Step 5 – Subject and Session details

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Step 5 – Subject and Session details

Make sure the correct patient's details are used.

Add a new patient or select an existing patient from the data tree.

Enter patient details:
Click Add and add a Clinical Gait Session:
Update the session details for the patient.

The following fields are relevant for the data processing:
- Weight: body weight is used to normalize joint moment and power curves. Note: By default we attempt to calculate the body weight from vertical forces applied in static trial. If there are no forces found in the active static trial or sum of forces is less then $force_threshold * 10, the body weight set by user as PAF field is used instead ($force_threshold can be set in [your project]\Templates\settings.php).
- Ankle width left/right: medio-lateral width of the ankle at the malleoli; used in the definition of the ankle joint centre. Required only for legacy Conventional Gait Model (CGM) if medial ankle marker does not exist and for CGM2 version 1.0 and 1.1, optional for other marker sets and markerless. Not used for model calculations when optional. More about biomechanics model in Appendix F.
- Knee width left/right: medio-lateral width of the knee at the epicondyles; used in the definition of the knee joint centre. Required only for legacy Conventional Gait Model (CGM) if medial knee marker does not exist and for CGM2 version 1.0, optional for other marker sets and markerless. Not used for model calculations when optional. More about biomechanics model in Appendix F.
- Leg length: (required for CGM2, optional for other marker sets and markerless) It is used for the normalisation of tempo-spatial data. If value is set to zero (default) length is taken from the marker distance from the ASIS to medial malleolus. For patients that are unable to stand with the knees fully extended in the static trial (e.g. fixed flexion contractures), the value needs to be measured and entered manually.
Create a sub-session: each condition that you are testing within a session requires a separate sub-sessions (e.g. barefoot, with shoes, etc.). When just testing a single condition, simply create a single sub-session only.

When creating a sub-session, you decide which marker set will be used and whether it is a full-body or lower-body session:
- CAST session
- CGM session
- CGM2 session
- Gait Overlay session
- IOR session
- Markerless session
- Stabilometry session
- Static Overlay session
- Video overlay session stores videos without any additional analysis available.
Enter the sub-session details:

CGM2 sub-session:

The following fields are relevant for the data processing:

Note that not all fields are available for all sub-session types.
- Test condition: used to identify different conditions when comparing sub-sessions. Enter a word or phrase that describes the test condition (barefoot, with shoes, with orthosis, ...).
- Ankle width left/right: see session details above (relevant for Conventional Gait Model only).
- Knee width left/right: see session details above (relevant for Conventional Gait Model only).
- Leg length left/right: see session details above.
- Event mode:
  
