Investigators at Johns Hopkins Medicine are studying how a small medical device can be placed on the brain before some patients have brain surgery to make the operation more precise, support recovery and assist with communication.

Their findings from a small feasibility study using a brain-computer interface (BCI) that’s smaller than a postage stamp were published Feb. 1 in Neurosurgical Focus.

“We’re always looking for ways to innovate and personalize procedures for patients,” says Kurt Lehner, the first study author and a neurosurgical fellow at Johns Hopkins. “One of the major challenges for BCI studies has been finding ways to trial new approaches to neural decoding without implanting a device permanently.”

BCIs are devices that connect electrical activity in a person’s brain to an external device, such as a computer or prosthetic limb. In most cases, they are permanently implanted and can provide life-changing benefits to people with paralysis, neurological conditions or speech impairments.

“Our goal is to learn how to preserve or restore neurological function using compact devices that enhance the precision and efficacy of neurosurgical procedures and neuroprosthetic devices,” says Nathan Crone, M.D., the senior study author and director of the Johns Hopkins Division of Epilepsy and Clinical Neurophysiology.

For this study, researchers implanted a temporary interface in four patients undergoing craniotomies. The device successfully mapped neural activity during the procedures and achieved high accuracy in helping participants communicate (by expressing four words) in addition to moving a cursor on a computer.

A tiny brain-computer interface is shown placed on top of the motor cortex. This model is being studied for its size, flexibility, safety and ability to be easily inserted and removed during surgery.

The researchers were able to connect the BCI to the patient’s neural activity in a very short time — less than 20 minutes (a process that used to take hours over the course of days to weeks) — and recorded activity in areas of the brain involved in patients’ ability to move their hand or speak. This sort of technology will hopefully enable neurosurgeons and neuroscientists to develop new strategies for brain-computer interfaces and potentially provide a more detailed picture of brain function during surgery, Lehner explains.

During the study, patients were able to move a cursor on the computer screen through neural activity. The participants did not experience adverse events using the device.

Studying these types of movements, Lehner and the authors noted, can also provide insight into how BCIs may support larger movement in the future, which could potentially help patients learn how to better use prosthetic legs, arms and hands.

This BCI model, a high-density micro-electrocorticography array, was designed and is being studied for its small size, flexibility, safety and ease of insertion and removal during surgery. It uses over 1,000 electrodes to record activity over a small area of the brain, making it one of the densest recording technologies used in humans to date.

“Concepts that seemed unimaginable decades ago are now becoming widely studied and tested for their ability to help patients who may be recovering from brain cancer or stroke, or living with a neurodegenerative condition like ALS regain control of brain areas that are critical to sending and receiving signals that coordinate language and movement,” says Lehner. “We hope insights from this study and others like it will spur ongoing innovation and research in this field.”

Medically reviewed by Kurt Lehner, M.D.