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22.32 Accelerometric assessment of gait parameters inorthopaedic and stroke patients
Chapter 22. Techniques' and methods' of posture and gait analysis
[•]
Changes in lower limb joint contributions to energy generation and absorption during gait related to cadence and laterality
[2~
S151
Stabilometric testing of a postural system
V.I. Usatchev 1, S.S. Sliva2, VE. Belyaev2. 1Saint-Petersburg Medical
academy, 2Taganrog University of Radio Engineering, Russia L. Teixeira-Salmela, S. Nadeau, M.H. Milot, D. Gravel, L.E RequiSo.
F~cole de rEadaptation, UniversitE de MontrEal et Centre de recherche interdisciplinaire en rEadaptation (CRIR), Institut de rEadaptation de MontrEal, Canada Introduction: Increases in gait speed imply additional energy
generation and absorption at the three lower extremity joints, as well as changes in their relative contributions. The aim of this study was to precisely quantify the relative contribution of each lower extremity joint to the total mechanical work during gait in relation to laterality and cadence. Fourteen healthy subjects were evaluated walking at natural and imposed cadences of 60, 80, and 120 steps/min. Methods: A 3-D Optotrak system with AMTI force platforms, and related software were used to obtain net joint powers and mechanical work generated and absorbed at the hip, knee, and ankle. The relative contributions to total positive and negative work across the four cadences were calculated for each joint. A three within-factor repeated measures ANOVA followed by contrasts was used to determine effects of laterality, joint, and cadence. Results: Mechanical work, power, and the contributions of individual joints to the total energy generated and absorbed was influenced by walking cadence, independent of laterality. The respective ankle, knee and hip contributions to the sum of the total energy generated and absorbed were 56%, 19%, and 26% at the lowest cadence and 35%, 31%, and 34% at the highest. No significant main or interaction effects for laterality were detected. Conclusions: The results provided reference values of relative energy joint contributions at different cadences for healthy subjects, which can be used to identify intra and inter-limb compensations for the production and absorption of energy during gait in individuals with locomotor disorders.
Introduction: The modern computer stabilometry development level has shown its unquestionable value for use in posturology. However, it should also be noted that there are many more problems than positively solved questions in stabilometry. These include a problem of norms, a problem of the choice of informative parameters for statokinesigram evaluation, a problem of flexible adaptation of stabilographs to the needs of a specific user and many others. Methodology: The stabilometric testing of all postural system sensors was carried out according to the original program consisting of 15 tests (visual, oculomotor, proprioceptive, dentimaxillary and podal tests). The analysis of statokinesigrams on the basis of a vector analysis enabled all the investigation to be carried out during 5 minutes. After the end of testing a summary of stabilometric indices was created which consisted of traditional indices, vector analysis indices and spectral analysis indices. Later this summary was converted into graphic form. Results: A study conducted on 30 healthy volunteers several times a day at 2-hour intervals during a week showed the instability of most stabilometric indices. Comparison of indices was made not on the whole for all the members of the group but individually for each person. Only the pressure center coordinates, equilibrium function quality coefficient (EFQC), sharp travel direction change coefficient (STDCC) and the angular acceleration asymmetry coefficient were stable. The most reliable index was that of pressure center coordinates on a frontal plane. Discussion and conclusions: The initial results were discouraging. Later we thought that it might be good to obtain such results since the number of informative parameters was minimized in this way and that it is quite enough to rely on a pressure center displacement analysis on a frontal plane, Romberg's factor and a plantar coefficient in testing a postural system.
