Medical technology: Spinal cord stimulation for upper-limb recovery after stroke

Epidural electrical stimulation of the cervical spinal cord improved arm and hand motor movements and strength in two patients with chronic post-stroke muscle weakness, reports a clinical study in Nature Medicine this week. These data provide preliminary evidence for the potential of spinal cord stimulation (SCS) as a restorative approach for upper-limb recovery after stroke.

Nearly three quarters of people who suffer a stroke exhibit long-lasting deficits in motor control of their arms and hands. These motor deficits persist in part due to the limitations of current neurorehabilitation approaches. Epidural SCS, a clinically approved technology that administers electrical stimulation to the spinal cord, has shown promise in promoting long-lasting recovery of leg motor function in people with spinal cord injury. Despite these encouraging findings, epidural stimulation of the cervical spinal cord to target upper-limb recovery has been largely unexplored.

Marco Capogrosso and colleagues implanted SCS leads for 29 days in the cervical spinal cords of two patients (both female, 31 and 47 years of age) with chronic post-stroke upper-limb weakness, targeting neural circuits that control arm and hand muscles. The authors then showed that continuous epidural SCS of these spinal cord circuits improved arm and hand strength and dexterity in these patients. The treatment also enabled fine motor skills such as opening a lock and manipulating utensils to eat independently, tasks that one patient had been unable to perform for 9 years. Furthermore, the authors showed that the functional benefits of SCS persisted for up to 4 weeks after the stimulation was stopped. They indicate that no serious adverse events were reported with this approach.

The authors conclude that further studies in larger cohorts are needed to validate the safety and efficacy of this approach. However, they suggest that this preliminary evidence indicates that cervical SCS could be used both as an assistive technology, to improve hand and arm motor function in patients when it is turned on, and as a restorative approach, to allow lost motor function to be regained when it is turned off.