Brain Implants may Restore Mobility in Stroke Patients With Partial Paralysis

by VR Sreeraman on Nov 14 2008 1:01 PM

Scientists suggest that neuroprosthetic brain implants may help stroke patients to overcome partial paralysis.

The researchers from Washington University School of Medicine in St. Louis discovered that implants known as brain-computer interfaces (BCI) may be able to detect activity on one side of the brain that is linked to hand and arm movements on the same side of the body.

They hope to use these signals to guide motorized assistance mechanisms that restore mobility in partially paralyzed limbs.

"In recent years, though, we've come to realize that there's actually some ipsilateral, or same-sided control signals involved in movement," said senior author Dr Eric C. Leuthardt, assistant professor of neurological surgery, of neurobiology and of biomedical engineering at Washington University School of Medicine in St. Louis and a physician at Barnes-Jewish Hospital.

"Now we've shown these signals can be detected and are separable from signals that control the opposite side of the body, which means we may be able to use a BCI to restore function," he added.

For the new study, researchers worked with six epilepsy patients. To identify brain areas where seizures originated for possible surgical removal, physicians had temporarily implanted grids of electrodes on the surfaces of patients' brains.

This allowed the researchers to ask the patients to perform tasks with their hands and check if the electrode grids could pick up ipsilateral brain signals during the tasks.

"We were able to identify distinct anatomic locations in the brain where these ipsilateral hand control signals occur and to show that they typically are found in the lower-frequency regions of the spectrum of brain activity detected by the BCI," said Leuthardt.

"Three of our patients could use these signals or opposite-sided hand control signals to move a computer cursor on a screen."

BCIs bridge gaps from brain damage and other injuries by using implanted electrodes to link the brain to a computer.

The implant relays brain signals to the computer, which interprets those signals to control prosthetic devices or other means of interacting with the environment.

The study was published online in the journal Stroke.