scholarly journals Electrical Stimulation Of The Cervical Dorsal Roots Enables Functional Arm And Hand Movements In Monkeys With Cervical Spinal Cord Injury

2020 ◽  
Author(s):  
B. Barra ◽  
S. Conti ◽  
M.G. Perich ◽  
K. Zhuang ◽  
G. Schiavone ◽  
...  

SUMMARYRegaining arm motor control is a high priority for people with cervical spinal cord injury1. Unfortunately, no therapy can reverse upper limb paralysis. Promising neurotechnologies stimulating muscles to bypass the injury enabled grasping in humans with SCI2,3 but failed to sustain whole arm functional movements that are necessary for daily living activities. Here, we show that electrical stimulation of the cervical spinal cord enabled three monkeys with cervical SCI to execute functional, three-dimensional, arm movements. We designed a lateralized epidural interface that targeted motoneurons through the recruitment of sensory afferents within the dorsal roots and was adapted to the specific anatomy of each monkey. Simple stimulation bursts engaging single roots produced selective joint movements. We then triggered these bursts using movement-related intracortical signals, which enabled monkeys with arm motor deficits to perform an unconstrained, three-dimensional reach and grasp task. Our technology increased muscle activity, forces, task performance and quality of arm movements. Finally, analysis of intra-cortical neural data showed that a synergistic interaction between spared descending pathways and electrical stimulation enabled this restoration of voluntary motor control. Spinal cord stimulation is a mature clinical technology4–7, which suggests a realistic path for our approach to clinical applications.

2020 ◽  
Author(s):  
Marco Capogrosso ◽  
Beatrice Barra ◽  
Sara Conti ◽  
Matthew Perich ◽  
Katie Zhuang ◽  
...  

Abstract Regaining arm motor control is critical for people with paralysis. Despite promising results on grasping, no technology could restore effective arm control. Here, we show that electrical stimulation of the cervical spinal cord enabled three monkeys with cervical spinal injury to execute functional arm movements. We designed an epidural interface that engaged surviving spinal circuits via the recruitment of large sensory afferents to produce movement. Simple stimulation bursts produced sustained joint movements which, triggered by movement-related intracortical signals, enabled monkeys with arm paralysis to perform an unconstrained, three-dimensional reach and grasp task. This restoration of voluntary motor control was enabled by the synergistic integration of spared descending commands and electrical stimulation within the spinal cord. The simplicity of this technology promises realistic clinical translation.


2008 ◽  
Vol 18 (2) ◽  
pp. 53-61 ◽  
Author(s):  
Rosalynn Miller ◽  
Milos Popovic ◽  
Adam Thrasher ◽  
Molly Verrier

OBJECTIVE AND IMPORTANCE: To present case studies of two individuals with chronic cervical spinal cord injury (SCI) who participated in functional electrical stimulation (FES) therapy with the objective to restore voluntary grasp function. CLINICAL PRESENTATION: Both individuals (right hand dominant males, age 24 and 31) had a sustained a cervical SCI (C6 and C4-5, respectively) at least 8 years prior to participation in this study. INTERVENTION: Both individuals participated in an individualized FES therapy program for 6 weeks. FES therapy was administered through a regimen of three, one-hour sessions, per week for three months. A single arm of each participant (n = 2) was treated. FES therapy is an integrative intervention strategy combining muscle strengthening, functional movement training and stretching. The participant's hand movement abilities were assessed pre and post FES therapy using the Manual Muscle Test (MMT), a modified Sollerman Hand Function Test (mSHFT), and the Reach, Grasp, Transport and Release Task (RGTR). DISCUSSION: As the injuries of participants in the current study were chronic and thus neurologically stable, no spontaneous improvements/recovery in hand function was expected. However, FES as part of an integrated therapeutic approach affected restoration and improvement of hand function in both participants. CONCLUSION: The concurrent improvement in strength, integrated motor function and object contact following FES therapy, demonstrated that there is potential for affecting change in hand function of individuals with chronic SCI.


Author(s):  
Nathan Greiner ◽  
Beatrice Barra ◽  
Giuseppe Schiavone ◽  
Nicholas James ◽  
Florian Fallegger ◽  
...  

ABSTRACTEpidural electrical stimulation (EES) of lumbosacral sensorimotor circuits improves leg motor control in animals and humans with spinal cord injury (SCI). Upper-limb motor control involves similar circuits, located in the cervical spinal cord, suggesting that EES could also improve arm and hand movements after quadriplegia. However, the ability of cervical EES to selectively modulate specific upper-limb motor nuclei remains unclear. Here, we combined a realistic computational model of EES of the cervical spinal cord with experiments in macaque monkeys to explore the mechanisms of this modulation and characterize the recruitment selectivity of cervical stimulation interfaces. Our results indicate that interfaces with lateral electrodes can target individual posterior roots and achieve selective modulation of arm motoneurons via the direct recruitment of pre-synaptic pathways. Intraoperative recordings suggested similar properties in humans. These results provide a framework for the design of neuro-technologies to improve arm and hand control in humans with quadriplegia.


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