Tomislav Milekovic, University of Geneva, Department of Fundamental Neuroscience, Geneva, Switzerland

Brain-controlled spinal cord stimulation to alleviate gait deficits in people with paraplegia

Funded in: 2018, 2019, 2020


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Problem:  Epidural Electrostimulation interferes with movement commands carried by residual brain-spine connections
Target: Advanced techniques to achieve accurate and robust decoding of locomotor events

Goal: A non-invasive brain-spine interface to trigger spatiotemporal EES protocol

 

Background

Spinal cord injury disrupts the communication between the brain and spinal cord. Epidural electrical stimulation (EES) of the dorsal spinal cord locally increases the excitability of spinal circuits, thus enhancing their ability to react to movement commands carried by brain-spine connections that survived the injury. Yet, EES will promote attempted movements only if delivered in phase with movement commands originating above the injury, while out-of-phase EES can disrupt the walking attempts. In our recent study, we decoded leg movement attempts from the activity of neurons in the brain to synchronize the location and timing of EES with the residual brain movement commands. This brain-spine interface restored weight-bearing locomotion of a paralyzed leg in spinal cord injured monkeys. The same EES protocols delivered continuously, without respecting the attempted movements, disturbed the gait. Thus, direct brain-control of EES delivery will improve clinical outcome.

Current problem

The brain-spine interface relies on the neuronal activity recorded using electrodes implanted in the brain. Their use requires brain surgery, which makes the clinical therapies risky and costly, and will dissuade many people that stand to benefit from brain-spine interfaces.

Proposed solution

We will leverage advanced techniques for the reconstruction of brain activity from non-invasive high-density electroencephalography to achieve accurate and robust decoding of locomotor events. We will use this technique to develop a non-invasive brain-spine interface in people with paraplegia.

Implementation

We will validate our brain-spine interface within the framework of the STIMO clinical trial, which is testing the efficacy of EES in people with paraplegia. STIMO participants will be equipped with a high-density electroencephalography system. Leg movement attempts decoded from electroencephalography signals will trigger spatiotemporal EES protocols delivered over the lumbar spinal cord. This brain-spine interface will excite spinal circuits in synchrony with the remaining brain movement commands, thus promoting attempted walking movements.