The Science Guy

John Geddes March 13 2000

The Science Guy

John Geddes March 13 2000



D’Arcy Jenish

“Alzheimer’s, Parkinson’s and ALS are the triad of age-dependent neurological disorders. Were going to see more of them as the population ages.” -Dr. Michael Strong, neurologist, London, Ont.

Strong, one of Canada’s leading researchers into amyotrophic lateral sclerosis, commonly known as Lou Gehrigs disease, works on what he calls one of the last frontiers of medicine. “ALS is not like cancer where there are treatments that can put a dent in the disease,” he says. “We’ve got nothing. This is dying at its worst.” While providing no comfort to ALS sufferers, the remark nicely sums up current medical understanding of a disease that kills the nerves controlling movement in the arms and legs and the muscles used in breathing, swallowing and talking. Of the dozens of degenerative neurological disorders, caused by the progressive death of specific groups of cells within the brain, ALS is at the top in terms of mortality, followed by Alzheimer’s and Parkinson’s diseases. There are no cures or even treatments to significantly slow the progress of ALS, the grim result being

ALS and Parkinson’s join Alzheimer’s at the top of the list of neurodegenerative diseases

that patients, on average, die peacefully of respiratory failure within five years of being diagnosed.

Between 1,500 and 2,000 Canadians, most of them over 50, are now coping with ALS. By comparison, 80,000 to 100,000 Canadians suffer from Parkinson’s disease, caused by the death of cells that produce the substance called dopamine that ensures smoothness of movement. ALS and Parkinson’s differ from Alzheimer’s in that they affect muscle control, not the capacity to think and reason. Parkinson’s patients often live 20 years or more with the non-fatal disorder, and die of other causes. Doctors can treat the disease with drugs or surgery, but its cause remains unknown, and there is no cure. “It’s very complicated,” says Dr. Janis Miyasaki, a neurologist at Toronto Western Hospital. “We’re talking about the brain, the seat of the soul.”

Growing numbers of those with Parkinson’s and ALS have given the conditions a higher public profile in recent years. Well-known Parkinson’s victims include Pope John Paul II,

former heavyweight boxing champion Mohammad Ali and Canadian-born actor Michael J. Fox, 38, who announced he was quitting the hit TV series Spin City in mid-January. ALS sufferers include the celebrated British physicist Stephen Hawking, who, against the odds, has lived with ALS for about 30 years. Yet some doctors, particularly those studying ALS, complain that the government provides too little support—at best $500,000 to $700,000 in a year—for research. “The funding is disastrous,” says Strong. “The problem is we don’t have hundreds of people with ALS banging on Parliament’s doors.”

Most, in fact, are too preoccupied with their rapidly deteriorating health. Chris Vais, a 37-year-old Presbyterian minister living near Vankoughnet in Ontario’s Muskoka district, was diagnosed with ALS three years ago. Since then, his legs have weakened to the point where he spends most days in a

wheelchair. He eats pureed food and his speech is slow and slurred. Despite his illness, Vais and his 35-year-old wife, Susan, decided to start a family, and she gave birth to a daughter, Clare, last May. “We just decided we would carry on with our plans,” says Vais. “There is so much happening in research, you never know when they will find a cure.”

Strong, who runs one of Canadas largest ALS clinics, says researchers could well the identify the causes of some forms of the disease within five years, and may even be able to develop drug treatments to halt its progress. There are various theories about what kills the nerve cells that control movement. Many researchers believe the cells cease to function properly after becoming flooded with a substance called glutamate, which plays a role in transmitting signals from the brain to muscles.

A more recent theory, now hody debated, suggests the cause may be viruses associated with flu or the common cold.

Until researchers find the cause of ALS and develop treatments, doctors can do little more than try to ease the symptoms. Typically, neurologists enlist the help of several specialists, including physiotherapists, nutritionists and social workers. “What we do now is rescue work,” says Montreal neurologist Angela Genge. “As for treatment of ALS, we’re at the level of cancer therapy in the early 1950s.”

Medical science has made much greater inroads against Parkinsons over the past three decades. A common treatments is a drug called levodopa, a dopamine substitute that can reduce common symptoms such as tremors, stiffness and lack of balance. But prolonged drug treatment almost inevitably leads to complications such as uncontrollable writhing, jerky movements or rigidity that makes movement impossible. “You can be so immobile that you become bedridden,” says Ottawa neurologist David Grimes. Several new drugs that produce fewer long-term side-effects are now available, but they are not effective on all patients.

Two surgical procedures are available for a small number of Parkinsons patients when drug therapies fail or severe complications develop. One operation, says Dr. Andres Lozano of Toronto Western Hospital, uses a wire electrode, inserted through a hole drilled in the skull, to destroy brain cells that have become overactive due to a deficiency of dopamine. In

the other, a surgeon implants an electrode in the brain, then mns a wire from it under the skin, down the neck and beneath the collarbone. There it is attached to a pacemaker implanted under the skin of the chest. Using a computer and a programming device placed on the skin above the pacemaker, the neurosurgeon can adjust the electrical current to regulate the behaviour of brain cells.

Two other experimental techniques are being tested in Canada. In 1997,

Lozano became the first surgeon in the world to perform an operation that feeds protein to the surviving cells that make dopamine. Lozano says the goal is to halt

the progress of the disease by preventing more cells from dying. And since 1996, neurosurgeon Ivar Mendez of the Queen Elizabeth II Health Sciences Centre in Halifax has performed an experimental and controversial transplant procedure on eight patients, giving them brain tissue from aborted fetuses to help them grow new dopamine-producing cells.

For many people with Parkinsons, surgery represents the last hope of relief. Keith Kennedy, 48, a former forest ranger from Middle Stewiacke, N.S., 75 km northeast of Halifax, who received a fetal-tissue transplant a little over a year ago, has cut back on his use of prescription drugs by more than 60 per cent. Kennedy says he has less stiffness and muscle pain, and the tremors that plagued him have almost disappeared. Similarly, Lynda McKenzie, 47, of Milton, Ont., 40 km northwest of Toronto, says a similar transplant, performed in Denver in December, 1998, has alleviated a painful rigidity that often left her flat on her back on the couch. “It’s been a slow change rather than a miracle,” she says. “But I feel like I’ve had my life handed back.” EH


Neurologists now distinguish between movement disorders, which spring from multiple causes, and degenerative neurological diseases, including Parkinsons and ALS, which are triggered by the death of specific groups of brain cells. The precise number of these diseases is open to debate, but the more prevalent include:

Progressive Supranuclear Palsy: Identified in 1963 by three Toronto neurologists, this Parkinsons-like disease can cause slowness, imbalance and blurred vision.

Multiple System Atrophy: Loss of sexual function is a common early symptom of this disease, which affects more men than women. As neurons die in the brain, movement, balance and co-ordination can suffer.

Diffuse Lewy Body Disease: The death of neurons throughout the brain causes a specific set of symptoms that includes memory loss, hallucinations, stiffness, tremors and lack of balance.