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sift:gait_measures:global_gait_asymmetry [2024/11/26 20:06] – wikisysopsift:gait_measures:global_gait_asymmetry [2024/12/17 20:22] (current) – [Mathematics of LGGA] wikisysop
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 The LGGA was developed to improve gait symmetry retraining methods and tests the effectiveness of classify induced asymmetry [1]. The original definition of the LGGA uses the three dimensional joint angles that are time normalized to left and right gait cycles, including the hip, knee, ankle, trunk wrt pelvis, and the pelvis wrt the lab [1]. The implementation of the LGGA in Sift follows the mathematical principals of Cabral et. al., however, allows users to specify the kinematic and kinetic measures to include. The LGGA was developed to improve gait symmetry retraining methods and tests the effectiveness of classify induced asymmetry [1]. The original definition of the LGGA uses the three dimensional joint angles that are time normalized to left and right gait cycles, including the hip, knee, ankle, trunk wrt pelvis, and the pelvis wrt the lab [1]. The implementation of the LGGA in Sift follows the mathematical principals of Cabral et. al., however, allows users to specify the kinematic and kinetic measures to include.
 +
 +----
  
 ==== Mathematics of LGGA ==== ==== Mathematics of LGGA ====
  
-the following equation considers xl and xr to be individual points of the left and right matching signal components. +The following equation considers xl and xr to be individual points of the left and right matching signal components. 
  
 All signals are time normalized to 101 points.  All signals are time normalized to 101 points. 
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 The following equation from Cabral et. al. has 15 individual GGA components (v15) in their asymmetry index [1]. The following equation from Cabral et. al. has 15 individual GGA components (v15) in their asymmetry index [1].
  
-{{:GGA_Equation.png?200}}+{{:GGA_Equation.png?300}} 
 + 
 +----
  
 ==== GGA in Sift ==== ==== GGA in Sift ====
  
 Here we will walk through an example of how to calculate GGA values on a dataset in Sift, and plot and export our results. This tutorial is a general example, and should be applicable to any gait data that has [[Visual3D:Documentation:Visual3D_Signal_Types:LINK_MODEL_BASED_Data_Type|LINK_MODEL_BASED]] signals and [[Visual3D:Tutorials:Events:Gait_Events|gait events]]. Here we will walk through an example of how to calculate GGA values on a dataset in Sift, and plot and export our results. This tutorial is a general example, and should be applicable to any gait data that has [[Visual3D:Documentation:Visual3D_Signal_Types:LINK_MODEL_BASED_Data_Type|LINK_MODEL_BASED]] signals and [[Visual3D:Tutorials:Events:Gait_Events|gait events]].
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 === Load Library === === Load Library ===
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 === LGGA Dialog === === LGGA Dialog ===
 {{ :gga_dlg_RON.png?400}} {{ :gga_dlg_RON.png?400}}
 +\\
 In the main toolbar, the Gait Scores icon {{:sift_gait_measures.png}} will open the dialog for selecting the GGA settings.  In the main toolbar, the Gait Scores icon {{:sift_gait_measures.png}} will open the dialog for selecting the GGA settings. 
  
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 The events are populated by Sift based on the event names in the underlying c3d files. Here we will select the LON and RON as the gait events for normalization. We then choose the signals to build our GGA components.  The events are populated by Sift based on the event names in the underlying c3d files. Here we will select the LON and RON as the gait events for normalization. We then choose the signals to build our GGA components. 
 +\\
 \\ \\
  
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 === Compute LGGA === === Compute LGGA ===
  
-After we are happy with the GGA/LGGA definition made in the dialog, we can choose to save these settings for future LGGA calculations by selecting the save icon on the top right of the LGGA Dialog. Previously defined settings can also be loaded here so users do not have to redefine the LGGA for multiple processing sessions. once computed, the LGGA1 and LGGA1_Components will appear in the groups window of Sift.+After we are happy with the GGA/LGGA definition made in the dialog, we can choose to save these settings for future LGGA calculations by selecting the save icon on the top right of the LGGA Dialog.  
 + 
 +Previously defined settings can also be loaded here so users do not have to redefine the LGGA for multiple processing sessions.  
 + 
 +once computed, the LGGA1 and LGGA1_Components will appear in the groups window of Sift.
  
 === View and Export Results === === View and Export Results ===
 +{{ :Export_GGA.png?300}}
 +We can view the LGGA results on the Sift [[Sift:Application:Explore_Page|Explore Page]] by plotting the LGGA or LGGA_Components group, depending on the kinds of comparisons we want to make. 
  
-We can view the LGGA results on the Sift [[Sift:Application:Explore_Page|Explore Page]] by plotting the LGGA or LGGA_Components group, depending on the kinds of comparisons we want to make. Here we have selected the LGGA1 group and all subgroups. Let's say we want to compare the asymmetry values between subjects, which are represented by their independent CMZ workspaces. I have selected plot workspace mean and standard deviation for my figure refinement. The LGGA scores computed for the c3d files are stored as metrics, and can be plotted as Metrics or Metric-Metric. To export figures, we can right click on the selected plot and hit [[Sift:Export:Export_Graphs_Dialog|export graph]]. To export our metric data results, we can select the [[Sift:Export:Export_Results_Dialog|export text results]] icon {{:sift_export_results.png}} in the [[Sift:Application:Toolbar|main toolbar]]. In this dialog we will change the default settings so that we export the workspace mean and standard deviation values of the LGGA results to reflect our plotted data.+On the figure below, we have selected the LGGA1 group and all subgroups. 
 + 
 +Let's say we want to compare the asymmetry values between subjects, which are represented by their independent CMZ workspaces. We have selected plot workspace mean and standard deviation for my figure refinement. The LGGA scores computed for the c3d files are stored as metrics, and can be plotted as Metrics or Metric-Metric.  
 + 
 +To export figures, we can right click on the selected plot and hit [[Sift:Export:Export_Graphs_Dialog|export graph]].  
 + 
 +To export our metric data results, we can select the [[Sift:Export:Export_Results_Dialog|export text results]] icon {{:sift_export_results.png?20}} in the [[Sift:Application:Toolbar|main toolbar]]. In this dialog we will change the default settings so that we export the workspace mean and standard deviation values of the LGGA results to reflect our plotted data. 
 + 
 +{{:GGAResults.png?}}
  
-{{:GGAResults.png}} 
  
-{{:Export_GGA.png}} 
  
 \\ \\
  
 +
 +----
  
 ==== References ==== ==== References ====
  
-<code>+
 [1] Cabral S., Resende R.A., Clansey A.C., Deluzio K.J., Selbie, W.S., Veloso A.P., "A Global Gait Asymmetry Index", Journal of Applied Biomechanics, 2016, 171-177. (https://pubmed.ncbi.nlm.nih.gov/26502455/) [1] Cabral S., Resende R.A., Clansey A.C., Deluzio K.J., Selbie, W.S., Veloso A.P., "A Global Gait Asymmetry Index", Journal of Applied Biomechanics, 2016, 171-177. (https://pubmed.ncbi.nlm.nih.gov/26502455/)
-</code>+
  
  
  
sift/gait_measures/global_gait_asymmetry.1732651587.txt.gz · Last modified: 2024/11/26 20:06 by wikisysop