[2~ [2~
Accelerometric assessment of gait parameters in orthopaedic and stroke patients
New gait analysis method based on three accelerometers fixed to the sacrum
R.C. van Lummel 1, S.C. Heikens 1, R.M.A. van der Slikke 1, R Thoumie 2. 1McRoberts BV, The Hague, The Netherlands'," 2Hopital
Rothschild, Paris', France R Thoumie 1, R.C. van Lummel 2, S.C. Heikens2, R.M.A. van der
Slikke 2. 1H@ital Rothschild, H@ital Rothschild, APHP, INSERM
Introduction: In 2003, a new ambulatory, modular and wireless
U731, Paris', France; :McRoberts BV, The Hague, The Netherlands'
gait analysis system (DynaPort MiniM°d) has been developed for use in applied clinical research and clinical practice. The equipment consists of a small (6.2 x 6.5 x 1.4 cm) measurement system (fixed to the sacrum). Method: Raw signals are divided up into single steps [1] and then normalized to calculate mean acceleration graphs and standard deviations for left and right steps for all three signals and the vector. Angles of the sacrum, acceleration amplitudes, standard deviations and the area under the curve are calculated using these mean signals. Mean acceleration signals (x, y, z, and xyz vector) are used as a template to compare step to step differences in the pattern, and to compute RMS. Results: Four categories of gait quality have been selected to represent quality of walking: speed, left-right asymmetry, step to step irregularity and efficiency. A selection of parameters was made, and assigned to one of the 4 categories. For the selected parameters, normbased scoring was used to calculate Z scores, by subtracting mean parameter values of the control group from each patient's value and dividing the difference by the standard deviation of the control group. Discussion and Conclusion: The DynaPort MmiM°d is easy to use, assessment can be done at different locations and takes just a little longer than patient's walking time. First reactions of clinicians to the clinical gait reports are positive.
Introduction: The aim of this study was to show the ease of use of
the DynaPort MiniM°d to measure and analyse gait parameters and to find out which parameters are useful for follow-up support during the rehabilitation of the patients. Methods: The measurement system (6.2x6.5xl.4cm) is fixed around the waist of the patient with a belt. Acceleration sensors measure in the walking direction (x), in the vertical direction (y) and in the left-right direction (z). Two walking trajectories (>10m) are assessed, marked and labeled. Walking parameters are calculated and devided up in 4 categories: 1) speed and step parameters; 2) let right asymmetry of step times, accelerations and vertical displacement; 3) irregularity of step times and accelerations and 4) inefficiency of acceleration amplitudes and acceleration integral. Results: 44 Healthy persons (mean age 69.6), 12 joint replacement patients (mean age 72.1) and 11 stroke patients (mean age 60.4) are assessed. Joint replacement and stroke patients walk slower, more asymmetric and more irregular than healthy control persons. Stroke patients are more inefficient than control persons and orthopaedic patients. Discussion and Conclusion: The DynaPort MmiM°d is an easy to use measurement system and provide changes in gait parameters which makes clinical application feasible for evaluation and follow-up of patients after stroke or arthroplasty.
References [1] Zijlstra et al., Gait & Posture, 2003; 18(2):1 10.
[•]
Changes in lower limb joint contributions to energy generation and absorption during gait related to cadence and laterality
[2~
S151
Stabilometric testing of a postural system
V.I. Usatchev 1, S.S. Sliva2, VE. Belyaev2. 1Saint-Petersburg Medical
academy, 2Taganrog University of Radio Engineering, Russia L. Teixeira-Salmela, S. Nadeau, M.H. Milot, D. Gravel, L.E RequiSo.
F~cole de rEadaptation, UniversitE de MontrEal et Centre de recherche interdisciplinaire en rEadaptation (CRIR), Institut de rEadaptation de MontrEal, Canada Introduction: Increases in gait speed imply additional energy
generation and absorption at the three lower extremity joints, as well as changes in their relative contributions. The aim of this study was to precisely quantify the relative contribution of each lower extremity joint to the total mechanical work during gait in relation to laterality and cadence. Fourteen healthy subjects were evaluated walking at natural and imposed cadences of 60, 80, and 120 steps/min. Methods: A 3-D Optotrak system with AMTI force platforms, and related software were used to obtain net joint powers and mechanical work generated and absorbed at the hip, knee, and ankle. The relative contributions to total positive and negative work across the four cadences were calculated for each joint. A three within-factor repeated measures ANOVA followed by contrasts was used to determine effects of laterality, joint, and cadence. Results: Mechanical work, power, and the contributions of individual joints to the total energy generated and absorbed was influenced by walking cadence, independent of laterality. The respective ankle, knee and hip contributions to the sum of the total energy generated and absorbed were 56%, 19%, and 26% at the lowest cadence and 35%, 31%, and 34% at the highest. No significant main or interaction effects for laterality were detected. Conclusions: The results provided reference values of relative energy joint contributions at different cadences for healthy subjects, which can be used to identify intra and inter-limb compensations for the production and absorption of energy during gait in individuals with locomotor disorders.
