Hear speech by brainwaves

Hear and hear thoughts and thoughts based on brainwaves?

01.02.2012

Heard speech can be detected by brain waves, US scientists report on the portal „PLoS Biology“. Perhaps thoughts could be overheard with a comparable procedure, so the daring thesis of the researchers.

The US research team led by Brian Pasley of the Helen Wills Neuroscience Institute at the University of California at Berkeley has found a way to recognize words heard from brainwaves. From the nerve signals of their subjects, the scientists were able to deduce what they just heard. Brian Pasley and colleagues conclude that the human brain employs established mechanisms „decode the very variable acoustic inputs into meaningful elements of the language such as phonemes and words.“

Electrodes in the brain capture the neural signals of speech processing
To capture data on brain language processing, US researchers used a very rare neurosurgical technique used in the treatment of epilepsy. As part of a neurosurgical intervention, Brian Pasley and colleagues were able to place electrodes in the brain of 15 epilepsy patients, and so on „neuronal activity“ right at the „cortical surface“ - the brain region important for speech recognition. That was the way it was „a unique opportunity“ for the study of speech recognition in the human brain, so the statement of the US researchers. In a first step of the experiment, the subjects were read several English words, whereby the US scientists identified the electrical signals occurring in the brain. On the basis of these determined neuronal signals, the scientists developed a computer model that can convert the recorded nerve signals back into sounds. These computer sounds were played to other fellow researchers and relatively often recognized as the words originally spoken. Even if not every word could be exactly identified, the speech recognition was well above a chance to be expected, the US scientists said.

Mind reading based on the brain waves?
There „some evidence“ for it, „that perception and imagination are similar in the brain“, speculated study director Brian Pasley already about a next procedural step in which the scientists could literally mind-reading. „If you understood the relationship between the brain records and the sound well enough, it would be“, according to the US scientist, „possible to make audible what a person is thinking.“ First of all, however, it has to be clarified whether even merely imaginary words produce comparable brain signals as words heard. If speculation by US scientists is confirmed, the electrodes in the brain could find medical use in a variety of ways. It might even be possible to enable speechless people to communicate again through words. However, numerous forms of abuse of such a method are conceivable. Thus, the electrodes in the brain could possibly replace previous methods of torture and be used to reach the thoughts of other people. Regardless of which applications are being developed based on current research, Brian Pasley, the US neurosurgeon, has definitely taken an important step toward understanding brain language processing. (Fp)

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Picture: Gerd Altmann