AcqKnowledge* includes a fully automated scoring system for EDA/GSR data, including event-related EDA analysis. The event-related EDA analysis requires stimulus event markers to drive the analysis process. It is possible to use the analysis on files that do not include stimulus event markers, but they have to be added manually.

The analysis will obtain statistics for all skin conductance responses: Skin Conductance Level, SCR Amplitude, SCR Rise Time when there is no information about the time of stimulus delivery. (The Stimulus Delivery Time and Response Latency measurements only apply to files that contain stimulus event markers.

To perform the analysis on a file without makers, place a marker 1 sec prior to every waveform onset of an SCR and then run the automated analysis with this marker as the stimulus.

Steps

1. First run Transform > Specialized Analysis > Electrodermal activity > Locate SCRs on the skin conductance level channel so that the SCR markers are placed in the record. For each SCR, three markers will appear: waveform onset, SCR and waveform end.

   1. Select the skin conductance channel (the one that will now have all the markers displayed on it)

2. Go to Transform > Find Cycle/Peak

   1. Check Locate cycles from events
   2. Start event should be waveform onset and the location should be the skin conductance level channel
   3. End event should be Skin conductance response and the location should be the skin conductance level channel

3. Click on the Selection tab.

   1. Set the left edge to starting event -3 sec
   2. Set the right edge to starting event -1 sec

4. Click on the Output tabs

   1. Go to the Events tab under the Output tab and select Output events.
   2. Choose Right Edge for event 1 and At edge. The output type should be something easy to remember and see - for example: Notes-> Flag. The Output channel can be the same as the skin conductance level channel.
   3. Event 2 should remain set to None.
5. Click Find All Cycles and a Flag will be placed just before each waveform onset.
6. Go to Analysis > Electrodermal activity > Preferences (or Transform > Specialized Analysis on older versions) and make sure either Text or Excel are specified as one of the output formats so that a text record of the measurements can be obtained.
7. Go to Analysis > Electrodermal activity > Event-related EDA analysis.
   1. Specify the skin conductance level channel in the first dialog box.
   2. Specify the event that corresponds to the stimulus delivery (if you used a flag, choose Notes > Flag).
   3. Specify the channel where the stimulus delivery marker was placed.
   4. The Maximum separation value should be 2 sec.
   5. The SCR count interval width should be set according to your preferences. See the software manual (the section for Event-related EDA analysis) for details.

   6. Click OK and the results will be displayed in the format specified in the Preferences earlier.

Notes

To apply the same find/peak operation to many files, simply keep AcqKnowledge open and keep applying the operation to new files. The settings will not be lost until the software is closed.

To save time, recently used transformation commands can be found under Transform > Recently Used.

*This feature requires at least AcqKnowledge 4 for Windows or AcqKnowledge 3.9 for Mac.