A paralysed man has "spoken" three different vowel sounds using a voice synthesiser controlled by an implant deep in his brain.

If more sounds can be added to the repertoire of brain signals the implant can translate, such systems could revolutionise communication for people who are completely paralysed.

"We're very optimistic that the next patient will be able to say words," says Frank Guenther, a neuroscientist at Boston University who led the study along with Philip Kennedy at Neural Signals, a firm based in Duluth, Georgia, that produces neural implants.
Conventional speech

Eric Ramsey is 26 and has locked-in syndrome, in which people are unable to move a muscle but are fully conscious.

A brain implant, which requires invasive surgery, may sound drastic. But lifting signals directly from neurons may be the only way that locked-in people like Ramsey, or those with advanced forms of ALS, a neurodegenerative disease, will ever be able to communicate quickly and naturally, says Guenther.

Devices that rely on interpreting residual muscle activity, such as eye blinks, are no good for people who are completely paralysed, while those that use brain signals captured by scalp electrodes are slow, allowing typing on a keyboard at a rate of one to two words per minute.

"Our approach has the potential for providing something along the lines of conventional speech as opposed to very slow typing," he says.