Brain Electrodes That Screw On the Skin 58
An anonymous reader writes "New Scientist says that attaching electrodes to the skin for monitoring brain activity (for example when 'installing brain implants that can allow disabled people to control machines using their mind') is tricky, especially on a hairy scalp, so the new solution from the University of Pittsbugh is an electrode that screws into the skin: its 'teeth dig into the upper layer of skin and become fixed in place, maintaining good electrical contact.' They say that the thing 'should be pain-free.' (Note: it does not go through the skull!)"
Re:Screwed Into Skin (Score:2, Informative)
RTFA. The patent picture is a 1/4" wood screw and a bottle of Jack Daniels. You aren't going to feel a thing.
But seriously, RTFA, or a least look at the pretty picture they throw up there before playing backseat scientist. I'm sure there's a lot of other things you can't think of, but somehow they're getting done!
Re:Umm, infection? (Score:3, Informative)
That sounds scary, but alternatives to this technology include needle EEGs and surgical brain implants (e.g., for disabled people to control protheses). I expect those also carry a risk of infection and are far more invasive. Compared to normal contact EEGs (another potential alternative), there may be an additional risk.
Re:Screwed Into Skin (Score:2, Informative)
Re:Screwed Into Skin (Score:4, Informative)
What I was told at phlebotomy school (class) was that the finger stick needles we use can only be 2.4mm in length by law. Everybody complains about them, whether that's because a lot of nerves end in the fingertips or they're just weak, unsure. Anything that penetrates the skin will hurt a little bit, it's just a matter of how much it will hurt because of your threshold for pain. Someone into the whole bondage thing won't care, but a child will definitely be alarmed, as well as the parent.
The fingers are, in fact, just full of nerves. I am into the whole bondage thing, and i can take a knife to the back till i bleed, but it still hurts when i prick my finger.
-Taylor
EEG (Score:2, Informative)
If they can use this for EEGs that would certainly make life a whole lot less miserable for those of use who have small kids with idiopathic epilepsies where you do a lot of 24 hour EEG sessions. (Yes, it's a hassle to deal with a 18 month old who likes to be everywhere and hates the electrodes that are stuck to his head with some disgusting white paste.)
Re:Umm, infection? (Score:3, Informative)
The idea behind these is that you can easily place the electrodes--easy being without cutting all their hair off.
Re:EEG (Score:3, Informative)
Re:Screwed Into Skin (Score:2, Informative)
Burdock seeds (Score:3, Informative)
It seems it may be like burdock seeds. These -are- pain-free, and they can attach even to skin. The tips of the spikes surrounding the burdock seeds end with tiny hooks with sharp tips. The tips easily pierce into skin, but due to the bend don't go any deeper than 0.2mm inside the skin, meaning they never get near neurons or blood vessels, never cause bleeding or pain, while retaining a good grip.
New Scientist's Lack Of Scientists (Score:4, Informative)
If they're going to report science they should have people capable of evaluating the present scientific, or the equivalent technical uses, rather than simply rewriting press releases and thinly veiled advertising. I've used pretty much every available kind of electrode in both settings.
Screw in electrodes were old when I managed the EEG lab at Virginia Tech and had to decide what to buy and use, and to justify those decisions. They weren't used then, and aren't like to now, because they're not more convenient or accurate, and certainly less comfortable than other alternatives.
The oldest versions are water soluble glue-on. Most people who've had EEGs done at hospitals are familiar with picking that sticky stuff out of their hair. They needn't have done that, since washing your hair gets it out.
Newer versions include elastic caps, very much like swimming caps with the electrodes built in. Conduction is based on conductive gel without needing the glue. Newer still is the electrodes sewn together with elastic threads. All the electrodes go on at once, up to 256 of them. The conductive gel gets injected into the center of the electrodes, and has no problem with hair. Conduction and impedance still need to be checked and balanced between electrodes and within the impedance range of the amps.
Even newer are high impedance electrodes (and impedance matching amps) that require no conduction gel. The electrodes are embedded in small cups containing sponge, and the whole thing gets dipped in salt water prior to application.
The newest, most accurate and convenient EEG electrodes all go on at once using the elastic thread net attachment. They have the preamplifiers built into the electrode, so impedance matching (ie. accuracy) is not an issue.
I've used all of them, and have a personal record of 256 channels of accurate, impedance artifact free EEG, being recorded in less than 8 minutes from the time the person sat in the chair.
I've used screw-pin electrodes as well as straight-needle electrodes for intraoperative electrophysiology (but not EEG, but only because the other options were available and better). These are suitable when the person is under anesthesia. However, skin is elastic and can be torn. Using it as the basis for electrode attachment will result in some of them being torn off, particularly when the person moves. Some of the other methods result in the electrodes being so displaced, but at least they don't break the epidermis and leave a path for infection. Where the skin is thinnest -- the scalp -- the epidermis/dermis thickness is the least, making infection more likely. If initial electrode placement is not optimal, worst present case is having to dissolve the glue and reset the electrode. All other cases are simply done by moving it. If the electrodes in TFA are misplaced, you leave an infection prone hole when you remove it and use a new electrode in the correct spot. Screw- and straight-needle electrodes are used in surgery because they person is adequately cleansed and the ER is fairly free of infective agents.
When the scalp is injured and recording is required ASAP (by EMT or ER personnel), the whole head caps/nets place the electrodes properly, as they place them according to predetermined sites regardless of condition and displacement of the scalp and will help hold each other and the scalp in place. Placing individual electrodes will require in this instance the same sort of head measurement and individual placement based on the "10-20" system. This is very slow. If the skin shifts due to injury, there goes the electrode placement. If the skin is loose, there goes the electrode. When the procedure is one of deep electrode implantation, a net of electrodes will still be a far better choice, and the few electrodes that must be moved for the implant site are easily shifted out of the way.
Note that an apparent benefit to these would be in an EMT/ER situation when only a few electrodes are required. The caps/nets still go on faster, and are faster s