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Optimal markers’ placement on the thorax for clinical gait analysis—A preliminary study
S54
Abstracts / Gait & Posture 30S (2009) S1–S153
O77
References
Optimal markers’ placement on the thorax for clinical gait analysis—A preliminary study
[1] [2] [3] [4]
Stephane Armand 1,∗ , Morgan Richard Baker 2
Sangeux 2 , Pierre
Hoffmeyer 1 ,
1
Geneva University Hospitals and Geneva University, Geneva, Switzerland 2 Murdoch Childrens Research Institute, Melbourne, Australia Summary This study aims to determine the optimal markers’ placement on the thorax to measure the 3D kinematic in clinical gait analysis. The model defined by the markers placed on T2, T10 and sternal manubrium presents less error than literature models.
Gutierrez EM, et al. Gait Posture 2003;18:37–46. Nguyen TC, Baker R. Clin Biomech 2004;19:1060–5. Starr R, et al. Gait Posture 2000;11:149. Challis JH. J Biomech 1995;28:733–7.
doi:10.1016/j.gaitpost.2009.08.081 O78 The development of a non-invasive, in vivo method of measuring subtalar joint movement during the contact phase of walking Ivan Birch University of Brighton, Eastbourne, East Sussex, United Kingdom
Conclusions Based on these preliminary results, the model defined by the markers placed on T2, T10 and sternal manubrium should be used to quantify the movements of the thorax for clinical gait analysis.
Summary The results of this investigation into the use of the CODA MPX30 to measure the movement of the subtalar joint during the contact phase of gait showed the methodology to produce results comparable to those produced by previously used invasive methodologies.
Introduction Patients with gait disorders present specific deformities and dysfunctions of the locomotor system that require specific strategies to keep their gait as efficient as possible. In clinical gait analysis, the upper body is often considered as the passenger part during walking and has not been investigated extensively. However, this is the heaviest part of the body and numerous compensatory mechanisms occur on this part. Before to study these compensations, we need to define the best way to quantify the movements of the thorax. Therefore, the objective of this preliminary study is to determine the most suitable model for calculating thorax kinematics during clinical gait analysis.
Conclusions The results indicated that the novel measurement strategy described in this study could be the basis of a viable non-invasive, in vivo method of assessing the movement of the subtalar joint during the contact phase of walking.
Patients/materials and methods Three subjects have performed two series of movements (arm, head, trunk) with large amplitude, during standing position and walking. Reflective markers were taped one the thorax (C7, T2, T4, T6, T8, T10, T12, manubrium, sternum, clavicules) and their 3D positions were captured with an opto-electronic system (VICON Mx40 – 10 cameras). Each combination of 3 or 4 markers have been tested and compared with the literature models [1–3]. The global error of each model was computed with the estimated position of the markers considering the thorax segment as a solid segment (Challis method [4]). Angles for each model have been computed according to ISB recommendations and Baker rotation sequences. The model with the minimum global error is used as reference to calculate the RMS error for computed angles between this model and literature models. Results The best model was defined by the markers T2, T10 and sternal manubrium with a RMS error of 6.2 mm. The literature models showed an error ranging from 6.7 to 11.8 mm. These errors generated errors on the thorax kinematics estimated between 2.2◦ and 17.8◦ . Discussion This preliminary study showed a non-negligible error linked with the deformation of the thorax segment and with the skin artefacts. One should be aware that literature models of the thorax present errors that could have an influence on the interpretation on clinical gait analysis results.
Introduction Movement at the subtalar joint is believed to be a fundamental contributor to foot function during walking. The complex structure and movement, and inaccessibility of the joint have resulted in limited published data with which to substantiate or refute theories regarding its movement during walking. The in vivo movement of the subtalar joint has been studied in a small number of subjects using invasive techniques. However, the variability in subtalar joint structure and function shown by these studies and previous in vitro studies, emphasises the need for the development of a viable noninvasive, in vivo method of measuring subtalar joint movement. Method This study investigated the use of the CODA MPX30 three dimensional motion analysis system and a purpose designed marker placement model as a strategy for measuring the movement of the subtalar joint during the contact phase of walking. The study was undertaken in four stages: an in vitro investigation into the reliability of the CODA; an X-ray investigation into the effect of skin movement on marker placement; an in vivo single subject study of the reliability of the methodology and a multiple subject trial of the methodology. Results The in vitro reliability of the measurement strategy, tested using 50 independently collected data sets, showed that estimations of marker position to varied by less than 2 mm and estimations of inter-segmental angles by less than 2◦ . The investigation into the effect of skin movement on surface marker location showed that although markers moved relative to the bones, angular orientations calculated from marker positions were representative of those calculated directly from the bones, frontal plane angles being over estimated by up to 5◦ while sagittal and transverse plane angles were underestimated by up to 1◦ . The in vivo reliability of the measurement strategy was shown to be good and the results produced were shown to be similar to those produced by invasive in vivo techniques. The multiple subject trial also produced results similar to those produced by invasive in vivo techniques.
