Using the Advanced Gait Workflow
- Gisela Roberts
- Ben Stanley
The Optimum Common Shape Technique (OCST) 1 , Symmetrical Center of Rotation Estimation (SCoRE) 2 and Symmetrical Axis of Rotation Analysis (SARA) 3 methods are based on research publications that can be obtained from Vicon on request. As the research and validation of the values produced by these methods is a continuing effort, it is recommended that OCST, SCoRE and SARA are used for investigative and research purposes. It is the responsibility of the user to review the scientific references and understand the methods. Any use of the methods as part of a clinical assessment is strictly at the discretion of the user.
Nexus 2 includes a feature called the Biomechanics Workflow. This area on the Data Management tab enables you to create a custom series of sequential steps that constitutes a collection protocol. These steps can automatically select aspects of Nexus for data collection and processing, including trial types, trial names, and processing pipelines.
The Advanced Gait Workflow (AGW) helps you to calculate a repeatable Hip Joint Center location using the SCoRE method, and an optimized Knee Joint Flexion Axis using the SARA method. The Advanced Gait Workflow also incorporates a mathematical approach (known as OCST) that finds the average or common shape for selected sets of markers. The OSCT method allows non-rigid arrangements of skin-based markers to be used in SCoRE and SARA calculations where rigidity is assumed. The Advanced Gait Workflow steps each have an associated step description in the Biomechanics Workflow area that guides you through the process from marker placement to capture and processing.
The Advanced Gait Workflow steps you through a series of trial captures and automated processes to:
- Calibrate the subject's labeling skeleton
- Calibrate the OCST pelvis, femur, and tibia segments
- Monitor the range of motion (ROM) of the hip and knee joints for SCoRE and SARA calibration
- Calibrate the SCoRE hip joint centers
- Calibrate the SARA knee flexion axes
- Capture a dynamic trial and use the calibrated OCST, SCoRE and SARA data to compute the hip joint centers and knee flexion axes for further analysis
The workflow enables you to accept the outcome of the current step and proceed to the next automatically or to reject it to repeat the step until the outcome is satisfactory. It illustrates how to use the Biomechanics Workflow and its corresponding features with the supplied Advanced Gait Workflow VSTs, but if required, you can modify it and the associated trial types, monitors and pipelines to suit your needs.
The following topics describe each step in the Advanced Gait Workflow along with its outcome. The final topic describes how to use the MATLAB Plug-in Gait scripts with the SCoRE and SARA data for further analysis.
