It's nothing short of a miracle! A group of scientists have given an almost totally paralyzed man a chance to speak again! An electrode implanted in his stroke-stricken brain has helped him regain his sense of speech.
Erik Ramsey was left almost totally paralyzed after a brain-stem stroke, however his mental faculties remained intact.
AdvertisementIn 2004, Philip Kennedy's team at Neural Signals, a company based in Duluth, Georgia, US implanted an electrode in his speech-motor cortex, hoping that the signal from Ramsey's cortex could help in restoring his speech.
Another team led by Frank Guenther at Boston University, Massachusetts, working on the same problem developed software that could identify and translate the patterns of brain activity during speech.
Kennedy and Guenther are now working together to read the signals from Ramsey's implanted electrode and work out the shape of the vocal tract that Ramsey is trying to form.
The information can then be fed to a vocal synthesizer that produces the corresponding sound.
The software is translating Ramsey's thoughts into sounds in real time so that hears his "voice" as he makes a sound, effectively bypassing the damaged region of his brain stem.
With the immediate feedback on his pronunciation, Ramsey is able sharpen his speaking skills.
The researchers found that while producing a vowel sound such as "ee" or "oh", Ramsey was right around 45 pct of the time and over few weeks his accuracy went up to 80 pct.
"The synthesizer is good for vowels, but not for consonants," New Scientist quoted Guenther, as saying.
"We're going to move to a synthesizer with better consonant capabilities, where the patient would have more control over jaw height, for instance," he added.
"Right now, Erik is controlling two dimensions to create vowels."
"But for consonants he would need seven dimensions - three to control tongue movement, two for lip movement, and one each for jaw and larynx height," he said.
Klaus-Robert Moller at the Technical University of Berlin in Germany believes that the technique might not be apt for fully "locked-in" patients, who can't control any muscles.
"If you have a completely locked-in patient then maybe the brain begins to degrade because they're not able to control anything," he says. "Those patients might be completely unable to communicate even using a brain-control interface," he added.
The results were presented at the Acoustics'08 Paris conference in France.