How to know if your cognionics flex sensors aren't working anymore?

#1

I’m using a pair of cognionics flex sensors for bipolar measurement with a wet electrode for the Right Leg Drive.

I can’t seem to collect the EOG signal anymore. I measured the electrodes impedance (each pin with respect to the metallic conductive part) and the impedance seems to be strangely higher than the first time I got them.

Could it be possible that the electrodes are damaged?

#2

Insaf, hi.

Have you contacted Cognionics for advise on your situation? Dry electrodes do wear out over time, but slowly. My guess is that they rate the number of uses you can expect.

My understanding from someone who examined their dry electrodes construction, is that they are first 3D printed in a flexible plastic, then plated multiple times with various conductive coatings. (Conductive carbon and silver / silver chloride?) If the top layer of plating wears significantly, this will raise impedance.

Other than normal scalp wear, it should not be easy to damage the plating. Unless the care instructions were not being followed.

If your amplifier has a way to measure skin impedance (not just ohmmeter reading of the electrode) – that would be the best way to track over time and report to Cognionics.

William

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