Inertial technology has spread widely in biomechanics as a result of its comfortable use, easy adaptability to various motor tasks and to its low cost. In this regard the main objective of this study is related to the investigation about the validity of the measurements produced by the inertial sensor baiobit (Rivelo Srl, BTS Bioengineering Group) both in quantifying the cervical spine range of motion and in the broad field of stabilometry. A further objective is that to determine the optimal positioning of the sensor in relation to the motor task analyzed. In order to quantify baiobit measurement reliability, it was compared with the gold standard instrumentation: the optoelectronic system. 10 healthy subjects were recruited. They were asked to perform flexion-extension, lateral bending and rotation movements for assessing cervical spine mobility and to keep an upright posture for 30 seconds - first with their eyes open and then closed - to evaluate their postural stability. In the former task the sensor was placed firstly at the level of the second cervical vertebra, then in the forehead and finally on the external occipital protuberance. In the latter, the sensor was placed at the level of the fifth lumbar vertebra and then at the level of the first sacral vertebra. Trough proper elaboration of data, the outcome measures of interest were obtained. They are the maximum angles and relative mean angular velocities for each aforementioned cervical movement and the parameters related to the oscillation of the centre of mass for what concerns stabilometry: oscillation range and mean velocity, both in anteroposterior and mediolateral direction, path length and confidence ellipse area (95%). On this set of data, a statistical analysis was performed, calculating the intraclass correlation coefficient (ICC) and assessing data agreement by means of Bland-Altman plots. The results extracted show that baiobit measurements have a good overall reliability (0.75 < ICC < 0.9) in both motor tasks. Moreover, regarding the cervical spine mobility, an excellent reliability (ICC > 0.9) is found both in the flexion angle and in the right and left lateral bending. Evaluating each positioning individually, the external occipital protuberance shows a ICC always greater than 0.64, while the forehead and the second cervical vertebra both have poor reliability (ICC < 0.5) in calculating the mean angular velocities for right and left lateral bending movement. For what concerns stabilometry, placing the sensor at the level of the fifth lumbar vertebra produced a remarkably higher reliability (0.75 < ICC < 0.9) that placing it on the first sacral vertebra (0.5 < ICC < 0.75). These results allow to conclude, first and foremost, that the inertial sensor baiobit is able to give accurate and reliable data both when assessing the cervical range of motion and in conducting a balance analysis. Furthermore, the optimal positioning for the first of these two tasks is the external occipital protuberance, with a bias of 5° in detecting angles and a mean bias of 7 °/s when calculating mean angular velocities, whereas the fifth lumbar vertebra is the most favorable placement when dealing with a posturography investigation with a maximal bias of 1 mm.
La strumentazione inerziale si è diffusa largamente nell’ambito della biomeccanica grazie alla sua comodità d’uso, alla facile adattabilità a diversi task motori e al suo basso costo. In questo ambito si colloca lo scopo principale di questo studio, ovvero le misure di accuratezza del sensore inerziale baiobit (Rivelo Srl, BTS Bioengineering Group) nel quantificare il range of motion cervicale e nell’analisi posturografica. Ulteriore scopo è la determinazione del posizionamento ottimale del sensore in relazione al task analizzato. Per quantificare l’affidabilità delle misurazioni ottenute da baiobit, queste sono state confrontate con quelle ottenute dal gold standard di riferimento: il sistema optoelettronico. Sulla base di un campione di 10 soggetti sani, dunque, sono stati acquisiti i movimenti di flesso-estensione, piegamento laterale e rotazione per la cinematica del rachide cervicale, mentre, per la parte di equilibrio, si è acquisito il mantenimento della postura ortostatica per 30 secondi, prima ad occhi aperti e poi ad occhi chiusi. Nel primo caso sono stati testati i posizionamenti sulla seconda vertebra cervicale, sulla fronte e sulla protuberanza occipitale esterna; nel secondo, invece, sulla quinta vertebra lombare e sulla prima vertebra sacrale. Dall’elaborazione dei dati sono stati estratti i parametri d’interesse: angoli massimi e velocità angolari medie di flessione, estensione, rotazione destra, rotazione sinistra, piegamento laterale destro e piegamento laterale sinistro per quanto riguarda la mobilità cervicale, l’oscillazione del centro di massa e la relativa velocità media (in direzione anteroposteriore e mediolaterale), la lunghezza della traccia e l’area dell’ellisse di confidenza al 95% per la stabilometria. Su questi dati è stata condotta un’analisi statistica basata sul calcolo