Brain Implant may Help Restore Speech in Paralysed Person

by VR Sreeraman on Nov 15 2007 7:17 PM

US neuroscientists are hoping to restore speech to a man who has been paralysed for eight years, and is unable to communicate other than through eye movements, with the help of a brain implant.

Eric Ramsey had a wireless electrode implanted about 6 millimetres below the surface of his brain in 2004. The electrode records the electronic pulses sent by 41 neurons that surround it in an area of the brain that generates the movements of the tongue and mouth when speech is being generated.

An analysis of the signals that are generated while Ramsey imagines speaking has enabled the researchers to developed software, which they believe may one day turn his thoughts into speech.

In a series of experiments over the last few years, Ramsey has imagined saying three vowel sounds: “oh”, “ee” and “oo”. The study of his brain activity has helped researchers identify patterns associated with the different sounds.

The researchers believe that they can correctly identify the sound Ramsey imagines around 80 per cent of the time. Ramsey’s thoughts would be translated into sounds, which he would hear immediately, with the help of a computer, Jonathan Brumberg of Boston University revealed while making a presentation at that Society for Neuroscience meeting in San Diego, California.

The researchers believe that the process would enable Ramsey to tune his thoughts so that he might consistently produce the vowel he wanted. “That will be really exciting. We hope it will be a breakthrough,” says Joe Wright of Neural Signals, a company based in Duluth, Georgia, that has helped develop the technology Ramsey is using.

Once the researchers achieve this target, they will extend the range of sounds to other vowels and also consonants, with the ultimate aim of enabling Ramsey to hold conversations.

Since this is the first time that such an experiment is being done, the researchers concede that it will take a long time before they may restore speech to Ramsey. “Conversation is what we’re hoping for, but we’re pretty far from that,” says Wright.