Feb 28 2013

Tattoo Electrodes

Headlines read: “Temporary tattoos could make electronic telepathy and telekinesis possible.” The technology is actually quite cool and interesting, but it is distressing how much of the mainstream reporting has been calculated to misinform for the sake of some cheap sensationalism. The technology is interesting enough without turning it into science fiction.

The temporary tattoos are really skin surface electrodes that can read electrical signals, such as EEG signals from the brain. They can also incorporate other sensors, like heat or light sensors. They can contain antenna to receive energy or communication, and wireless technology to communicate to devices.

The electrode circuits are also thin (100 microns), flexible, and small. Combining several features into such a small device is the real advance here, expanding the number of feasible applications of such technology.

Nothing about these devices, however, has any advantage for brain-machine interface, which is the misleading implication of the article. In fact, they will still suffer all of the limitations of skin surface electrodes for reading brain activity. Invasive implanted electrodes are still far superior in terms of creating a detailed interface with brain activity.

Such tattoo electrodes, therefore, will not be very good at reading brain signals. This will be a significant limitation for controlling devices (what the headline writer thought they could call “telekinesis”). This will mostly be just a more portable version of existing brain-machine interface technology, and does nothing to address the inherent limitations of using skin surface electrodes.

It is possible to use such electrodes for BMI and therefore to control devices, but such control is much more crude than is allowed for with brain surface electrodes. The article makes one quick mention of this, quoting the developer, Todd Coleman:

Invasive brain implants remain better at reading brain activity, Coleman notes.

What about telepathy? There are potentially two methods the article touches on that could create the effect of telepathy – remotely communicating with just thoughts. The first is reading thoughts from the brain through BMI. As stated above, this technology does not advance the BMI itself, just makes them more portable and versatile. Skin surface electrodes would likely not have the resolution necessary to decode actual thoughts.

I could also point out that this technology has nothing to do with developing the software necessary to decode electrical brain activity into words.

The second approach is more feasible, and the article refers to this as “telepathy-like.” This approach is to use subvocalizations – minute muscle movements that people tend to involuntarily make when thinking words. If you say a sentence in your mind, you will subtly move your facial, lingual, and throat muscles in the same way you would when actually speaking those words.

Skin surface electrodes could theoretically be used to detect these muscle movements, send this information to a device which could then decode them into the words they represent. There is some research into this technology, but no one has yet developed it (that I can find).

This is more accurately called “silent communication” rather than telepathy – because the signals are not coming directly from the brain but rather from muscles. It’s really no more telepathy than actual speaking.

The tattoo leads may have applications in detecting subvocalizations. If this technology pans out there could be numerous applications – dictating, communicating underwater or in space, taking notes or communicating in a location where speaking out loud is inappropriate or undesirable, or silent voice commands for devices.

Overall the tattoo leads are an intriguing technology, and reflect recent advances toward making thin and flexible electronics. It’s unfortunate that communicating the real advances represented here was muddied with sensational and misleading reporting.

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