Band Power metric differs between other consumer headsets
Hi, I am approaching recently to Python and open EEG device so I am rather inexperienced.
Making comparisons between openBCI and other "branded" devices I noticed that while the band power of openBCI is for example 0.0459 for alpha, the other devices have 11.3. This mismatch does not allow me to make direct comparisons also regarding index like focus/meditation and I was wondering where I should intervene to change the yield of this type. Can i take action upstream in the OpenBCI software, need a different type of filtering or is it simply a matter of converting units of measurement to be done in post-processing?
Sorry if the question is not very clear but as I said I’m starting now and I’m trying to learn from the base
Comments
Hi Clat,
A great deal of variation is possible because of the placement of electrodes on the scalp and type of electrodes being used. Alpha is stronger in the posterior portion of the scalp. And a frequent location for measuring that might be 10-20 locations O1 O2 or Oz. It is also strong in Parietal lobe at P3 P4 or Pz.
What electrodes are you using? if using the dry comb electrodes, more pressure is required from the headband. In comparison to electrodes that use electrolyte paste or gel.
As you say, the filtering may also differ on these other devices.
William
Hi, thank you! This is the difference between commercial eeg with 1 channel (up) and openbci also 1 channel (down).
I'm using the dry electrodes with good pressure on frontal lobe.
The results of Openbci waves is good or maybe there is something wrong?
Clat,
Both headsets are showing muscle artifact from eye movement. Those are the large deflections. I'm sure you see this when you use the GUI. The top headset filtering, is NOT blocking higher frequency EEG, whereas your lower headset filtering (OpenBCI) is blocking almost all the high frequency EEG. This is your responsibility to set the filtering in a similar manner.
Regards, William
As mentioned previously, frontal area is not best for alpha. That is stronger in the back of the scalp.