Breakthrough Therapy May Help Paralyzed Patients Walk Again
Personalized mapping of neuroanatomy and physiology enables big advances.
Posted March 29, 2022 | Reviewed by Michelle Quirk
- Electrical stimulators implanted near the spinal cord have shown promise for restoring movement, but only after many months of rehabilitation.
- Following implants of electrical stimulators in a Swiss clinical trial, patients with spinal cord injury regained motor function in just one day.
- The key to this advance was meticulous imaging, computer modeling, and electrode placement highly customized to each patient.
Patients with spinal cord injuries are told that if prolonged rehabilitation efforts don’t ultimately restore movement in their legs, they are highly unlikely to ever walk again.
But a clinical trial of spinal cord injury patients in Switzerland has shown that this grim prognosis doesn’t always have to be true, even in those who have been paralyzed for years.
Dr. Andreas Rowland and colleagues at Switzerland’s Center for Neuroprosthetics and Brain Mind Institute, in a February 2022 article in Nature Medicine titled “Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis,” demonstrated that a combination of sophisticated imaging, computer modeling, and implantation of customized spinal stimulators restored motor function in patients who had been paralyzed up to nine years.
Epidural Electrical Stimulation
The epidural electrical stimulation (EES) technique of the Swiss team built upon previous work that showed that stimulation of the dorsal roots of the spine (which contain sensory nerves from the trunk and legs) can, after many months of rehabilitation, restore some motor function in spinal patients.
However, the previous work, although promising, mostly employed a “one-size-fits-all” approach with limited patient-by-patient customization of the stimulating electrodes, electrode placement, and pattern of electrical stimulation.
Customizing for Each Patient
Theorizing that better results with EES could be achieved through careful study of the unique neuroanatomy and neurophysiology of each patient and subsequent delivery of customized treatment based upon the results of these studies, Rowland’s team undertook a meticulous, painstaking assessment of each patient using computed tomography (CAT) scans, functional magnetic resonance imaging (fMRI), and electrophysiological recordings to construct ultra-sophisticated computer models of each patient’s spinal sensorimotor system.
Armed with these highly detailed, customized 3D computer models, neurosurgeons carefully placed an array of stimulating electrodes near the spinal dorsal roots of three patients, after which the Swiss team worked with patients to develop precise patterns of stimulating pulses that were most effective in supporting coordinated movement in the trunk and legs, varying the pattern of stimulation according to the type of movement (e.g., walking, standing, swimming, cycling) desired.
The results in those three patients were spectacular. Rowland et al. reported that “Within a single day, activity-specific stimulation programs enabled these three individuals to stand, walk, cycle, swim and control trunk movements.”
Although the Swiss team’s approach will not necessarily work for all spinal cord patients (participants enrolled in the study had some spinal cord pathways intact), the implications of their work are profound, because the results imply that other, previously intractable deficits produced by trauma to the central nervous system, such as stroke and brain injury, might one day be at least partially overcome through similar, highly customized image-based modeling, implantation, and patterning of neuroprosthetics.