Moving to recovery

A pioneering doctor who treated Christopher Reeve says exercise may be the way to fight paralysis

Health & Fitness

September 16, 2005|By Jonathan Bor | Jonathan Bor,SUN STAFF

Dr. John McDonald wore a satisfied expression as a 21-year-old patient, paralyzed from the neck down in a diving accident, walked on a slow-moving treadmill.

It wasn't walking as most people know it. Without electrodes firing his weakened muscles, his legs would barely move. Without two therapists physically placing one foot in front of the other, he would likely stumble. And without a body sling suspended from above, he would surely fall.

To McDonald, recruited earlier this year to head a spinal-cord injury program at Baltimore's Kennedy Krieger Institute, there is nothing futile about exercising limbs that can barely move on their own.

The 43-year-old neurologist says his work with the late actor Christopher Reeve demonstrated that exercise might hold the key to something scientists long considered impossible - reactivating neural pathways that have been silent for years.

"In this new world, the nervous system is much more capable of change than we ever thought," McDonald said in a characteristic burst of enthusiasm. "Old ideas are starting to fade away."

McDonald arrived in May with a treatment team from his former base, Washington University in St. Louis. It was partly on the strength of his work there with Reeve that Kennedy Krieger hired him to elevate its spinal cord program, which lacked the national reputation of its programs in autism, cerebral palsy, lead poisoning and other neurological disorders.

"We weren't pushing the frontier to make [the condition] better," said Dr. Gary Goldstein, president and chief executive officer.

With the hiring of McDonald and the opening of new labs and a rehabilitation gym, Goldstein hopes Kennedy Krieger will become a major referral center for spinal cord injuries. Already, the hospital is showing signs of that, with patients coming not just from the Mid-Atlantic region but from places as far-flung as Texas and California, Greece and Colombia.

Goldstein, who remembered McDonald as a bright young medical student at the University of Michigan, offered him an arsenal to enhance his efforts to get paralyzed people moving again: support for stem cell research, collaboration with neighboring Johns Hopkins and the latest imaging technology.

It also promised an ideal patient profile, heavy on children whose still-developing nervous systems may stand to gain the most.

"With children, you're walking in on something that's moving, not something that's static," Goldstein said. "Not that there isn't potential in adults, but if you're going to try something out, you should try it in children."

Exercise is the core of McDonald's program. It is based on the theory that repetitive activity can awaken the spinal cord to grow new cells, sprout connections and direct movement independently of the brain.

In the institute's new rehabilitation gym, patients are helped onto stationary bikes and hooked to electrodes that cause their leg muscles to contract. Some, like 21-year-old Robby Beckman, work out on treadmills, aided by electricity and therapists.

Tall, lanky and still projecting an athlete's vigor, Beckman is what doctors call an "incomplete quad" - largely paralyzed from the neck down but capable of short, weak movements in his arms and legs.

Though held in a sling, the former pitcher for Salisbury University was positioned low enough so that his legs were forced to bear some weight on their own.

"You like doing that much weight bearing?" asked McDonald, standing to one side with arms crossed.

"I'd like to do more," said Beckman.

"Great, isn't it?" the doctor replied, smiling in approval.

Pattern generator

With boyish looks and irrepressible optimism, McDonald has become one of the most visible and charismatic proponents of activity-based therapy. But the idea wasn't his alone.

In the 1930s, nurses tried in vain to restore movement to polio victims by forcibly moving their limbs and encouraging them to float in pools.

The strategy didn't work, McDonald said, because it addressed the wrong disease. Polio destroyed neurons along the spinal cord, damage too diffuse to benefit much from exercise.

In contrast, a spinal injury damages a narrow band of spinal tissue, disrupting the flow of signals from the brain to the places below the injury. Similarly, information gathered in the extremities has no way of crossing the breach to reach the brain, which is why patients lack sensation in affected areas.

But what if the spinal cord had its own mini-brain that played a role in directing movement? For decades, biologists uncovered some evidence of that in a collection of cells at the base of the cord that helped control rhythmic movements such as walking and cycling.

The region, called the pattern generator, was identified in locusts and lampreys as well as cats and rats. Then, in 1991, a Canadian scientist demonstrated that a cat whose spine was crushed could learn to walk again if trained, raising the possibility that forced movement retrained the pattern generator to act on its own.

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