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Event-related potentials (magnetic fields are not yet supported)

To analyse ERP/ERF data, create and select a study folder, then select the ERPERF analysis and your data format (only BDF and EGI currently supported) on the file toolbar.

Processing is performed sequentially in steps, with pauses to inspect the last processing step visually. The first step is started after selecting a data file. All following steps are initiated by pushing the "Resume analysis" button, on the file toolbar. The calculation of ERPs in EMEGS (Qt version) involves 6 steps:

  1. opening a data file
  2. transposing, filtering (and rereferencing if necessary)
  3. extracting data epochs
  4. occular correction
  5. calculation of epoch statistics
  6. artefact threshold & event related averaging

All these steps can be preconfigured on the configure-study-dialog shown below. Each processing step can also be configured during processing, if the corresponding "prompt for settings"-options are activated in the study configuration. Initial settings of the prompts are taken from the (deactivated) "use the settings"-sections of the study configuration, therefore taking the time to configure the analysis beforehand can save you the trouble of selecting the right options later on.

Batch processing:
If the analysis is started using the "run batch processing" button, files listed on the batch docking widget are processed automatically according to the "use the settings"-sections of the study configuration one after the other. All files in the batch must have the same (selected) file format and the same (preselected) sample rate, and should have the same sensor configuration, although slight variations may work depending on the data format and sensor configuration files.

A report is written to harddisk and the "log" docking widget during the processing. The logfile written to harddisk is saved in the study folder. It is a standard html-format file called qemegslog.html and can be opened with any html-browser. Preprocessing in the same directory is appended to this file, such that subsequent analyses will not erase the log of previous processing. Log entries contain date and time information to allow back tracing of all performed operations.