What is the importance of isolating EEG sensors if they are connected to 12V ? ?

Question

Is this just a matter of "let's be really, really safe," or is there some other serious danger that I am unaware of? Really... 12V sensors? Has anyone (human or animal for that matter) actually been hurt by them before?

Answer 1

Try this:

Take a 9V battery and touch the electrodes to the tip of your toungue.  

You can definitely feel it, right?  and that's only *nine* volts!

Under the right circumstances, with high-conductive skin pads, enough current can be forced through the heart to cause it to stop, or through the brain to cause neural damage.

It's not about the voltage, its all about the current.  Those skin pad electrodes make for much lower skin resistance, so that even a few hundred MICROamps of leakage current could cause problems under the right circumstances.

People *have* actually been hurt and even killed from poorly designed medical equipment with high leakage current (non-isolated).

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