Filtering GSR data
Posted: Thu Jul 15, 2010 5:00 pm
Dear all,
We are currently analysing GSR data collected using a 512 Hz Active 2 Biosemi system.
As is generally the case with GSR data, there is a very sizable baseline shift in the data from the start to the end of the task and we are having some trouble finding the appropriate high-pass filter to apply. The literature seems to be fairly ambiguous (I have seen anything from 0.05Hz to 2Hz quoted, and even applying different high pass filters in fairly small increments between these values can have dramatic effects on the evoked responses we are seeing).
Further, we are conducting our analysis using both BESA 5.2 and the EEGLAB toolbox, and both show large differences when what I though were the same filters are applied. Presumably this is a result of small differences in the filters used between these two software packages.
Does anyone have some advice as to what the appropriate high-pass filter should be? This would be very much appreciated.
Peter Murphy
We are currently analysing GSR data collected using a 512 Hz Active 2 Biosemi system.
As is generally the case with GSR data, there is a very sizable baseline shift in the data from the start to the end of the task and we are having some trouble finding the appropriate high-pass filter to apply. The literature seems to be fairly ambiguous (I have seen anything from 0.05Hz to 2Hz quoted, and even applying different high pass filters in fairly small increments between these values can have dramatic effects on the evoked responses we are seeing).
Further, we are conducting our analysis using both BESA 5.2 and the EEGLAB toolbox, and both show large differences when what I though were the same filters are applied. Presumably this is a result of small differences in the filters used between these two software packages.
Does anyone have some advice as to what the appropriate high-pass filter should be? This would be very much appreciated.
Peter Murphy