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Gait symmetry and regularity in transfemoral amputees assessed by trunk accelerations.

Tura A, Raggi M, Rocchi L, Cutti AG, Chiari L - J Neuroeng Rehabil (2010)

Bottom Line: Indices of step and stride regularity (Ad1 and Ad2, respectively) were obtained by the autocorrelation coefficients computed from the three acceleration components.Step and stride durations were calculated from the plantar pressure data and were used to compute two reference indices (SI1 and SI2) for step and stride regularity.The use of a simple accelerometer, whose components can be analyzed by the autocorrelation function method, is adequate for the assessment of gait symmetry and regularity in transfemoral amputees.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronics, Computer Science and Systems, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.

ABSTRACT

Background: The aim of this study was to evaluate a method based on a single accelerometer for the assessment of gait symmetry and regularity in subjects wearing lower limb prostheses.

Methods: Ten transfemoral amputees and ten healthy control subjects were studied. For the purpose of this study, subjects wore a triaxial accelerometer on their thorax, and foot insoles. Subjects were asked to walk straight ahead for 70 m at their natural speed, and at a lower and faster speed. Indices of step and stride regularity (Ad1 and Ad2, respectively) were obtained by the autocorrelation coefficients computed from the three acceleration components. Step and stride durations were calculated from the plantar pressure data and were used to compute two reference indices (SI1 and SI2) for step and stride regularity.

Results: Regression analysis showed that both Ad1 well correlates with SI1 (R2 up to 0.74), and Ad2 well correlates with SI2 (R2 up to 0.52). A ROC analysis showed that Ad1 and Ad2 has generally a good sensitivity and specificity in classifying amputee's walking trial, as having a normal or a pathologic step or stride regularity as defined by means of the reference indices SI1 and SI2. In particular, the antero-posterior component of Ad1 and the vertical component of Ad2 had a sensitivity of 90.6% and 87.2%, and a specificity of 92.3% and 81.8%, respectively.

Conclusions: The use of a simple accelerometer, whose components can be analyzed by the autocorrelation function method, is adequate for the assessment of gait symmetry and regularity in transfemoral amputees.

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Related in: MedlinePlus

Regression plots for Ad2V, Ad2ML, Ad2AP against SI2. Solid circles: AMPs; empty circles: CTRLs. Blue, green, red symbols represent slow, natural, fast walks, respectively. Regression related to all tests together is significant for each Ad2 index (R2 = 0.524, R2 = 0.177, R2 = 0.266, respectively, P < 0.0001). Regression lines are Y = 0.965+0.028·X, Y = 0.972+0.020·X, Y = 0.969+0.024·X, respectively.
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Figure 4: Regression plots for Ad2V, Ad2ML, Ad2AP against SI2. Solid circles: AMPs; empty circles: CTRLs. Blue, green, red symbols represent slow, natural, fast walks, respectively. Regression related to all tests together is significant for each Ad2 index (R2 = 0.524, R2 = 0.177, R2 = 0.266, respectively, P < 0.0001). Regression lines are Y = 0.965+0.028·X, Y = 0.972+0.020·X, Y = 0.969+0.024·X, respectively.

Mentions: Figures 3 and 4 report the results of the univariate regression analysis between accelerometry-based and pressure-based indices. When considering all the test sessions for all the subjects (AMPs+CTRLs) we found a good level of association between the indices. In particular, the highest correlations were found between SI1 and Ad1AP (R2 = 0.735, P < 0.0001), and between SI2 and Ad2V (R2 = 0.524, P < 0.0001). Therefore, any one of the three Ad1 indices may be considered a good surrogate of SI1 for the assessment of step regularity, and the same states for Ad2 indices for the assessment of stride regularity. Values of R2 (and corresponding P) for all the indices are listed in captions of Figures 3 and 4.


Gait symmetry and regularity in transfemoral amputees assessed by trunk accelerations.

Tura A, Raggi M, Rocchi L, Cutti AG, Chiari L - J Neuroeng Rehabil (2010)

Regression plots for Ad2V, Ad2ML, Ad2AP against SI2. Solid circles: AMPs; empty circles: CTRLs. Blue, green, red symbols represent slow, natural, fast walks, respectively. Regression related to all tests together is significant for each Ad2 index (R2 = 0.524, R2 = 0.177, R2 = 0.266, respectively, P < 0.0001). Regression lines are Y = 0.965+0.028·X, Y = 0.972+0.020·X, Y = 0.969+0.024·X, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2821382&req=5

Figure 4: Regression plots for Ad2V, Ad2ML, Ad2AP against SI2. Solid circles: AMPs; empty circles: CTRLs. Blue, green, red symbols represent slow, natural, fast walks, respectively. Regression related to all tests together is significant for each Ad2 index (R2 = 0.524, R2 = 0.177, R2 = 0.266, respectively, P < 0.0001). Regression lines are Y = 0.965+0.028·X, Y = 0.972+0.020·X, Y = 0.969+0.024·X, respectively.
Mentions: Figures 3 and 4 report the results of the univariate regression analysis between accelerometry-based and pressure-based indices. When considering all the test sessions for all the subjects (AMPs+CTRLs) we found a good level of association between the indices. In particular, the highest correlations were found between SI1 and Ad1AP (R2 = 0.735, P < 0.0001), and between SI2 and Ad2V (R2 = 0.524, P < 0.0001). Therefore, any one of the three Ad1 indices may be considered a good surrogate of SI1 for the assessment of step regularity, and the same states for Ad2 indices for the assessment of stride regularity. Values of R2 (and corresponding P) for all the indices are listed in captions of Figures 3 and 4.

Bottom Line: Indices of step and stride regularity (Ad1 and Ad2, respectively) were obtained by the autocorrelation coefficients computed from the three acceleration components.Step and stride durations were calculated from the plantar pressure data and were used to compute two reference indices (SI1 and SI2) for step and stride regularity.The use of a simple accelerometer, whose components can be analyzed by the autocorrelation function method, is adequate for the assessment of gait symmetry and regularity in transfemoral amputees.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronics, Computer Science and Systems, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.

ABSTRACT

Background: The aim of this study was to evaluate a method based on a single accelerometer for the assessment of gait symmetry and regularity in subjects wearing lower limb prostheses.

Methods: Ten transfemoral amputees and ten healthy control subjects were studied. For the purpose of this study, subjects wore a triaxial accelerometer on their thorax, and foot insoles. Subjects were asked to walk straight ahead for 70 m at their natural speed, and at a lower and faster speed. Indices of step and stride regularity (Ad1 and Ad2, respectively) were obtained by the autocorrelation coefficients computed from the three acceleration components. Step and stride durations were calculated from the plantar pressure data and were used to compute two reference indices (SI1 and SI2) for step and stride regularity.

Results: Regression analysis showed that both Ad1 well correlates with SI1 (R2 up to 0.74), and Ad2 well correlates with SI2 (R2 up to 0.52). A ROC analysis showed that Ad1 and Ad2 has generally a good sensitivity and specificity in classifying amputee's walking trial, as having a normal or a pathologic step or stride regularity as defined by means of the reference indices SI1 and SI2. In particular, the antero-posterior component of Ad1 and the vertical component of Ad2 had a sensitivity of 90.6% and 87.2%, and a specificity of 92.3% and 81.8%, respectively.

Conclusions: The use of a simple accelerometer, whose components can be analyzed by the autocorrelation function method, is adequate for the assessment of gait symmetry and regularity in transfemoral amputees.

Show MeSH
Related in: MedlinePlus