More MS news articles for April 2002

Neurosurgeons Use New Methods for Motor Restoration

Researchers hope to restore neurological function to patients through direct brain to computer interface. The study will be presented during the 70th Annual Meeting of the American Association of Neurological Surgeons.

American Association of Neurological Surgeons (AANS)

CHICAGO (April 8, 2002) - Researchers hope to restore neurological function to patients through direct brain to computer interface. The study, "Direct Cortical Interface for Motor Restoration," will be presented by Robert E. Isaacs, MD, and Andrew B. Schwartz, PhD, on Monday, April 8, from 2:45 to 5:30 p.m., during the 70th Annual Meeting of the American Association of Neurological Surgeons (AANS).

By studying movement information within the brain, neurosurgeons are learning how to eavesdrop on the brain to control prosthetic devices such as computer cursors, artificial arms and paralyzed limbs. This study shows that a direct brain to computer interface for motor restoration is now feasible.

"Neurons from many parts of the nervous system are sensitive to movement direction," said Robert E. Isaacs, MD, an author of the study and AANS member. "Cells associated with arm movement generally have functions that span all directions, suggesting that all arm movement cells contribute to each movement and behave as a large population."

The authors have developed a new method to quickly and accurately predict movement behavior from a cortical signal using instantaneous discharge rates. This new method compares "thought" or neural activity to the instantaneous velocity (direction and magnitude) of hand movement. The population of motor cortical cell activity alters as the arm moves; the key is to teach a computer how to define these characteristic changes. Once the computer learns how to interpret neural activity, thought can then be used to drive some effector device (i.e. a robot arm) or even potentially one day it could be used to reanimate a paralyzed limb.

In the study, rhesus monkeys were surgically implanted with chronic electrodes centered on the proximal arm area of the motor cortex. The proof that chronic (or long-term) electrodes could be used for this purpose is a key step in the eventual application of this technology into humans.

Neural activity could be isolated from the signals recorded from the electrodes. Current analogue-to-digital technology (cell phones) allows for a real-time acquisition of the signal and conversion to data for functional use.

The recordings tended to stabilize about two weeks after the implant surgery. Most of the units were the same from day to day. Over a two-month period of time, the system was able to predict hand movement. The authors developed an algorithm that was operational in real time. Significant ability to predict movement in real-time can currently be shown.

In the next phase of this project, the animal will learn to pick up food morsels by using the control signs to move a robotic arm. The authors expect that the algorithm will accurately predict neural output, and that the animal will learn to adapt--optimizing the signal to maximize the control of its new "hand."

In summary, it might well be possible one day soon to restore neurological function through a direct brain to computer interface.

Founded in 1931 as the Harvey Cushing Society, the American Association of Neurological Surgeons is a scientific and educational association with nearly 5,500 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery. Neurological surgery is the medical specialty concerned with the prevention, diagnosis, treatment and rehabilitation of disorders that affect the entire nervous system including the spinal column, spinal cord, brain and peripheral nerves.

Media Representatives: If you would like to cover the meeting or interview a neurosurgeon - either on-site or via telephone - please contact the AANS Communications Department at (847) 378-0517 or call the Annual Meeting Press Room beginning Monday, April 8 at (312) 949-3201 (3202).

Heather Monroe -  847/378-0517

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