Deep brain stimulation instantly improves arm and hand function post-brain injury

Deep brain stimulation may provide immediate improvement in arm and hand strength and function weakened by traumatic brain injury or stroke, University of Pittsburgh School of Medicine researchers report today in Nature Communications.

Encouraging results from extensive tests in monkeys and humans open a path for a new clinical application of an already widely used brain stimulation technology and offer insights into neural mechanisms underlying movement deficits caused by brain injury.

“Arm and hand paralysis significantly impacts the quality of life of millions of people worldwide,” said senior and corresponding author Elvira Pirondini PhD, assistant professor of physical medicine and rehabilitation at Pitt. “Currently, we don’t have effective solutions for patients who suffered a stroke or traumatic brain injury but there is a growing interest in the use of neurotechnologies that stimulate the brain to improve upper-limb motor functions.”

Brain lesions caused by serious brain trauma or stroke can disrupt neural connections between the motor cortex, a key brain region essential for controlling voluntary movement, and the muscles. Weakening of these connections prevents effective activation of muscles and results in movement deficits, including partial or complete arm and hand paralysis.

To boost the activation of existing, but weakened, connections, researchers proposed to use deep brain stimulation, a surgical procedure that involves placing tiny electrodes in specific areas of the brain to deliver electrical impulses that regulate abnormal brain activity. Over the past several decades, deep brain stimulation has revolutionized the treatment of neurological conditions such as Parkinson's disease by providing a way to control symptoms that were once difficult to manage with medication alone.

“Deep brain stimulation has been life-changing for many patients. Now, thanks to ongoing advancements in the safety and precision of these devices, deep brain stimulation is being explored as a promising option for helping stroke survivors recover their motor functions,” said senior author and surgical leader of the project, Jorge González-Martínez MD PhD, professor and vice-chair of neurosurgery and director of the epilepsy and movement disorders program at Pitt. “It offers new hope to millions of people worldwide.”

Taking cues from another successful Pitt project that used electrical stimulation of the spinal cord to restore arm function in individuals affected by stroke, scientists hypothesized that stimulating the motor thalamus – a structure nested deep in the brain that acts as a key relay hub of movement control – using deep brain stimulation could help restore movements that are essential for tasks of daily living, such as object grasping. However, because the theory has not been tested before, they first had to test it in monkeys, which are the only animals that have the same organization of the connections between the motor cortex and the muscles as humans.

To understand the mechanism of how deep brain stimulation of the motor thalamus helps improve voluntary arm movement and to finesse the specific location of the implant and the optimal stimulation frequency, researchers implanted the FDA-approved stimulation device into monkeys that had brain lesions affecting how effectively they could use their hands.

As soon as the stimulation was turned on, it significantly improved activation of muscles and grip force. Importantly, no involuntary movement was observed.

To verify that the procedure could benefit humans, the same stimulation parameters were used in a patient who was set to undergo deep brain stimulation implantation into the motor thalamus to help with arm tremors caused by brain injury from a serious motor vehicle accident that resulted in severe paralysis in both arms.

As soon as the stimulation was turned on again, the range and strength of arm motion was immediately improved: The participant was able to lift a moderately heavy weight and reach, grasp and lift a drinking cup more efficiently and smoothly than without the stimulation.

To help bring this technology to more patients in the clinic, researchers are now working to test the long-term effects of deep brain stimulation and determine whether chronic stimulation could further improve arm and hand function in individuals affected by traumatic brain injury or stroke.

Other authors of this research are Jonathan Ho BS, Erinn Grigsby PhD, Arianna Damiani MS, Lucy Liang MS, Josep-Maria Balaguer MS, Sridula Kallakuri, Lilly Tang BS, Jessica Barrios-Martinez, MD, Vahagn Karapetyan MD PhD, Daryl Fields MD PhD, Peter Gerszten MD, T Kevin Hitchens PhD MBA, Theodora Constantine PA-C, Gregory Adams BS, Donald Crammond PhD, and Marco Capogrosso PhD, all of Pitt.

This research is supported by internal funding from the departments of Physical Medicine and Rehabilitation and of Neurological Surgery at Pitt. Additional funding was provided by the Walter L. Copeland Foundation, the Hamot Health Foundation, and the National Institutes of Health (R01NS122927-01A1).

Source: News Release
University of Pittsburgh
October 1, 2024