Key takeaways
- A brain-computer interface (BCI) reads signals from the brain and turns them into text, speech or computer commands. Studies in the last few years have shown people with paralysis communicating this way.
- In a 2023 Nature study, a participant with ALS reached 62 words per minute. In a 2024 New England Journal of Medicine study, a speech implant reached 97.5% accuracy over 8.4 months.
- These are research studies with a handful of people, not products you can buy. The numbers come from single participants or small groups.
- In September 2026 an NIH-funded team reported a system that decodes speech and gestures at the same time, as a “proof-of-concept.”
This article is general information about published research, not medical advice.
What a BCI does
Many people with ALS (amyotrophic lateral sclerosis) or brainstem strokes lose the ability to move or speak. The NIH says eye-tracking technology, the current standard of care, allows text-to-speech, but it is “slow, offer[s] limited forms of expression, and can be physically exhausting to use.” A BCI tries a different route: sensors on or in the brain record the activity that would normally drive speech or movement, and software decodes it.
Typing by imagining handwriting (Nature, 2021)
In a 2021 study in Nature, researchers decoded attempted handwriting movements from the motor cortex of a participant whose hand was paralysed by a spinal cord injury. The participant reached 90 characters per minute with 94.1% raw accuracy online, and over 99% accuracy offline with an autocorrect. The authors said this was faster than any other BCI reported and comparable with typical smartphone typing speeds for the participant’s age group (115 characters per minute).
Speech from the brain (Nature, 2023)
A 2023 Nature study used tiny electrode arrays implanted in the brain of a participant with ALS who could no longer speak intelligibly. The reported results:
- 9.1% word error rate on a 50-word vocabulary.
- 23.8% word error rate on a 125,000-word vocabulary, which the authors described as the first successful demonstration of large-vocabulary decoding.
- 62 words per minute, which the authors say is 3.4 times as fast as the previous record, and compares with about 160 words per minute in natural conversation.
A word error rate of 23.8% means roughly one word in four was wrong. It was a milestone, but not yet like normal speech.
A faster, more accurate speech implant (NEJM, 2024)
A 2024 study in the New England Journal of Medicine followed a 45-year-old man with ALS who had four microelectrode arrays implanted in his brain. The paper reported:
- 99.6% accuracy on a 50-word vocabulary on the first day of use, 25 days after surgery.
- 90.2% accuracy on a 125,000-word vocabulary on the second day, after about 1.4 more hours of training.
- 97.5% accuracy sustained over 8.4 months, and self-paced conversation at about 32 words per minute for more than 248 hours in total.
The authors concluded this level of performance was “suitable to restore conversational communication after brief training” in this person. It was one participant, in a trial registered as BrainGate2.
A less invasive route (JAMA Neurology, 2023)
Most implants need open-brain surgery. The SWITCH study tested a device called a Stentrode, delivered by catheter through the jugular vein to a blood vessel near the brain’s motor area. It was a first-in-human study at one hospital in Australia. Four patients with severe paralysis (ALS or primary lateral sclerosis) completed 12 months of follow-up with no serious adverse events, and no vessel blockage or device migration. All four controlled a computer with the BCI. The authors said it was an alternative to open-brain surgery and could promote wider and more rapid translation of BCIs, but the study was very small.
Speech and gestures at once (NIH, September 2026)
On September 14, 2026, the NIH announced results from an NIH-funded team at the University of California, San Francisco. Using sensors on the surface of the brain’s motor cortex, they decoded speech and upper-body gestures at the same time in three patients and controlled a full-body virtual avatar in two. The NIH said this was the first system to enable both at once. The lead author called it a “proof-of-concept.” The system used a wired connection to external equipment, and the team said it will “soon test” a fully implantable wireless version.
What these studies do not show
- These are very small studies. Typically one to five participants, chosen for the trial.
- They are research devices. The FDA’s 2021 guidance on implanted BCIs is written for the studies (investigational device exemptions) that test them, and says the field is moving from discoveries to “translational applications and market access.” This article does not claim any implanted BCI is approved for sale.
- They need surgery and a team. Most involve brain implants, training with researchers and equipment.
- Accuracy varies. The same system can score 99.6% on 50 words and 90.2% on a 125,000-word vocabulary.
- Long-term safety is still being studied. The reports above follow people for months or about a year.
What to take from this
BCIs are no longer science fiction for people with paralysis who take part in trials, and the results are improving quickly. They are not yet a treatment you can ask your doctor for. If you or a family member has ALS or paralysis and are interested, a doctor or the registry of clinical trials at ClinicalTrials.gov is the place to begin. (The 2024 NEJM study is listed there as NCT00912041.)
For other fast-moving health technology, see our guide to AI and diagnosis.
Frequently asked questions
What is a brain-computer interface? A system that records brain activity and decodes it into commands, text or speech.
Who can use one today? Only participants in clinical trials. The studies here involved people with ALS, spinal cord injury or severe paralysis.
How fast is it? Up to 62 words per minute in a 2023 study, compared with about 160 in natural conversation.
Do you need brain surgery? Most of the studies above used implants placed by open-brain surgery. The Stentrode study used a catheter through a blood vessel instead.
Has the FDA approved a BCI? This article doesn’t claim that. The FDA has published guidance for studies of implanted BCIs for paralysis or amputation.
Information checked on: November 13, 2026. This field changes quickly, so check current sources.
Sources
- High-performance brain-to-text communication via handwriting. Nature, 2021
- A high-performance speech neuroprosthesis. Nature, 2023
- An Accurate and Rapidly Calibrating Speech Neuroprosthesis. New England Journal of Medicine, 2024
- Assessment of Safety of a Fully Implanted Endovascular Brain-Computer Interface for Severe Paralysis in 4 Patients (SWITCH study). JAMA Neurology, 2023
- National Institutes of Health, “Neuroprosthesis for paralysis enables simultaneous speech and body language” (September 14, 2026)
- US Food and Drug Administration, Implanted Brain-Computer Interface (BCI) Devices for Patients with Paralysis or Amputation: guidance (May 2021)
