Study of Postural Stability After 5-Day Dry Immersion with Two Posturology Methods: Comparative Analysis of Video Motion Capture and Inertial Motion Sensors Доклады на конференциях
Язык | Английский | ||
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Тип доклада | Устный | ||
Конференция |
41st Annual the International Society of Gravitational Physiology Meeting 24-27 мая 2021 , Техас |
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Реферат:
Introduction: At the moment, there is a large selection of posturology methods that differ in size, complexity in operation and technical characteristics. The Video Motion Capture method (VMC) is based on continuous registration of the position of markers attached to the human skin. It has established itself in posturology, but has high requirements for the room size, and for the level of illumination, the complexity of application. Inertial Motion Sensors (IMS) measure linear acceleration and angular velocities of the body segment to which they are attached. They are lightweight, easy to transport, undemanding to illumination, and can be used not only in clinical conditions but also in the field. While both methods have worked well, they are based on different principles as outlined above. In this work, we tried to bring the data of both methods to a comparable representation by calculating the volume of ellipses for each marker and sensor. The aim of this work was to study a correlation and analyze an interchangeability and directionality of these two methods. Methods: Six healthy volunteers (mean±SD: age 35.50±4.18 yrs, height 172.1±6.9 cm, body mass 74.00±8.69 kg) were included in the study. 5-day Dry Immersion (DI) (see details in Tomilovskaya, 2019) was used as a model of weightlessness. Determination of the subjects’ postural characteristics was performed before and after DI while standing with eyes open and closed on a soft and stable surface. The VMC analysis (Qualisys, Sweden) and the IMS system (Emerald, USA) were used to track the postural kinematic characteristics. VMC included 4 high speed infrared cameras Oqus 100. Reflective markers (10 mm in diameter) were attached to the subjects’ skin in the area of the forehead, left/right processus zygomaticus, acromion, trochanter major, epicondylus lateralis, malleolus lateralis, phalanx distalis I of the feet. IMS were located at these points: forehead, sternum, lower back, popliteal fossa, lateral ankle, phalanx distalis I of the feet. The angular velocities and acceleration were calculated in x, y, z coordinates. Due to post-analysis of the data was used in this study, markers and sensors matched only on the forehead and right and left phalanx distalis I. For the analysis, a mathematical algorithm was created that calculates the scattering ellipsoids using the three coordinates of the IMS and VMC markers, which include 90% of the data. Statistical analysis was performed using ANOVA test followed by post-hoc Bonferroni correction and it was performed to decompose any significant effects (α=0.05). Correlation was used only for matching markers and sensors. The results are presented as mean±SD. Results. The scatter of data obtained both by the method of VMC and by the method of IMS was quite large and, together with a small sample, no significant differences were obtained. Interesting tendencies were observed at the forehead point - the volumes of movements obtained using IMS and VMC cameras tended to increase. The opposite reaction was observed at the point of the loin - after the end of the DI, the values tended to decrease significantly. These observations were true for both closed and open eyes. The values on the soft platform were naturally higher than on the hard one, but they also fit into this pattern. However, when conducting a correlation analysis between the data of the two methods, reliable links were found. So, at the forehead point, the correlation was r = 0.6589, p = 0.0001 for a hard platform and r = 0.5983 p = 0.5983 for a soft one. For other survey points located on the large one, significant correlations were also obtained. Limitations: A small sample of the study allows only preliminary conclusions to be built. Since in this work previously obtained data were analyzed, it was not possible to fix all the markers and sensors at one point in order to carry out the correlation. Conclusion: Thus we can conclude that correlation between the data of IMS and data of VMC was revealed. The most pronounced changes were observed in the area of the fifth lumbar vertebra (only IMS), the area closest to the human center of gravity and in forehead (for VMC and IMS). The use of both methods expands the range of possibilities. The study is supported by the Russian Academy of Sciences (63.1).
Библиографическая ссылка:
Abu Sheli N.
, Ermakov I.
, Shishkin N.
, Amirova L.
, Tomilovskaya E.
Study of Postural Stability After 5-Day Dry Immersion with Two Posturology Methods: Comparative Analysis of Video Motion Capture and Inertial Motion Sensors
41st Annual the International Society of Gravitational Physiology Meeting 24-27 May 2021
Study of Postural Stability After 5-Day Dry Immersion with Two Posturology Methods: Comparative Analysis of Video Motion Capture and Inertial Motion Sensors
41st Annual the International Society of Gravitational Physiology Meeting 24-27 May 2021