256 Dense Array EEG

[zombelina]

I have simple partial seizures that never show up on an EEG. They told me that my seizures are probably coming from too deep in the brain for the scalp electrodes to pick up the activity. My doctor said I could try something called dense array EEG. It is a cap that has 256 electrodes. They said it could help find where the seizures are coming from. Has anyone heard of this type of EEG or had one done?

I don't totally understand how having more electrodes on the scalp could help detect activity deeper in the brain. But I really hope it works!

 

[resaebiunne]

Never heard of this, skeptical that it would work. More electrodes doesn't mean greater sensitivity, but hey, it can't hurt to try.

 

[Nakamova]

One reason why the higher number of electrodes is a plus is that information can be lost if the sensors are spaced greater than 2 centimeters apart. With the 10-20 system placement of a conventional EEG, the electrodes are as far as 7 cm apart.

The 256 dEEG (dense array EEG) won't get all the way there (you would need 500 sensors for that), but it's much better than the conventional EEG (19 channels).

Another big advantage of the dEEG is that it's a mesh cap -- no glue! You can see a picture here:
https://www.researchgate.net/figure...et-Note-the-electrode-coverage_fig1_221916518

 

[resaebiunne]

I think you might need to be more specific? The greater spacial density of the electrodes will give you more accurate localization of where the seizures are coming from, but the ultimate ability of the electrodes to sense voltage from within the scalp is still limited by physics

 

[Nakamova]

I agree that the dEEG won't necessarily pick up deeper seizures. I think that in this respect the neuro misspoke. But it will pick up electrical activity (including interictal activity) that the conventional eeg misses, and is much more useful in localizing seizure activity (esp. helpful when considering surgery).

It is at this point primarily used as a pre-surgical tool. But in studies, the denser array is yielding useful information about the nature of seizure activity that might potentially be useful in treatment. For instance, it appears that absence seizures are not truly "generalized" -- the whole brain is not involved. And in some instances of TLE, where a conventional EEG might record seizure activity in solely the left or right lobe, the denser array reveals that both lobes are contributing.

 

[zombelina]

Sorry - for some reason I missed these responses. Thank you both! Your explanations really helped answer my questions! I guess i just have to hope it picks up on something that the regular EEGs miss. I’m having the test next Fri pending insurance approval. Fingers crossed!

 

[Nakamova]

Good luck -- let us know how it goes.