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Tuesday, May 21, 2024
Dr. Brown: The long and winding road to walking again, with help
Dr. William Brown.

We take for granted our extraordinary ability to get about on two legs.

Whether walking, running, dancing, skiing or skating, we do it all, depending on our age, without much thought.

Bipedalism for species ancestral to ours, evolved more than three million years ago, evidence for which may be found in the bipedal tracks left behind in east Africa by Lucy’s species, australopithecus afarensis, and closely related species variants. 

Tragically some of us lose that ability in part or whole as the result of trauma involving the spine or, insidiously in later life, the result of degenerative disease affecting the vertebra and discs in the cervical, thoracic or lumbosacral regions.

Other causes of similar impairments may be strokes, amyotrophic lateral sclerosis or, in young adults, multiple sclerosis. 

The result is weakness in the legs, especially in the hip flexor, knee flexor and the muscles which dorsiflex and evert the feet.

Sometimes the arms and hands are also affected. Sometimes patients lose control over their bowel and bladder and, in males, the ability to develop an erection. Along with those motor and autonomic changes, patients may lose sensation at and below the levels of lesions. 

Over the years, there have been many attempts to improve lost motor functions with medications to relieve spasticity (stiffness) in the affected muscles.

Physiotherapy can be helpful, especially in mild to moderate cases, but for serious impairments of motor and sensory function, there’s little that can be done except to use assist devices such as canes and walkers early on, and wheelchairs in severe cases. 

That hasn’t stopped surgeons from trying to relieve mechanical compressions from discs and bone on the spinal cord or in the extreme, even cutting out the most severely damaged part of the spinal cord and suturing what’s left together.

Fortunately, the latter highly publicized attempt in the 1960s was stopped for lack of evidence that it helped.   

Recently, there has been a flurry of studies, some involving the implantation of a multielectrode on the surface of the brain’s neocortex to record the electrical activity associated with intended movements and linking that activity with external devices such as a computer and prostheses to restore lost motor functions.

Unfortunately, the benefits were small; patients were tethered to cumbersome equipment, for little gain in function. Those studies and closely related ones were “proof of concept studies” of little practical value to patients.  

Then, in 2018, scientists from the Swiss Federal Institute of technology reported another approach to restore walking in paraplegic patients resulting from trauma.

They stimulated the region of the spinal cord affected by the trauma with electrical stimuli using an electrode implanted in the epidural space. The latter, combined with an aggressive program of physiotherapy, led to significant improvements in some patients.

For example, some patients, who were completely paralyzed in their legs beforehand, regained the ability to stand and walk, albeit for short distances and with support.

Later studies by the same Swiss group and other groups, confirmed the effectiveness of electrical stimulation in restoring function in partially or completely paraplegic patients. 

Later studies in animals suggested the effect was mediated by interneurons – nerve cells interposed between the input sensory and output motor nerve cells in the spinal cord.  

But whatever the techniques for restoring function to paralyzed legs, the challenge is the same: to restore lost or badly impaired functions of the brain or spinal cord by some sort of electrical boost or corralling preserved signals in the brain to bridge lesions further downstream between the brain and muscles. 

Over recent years, I’ve highlighted several claims for methods designed to restore meaningful speech, movement in paralyzed muscles caused by amyotrophic lateral sclerosis and other paralyzing diseases, and most recently in The Lake Report, boosting memory in patients with dementia. 

The experiments and trials are always complex, involve a lot of technical support and staff, plus much time and effort on the part of patients and staff for meagre (so far at least) benefits.

Even so, I believe it’s worth the effort given the severity of the disabilities in many cases and the steep learning curve for all concerned, to find out what works, what doesn’t work and overcome major technical and engineering hurdles.

If I may use an analogy, we are very much in the Orville and Wilbur stage of flight – full of promise, but a very long way to go.

Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.  

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