Last week, the new York Times ran a fascinating article describing the case of a man with severe, debilitating Parkinson”™s disease — who, while remaining largely able to walk, can ride his bike for several miles every day. Here is a link to a video showing him riding.
Since the article ran, I”™ve received several emails from ICI subscribers, students, and classmates alike — all asking the same thing: “What”™s the deal with this? How is this possible?” Truth be told, I had no idea. So, I decided to find out.
UPDATE: 2/10/14 There has been considerable research done to quantity the symptom relief experienced by people suffering with Parkinson's disease, by riding a tandem bicycle or on Indoor Cycles. Learn more by listening to this interview with Dr. Jay Alberts with Pedaling for Parkinson's.
UPDATE September 25 2014:
We are now offering an ACE approved Parkinson”™s Cycling Coach training program. To learn if you qualify click here.
What is Parkinson”™s Disease?
Parkinson”™s disease is a neurodegenerative condition (primarily affecting older people, though can occur any time) characterized by progressive destruction of part of the brain called the substantia nigra, which is responsible for the production of a brain chemical signaling molecule (see also: neurotransmitter) called dopamine. Since dopamine is the primary neurotransmitter of movement, Parkinson”™s disease is marked by gradually worsening motor function. Its cardinal signs include difficulty initiating movements (“akinesia”) and slowness in maintaining movements (“bradykinesia”), including swallowing and speaking. Problems with balance, gait, and tremor are also very common1.
Current treatment options include Levodopa (essentially, synthetic dopamine) with supplemental use of drugs that boost dopamine or block its breakdown. Deep brain stimulation of the affected portions of the brain has also shown promising results. Still, even with treatment, the disease often causes significant disability and decreased quality of life2.
The Role of Exercise
The focus of treatment for Parkinson”™s disease is largely medication-based. While a role for supplemental therapy with non-medication treatments (including exercise) has been thought to be important, most research over the years has focused on its effects on quality of life, not motor symptoms directly. In recent years, this is changing. There have now been recent studies demonstrating improved independent functioning3, balance and gait4, and walking endurance with exercise therapy5. In animal models, exercise has been thought to contribute protection against further brain deterioration6 — and even to potentially induce repair at the level of the brain7.
Can”™t Walk but Can Ride a Bike?
Although exercise is recommended for patients with Parkinson”™s disease to supplement their treatment with medications, the scenario described in the new York Times article is not the norm. What appears to be at play here is not merely a success story of exercise therapy; rather, it is a specific neurological phenomenon. Bike-riding, in this case, is not functioning merely as exercise. It is actually a mechanism whereby damaged brain pathways are being overridden. Allow me to explain.
You see, movement initiation can be in response to either an external (“exogenous”) or internal (“endogenous”) stimulus. Turns out, “akithesia” (lack of movement initiation) in Parkinson”™s disease is largely a failure of ability to respond to endogenous stimuli. The exogenous pathway, however, remains intact8.
A phenomenon called “akinesia paradoxa” (like it sounds: paradoxical akinesia) has been well-described in the neurological literature since the late 1960s. This refers to the ability of people who have difficulty initiating movement somehow being able to move in the presence of visual cues (lines, objects, colors) at their feet8. Remove visual cues? “Frozen” again.
There is no research specifically on cycling-supplied visual cues responsible for akinesia paradoxa. It is reasonable, however, to think that perhaps it is the repetitive linear road markings that might be at work here. Or perhaps the cue isn”™t visual at all — like music, which has also been studied in relationship to akinesia paradoxa, any one of the sounds (gliding, scraping, squeaking, etc.) we hear our bikes make as we ride can also be thought of as a repetitive cue. What may go unnoticed to us and our preoccupied senses may indeed be responsible for creating movement in the movement-less.
As amazing as this sounds, we must be careful not to go too far in our interpretations. All we know is that akinesia paradoxa happens — in response to a visual cue that generates a brain signal for movement, movement can happen. Research is still lacking as to whether these successful “cued movement” episodes have any long-term impact on disease severity. Still, this is an active and fascinating area of ongoing research. We”™ll see what happens…
The writer is a third-year medical student at the University of Vermont College of Medicine. She is also a STAR 3 Spinning instructor, Certified Personal Trainer (ACE), and author of the popular blog Spintastic (http://spintastic.blogspot.com/), which applies patient-centered medicine to motivational coaching..
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