Dr. Frank Guenther and his colleagues at Boston University’s CNS Speech Lab have made a giant step towards allowing a “locked-in” patient to speak by interpreting his thoughts. So far the patient has been able to produce three vowel sounds through a synthesizer and work has begun on consonants. Ultimately, the team hopes that complete words will be possible within 3-5 years.
Most brain-computer interfaces use electrodes attached to the skull. However, Guenther’s team has embedded the electrode in a specific brain region and encouraged neuronal interfacing by impregnating the electrode with neurotrophic factors.
Kerri Smith over at the Nature News explains:
Guenther and his team first had to determine whether the man’s brain could produce the same speech signals as a healthy person’s. So they scanned his brain using functional magnetic resonance imaging (fMRI) while he attempted to say certain vowels.
Once the researchers were happy that the signals were the same, they implanted an electrode — designed by neuroscientist Philip Kennedy of the firm Neural Signals in Duluth, Georgia — into the speech-production areas of the man’s brain. The electrode will remain there for the forseeable future.
Once the electrode was implanted, the team used a computer model of speech that Guenther had developed over the past 15 years to decode the signals coming from the man’s brain and discern which vowel sounds he was thinking about. Guenther presented the results at the Society for Neuroscience meeting in Washington DC on the 19th of November.
Their efforts are appreciated by the patient too. "When we first arrived to install this system he was obviously very excited — you can tell from his involuntary movements, and he was trying to look at us the whole time," Guenther says. As the man’s father told the team, "he really has a new lease on life".
The team’s next step is to train their computer decoder to recognize consonants so that patients can form whole words, and even sentences. They also hope that with developments in technology, they can implant more electrodes in their next patient to transmit a more detailed signal.
Here’s video of the procedure from Dr. Guenther’s lab:
More from the Nature News: Brain implant allows mute man to speak, 21 November 2008, Nature doi:10.1038/news.2008.1247
CNS Speech Lab…
Neural Signals website…
Flashback: Visualized: Hearing Inside the Brain…
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