Deep brain stimulation could potentially lead to immediate enhancements in arm and hand strength and functionality for individuals suffering from traumatic brain injuries or strokes.
Researchers from the University of Pittsburgh School of Medicine announced today in Nature Communications that deep brain stimulation may offer quick improvements in arm and hand strength and function compromised due to traumatic brain injury or stroke.
Positive findings from extensive studies involving both monkeys and humans pave the way for a new clinical use of an already well-established brain stimulation technique, shedding light on the neural processes that contribute to movement challenges following brain injuries.
“The paralysis of arms and hands can severely diminish the quality of life for millions globally,” stated Elvira Pirondini, Ph.D., the lead author and assistant professor of physical medicine and rehabilitation at Pitt. “At this moment, we lack effective treatments for those who have experienced a stroke or traumatic brain injury, but there is an increasing interest in the use of neurotechnologies that stimulate the brain to enhance upper-limb motor capabilities.”
Severe brain injuries or strokes can create lesions that interrupt the neural pathways between the motor cortex—a vital brain area responsible for voluntary movements—and the muscles. This disruption inhibits effective muscle activation, leading to movement impairments, including partial or total paralysis of the arms and hands.
To enhance the activation of existing, albeit weakened, pathways, scientists suggested employing deep brain stimulation (DBS), a surgical method that positions small electrodes in particular regions of the brain to emit electrical impulses that help regulate abnormal brain activities. Over the years, DBS has transformed the treatment landscape for neurological disorders like Parkinson’s disease, providing a mechanism to control previously difficult-to-manage symptoms solely through medication.
“DBS has significantly improved the lives of numerous patients. Now, with ongoing improvements in the precision and safety of these devices, DBS is being considered a promising option for aiding stroke survivors in regaining their motor abilities,” remarked Jorge González-MartÃnez, M.D., Ph.D., a senior project author and head of the surgical team, who also serves as a professor and vice-chair of neurosurgery as well as the director of the epilepsy and movement disorders program at Pitt. “It brings new hope to millions around the globe.”
Drawing inspiration from another successful initiative at Pitt that utilized electrical stimulation of the spinal cord to restore arm functionality in stroke patients, researchers speculated that stimulating the motor thalamus—a deep brain structure serving as a crucial relay for movement control—via DBS could aid in reinstating movements necessary for daily activities, such as gripping objects. However, since this concept was untested prior, they first validated it in monkeys, which possess a similar structure of motor cortex-to-muscle connections as humans.
To investigate how DBS of the motor thalamus enhances voluntary arm movement and optimize the placement of the implant along with the ideal stimulation frequency, scientists tested an FDA-approved stimulation device on monkeys that had brain lesions impairing their hand usage.
Upon activating the stimulation, there was a marked enhancement in muscle activation and grip strength, with no unintended movements observed.
To confirm the procedure’s applicability to humans, the same stimulation settings were applied to a patient preparing to receive DBS in the motor thalamus intended to alleviate arm tremors stemming from a severe motor vehicle accident that had left both arms largely paralyzed.
Immediately after the stimulation was initiated, there was a noticeable improvement in both the range and strength of arm movements: The participant was able to lift a reasonably heavy object and effectively reach for, grasp, and lift a drinking cup with greater proficiency and fluidity than before the stimulation.
To facilitate the adoption of this technology for more patients in clinical settings, researchers are now working on assessing the long-term impacts of DBS, as well as determining whether extended stimulation could further enhance arm and hand functionality in those affected by traumatic brain injuries or strokes.
Contributors to this research include Jonathan Ho, B.S., Erinn Grigsby, Ph.D., Arianna Damiani, M.S., Lucy Liang, M.S., Josep-Maria Balaguer, M.S., Sridula Kallakuri, Lilly Tang, B.S., Jessica Barrios-Martinez, M.D., Vahagn Karapetyan, M.D., Ph.D., Daryl Fields, M.D., Ph.D., Peter Gerszten, M.D., T. Kevin Hitchens, Ph.D., M.B.A., Theodora Constantine, P.A.-C., Gregory Adams, B.S., Donald Crammond, Ph.D., and Marco Capogrosso, Ph.D., all from Pitt.
This research received support from internal funding provided by the departments of Physical Medicine and Rehabilitation and Neurological Surgery at Pitt, along with additional funding from the Walter L. Copeland Foundation, the Hamot Health Foundation, and the National Institutes of Health (R01NS122927-01A1).