Introduction: The modern computer stabilometry development level has shown its unquestionable value for use in posturology. However, it should also be noted that there are many more problems than positively solved questions in stabilometry. These include a problem of norms, a problem of the choice of informative parameters for statokinesigram evaluation, a problem of flexible adaptation of stabilographs to the needs of a specific user and many others. Methodology: The stabilometric testing of all postural system sensors was carried out according to the original program consisting of 15 tests (visual, oculomotor, proprioceptive, dentimaxillary and podal tests). The analysis of statokinesigrams on the basis of a vector analysis enabled all the investigation to be carried out during 5 minutes. After the end of testing a summary of stabilometric indices was created which consisted of traditional indices, vector analysis indices and spectral analysis indices. Later this summary was converted into graphic form. Results: A study conducted on 30 healthy volunteers several times a day at 2-hour intervals during a week showed the instability of most stabilometric indices. Comparison of indices was made not on the whole for all the members of the group but individually for each person. Only the pressure center coordinates, equilibrium function quality coefficient (EFQC), sharp travel direction change coefficient (STDCC) and the angular acceleration asymmetry coefficient were stable. The most reliable index was that of pressure center coordinates on a frontal plane. Discussion and conclusions: The initial results were discouraging. Later we thought that it might be good to obtain such results since the number of informative parameters was minimized in this way and that it is quite enough to rely on a pressure center displacement analysis on a frontal plane, Romberg's factor and a plantar coefficient in testing a postural system.
[2~ [2~
Accelerometric assessment of gait parameters in orthopaedic and stroke patients
New gait analysis method based on three accelerometers fixed to the sacrum
R.C. van Lummel 1, S.C. Heikens 1, R.M.A. van der Slikke 1, R Thoumie 2. 1McRoberts BV, The Hague, The Netherlands'," 2Hopital
Rothschild, Paris', France R Thoumie 1, R.C. van Lummel 2, S.C. Heikens2, R.M.A. van der
Slikke 2. 1H@ital Rothschild, H@ital Rothschild, APHP, INSERM
Introduction: In 2003, a new ambulatory, modular and wireless
U731, Paris', France; :McRoberts BV, The Hague, The Netherlands'
gait analysis system (DynaPort MiniM°d) has been developed for use in applied clinical research and clinical practice. The equipment consists of a small (6.2 x 6.5 x 1.4 cm) measurement system (fixed to the sacrum). Method: Raw signals are divided up into single steps [1] and then normalized to calculate mean acceleration graphs and standard deviations for left and right steps for all three signals and the vector. Angles of the sacrum, acceleration amplitudes, standard deviations and the area under the curve are calculated using these mean signals. Mean acceleration signals (x, y, z, and xyz vector) are used as a template to compare step to step differences in the pattern, and to compute RMS. Results: Four categories of gait quality have been selected to represent quality of walking: speed, left-right asymmetry, step to step irregularity and efficiency. A selection of parameters was made, and assigned to one of the 4 categories. For the selected parameters, normbased scoring was used to calculate Z scores, by subtracting mean parameter values of the control group from each patient's value and dividing the difference by the standard deviation of the control group. Discussion and Conclusion: The DynaPort MmiM°d is easy to use, assessment can be done at different locations and takes just a little longer than patient's walking time. First reactions of clinicians to the clinical gait reports are positive.
Introduction: The aim of this study was to show the ease of use of
the DynaPort MiniM°d to measure and analyse gait parameters and to find out which parameters are useful for follow-up support during the rehabilitation of the patients. Methods: The measurement system (6.2x6.5xl.4cm) is fixed around the waist of the patient with a belt. Acceleration sensors measure in the walking direction (x), in the vertical direction (y) and in the left-right direction (z). Two walking trajectories (>10m) are assessed, marked and labeled. Walking parameters are calculated and devided up in 4 categories: 1) speed and step parameters; 2) let right asymmetry of step times, accelerations and vertical displacement; 3) irregularity of step times and accelerations and 4) inefficiency of acceleration amplitudes and acceleration integral. Results: 44 Healthy persons (mean age 69.6), 12 joint replacement patients (mean age 72.1) and 11 stroke patients (mean age 60.4) are assessed. Joint replacement and stroke patients walk slower, more asymmetric and more irregular than healthy control persons. Stroke patients are more inefficient than control persons and orthopaedic patients. Discussion and Conclusion: The DynaPort MmiM°d is an easy to use measurement system and provide changes in gait parameters which makes clinical application feasible for evaluation and follow-up of patients after stroke or arthroplasty.
References [1] Zijlstra et al., Gait & Posture, 2003; 18(2):1 10.