dei coefficienti di correlazione intraclasse e sui grafici di Bland-Altman. I risultati dell’analisi statistica mostrano come i dati ottenuti dal sensore inerziale baiobit abbiano una buona affidabilità complessiva (0.75 < ICC < 0.9) in entrambi i gesti motori analizzati. Nel caso della cinematica cervicale, inoltre, l’angolo di massima flessione e piegamento destro mostrano un’affidabilità eccellente (ICC > 0.9). Per quanto riguarda i singoli posizionamenti, la protuberanza occipitale esterna registra un ICC sempre maggiore di 0.64, a differenza della fronte e della seconda vertebra cervicale che presentano una scarsa affidabilità (ICC < 0.5) nelle velocità angolari medie di piegamento (destra e sinistra). Nel confronto tra la quinta vertebra lombare e la prima vertebra sacrale, invece, il primo posizionamento risulta nettamente migliore in termini di affidabilità (0.75 < ICC < 0.9) rispetto al secondo (0.5 < ICC < 0.75). Si conclude, quindi, che il sensore inerziale baiobit produce misure affidabili e accurate circa la mobilità cervicale e la capacità di mantenimento della postura ortostatica e che, inoltre, il posizionamento ottimo per la rilevazione della mobilità cervicale sia la protuberanza occipitale esterna, con un bias negli angoli massimi inferiore ai 5° e un bias medio nelle velocità angolari di circa 7°/s, mentre quello per l’analisi posturografica sia la quinta vertebra lombare, con bias medio nelle oscillazioni di circa 1 mm.
Analisi posturografica e misura della mobilità cervicale : validazione ed affidabilità del sensore inerziale baiobit
PALMIERI, MARTINA
2020/2021
Abstract
Inertial technology has spread widely in biomechanics as a result of its comfortable use, easy adaptability to various motor tasks and to its low cost. In this regard the main objective of this study is related to the investigation about the validity of the measurements produced by the inertial sensor baiobit (Rivelo Srl, BTS Bioengineering Group) both in quantifying the cervical spine range of motion and in the broad field of stabilometry. A further objective is that to determine the optimal positioning of the sensor in relation to the motor task analyzed. In order to quantify baiobit measurement reliability, it was compared with the gold standard instrumentation: the optoelectronic system. 10 healthy subjects were recruited. They were asked to perform flexion-extension, lateral bending and rotation movements for assessing cervical spine mobility and to keep an upright posture for 30 seconds - first with their eyes open and then closed - to evaluate their postural stability. In the former task the sensor was placed firstly at the level of the second cervical vertebra, then in the forehead and finally on the external occipital protuberance. In the latter, the sensor was placed at the level of the fifth lumbar vertebra and then at the level of the first sacral vertebra. Trough proper elaboration of data, the outcome measures of interest were obtained. They are the maximum angles and relative mean angular velocities for each aforementioned cervical movement and the parameters related to the oscillation of the centre of mass for what concerns stabilometry: oscillation range and mean velocity, both in anteroposterior and mediolateral direction, path length and confidence ellipse area (95%). On this set of data, a statistical analysis was performed, calculating the intraclass correlation coefficient (ICC) and assessing data agreement by means of Bland-Altman plots. The results extracted show that baiobit measurements have a good overall reliability (0.75 < ICC < 0.9) in both motor tasks. Moreover, regarding the cervical spine mobility, an excellent reliability (ICC > 0.9) is found both in the flexion angle and in the right and left lateral bending. Evaluating each positioning individually, the external occipital protuberance shows a ICC always greater than 0.64, while the forehead and the second cervical vertebra both have poor reliability (ICC < 0.5) in calculating the mean angular velocities for right and left lateral bending movement. For what concerns stabilometry, placing the sensor at the level of the fifth lumbar vertebra produced a remarkably higher reliability (0.75 < ICC < 0.9) that placing it on the first sacral vertebra (0.5 < ICC < 0.75). These results allow to conclude, first and foremost, that the inertial sensor baiobit is able to give accurate and reliable data both when assessing the cervical range of motion and in conducting a balance analysis. Furthermore, the optimal positioning for the first of these two tasks is the external occipital protuberance, with a bias of 5° in detecting angles and a mean bias of 7 °/s when calculating mean angular velocities, whereas the fifth lumbar vertebra is the most favorable placement when dealing with a posturography investigation with a maximal bias of 1 mm.| File | Dimensione | Formato | |
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Descrizione: File PDF Tesi Martina Palmieri
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https://hdl.handle.net/10589/173857