[BobbyB]

Turning Thoughts into Action
Published: Jun 28, 2007 Imagine a machine that can sense what you think and act on your commands. Sound scary? Not so for people with paralyzed limbs or debilitating conditions such as Amyotrophic Lateral Sclerosis (Lou Gehrig’s disease). Machines like this could let them communicate and even move artificial limbs.

Many diseases that paralyze people leave their brains unaffected. These people can think about moving or talking but can’t because they have problems in their spinal cord, nerves, muscles, or maybe they don’t have a limb.

Brain-computer interfaces (BCIs) provide a connection. They record electrical activity in the brain and translate it into real commands such as moving a computer cursor or controlling an electric wheelchair. BCIs, already implanted in humans and animals, have potential to change lives.

Restoring speech
For the past 10 years Philip Kennedy has been implanting humans with electrodes, refining ways to record, preserve, and separate signals from the brain. Kennedy started Neural Signals, Atlanta, to work on brain-to-computer interfacing and is now aiming at restoring speech. Patients enrolled in the study, typically brain-stem stroke victims, are implanted with what’s called a Neurotrophic Electrode. It is shaped like a cone with a hollow tip and four gold wires inside. “Brain tissue grows into the tip and we record electrical activity across the Teflon-insulated wires,” says Kennedy. The implant goes inside the brain tissue and is wirelessly powered by a power-induction system which lies just under the scalp.

The system works like this: “We have the patient say a phoneme in his head,” says Kennedy. Phonemes are the smallest unit of sound in a language, for example, the ‘b’ in book, or ‘th’ in that. “There’s a different firing pattern for each phoneme. In one patient, the computer can recognize 32 of the 39 English phonemes.”

Continue to read this article on Medical Design
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