EMG pre/post treatment comparisons

[Mulavara, Ajit]

Dear ALL:

We are currently involved in a project which included the use of surface EMG
during a voluntary movement. Data collection sessions were separated by
several months. We are interested in comparing the amplitude of the activity
between the two sessions, however, due to factors such as electrode
placement, possible changes in muscle strength, changes in muscle fat
content, etc. we do not feel comfortable just comparing the pre and post
treatment data. To place the pre and post treatment data on the same scale
the following has been suggested to us. Develop indiviudual muscle average
activation waveforms for the data obtained from the pre and post test
sessions, sum the activity in each waveform, add the two activity totals and
divide by two. The result would become the normalization value (i.e.
divisor) for both the pre and post treatment waveform. We are interested in
comments about this technique and welcome any other suggestions which would
enable us to make meaningful comparisions across data collection sessions

All replies will be summarized and posted

Thanks,
Ajit