I have a good friend named Sue Cairn. Though I am an avid hiker, I have trouble keeping up with her on the trails — even though she wears a helmet and knee pads and poles when she and her husband Rich go on treks in the Valley, or New Hampshire, or the Alps.
Sue has Parkinson’s disease (PD). It was named after James Parkinson, an apothecary and physician, who in 1817, described six patients with “involuntary tremulous motion, with lessened muscular power… with a propensity to bend the trunk forward, and to pass from a walking to a running pace: the senses and intellects being uninjured.”
In the 1890s, the French neurologist Jean-Marie Charcot further refined the diagnosis by noting “a slowness in execution of movement… between thought and action there is a considerable time lapse….” He advocated a variety of treatments, including the antihistamine hycosamine — used today as a treatment for IBS, and still sometimes used to help with tremors and muscle stiffness with PD. He also advocated electrical stimulation — now being investigated as a possible treatment.
But real progress had to wait until two advances:
First, the cause of the disease: Our brains contain a protein that facilitates communication between neurons, called alpha syn nuclein. In Parkinson’s this protein folds in on itself, forming what are called Lewey bodies. This causes dopamine depletion in the brain, and the multiple symptoms of the disorder. This finding also led to the discovery, in the 1960s, that Levo dopa ameliorates the symptoms of PD. Today — though there are many new possible treatments on the horizon — Levo dopa and its analogs are the standard of care. (This medicine, unfortunately, only treats the symptoms of PD, not the root cause. And it may lead to involuntary jerky motions called dyskinesia, similar to symptoms of the disease.)
The second advance is better diagnosis. “Family Ties” and “Back to the Future” star Michael J. Fox drew needed attention to the disorder when his disease was diagnosed in 1991 at age 29. The Michael J. Fox Foundation is a now a major funder of research and education on PD. But the disease still often goes undetected in the early stages.
Sue told me that nine years ago, at age 54, she noted a clanking sound coming from her crankset when she rode her bicycle. She thought it was a mechanical problem but eventually she discovered that the sound was caused by her left leg lagging behind her right. Then she noticed that her left hand would stop moving when she lathered her hair while shampooing. Finally, a friend observed that her left arm was not swinging when she was walking.
She went to her primary care physician, who said, “You can’t have Parkinson’s disease because you don’t have a tremor.”
Sue finally went to a neurologist specializing in movement disorders. He made the diagnosis, after a history and physical exam, even though she was still young for the onset of this disorder; PD usually strikes people over the age of 60. This is the type of physician best suited to diagnosing and treating Parkinson’s.
Sue describes what the disease is like for her. “I shuffle and my left foot drags. My brain thinks I’m lifting my feet and I’m not,” which leads to falls (the reason for the protective equipment while hiking).
She also has trouble with word finding, and her voice softens when she is tired.
Insomnia is a common problem with Parkinson’s, and she explains why “My rigidity makes turning over in bed painful.”
(Other significant symptoms that may accompany the disease include bladder dysfunction, constipation, excessive sweating, and anxiety.)
After five years of more or less toughing it out, Sue began the current gold standard treatment for the disease, carbidopa-levodopa. She goes to speech therapy and physical therapy.
But, she says, “The one proven thing you can do to slow progression of the disease is high intensity exercise.”
Which is not difficult for her. “Cairn” is not her family name. Their love of mountain climbing led Sue and Rich to choose this word as their surname when they married!
A hip replacement put a damper in Sue’s regimen, and her Parkinson’s symptoms worsened significantly, but within weeks, she was biking and hiking and feeling better again.
Parkinson’s disease was rare until the latter part of the twentieth century. World prevalence surged from 2.5 to 3 million people in 1990 to 10 to 12 million in 2025. Better diagnosis, and patients living longer with the disease are certainly two reasons, but the other explanations are the hazards of industrialized society, like ultra processed food and air pollution, specifically particulate matter, and pesticides.
The pesticide rotenone, inhibiting mitochondrial complexes in animals and humans, is actually used in the lab to produce PD. Rotenone was banned for household use by the EPA in 2010; it is still used to control unwanted fish populations.
The herbicide paraquat has been linked to Parkinson’s disease in numerous scientific studies over the last decade. It is so toxic that a single swallow can cause death. It is used by 35% of U.S. commercial farms producing soybeans, corn and cotton. In 2001, the Natural Resources Defense Council won a lawsuit that banned this chemical in the U.S. But in 2017, Scott Pruitt, Trump’s first EPA Administrator in his first term, overturned this ban after several meetings with company officials.
Sue thinks she may have been exposed to this pesticide while growing up near farms and later working as a volunteer on a Food Bank Farm. She works as an advocate for the Parkinson’s Foundation, trying to ban paraquat from all uses, like 74 countries and two states have already done.
In the meantime, Sue’s advice, for anyone facing a chronic debilitating illness is this: “Grieve what you have lost; and then find meaning and purpose. Practice gratitude and do what you love even if you have to do it differently.”
David Gottsegen is a local physician. The Parkinson’s Foundation and the Michale J. Fox Foundation are 4 star rated charities raising awareness of the disease, and looking for a cure. They are working with the respected nonprofit organizations Environmental Working Group and Earthjustice to ban paraquat use in the U.S.