Mobility Lab is designed for brief, clinical assessments of pre-defined tasks (e.g., the Timed Up and Go, or the 2-minute Walk). In almost all environments, it is desirable to capture the data using the Wireless Streaming Mode, where you can instantly view the analysis results for your recorded trials. Under some circumstances, however, it is not optimal to collect data using the wireless streaming mode. For example:
- You are trying to capture a Walk trial in a subject's home and bringing and setting up a laptop for the wireless data capture is not possible due to time and/or space constraints
- You are recording data in an environment with severe wireless interference
- You are recording data where the subject may be at a distance and cannot be close to the access point at the beginning of each trial to initiate the recording or at the end of the trial to stream the recorded data
Included as a part of a software update released March 30, 2019 (requires internet connection), you can now easily enable logging mode and directly import logged recordings as a trial within Mobility Lab. This guide will outline each step to accomplish this process.
Configuring for synchronized logging mode
1. Navigate to Options - Display Options
At the top of the application window, select the Options tab followed by the Display Options button to navigate to the Logging Mode controls. Click the "Allow Logging" check box to enable access to Logging Mode at the Hardware Configuration screen. Please note that by checking "Allow Logging", users will be allowed to configure Opals for logging mode for use without an Access Point. When configured for logging, users will be unable to administer tests through the "New Test" option on a subject's page.
2. Configure Hardware for Logging Mode
With your APDM equipment connected to the computer, click the Hardware Configuration tab at the top of the window to navigate to the Hardware Configuration view. The "Allow Logging" option enables a "Recording Mode" drop-down menu to select between Streaming and Logging recording modes at hardware configuration. Select the Logging option from the list and click "Apply Configuration" to confirm the recording mode change.
3. Complete Configuration and Collect Data
When Hardware Configuration is complete, you may now collect data in logging mode. The Opals will begin recording as soon as they are undocked and synchronized (blinking in unison), and will continue recording until they are docked again. In order to analyze segments of a logged recording after collection corresponding with a specific test type (e.g., Sway, Walk, etc.), please read the appendix at the end of this article. When you are ready to import a logged recording, first select the subject that you would like to add the trial to. From the Cog icon menu, select "Create trial from data logged to your Opals" to begin the import process.
4. Select Overlapping recordings, Identify Trial & Condition type, Convert
Mobility Lab will check all connected Opals for overlapping recordings and present a list of all found trials. Clicking on any of the recordings will cause overlapping recordings to highlight in green to more easily identify groups of files. When a recording of interest is found, click the "select highlighted" button to mark that collection of overlapping recordings for conversion. To apply Mobility Lab's built-in analysis to the recording, identify the Test type and Condition from the drop-down menus at the bottom of the conversion window. When complete, click "Convert" to import the logged recording as a trial. The date and time from the recording file will be used.
Appendix - Segmenting Logged Data with Button Events or Timestamps for Use as a Trial
If you intend to use logged data recordings with Mobility Lab for analysis, "segmenting" the data to align with a prescribed test type is required. This is because the Opals start recording as soon as they are undocked and record until they are docked again. Without segmenting, you will be analyzing the entire recording, including putting the sensors on the subject and removing them from the subject.
There are a few ways to identify the correct segments of logged recordings, but the goal is to extract segments of the recording that correspond to the Mobility Lab trial you are attempting to perform, including a minimum 3 second still period at the beginning of the activity. A few ways to identify the correct data segments are:
- Button events: The most foolproof way to identify the trial segments is through the use of button events. A single Opal can be configured to have each button act as a trigger to write a user-defined text string to the annotations field of the recording, along with a precise timecode stamp to indicate the event. As an example, button 1 could write "StartTrial" to the annotations field to indicate the beginning of a trial, and button 2 could be configured to write "StopTrial" to indicate the trial event has ended. These button events are recorded along with the inertial data and can be used at the time of import and conversion to specify the segment corresponding to your trial. Configuring an Opal log button events does not interrupt normal function and can still be used to gather inertial data. We recommend the following linked support article for more information on using Button Events to segment logged recordings. Note that if you configure button events in Motion Studio, it is recommended that you reconfigure in Mobility Lab or Moveo Explorer to ensure that you are configured correctly for data collection. Reconfiguration in Mobility Lab or Moveo Explorer will not interfere with your button event configuration.
- Computer clock: The Opal's internal clocks are set at configuration time, and should closely match the clock on the computer used for configuration. When a subject performs a trial, note the time (to the second) of the start and end. You should use the clock on the computer used for configuration for this task, or another clock that is set identically or has a known offset. These times will be used when the data is imported and converted into a trial.
- Visual inspection: You can have the subject perform some type of easily identifiable movement indicating the beginning and end of a trial. For example, you can have the subject clap 3 times with a fixed duration (e.g., 1s between claps) before the start of the trial and after the end of the trial. You can then initially import the complete recording and locate the time stamps of these events by visual inspection of the raw data (in the clapping example, the right and left arm sensors would display 3 sharp peaks at the same time). You would then re-import the trial specifying these time stamps, deleting the original trial when complete. This approach is particularly tedious, but is included here for completeness.