Fox Battles Parkinson's Disease
The early symptoms can be minor and easy to ignore - a leg that drags when the victim is walking, an inexplicable difficulty fastening an earring or a voice that gradually weakens to a whisper. In the case of Canadian-born television and movie star Michael J. Fox, the first ominous sign came seven years ago when he noticed a twitching in the little finger of his left hand. He went to a doctor and learned that, like about 100,000 Canadians, he has Parkinson's disease, a neurological disorder that causes tremors, rigidity and progressive loss of control over physical movements. Parkinson's is incurable, and scientists do not fully understand its causes. But treatment has improved steadily in recent years with the development of new drugs and surgical techniques. Fox revealed in an interview published in People magazine last week that he has undergone surgery in which some brain cells were destroyed to reduce stiffness and tremors in the left side of his body. "We have," says Dr. Donald Calne, a Parkinson's researcher at the University of British Columbia in Vancouver, "powerful ways of treating the symptoms of this disease."
But not of curing it. And even though drugs can often control patients' worst symptoms for up to a decade, they usually become less effective over time. Despite the difficulties, some Parkinson's patients - notably U.S. Attorney General Janet Reno, evangelist Billy Graham and Chinese leader Deng Xiaoping, who died last year at 92 - manage to remain active for years. Fox, who declined interview requests last week, is still appearing in the popular ABC/CTV series Spin City. But he told People that rehearsals can be a challenge - "I can't do things a million times. I can only do them once or twice." Parkinson's advocates, who praised Fox for making his illness public, seized on his revelations to plead for cash to further Parkinson's research. "There is never enough money for this," said Blair McRobie, president of the Toronto-based Parkinson Foundation of Canada.
A remorseless and baffling disease, Parkinson's sets in when nerve cells begin dying in a region of the brain that produces dopamine, the chemical messenger that plays a key role in controlling muscle movements. Parkinson's tends to strike late in life - at 55, one person in 1,000 will get the disease, with the incidence rising to one in 100 after 65. But it can also happen much earlier: experts estimate that between 10 and 15 per cent of all cases are diagnosed in people under 40. Fox, who has been married for 10 years to actress Tracy Pollan, one of his TV girlfriends on the popular 1980s sitcom Family Ties, was just 30 when he first experienced symptoms. They have a nine-year-old son, Sam, and three-year-old twin daughters, Aquinnah and Schuyler.
Symptoms usually begin with the trembling of a limb. But as the disease progresses, patients experience rigidity in parts of their bodies and difficulty in moving. Eventually, they may develop a shuffling gait, a stooped posture and a lack of facial expression. As well, Parkinson's patients sometimes experience depression, personality changes and speech impairment. The disease can be exhausting and frustrating. "Things that you've never had to think about - tying a shoelace, getting out of a chair or turning over in bed - become very difficult," says nurse Susan Calne, co-ordinator at the UBC hospital's movement disorders clinic and Donald Calne's wife.
The armory of treatments that can curb Parkinson's symptoms is growing rapidly - though new therapies can bring added problems. The first line of defence is levodopa, a drug first used in 1967, that the brain can convert into dopamine. As Parkinson's progresses, increased doses of levodopa can trigger involuntary muscle movements. When that happens, physicians turn to "agonist" drugs that mimic dopamine and are often used in conjunction with levodopa. The combination can control symptoms - but it can also induce psychotic events, including hallucinations and delusions.
Newer therapies are showing promise. During the past two years, surgeons have begun implanting electrodes in patients' brains that can control tremors and rigidity. "It's very dramatic," says Dr. Ivar Mendez, a Halifax neurosurgeon who performs the operation. "When the implant is in the right place, it stops the tremors." Meanwhile, clinical studies are under way in Canada and the United States to determine whether transplanted fetal brain tissue can restore dopamine production in patients' brains. The use of fetal tissue is controversial. But experts predict that, if the therapy works, doctors will eventually use laboratory-bred brain cells for the transplants.
Scientists may finally be zeroing in on the elusive roots of Parkinson's. Many researchers believe that exposure to an environmental toxin or a virus probably triggers most cases - and the hunt is on for the culprits. Hereditary factors can also play a role. During the past 18 months, American and Japanese research teams have identified two genes that cause some Parkinson's cases. Scientists hope that study of the genes may shed new light on the underlying causes of Parkinson's, knowledge that in turn might eventually yield a cure for a cruel disease that can slowly cripple without killing its victims.
Maclean's December 7, 1998