Review: Active electrodes

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Active EEG electrodes, which contain a pre-amplifier embedded in each electrode head to boost the signal before it ever reaches the amplifier, have long been one of the most attractive technologies in EEG from the point of view of the day-to-day trainer. They use snap-in disposable electrodes. No paste is required for any site without hair. There is no prep required anywhere. That's right: No scrubbing with NuPrep! Just clear the hair away from the scalp and place the electrodes with a dab of paste or use self-adhesives on areas without hair. When I started using active electrodes to do assessments, I shaved 10 minutes off my time! When you are done, wipe off paste with a paper towel or unsnap the self-adhesives and toss them away. No need to heat water, get out the q-tips and alcohol. Faster hookups, faster cleanups. And you get a zero-impedance signal--better than the best signal you can get by hand with scrubbing! What's not to like?!

Unforunately the only commercially avalable version of these electrodes gave us LOTS not to like. Brainquiry's ActivEEG electrodes were powered by a 9-volt battery that required changing by removing the back of the power box, shaking out the battery and prying it free of the battery cable (which invariably eventually pulled loose from the stress of changing batteries, creating irritating short-circuits). The power was turned on/off with a tiny slide switch that people without fingernails struggled to use. And the electrodes themselves were relatively short, meaning that you had to keep the power box in fairly close proximity to the head and the amplifier even closer. When they worked, they were great! Too often they didn't work or provided on-again-off-again signals. To get them fixed, you had to send them to the Netherlands and wait.

I just finished testing the first available (to my knowledge) alternative to the ActivEEG's, and I feel like the promise of this technology has taken a giant step toward fulfillment. The Intellectrode power box is beautifully made and finished, smaller and sleeker and nicely designed. Like the ActivEEG, it has a belt clip on the back, but instead of placing the plugs on the front of the box, the Intellectrode has them on top, which makes much more sense if the client is wearing the box. Because each electrode plugs individually into the amplifier, you can use 3 if you are doing 1-channel training or 5 for 2-channel--and you can use a jumper.

Gone is the 9-volt battery! It is replaced by an internal rechargeable lithium-ion battery and comes with a 110/240 volt recharger. No opening the case or prying the battery out. The battery is supposed to last for 2 days of training without recharge (though it would make more sense to recharge at the end of each training day). The unit comes with an extension with a 9-volt battery connector on it. The idea is that you can plug this into the power box for the actives and use it to power your 9-volt amplifier. This reportedly reduces the battery life to one day of training. This cable is relatively short, so using it means that the amplifier and active power box must be essentially in the same place.

The on/off switch is pressed in (a green light goes on) to turn it on and pressed again to turn it off. You could do it (if you trained somewhere like, say, Minnesota) with gloves on, if you wanted to!The electrodes themselves have the heavier insulation used by ActivEEG's, but the Intellectrodes have also upgraded this part of the design: Instead of the finer wire about 4 inches long that ran from the power plug to the amplifier, the new electrodes have heavier leads a full 60 inches long, so you can reach the power box from the amplifier almost no matter where you put it. And the electrode head are on a heavier lead 36 inches long. They come with two yellow, two red and a black, so you can decide which color you want to use for active and which for reference electrodes and use black for the ground. Of course any electrode can plug into the power box in any input, since it only provides power.

OK, you may have been toting this up in your head as you read: heavier electrode wire and more of it, better design, better switch, lithium-ion battery, recharger, 9-volt extension. What's this baby going to cost? The ActivEEG's run U$840 (plus the disposable electrode supply package). Brain-trainer.com now sells the Intellectrodes for $675--20% LESS than the ActivEEG's! If you already use disposable electrodes or have the disposables package for ActivEEG's, you can use them, of course, with the Intellectrodes.

The box is warrantied for 1 year and the electrodes for 30 days. The only maintenence that should be required would be replacement of the Lithium Ion battery pack after a couple years.

Active electrodes are one of those technologies that have the potential to transform the way you do neurofeedback, but, as we have learned more than once, the devil's in the details. With Intellectrodes it finally appears that someone has gotten the details right!

You can see or order the Intellectrodes at http://www.brain-trainer.com/cgi-bin/shop.pl?shop=get_item & item_id=78

Pete-- Van Deusenpvdtlc@...http://www.brain-trainer.com

305/433-3160The Learning Curve, Inc.