  Event modes are not available for CGM2. Only 'Multiple forceplates' and 'Single forceplate' event modes work for Gait Overlay session.
  - Manual: events must be identified by hand in QTM, useful if no force plates are present or if pathological gait makes it impossible to use automatic event recognition in Visual3D.
  - Multiple forceplates (default): Visual3D will use automatic event recognition for both legs). By default, the reports show all gait cycles in consistency graph. For Word report there is an option to delete all events prior to the first force plate contact and after one stride for each body side. To turn this on, open the file [project folder]\Templates\settings.php and set the setting for '$auto_range' to 'true'.
  - Single forceplate: Visual3D will prompt the user to select one template file for the right and left leg. In the template file, the corresponding foot must make contact with the force plate.
  - No forceplate (using template file): will prompt the user for one template file for the right and left leg. In the template file, you must manually add a single left heel strike (LHS), left toe off (LTO), right heel strike (RHS) and right toe off (RTO) event before executing the analysis. It is possible to use the same template file for left and right or to use two different files.
  - No forceplate (automatic): uses relations between pelvis and heel to detect heel strikes and toe off. Note: this event mode may not work properly with pathological gait. For pathological gait, “No forceplate (using template file)” should be preferred instead. The algorithm that is used is described in this paper (Coordinate Based Algorithm): Zeni JA, Richards JG, Higginson JS (2008) Two simple methods for determining gait events during treadmill and overground walking using kinematic data. Gait & Posture 27, 710-714
  - Instrumented treadmill (split belt): will detect events based on the force data for all steps. Requires (1) that the treadmill speed is entered by the user for each recorded file and (2) that the feet are on separate belts of the treadmill at all times. If both feet are on the same belt, the force assignment to the feet will be incorrect and events cannot be detected.
  - Instrumented treadmill (single belt): events are detected based on the acceleration of the COP. Requires that treadmill speed is entered by the user for each dynamic trial. Inverse dynamics results are only valid while a single foot is in contact with the treadmill.
  - Instrumented treadmill (manual): can be used when event detection from forces cannot be used. It expects LHS/RHS/LTO/RTO events to be set manually in QTM for each trial.
  - Instrumented treadmill (automatic): can be used when event detection from forces cannot be used. It is using Zeni (2008) algorithm and defects event automatically.
  - Instrumented treadmill (using template file): can be used when event detection from forces cannot be used. Visual3D prompts for one measurement in which events are labeled manually. This trial will be used as a template for all other active trials and algorithm will attempt to detect events automatically.
  Manual events override. If at least one manually entered LHS and RHS exist in a trial, this trial is skipped by event detection algorithm listed below. It is expected that all relevant events (LHS, RHS, LTO, RTO, LON, RON, LOFF, ROFF) exist in the trial that has manual LHS and RHS, so these events must be entered manually in QTM if applicable (fox example there might be no manual ON and OFF events if no FP is available). This manual override applies to the following event modes:
  - Multiple forceplates
  - Single forceplate
  - Instrumented treadmill (single belt)
  - Instrumented treadmill (split belt)
  - Instrumented treadmill (using template file)
  Override has no effect on other event modes:
  - Manual
  - No forceplate (automatic)
  - No forceplate (using template file)
  - Instrumented treadmill (manual)
  - Instrumented treadmill (automatic)
- Body weight mode: User can chose how body weight would be retrieved. When set to 'Automatic', module will look for manually entered value in PAF field and use it if found. If body weight is zero and force plates are loaded in static trial, force will be used to calculated body weight. If body weight is not set manually in PAF field and force plates are not loaded, Visual3D will pop up a pipeline breakpoint and stop processing. Note that patient can stand on one force plate or on two for plates, but make sure that both feet are fully placed on the force plates. When mode is set to 'From forceplate', body weight will be calculated from force data in static trial. When set to 'Entered', PAF field value will be used.
- Left/right foot normalised to static trial: if the box is checked, the foot is assumed to be flat on the floor in the static trial. The long axis of the foot will be assumed to be parallel to the floor. The height of the heel and toe markers will not affect the slope of the long axis of the foot. This setting affects ankle dorsiflexion, ankle inversion, foot pitch angle and foot progression angle (for CGM, ankle inversion is not affected). If Oxford Foot is selected, hallux dorsiflexion angle is also normalised to static trial.
- Multisegment foot (not available for CGM2): Two multisegment foot models are supported: Oxford Foot and Rizzoli Foot. If set to one of these options, the multisegment foot model will be appended to the model and related graphs added to the reports. Further information can be found in “Appendix D - Oxford Foot Model ” or “Appendix E - Rizzoli Foot Model ”.
- Normative data: you can define specific sets if normative data for different age groups. Further information on how to generate normative data sets can be found in “Appendix B - Reference data”. File names for user-generated normative data files can be adapted in Templates\settings.php.
  Note: Normatives cannot be selected for CGM2. Normatives shown for CGM2 model are based on paper published by Schwartz in 2008, "The effect of walking speed on the gait of typically developing children". Data are available at Excel format at https://github.com/pyCGM2/pyCGM2/tree/Master/pyCGM2/Data/normativeData. Subset with 'Spontaneous speed' is used.
- CGM2 model (available for CGM2 only): This field allows to change model applied CGM2 model. It also includes option to choose original CGM model (CGM1.0). Please refer to https://pycgm2.netlify.app/cgm/ for details about various versions of the CGM2 model. By default the CGM2.3 model is applied.
- IkAccuracy (available for CGM2 only): This fields sets accuracy of pyCGM2 solver. Lower accuracy generate noisier data but processing takes less time. Default value is 0.00001. Minimum value is 0.001.
- Head normalised to static trial (available for CGM2 only): if the box is checked, the head long axis is assumes to be vertical.
- Shoes (available for CGM2 only): field has no effect on the model.
- Moment Projection (available for CGM2 only): default is Joint Cooridnate System (JCS).
- Update existing web report: By default each time the report it uploaded to report center, previous report is replaced by latest upload. If checkbox is deselected, each upload is saved as separate report.