Tagged: EEG Quality Issues
- This topic has 1 reply, 2 voices, and was last updated 1 year, 12 months ago by luckham jerill.
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December 25, 2022 at 1:30 am #1324
Hi – I can get 100% (all green) on the contact quality, but the EEG quality is proving very difficult. I can get it to go to 100% but it will not stay at 100% – it jumps all over the spectrum sometimes staying at 0% for some time, then suddenly jumping sporadically all over the place. It doesn’t seem to correlate with movements or shifting of the headset. I can be sitting perfectly still and and get a reading of 100%, then it will jump to 52, then 0, then 7, then 92, then 58, the 75 etc all in a matter of a minute. I’ve tried sitting very still for several minutes, rewetting the felt pads, adjusting the sensors, moving the rubber pads from M1/M2 to P3/P4. I’ve tried using someone with very little hair to see if it was just my long hair interfering but that didn’t seem to make any difference. Any ideas on why I can’t get a stable EEG qualify?
December 26, 2022 at 10:02 pm #1325Hello!
EEG quality (EQ) is the new feature we have recently added to EmotivPRO software. The EQ map is measuring the quality of the brain signal for each sensor, and it takes into account movement, noise, signal amplitude, and many other parameters that make it much more sensitive. It is totally normal for the EQ to flicker and it DOES take time for the signal to settle, so adjust each sensor individually, sit still and wait patiently for 3-5 seconds. If the signal flickers green at any point, it’s likely the signal is good, but it is imperative to sit still to see if it maintains the green.
In general, EQ is designed to give a quick way to understand and evaluate the raw EEG signal for those who do not have a trained eye. Expect the EQ to flicker as the experiment runs and the participant moves and for this output to be reflected in your PRO export. A consistently low EQ score may mean up to 3 sensors are showing significant noise or artifacts. It is expected that the EQ signal will flicker – this is an indication that we are detecting movement, noise, or other interferences that mean the brain signal is not perfect. To reiterate, it behaves very differently to CQ and it is NOT expected to remain steady at all moments in the recording, particularly if people are not sitting still.
If your sensors remain orange or red, ensure your hair is out of the way, the sensor is touching the scalp and there is enough prime fluid, gel, or saline solution. You can refer to this link for more information about our CQ and EQ. If you have any additional questions in the meantime, feel free to let me know!
- This reply was modified 1 year, 12 months ago by luckham jerill.
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