Cycling for Freezing of Gait
On April 1, 2010, the New England Journal of Medicine published a case study about a Parkinson's patient with advanced disease who surprised his doctors by his ability to cycle. The study author, Bastiaan Bloem, PhD at the Radboud University Nijmegen Medical Centre is a recipient of an MJFF award to support PARKFIT, a study that aims to identify and overcome the behavioral barriers to physical activity in PD patients as well as to investigate the effects of exercise on disease progression.
The Michael J. Fox Foundation spoke with Dr. Bloem about the case study and his work to improve physical activity in PD patients.
MJFF: Let's start with some background. You've been funded by MJFF to study exercise and PD. Why is this area of research important?
BB: There are many good reasons to study exercise and PD. Exercise may alleviate some of the physical and cognitive symptoms of PD, and also constipation, sleep disturbances or depression. Exercise also slows down osteoporosis and can reduce the risk of cardiovascular disease.
In studies with rodents with experimental parkinsonism there have been some exciting findings to suggest that exercise can induce adaptive changes in the dopaminergic system, and may thereby be able to modify the course of the disease. It is a provocative finding, and we're now looking at the full spectrum of these clinical and disease-modifying effects.
MJFF: Going back to the case study, what does this mean for patients? Should doctors start advising PD patients to take up cycling?
BB: I think everybody agrees that exercise is probably good for PD patients. The reason I say probably is that there can be adverse effects as well. For example, falling is a disease of people who are active. So if you start to blindly promote exercise in unstable patients you may see more hip fractures. The other reason for caution is that there is reasonably good evidence to show that PD patients are at increased risk for cardiovascular disease, so for some patients, exercise may increase myocardial infarctions. So it's important that we continue to investigate this area of research and patients should talk to their doctors or physical therapists before taking up exercise. Patients should also discuss the specific activities that may be best suited to each individual's needs.
But cycling is a very interesting exercise for PD patients because it restores their ability to participate in social life. The man featured in the New England Journal of Medicine was cycling 10-20 miles each day which restored his independence because he couldn't walk due to freezing of gait. Although he has trouble with traffic lights, his wife is able to accompany him and he can get from place to place. What's interesting is that I've now been contacted by companies making tricycles. This may be a safer alternative that still provides the benefits.
MJFF: Do you think the finding is specific to cycling? Are there other examples of PD patients who have difficulty walking but can perform other actions?
BB: What we know about Parkinson's disease is that patients can move unexpectedly well under certain circumstances. Examples include emotions, like the well-known story of a fire breaking out in a nursing home and the first person outside is a PD patient, only to become immobile again once outside. We also know that visual cues are very powerful in affecting movement as well as rhythmic auditory cues. And then there are the exciting examples of motor abilities that seem to be preserved in the face of otherwise severe disease. Ice skating and climbing stairs are examples that are known, but cycling is a completely novel observation. And I think the reason cycling has stirred so much interest is because you can easily get around if you can ride a bike.
MJFF: Do you think the finding is specific to an individual? For example, if a PD patient grew up cycling, he or she may be more likely to be able to cycle even with advanced disease?
BB: I think so. I have a beautiful video of a patient of mine who was a former badminton champion in Holland. If you give him a racket and a shuttle, he beats me every time. It's not good fun for me to play him! It may be that these movements that are learned early on are stored in different areas of the brain.
MJFF: What does this tell us about how the brain controls movement? Does this tell us anything new about Parkinson's?
BB: One of my areas of focus is looking at the ability of the brain to compensate for disease. Parkinson's is, at least in the initial stages, a focal brain disease affecting the basal ganglia and there are many intact brain areas that show a powerful ability to compensate for the focal deficits. Cuing is one example of how the brain overcomes defects. Skating or cycling is another powerful example. And I actually have a whole truckload of videos of amazing examples of how patients come up with clever solutions to overcome movement difficulties.
MJFF: Does this mean that the area of the brain that controls walking versus cycling or skating may be a different region?
BB: I think so. To explain further, movements are initiated by the primary motor cortex. But the primary motor cortex needs to receive start signals from the basal ganglia. And when that's defective, movements become difficult to start or maintain. What is interesting is that the same motor cortex can be reached by areas of the brain that are not normally involved in generating movement, such as the visual or auditory areas. So they can bypass the defective connections between the basal ganglia and the motor cortex, generating movements from the same motor cortex, but by exploiting different neural circuitries.
And that's why I think the word hope really is in place here, because it shows that even in the face of severe disability, there is still this powerful ability of patients to exploit intact brain areas and generate movement.
MJFF: What are the next steps for this area of research?
BB: We really need to explore the behavioral strategies adopted by patients in more detail which is why I collect all these videos of different compensatory strategies. But we also need to better understand how this works in the brain. In other ongoing work at our center, we are using functional magnetic resonance imaging of the brain to see which areas are specifically involved in generating these compensatory movements. The hope is that once these areas are identified, we may be able to stimulate them and generate new treatments.