EMG-Cleaning-Tutorial

1. Before even getting in your first participant: Procedure programming

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In E-prime or Inquisit, you should make sure that there are marker send to identify each stimuli uniquely or a type of stimuli (several stimuli belonging to the same type getting the same marker).

Running the experiment and recording physiology data using Biolab, an event file for each participant is created showing these very markers, as you can see below. It is written out through Biolab and saved in the same folder as the physiological data. An event marker is named: “sync summary event # 2”. The “2” is the marker you have defined in you experiment program.

2. DATA ACQUISTION COMPLETED: EVENT FILE PREPARATION

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If you experiment used different marker for every stimuli, but for analyses you need to create groups/types of stimuli you can collapse the marker into fewer categories. For doing this make use of the “Mass Search and replace tool” (can be downloaded). E.g. replace the stimuli marker 55 and 65 by the markers that you want to use for analyses. See Image2 for an example.

See that only the stimuli got a marker, the baseline (event #200) and the practice trials (#2) are not replaced by markers. Now, the EMG program can make use of the markers as a group, instead of having to analyze each stimulus separately.

REMEMBER, make sure each participant has a physiology file (*.mw), a video file (*.avi or *.mpg) and an event file (*.txt).

3. EMG Data Cleaning

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Open the EMG program.

Choose the file of the participant you want to analyze (*.mw ).
Now, choose the right names for each channel. Confirm if the document is the right one. Then it will look like Image4.