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August 14, 2025<\/p>\n
4 min read<\/p>\n
New Brain Device Is First to Read Out Inner Speech<\/p>\n
A new brain prosthesis can read out inner thoughts in real time, helping people with ALS and brain stem stroke communicate fast and comfortably<\/p>\n
By Emma R. Hasson edited by Allison Parshall<\/span><\/p>\n Andrzej Wojcicki\/Science Photo Library\/Getty Images<\/p>\n After a brain stem stroke left him almost entirely paralyzed in the 1990s, French journalist Jean-Dominique Bauby wrote a book about his experiences\u2014letter by letter, blinking his left eye in response to a helper who repeatedly recited the alphabet. Today people with similar conditions often have far more communication options. Some devices, for example, track eye movements or other small muscle twitches to let users select words from a screen.<\/p>\n And on the cutting edge of this field, neuroscientists have more recently developed brain implants that can turn neural signals directly into whole words. These brain-computer interfaces (BCIs) largely require users to physically attempt to speak, however\u2014and that can be a slow and tiring process. But now a new development in neural prosthetics changes that, allowing users to communicate by simply thinking what they want to say.<\/p>\n The new system relies on much of the same technology as the more common \u201cattempted speech\u201d devices. Both use sensors implanted in a part of the brain called the motor cortex, which sends motion commands to the vocal tract. The brain activation detected by these sensors is then fed into a machine-learning model to interpret which brain signals correspond to which sounds for an individual user. It then uses those data to predict which word the user is attempting to say.<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n But the motor cortex doesn\u2019t only light up when we attempt to speak; it\u2019s also involved, to a lesser extent, in imagined speech. The researchers took advantage of this to develop their \u201cinner speech\u201d decoding device and published the results on Thursday in Cell. The team studied three people with amyotrophic lateral sclerosis (ALS) and one with a brain stem stroke, all of whom had previously had the sensors implanted. Using this new \u201cinner speech\u201d system, the participants needed only to think a sentence they wanted to say and it would appear on a screen in real time. While previous inner speech decoders were limited to only a handful of words, the new device allowed participants to draw from a dictionary of 125,000 words.<\/p>\n A participant is using the inner speech neuroprosthesis. The text above is the cued sentence, and the text below is what’s being decoded in real-time as she imagines speaking the sentence.<\/p>\n \u201cAs researchers, our goal is to find a system that is comfortable [for the user] and ideally reaches a naturalistic ability,\u201d says lead author Erin Kunz, a postdoctoral researcher who is developing neural prostheses at Stanford University. Previous research found that \u201cphysically attempting to speak was tiring and that there were inherent speed limitations with it, too,\u201d she says. Attempted speech devices such as the one used in the study require users to inhale as if they are actually saying the words. But because of impaired breathing, many users need multiple breaths to complete a single word with that method. Attempting to speak can also produce distracting noises and facial expressions that users find undesirable. With the new technology, the study’s participants could communicate at a comfortable conversational rate of about 120 to 150 words per minute, with no more effort than it took to think of what they wanted to say.<\/p>\n Like most BCIs that translate brain activation into speech, the new technology only works if people are able to convert the general idea of what they want to say into a plan for how to say it. Alexander Huth, who researches BCIs at the University of California, Berkeley, and wasn\u2019t involved in the new study, explains that in typical speech, \u201cyou start with an idea of what you want to say. That idea gets translated into a plan for how to move your [vocal] articulators. That plan gets sent to the actual muscles, and then they carry it out.\u201d But in many cases, people with impaired speech aren\u2019t able to complete that first step. \u201cThis technology only works in cases where the \u2018idea to plan\u2019 part is functional but the \u2018plan to movement\u2019 part is broken\u201d\u2014a collection of conditions called dysarthria\u2014Huth says.<\/p>\n According to Kunz, the four research participants are eager about the new technology. \u201cLargely, [there was] a lot of excitement about potentially being able to communicate fast again,\u201d she says\u2014adding that one participant was particularly thrilled by his newfound potential to interrupt a conversation\u2014something he couldn\u2019t do with the slower pace of an attempted speech device.<\/p>\n To ensure private thoughts remained private, the researchers implemented a code phrase: \u201cchitty chitty bang bang.\u201d When internally spoken by participants, this would prompt the BCI to start or stop transcribing.\u00a0<\/p>\n Brain-reading implants inevitably raise concerns about mental privacy. For now, Huth isn\u2019t concerned about the technology being misused or developed recklessly, speaking to the integrity of the research groups involved in neural prosthetics research. \u201cI think they\u2019re doing great work; they\u2019re led by doctors; they\u2019re very patient-focused. A lot of what they do is really trying to solve problems for the patients,\u201d he says, \u201ceven when those problems aren\u2019t necessarily things that we might think of,\u201d such as being able to interrupt a conversation or \u201cmaking a voice that sounds more like them.\u201d\u00a0<\/p>\n For Kunz, this research is particularly close to home. \u201cMy father actually had ALS and lost the ability to speak,\u201d she says, adding that this is why she got into her field of research. \u201cI kind of became his own personal speech translator toward the end of his life since I was kind of the only one that could understand him. That\u2019s why I personally know the importance and the impact this sort of research can have.\u201d<\/p>\n The contribution and willingness of the research participants are crucial in studies like this, Kunz notes. \u201cThe participants that we have are truly incredible individuals who volunteered to be in the study not necessarily to get a benefit to themselves but to help develop this technology for people with paralysis down the line. And I think that they deserve all the credit in the world for that.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":" August 14, 2025 4 min read New Brain Device Is First to Read Out Inner Speech A new brain prosthesis can read out inner thoughts in real time, helping people with ALS and brain stem stroke communicate fast and comfortably By Emma R. Hasson edited by Allison Parshall Andrzej Wojcicki\/Science Photo Library\/Getty Images After a<\/p>\n","protected":false},"author":1,"featured_media":15785,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[50],"tags":[2121,1965,2563,1053],"class_list":{"0":"post-15784","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-brain","9":"tag-device","10":"tag-read","11":"tag-speech"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/15784","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=15784"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/15784\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/15785"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=15784"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=15784"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=15784"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}On supporting science journalism<\/h2>\n