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Recommendation for microvolt conversion

Posted: Fri May 05, 2023 10:59 am
by travelmail26
Is there a recommended way to convert the raw microvolt values into the 0-100 range?

I'm reading that RAW eeg microvolts are usually in the range of 0-100, but the measures from mind-monitor/interaxon are much higher.

https://www.learningeeg.com/terminology-and-waveforms

I tried reading on the other forum posts about conversations (i saw notes about using logarithms or Bels) and also looked at the web archived Muse site. I didn't see any easy way to convert RAW eeg scores that are closer to 800uV into the typical 0-100 range.

Any recommendations?

thanks!

Re: Recommendation for microvolt conversion

Posted: Fri May 05, 2023 11:58 am
by James
The values are correct. If you were to force them into a different range, they wouldn't be volts anymore. The number is the voltage as read from the head. It's not going to be zero unless you're dead and fossilized ;-)

If you want to normalize it, then you can subtract the average from the session (~800mV depending on model), but that won't give you a 0-100 range.
Remember the Muse is essentially a fancy volt meter. ;-)

Re: Recommendation for microvolt conversion

Posted: Fri May 05, 2023 12:44 pm
by travelmail26
I’m still confused and could use some advice then. i’m using a python package that seems be to measuring raw EEG signal in the 50-100 range. I read that this was more typical.

In this python notebook detecting slow wave sleep patterns (below, (what i believe is) the raw signal has a uV value much lower than whats produced by the Muse. The y-axis on the graph shows a peak of around 150.

https://github.com/raphaelvallat/yasa/b ... tion.ipynb

In fact, i couldn’t find anything online where total uV is in ranges closer to 800.

So, i guess im confused why this python package has a much lower range for raw EEG (and so goes the other literature).

Any help you could give would be great. Still trying to understand all the details :)

Re: Recommendation for microvolt conversion

Posted: Fri May 05, 2023 2:57 pm
by James
Given that their data is also going negative, it's probably just normalized.

Re: Recommendation for microvolt conversion

Posted: Mon May 15, 2023 6:57 am
by travelmail26
The definitions of microvolts for different sleep stages is in that range. Most sleep stages have a uV less than 150 microvolts

https://emedicine.medscape.com/article/ ... verview#a3

I tried posting on Muse direct developer website and no one got back to me. The Muse ranges just aren’t compatible with software that categories sleep staging and i’m not sure why.

It appears others have had this issue but no resolution

https://openbci.com/forum/index.php?p=/ ... -output/p2

appreciate any insight :)

thanks

Re: Recommendation for microvolt conversion

Posted: Mon May 15, 2023 9:16 am
by James
Try calling their support desk? If they give you an answer, please post here.