Preprocessing raw data

[ty22]

Hi,
I really like your app thanks!
I'm some questions:
1. how do you preprocessing the data to remove the artefacts?
2. if I have a piece of recorded data and I want to know if the person is in a highly nervous/frightened state, should I compute the average value of all 4 electrodes for Beta band or is there any other ways?

Thanks!
Jeanne

[James]

1 - I don't. It's done automatically by the Interaxon SDK before my code gets the values. I believe they are removing blinks and power line interference.
2 - I'm not sure sorry. My personal research has been focused on relaxation.

[ty22]

1 - I don't. It's done automatically by the Interaxon SDK before my code gets the values. I believe they are removing blinks and power line interference.
2 - I'm not sure sorry. My personal research has been focused on relaxation.

Thanks for your reply, I've read many articles on how brain works, about frequency, DSP and so on.
But it is still difficult for me to understand the data from Muse monitor. So could you tell me about what kind of brain activity can be seen on this picture? Does the Session Average Relative tell anything about asymmetry?

link: https://imgur.com/a/93JWB0D


Thank you so much!

[James]

All I can tell from this is that the subject wasn't relaxed. Sorry, like I said, my personal research is on relaxation!

Regarding symmetry, the little graph in the bottom left, shows the left vs right power for each wave.

In this example you can see it was more left than right. If you hover your mouse over the individual bars it'll show you the actual numbers.

[ty22]

All I can tell from this is that the subject wasn't relaxed. Sorry, like I said, my personal research is on relaxation!

Regarding symmetry, the little graph in the bottom left, shows the left vs right power for each wave.

In this example you can see it was more left than right. If you hover your mouse over the individual bars it'll show you the actual numbers.

Thanks James! Could you also tell me how this bottom left graph is computed? Is it averaging each frequency band from all four electrodes? Why is the left one always negative? Thanks!

[James]

The bottom left graph is the average of the left and the average of the right for each band over the entire session.
If you click on a specific point on the graph, you will get another graph shown under it showing just that point in time.

The left side is always negative so that it renders correctly with the blue bars on the left and the red bars on the right.

[ty22]

The bottom left graph is the average of the left and the average of the right for each band over the entire session.
If you click on a specific point on the graph, you will get another graph shown under it showing just that point in time.

The left side is always negative so that it renders correctly with the blue bars on the left and the red bars on the right.

Thank you for your reply! Do you know if subject's emotional reaction to sudden visual stimuli (for example, a terrifying face) could be reflected on the Alpha (or Beta) change, or frontal asymmetry values, right after the onset of stimuli?
Thank you very much!

[James]

Probably, but I'm not sure what it would look like.

[ty22]

Probably, but I'm not sure what it would look like.

Hi James, since the voltage of raw EEG signal usually lies between 850+-100uV, I see a lot of outliers due to lack of contact of sensors during the tests. Do you think I can remove some noise by deleting everything out of this range?

[James]

Sure.