User Tutorial:P300 GUI for Offline Analysis Tutorial

• Run src/contrib./Tools/P300GUI/P300_GUI.m
• Close the Editor window that appears, and type in P300_GUI
• In the upper left-hand column, click on ‘Select Training Data’
• Select the data files collected from the runs for THE, QUICK, BROWN, and FOX
• In the lower left-hand column, press the Generate Feature Weights button
• A pair of graphs should be displayed, similar to those below.
  • The important feature is to notice that the red line in the upper graph, the accuracy, increases with more flashes
• Close the window of the graphs
• In the lower-middle column, type Training for '‘File Prefix:'’, and 1 for '‘File #s to Save’'
• Click on '*.prm (v2)’
  • This will generate a .prm (parameter) file in the same folder as the data files
• Returning to BCI2000, click on ‘Config’ and ‘Load Parameters’, selecting the new .prm file
• In the ‘Application’ tab, change TextToSpell to JUMPS, and click ‘Set Config’
• Press ‘Start’ to collect one more run of data
• Once the last run of data has finished, go back to the P300_GUI program and click ‘Add Test Data’ in the upper right-hand column
• Select the newest set of data, and click ‘Apply Feature Weights’ in the lower right-hand column - A new window of graphs will appear
• The important thing to see from these graphs is where the red line in the upper graph reaches 100%.
  • In the example below, this is from 9 to 11, and then drops. This means that 10 flashes gives the best accuracy.

• If this does not give an acceptable level of accuracy, (typically 95% or higher), repeat more test runs to collect more data files. Add these data files as above, and click Apply Feature Weights in the lower right-hand column to look for how many flashes is needed. Repeat as necessary.
• In the lower middle column, type Trained for File Prefix and 1 for File #s to Save
• Click *.prm (v2) again to generate a Trained parameter file
• Close BCI2000, MatLab, and the P300_GUI programs
• Open BCI2000 with the batch\P3Speller_<Your_Amplifier>.bat file
• Click on Config, and Load Parameters
• Load the base parameter file for your amplifier, and then the Trained parameter file.
• In the Filtering tab, set EpochsToAverage to the ideal number found by how many flashes were needed to attain maximum accuracy. In our example, this would be 10.
• In the Application tab:
  • NumberOfSequences to this number as well
  • Delete the contents of the Text to Spell field
  • Set InterpretMode → online free mode
  • Make sure the DisplayResults box is checked
• Click Save Parameters and name as you see fit. Typically this parameter file would be P300_<Your Amplifier>_<Volunteer's Intials>_Free_Spelling.prm This file is now the file used for that volunteer in later P300 Spelling sessions

To continue onto performing P300 spelling experiments, continue to Performing a P300 Spelling Session.