How to count muscle activation?

[Larry To]

Hi guys,

I am working on long-term EMG studies on unimpaired human individuals. My goal is to calculate number & magnitude of muscle activation throughout the data collection period. I let test subjects to wear a portable EMG system(OpenBCI) with surface electrodes, attaching on their bicep, tricep, FCU and ECR, for 4 hours while they will resume their normal activities (doing what they are normally doing for the day). After retrieving all the EMG data, I will perform the conventional signal processing. (highpass, rectify, lowpass).

And HERE'S THE PROBLEM:
How can I count individual activation with unknown activities? (it is really difficult for test subjects to write everything they have done throughout the day) The challenge is there are short and long activations that it is difficult to set time threshold without over-passing/over-counting different activation.

Thank you guys

[Edmund Cramp]

Re: How to count muscle activation?

How can I count individual activation with unknown activities?

Essentially you have to figure out a way of making the "unknown activities" into known activities. I would suggest that you start recording data from the OpenBCI 3-axis accelerometer and include the accelerometry data as part of your analysis - at least this will tell you that something was happening at specific times even if you don't know what it was that the subject was doing. If that's not enough then you need to add more sensors to provide activity feedback - GPS etc.

This is a good example of cheap, accurate, easy to use - pick any two - you can't have all three.

[Larry To]

Re: How to count muscle activation?

Thank you so much for your reply!!! That will be useful.

My follow-up question will be what information will be useful for physical therapists or physicians to know. Will it be useful for them to know number of burst? or number of activities? I think this question is crucial for me to set threshold for counting activations. I can count number of peaks (anytime the signal passes through a certain threshold) or I can count one big continuous activation that may correspond to a specific, yet unknown activity.

[Neal Wiggermann]

Re: How to count muscle activation?

Adding additional sensors for context is a good idea. In an epidemiological study where we had to determine types of work activity throughout a shift, I put accelerometers / pedometers that recorded with time stamps on subjects and then at the end of the day loaded their data and had the subjects walk me through their day. It was surprising how well this worked to spark their memory. It takes a bit of extra time but I highly recommend trying this.