Summary: Researchers report epidural stimulation helped two people with quadriplegia to improve voluntary hand movements.
In past research, electrical stimulation of the lower spinal cord, combined with motor training, allowed patients who were paralyzed below the chest because of spinal cord injuries to regain some voluntary movement of their legs.
A team led by Dr. Daniel Lu at the University of California, Los Angeles (UCLA), set out to test whether epidural stimulation could restore some hand strength and control in people with tetraplegia, also known as quadriplegia (the loss of use of all 4 limbs). The study was funded in part by NIH’s National Institute of Biomedical Imaging and Bioengineering (NIBIB) and other NIH components. Results appeared online on May 18, 2016, in Neurorehabilitation and Neural Repair.
The study included 2 people with severe injuries to their cervical spines—the spinal cord at the level of the neck. Both had been paralyzed for more than 18 months. They were implanted with an array of 16 electrodes that spanned their injury sites. The participants practiced grasping and moving a handgrip while receiving varying levels of electrical pulses from the devices. One person was tested daily over 7 days while the other had weekly sessions for 8 weeks.
The participants’ hand strength improved over the course of a single session. With additional sessions, the force they could generate gradually increased. Hand control, including hand opening and closing, improved as well. These effects were maintained even in the absence of stimulation.
Both individuals made large gains in feeding, dressing, bathing, and grooming. Their mobility in bed and ability to get themselves in and out of bed improved as well. One participant regained the ability to pick up and drink from a cup.
This is the first time that this approach has been used to improve function in the upper limbs of people with severe spinal cord injuries. The researchers believe that stimulation affects the spinal cord’s underlying circuitry, reawakening networks that have been silent since the injury. The circuitry starts to relearn and reorganize to become more functional.
“In this study we demonstrate that through cervical epidural stimulation, hand and upper extremity function can be substantially improved, imparting the ability to participate in activities of daily living, self-care and transfer, and to live independently,”Lu says.
“Even relatively minor gains in function of the upper limb can make huge differences in the quality of life for a person who can’t grasp anything,” adds co-author Dr. V. Reggie Edgerton of UCLA.
The team is planning future studies in more patients to further evaluate the long-term safety and optimal conditions for using the approach. The group reported last year on a noninvasive technique that goes through the skin, called transcutaneous stimulation. That approach allowed 5 men with complete lower-limb paralysis to make step-like movements. The team is currently investigating the approach in the upper body as well.
Funding: NIH’s National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institute of Neurological Disorders and Stroke (NINDS), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), and National Center for Advancing Translational Sciences (NCATS); UCLA Department of Neurosurgery; J. Yang & Family Foundation; Paul & Daisy Soros Fellowship for New Americans; and Russian Science Foundation.
Image Source: This NeuroscienceNews.com image is adapted from the NIH press release.
Original Research: Abstract “Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients” by Daniel C. Lu, V. Reggie Edgerton, Morteza Modaber, Nicholas AuYong, Erika Morikawa, Sharon Zdunowski, Melanie E. Sarino, Majid Sarrafzadeh, Marc R. Nuwer, Roland R. Roy, and Yury Gerasimenko in Neurorehabilitation and Neural Repair. Published online May 18 2016 doi:10.1177/1545968316644344
Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients
Background. Paralysis of the upper limbs from spinal cord injury results in an enormous loss of independence in an individual’s daily life. Meaningful improvement in hand function is rare after 1 year of tetraparesis. Therapeutic developments that result in even modest gains in hand volitional function will significantly affect the quality of life for patients afflicted with high cervical injury. The ability to neuromodulate the lumbosacral spinal circuitry via epidural stimulation in regaining postural function and volitional control of the legs has been recently shown. A key question is whether a similar neuromodulatory strategy can be used to improve volitional motor control of the upper limbs, that is, performance of motor tasks considered to be less “automatic” than posture and locomotion. In this study, the effects of cervical epidural stimulation on hand function are characterized in subjects with chronic cervical cord injury.
Objective. Herein we show that epidural stimulation can be applied to the chronic injured human cervical spinal cord to promote volitional hand function.
Methods and Results. Two subjects implanted with a cervical epidural electrode array demonstrated improved hand strength (approximately 3-fold) and volitional hand control in the presence of epidural stimulation.
Conclusions. The present data are sufficient to suggest that hand motor function in individuals with chronic tetraplegia can be improved with cervical cord neuromodulation and thus should be comprehensively explored as a possible clinical intervention.
“Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients” by Daniel C. Lu, V. Reggie Edgerton, Morteza Modaber, Nicholas AuYong, Erika Morikawa, Sharon Zdunowski, Melanie E. Sarino, Majid Sarrafzadeh, Marc R. Nuwer, Roland R. Roy, and Yury Gerasimenko in Neurorehabilitation and Neural Repair. Published online May 18 2016 doi:10.1177/1545968316644344