetables as well as carotenoids. This suggests that consumption of a diet rich in carotenoids (especially lutein and beta-carotene) is associated with lower VFA, which is a good predictor of cardiovascular disease, especially in women. This study is the first to comprehensively evaluate the association between serum carotenoid levels and VFA in healthy individuals.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Manjot Kaur Grewal ◽  
Shruti Chandra ◽  
Alan Bird ◽  
Glen Jeffery ◽  
Sobha Sivaprasad

AbstractTo evaluate the effect of aging, intra- and intersession repeatability and regional scotopic sensitivities in healthy and age-related macular degeneration (AMD) eyes. Intra- and intersession agreement and effect of age was measured in healthy individuals. The mean sensitivity (MS) and pointwise retinal sensitivities (PWS) within the central 24° with 505 nm (cyan) and 625 nm (red) stimuli were evaluated in 50 individuals (11 healthy and 39 AMD eyes). The overall intra- and intersession had excellent reliability (intraclass correlation coefficient, ICC > 0.90) and tests were highly correlated (Spearman rs = 0.75–0.86). Eyes with subretinal drusenoid deposit (SDD) had reduced PWS centrally, particularly at inferior and nasal retinal locations compared with controls and intermediate AMD (iAMD) without SDD. There was no difference in MS or PWS at any retinal location between iAMD without SDD and healthy individuals nor between iAMD with SDD and non-foveal atrophic AMD groups. Eyes with SDD have reduced rod function compared to iAMD without SDD and healthy eyes, but similar to eyes with non-foveal atrophy. Our results highlight rod dysfunction is not directly correlated with drusen load and SDD location.


2002 ◽  
Vol 13 (05) ◽  
pp. 236-245 ◽  
Author(s):  
Gary Rance ◽  
Field Rickards

This retrospective study examines the relationship between auditory steady-state evoked potential (ASSEP) thresholds determined in infancy and subsequently obtained behavioral hearing levels in children with normal hearing or varying degrees of sensorineural hearing loss. Overall, the results from 211 subjects showed that the two test techniques were highly correlated, with Pearson r values exceeding .95 at each of the audiometric test frequencies between 500 and 4000 Hz. Analysis of the findings for babies with significant hearing loss (moderate to profound levels) showed similar threshold relationships to those obtained in previous studies involving adults and older children. The results for infants with normal or near-normal hearing did, however, differ from those reported for older subjects, with behavioral thresholds typically 10 to 15 dB better than would have been predicted from their ASSEP levels.


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