A paralysed woman, who is "almost completely locked in," has become the first person to use a fully implanted brain-computer interface at home in day-to-day life without constant doctor supervision.

The work was presented at the annual Society for Neuroscience meeting by Nick Ramsey, a specialist in brain-computer interfaces (BCI) at the Brain Center Rudolf Magnus at UMC Utrecht in the Netherlands. The research paper is published this month in the New England Journal of Medicine.

The patient, who is 58 years old and wishes to remain anonymous, was diagnosed with amyotrophic lateral sclerosis (ALS) in 2008. ALS, also known as Lou Gehrig's disease or motor neurone disease, destroys the neurons that are required for voluntary muscle control. There's no known cure. Within a couple of years, ALS usually causes complete paralysis. In this case the patient still has control of her eyes, but that's about it.

The doctors and engineers at UMC Utrecht installed a relatively simple brain implant called an electrocorticograph (ECoG). An ECoG is very similar to an EEG, only the electrical sensors are placed inside your skull against your brain, rather than externally on your scalp. Thus, the readings from an ECoG are a little sharper than an EEG, though no where near as clear or high-resolution as other techniques. The most important thing in this case, though, is that the ECoG implant and computer interface are very small and lightweight, letting the patient use it at home or outside without supervision or support.

The ECoG implant used by the patient consists of four electrode strips, two on the region of her brain that would control the movements of her right hand, and two more over an area that would be used for counting backwards. For now, only the hand-moving electrodes are used; the other is a backup, in case her brain degenerates.

Each electrode strip is about 5 centimetres long, with four small electrodes in a line. During the surgery to install the implant, leads from the electrodes are connected to an amplifier and transmitter device placed subcutaneously below the left clavicle. To activate the implant, another device is placed on the patient's chest, which wirelessly connects to the transmitter and outputs the data to a receiver—and then onward to a tablet computer (see diagram above).

To make use of the BCI, the patient first had to do a bunch of training sessions (playing Pong and whack-a-mole) so that she could learn how to use the correct region of her brain to perform a "brain click"—thinking about moving her right hand for about 1 second. Ramsey says she had an accuracy of 95 percent after six months of training, but even then it's still not the fastest input method: it takes about 20 seconds to select a letter from an on-screen keyboard; a few minutes to write a word.

It sounds like the patient still primarily uses her normal eye-tracking input method when she's indoors because it's faster, but she switches over to the brain implant when she's outside because the eye-tracker doesn't work so well in bright light. ALS may eventually render her eye muscles unusable, too, in which case the brain implant will be very handy indeed. “Now I can communicate outdoors when my eye-track computer doesn’t work,” said the patient, as quoted by New Scientist. “I’m more confident and independent now outside.”

Moving forward, Ramsey said that one of the main focuses is to improve the software on the tablet, so that typing is faster (presumably via autocomplete tech), and so that brain clicks can be used for a wider range of functions—such as turning the TV on, tweaking the temperature of the house, making a phone call, and so on. “My dream is to be able to drive my wheelchair," said the patient.

If you'd like some further reading, New Scientist has a rather fascinating interview with the first person to use a brain implant at home.

The New England Journal of Medicine, 2016. DOI: 10.1056/NEJMoa1608085