‘Brain reader’ could restore ability to speak

A DEVICE that can effectively read your brain could give the power of speech back to those who have lost it.

The prototype machine uses electrodes inserted into the user’s brain to pick up on patterns and translates them into sounds using a synthesiser.

It works by decoding the brain signals we produce when we move our vocal apparatus, our jaw, mouth, larynx, lips and tongue. It means that even though someone has lost their voice due to muscular paralysis or nerve damage, if they can still imagine moving their lips and mouth they could still speak.

The device can produce words at the pace of a normal conversation – allowing people to speak at 150 words per minute.

Current machines operate on the user picking out just one letter at a time, a painstaking process that limits them to around 8-10 words per minute.

The research, led by Dr Edward Chang from the University of California at San Francisco, is reported in the latest issue of Nature. The scientists wrote: ‘Our results may be an important next step in realising speech restoration.’

To create the machine, scientists first analysed the brain signals produced in people’s minds when they talk.

To do so, five volunteers with normal speaking ability read several hundred sentences aloud, training the device.

Using the recordings, the US team devised a system capable of translating brain signals responsible for individual movements of the vocal tract.

Finally, the decoded signals were fed to a computer linked to a voice synthesiser.

The late physicist Stephen Hawking spoke by twitching his cheek, which allowed him to move a cursor on a computer screen to pick out letters and form words spoken by a speech synthesiser – at a rate of about ten words per minute.