User Tutorial:P300 GUI for Offline Analysis Tutorial

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  • 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.
9to11.PNG
  • 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 now many flashes were needed to attain maximum accuracy. In our example, this would be 10.
  • In the ‘Application’ tab:
    • Set NumberOfSequences to this number as well
    • Delete the contents of the '‘Text to Spell'’ field
    • Set '‘InterpretMode’' to 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.