A neuroprosthesis, a device that replaces missing neurological functions, holds the promise of restoring the ability to communicate for patients who are unable to speak or type due to paralysis.
A study published in Nature Communications reports on a neuroprosthesis that decodes the brain activity of an aphasic paralyzed subject as the subject silently tries to spell out words to form complete sentences.
The researchers designed this neural prosthesis to translate brain activity into individual letters that spell out complete sentences in real time.
They then applied it to a patient who had limited communication due to severe vocal cord and limb paralysis.
In the test, the device was able to decode the subject’s brain activity and then generate sentences from a vocabulary of 1,152 words at a rate of 29.4 characters per minute, with an average character error rate of 6.13 percent, as the subject tried to pronounce each letter silently.
Through further experiments, the researchers found that this method could be generalized to vocabularies containing more than 9,000 words with an average error rate of 8.23%.
This study suggests that a voiceless-controlled speech neural prosthesis can generate sentences through a spelling-based approach.