Abstracts / Gait & Posture 30S (2009) S1–S153
O77
References
Optimal markers’ placement on the thorax for clinical gait analysis—A preliminary study
[1] [2] [3] [4]
Stephane Armand 1,∗ , Morgan Richard Baker 2
Sangeux 2 , Pierre
Hoffmeyer 1 ,
1
Geneva University Hospitals and Geneva University, Geneva, Switzerland 2 Murdoch Childrens Research Institute, Melbourne, Australia Summary This study aims to determine the optimal markers’ placement on the thorax to measure the 3D kinematic in clinical gait analysis. The model defined by the markers placed on T2, T10 and sternal manubrium presents less error than literature models.
Gutierrez EM, et al. Gait Posture 2003;18:37–46. Nguyen TC, Baker R. Clin Biomech 2004;19:1060–5. Starr R, et al. Gait Posture 2000;11:149. Challis JH. J Biomech 1995;28:733–7.
doi:10.1016/j.gaitpost.2009.08.081 O78 The development of a non-invasive, in vivo method of measuring subtalar joint movement during the contact phase of walking Ivan Birch University of Brighton, Eastbourne, East Sussex, United Kingdom
Conclusions Based on these preliminary results, the model defined by the markers placed on T2, T10 and sternal manubrium should be used to quantify the movements of the thorax for clinical gait analysis.
Summary The results of this investigation into the use of the CODA MPX30 to measure the movement of the subtalar joint during the contact phase of gait showed the methodology to produce results comparable to those produced by previously used invasive methodologies.
Introduction Patients with gait disorders present specific deformities and dysfunctions of the locomotor system that require specific strategies to keep their gait as efficient as possible. In clinical gait analysis, the upper body is often considered as the passenger part during walking and has not been investigated extensively. However, this is the heaviest part of the body and numerous compensatory mechanisms occur on this part. Before to study these compensations, we need to define the best way to quantify the movements of the thorax. Therefore, the objective of this preliminary study is to determine the most suitable model for calculating thorax kinematics during clinical gait analysis.
Conclusions The results indicated that the novel measurement strategy described in this study could be the basis of a viable non-invasive, in vivo method of assessing the movement of the subtalar joint during the contact phase of walking.
Patients/materials and methods Three subjects have performed two series of movements (arm, head, trunk) with large amplitude, during standing position and walking. Reflective markers were taped one the thorax (C7, T2, T4, T6, T8, T10, T12, manubrium, sternum, clavicules) and their 3D positions were captured with an opto-electronic system (VICON Mx40 – 10 cameras). Each combination of 3 or 4 markers have been tested and compared with the literature models [1–3]. The global error of each model was computed with the estimated position of the markers considering the thorax segment as a solid segment (Challis method [4]). Angles for each model have been computed according to ISB recommendations and Baker rotation sequences. The model with the minimum global error is used as reference to calculate the RMS error for computed angles between this model and literature models. Results The best model was defined by the markers T2, T10 and sternal manubrium with a RMS error of 6.2 mm. The literature models showed an error ranging from 6.7 to 11.8 mm. These errors generated errors on the thorax kinematics estimated between 2.2◦ and 17.8◦ . Discussion This preliminary study showed a non-negligible error linked with the deformation of the thorax segment and with the skin artefacts. One should be aware that literature models of the thorax present errors that could have an influence on the interpretation on clinical gait analysis results.
Introduction Movement at the subtalar joint is believed to be a fundamental contributor to foot function during walking. The complex structure and movement, and inaccessibility of the joint have resulted in limited published data with which to substantiate or refute theories regarding its movement during walking. The in vivo movement of the subtalar joint has been studied in a small number of subjects using invasive techniques. However, the variability in subtalar joint structure and function shown by these studies and previous in vitro studies, emphasises the need for the development of a viable noninvasive, in vivo method of measuring subtalar joint movement. Method This study investigated the use of the CODA MPX30 three dimensional motion analysis system and a purpose designed marker placement model as a strategy for measuring the movement of the subtalar joint during the contact phase of walking. The study was undertaken in four stages: an in vitro investigation into the reliability of the CODA; an X-ray investigation into the effect of skin movement on marker placement; an in vivo single subject study of the reliability of the methodology and a multiple subject trial of the methodology. Results The in vitro reliability of the measurement strategy, tested using 50 independently collected data sets, showed that estimations of marker position to varied by less than 2 mm and estimations of inter-segmental angles by less than 2◦ . The investigation into the effect of skin movement on surface marker location showed that although markers moved relative to the bones, angular orientations calculated from marker positions were representative of those calculated directly from the bones, frontal plane angles being over estimated by up to 5◦ while sagittal and transverse plane angles were underestimated by up to 1◦ . The in vivo reliability of the measurement strategy was shown to be good and the results produced were shown to be similar to those produced by invasive in vivo techniques. The multiple subject trial also produced results similar to those produced by invasive in vivo techniques.