What Is A Muap Shape Non-Stationarity In Emg Signal Decomposition?

Question

[Rogcg]

Hello, I'm studying the article

EMG signal decomposition: how can it be accomplished and used? by Dan Stashuk

And it uses the term non-stationary for MUAPs, etc..

My doubt is what it really is, what the author wanted to say with the non-stationary term.

Thanks.

Answer 1

[Neilfws]

I did a quick Google search for "non-stationary signal". There's a lot of very technical literature out there, but this Wikipedia page states that non-stationary signals are those:

whose frequency distribution and magnitude vary with time

Answer 2

[Casey Bergman]

The author states on p160 that "Signal non-stationarity occurs if the electrode moves relative to the fibres, which in turn causes the shapes of the MUAPs to change"