Posts Tagged ‘microelectrodes’
Implanted Electrodes Loaded With Drugs Could Monitor Brain And Treat It When Necessary
The team is developing a new polymer-coated electrode that can both monitor and treat a patient immediately, a capability that could be life-changing--or even life-saving--for those living with conditions like epilepsy. Their device is basically a microelectrode like any other, but it has been covered in a conductive polypyrrole film. Chambers in the film are loaded up with different drugs and neurotransmitters like dopamine or GABA.
Under certain electrical conditions, the polymer warps in certain ways, and when it does so its pharmaceutical payloads are released. By matching up certain tell-tale electrical signals associated with things like seizures to drugs that inhibit that activity, a microelectrode array can detect something like a seizure at its onset and begin delivering treatment straight to the brain immediately.
Once the polymer coating delivers its drugs, however, it is pretty much impossible to resupply it without basically replacing it--a procedure patients really don’t want to undergo too terribly often. The team is now looking at ways add drug reservoirs, possibly in the form of carbon nanotubes.
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Researchers Translate Thoughts into Speech, Potentially Allowing “Locked-In” Patients to Communicate
The method leaves a lot of room for improvement, but it does prove out some technology that could make thought-to-speech technology more reliable for patients suffering from traumatic brain injuries or illnesses that render them unable to communicate with others. Using two grids of 16 microelectrodes placed over two regions of the brain known to generate human speech, the team was able to record brain signals for 10 useful words – yes, no, hot, cold, thirsty, hungry, goodbye, hello, more and less – and use that data to discern between any two words a patient was thinking between 76 and 90 percent of the time.
But when they tried to distinguish between all ten words at the same time, that success rate dropped to between 28 percent and 48 percent. That’s better than chance – which would be one-in-ten or just 10 percent – but less than reasonably useful.
The electrodes used were non-penetrating, meaning they sit between the patient’s brain and skull, but do not actually poke into the brain. That means they are closer and more sensitive to specific brain waves than externally worn EEG caps, but are less invasive than penetrating electrodes. These electrodes can pick up on weak electrical signals within the brain, meaning they are more nuanced than other brain monitoring sensors and could possibly provide the technological sensitivity needed to get reliable thought-to-speech translation working.
But first the researchers will have to refine their translation techniques to raise the success rates from one-in-four to something more like three-in-four, and ideally be able to distinguish between more than just 10 words. To get to that point, the next round of tests will involve larger, 11-by-11 arrays containing 121 electrodes each. Those larger implants should yield much more brain signal data that could in turn improve translation accuracy to the point that thought-to-speech translation could become a viable clinical solution.
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