The Parkinson’s Action Network (PAN) has heard from advocates across the country that there are people with “Parkinsonisms” in their local support groups and who are active advocates, so we wanted to provide an overview of the similarities and differences between Parkinson’s disease and Parkinsonisms.
PAN works closely with CurePSP, an organization devoted to raising awareness about progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), multiple system atrophy (MSA, also known as Shy-Drager syndrome), and other rare neurodegenerative disorders that are often classified as “Parkinsonsisms.”
Our thanks to Dr. Dennis Dickson, neuro-pathologist and researcher in the Neuropathology Laboratory at the Mayo Clinic in Jacksonville, Florida, who was the primary source for this information.
What is a “Parkinsonism?”
Parkinsonism is the clinical definition of a variety of different underlying pathologies that can cause Parkinson’s-like symptoms such as slowing of movement, tremor, rigidity or stiffness, and balance problems. There are a number of disorders that can produce the symptoms referred to as Parkinsonisms; Parkinson’s disease is just one of them.
So, what’s the difference between being diagnosed with Parkinson’s disease and having what are known as Parkinsonisms? According to Dr. Dickson the typical Parkinson’s patient has Lewy bodies (aggregates of a protein called alpha-synuclein) in the brain’s neurons. When that patient is given dopamine replacement therapy (e.g., Sinemet), those symptoms go away.
By contrast, Parkinsonisms – also sometimes referred to as atypical Parkinson’s –have features in addition to typical Parkinson’s disease symptoms, and those symptoms do not respond to dopamine replacement therapy.
Parkinsonisms fall into two classes:
- One type – of which MSA is an example — that produces alpha-synuclein clusters in the brain’s glial cells (the cells that protect the neurons in the brain) instead of in the neurons, as is the case with Parkinson’s disease; and,
- A second type that involves defective tau proteins which act as a binder and stabilizer of microtubules of cells (microtubules are like the skeleton of neurons). A dysfunction in the tau proteins is what causes PSP and CBD.
So, why do PSP, CBD, and MSA– despite their different origins in the brain – get grouped together under the category of Parkinsonisms? According to Dr. Dickson, “They’re Parkinsonisms because they have overlapping clinical symptoms of typical Parkinson’s disease, and because dopamine-producing cells in the brain are affected in all these disorders.”
Therein lies the distinction: if a person’s symptoms do not respond to dopamine replacement therapy, or only do so for a very short period of time, then, it is believed they do not have typical Parkinson’s, and instead may have PSP, CBD, or MSA.
Dickson believes physicians have been “really good” at getting the diagnosis right when it comes to PSP, CBD, and MSA. He says, “It’s not 100%, though. Movement disorder experts get it right 80-90% of the time. Neurologists get it right maybe 75% of the time. Those doctors who’ve seen a lot of PSP patients get it right 90% or more of the time. Sadly, CBD only has a 50% diagnosis rate.”
Just as with Parkinson’s disease, there are no clear, obvious biomarkers or tests for PSP, CBD, and MSA. Right now, the only way to diagnose a Parkinsonism is to assess response to dopamine replacement therapy. And, just like Parkinson’s disease, the only way to diagnose with absolute certainty PSP, CBD, or MSA is after an autopsy of the brain.
What are some other symptoms associated with Parkinsonisms?
When it comes to looking at the spectrum of symptoms, there are some differences that might help a clinician know if a patient has a particular form of Parkinsonism:
- PSP patients have palsy – at first, a weakness of eye movements that gives them great difficulty in looking up and down. As the disease progresses, their eyes become frozen and they can’t move them in any direction.
- Patients with MSA have severe autonomic dysfunctions: they can’t maintain blood pressure, and they also suffer from urinary incontinence and, in men, erectile dysfunction. These non-motor features sometimes overlap with PD symptoms, so the way to tell, again, is whether or not the patient responds to dopamine replacement therapy like Sinemet.
Is it possible that Parkinson’s is not only a disease, but rather a broad spectrum of disorders?
Dr. Dickson says “yes.” He explained that for any category of disease, researchers do what’s called “lumping and splitting,” meaning you can split diseases into various subtypes – in fact, Dickson added, “researchers and pathologists already see differences in PSPs, so we know there are various types of PSP.”
With regard to lumping, that means researchers drill down to the molecular level and study what molecular links there might be between Parkinson’s disease and Parkinsonisms. That’s why these diseases are often grouped, or lumped, together.
What treatments are available to people with PSP, CBD, or MSA?
Right now, the only treatment is first to see if the patient responds to dopamine replacement therapy. If not, then the clinician knows it’s not Parkinson’s disease. According to Dickson, it’s only non-pharmacologic treatments that might be helpful in managing Parkinsonism disorders such as PSP and MSA. These include:
- physical therapy;
- occupational therapy;
- glasses with special prism lenses to allow a person with PSP to have a broader range of vision;
- helmets to protect against head injury in case of falling in MSA, CBD, and PSP patients;
- Botox to reduce excessive drooling so the person with PSP doesn’t choke; and
- blood pressure medication and other drugs to help with the autonomic dysfunctions that MSA patients suffer from.
But, to reiterate, these are all symptomatic treatments. Just as there are no disease-modifying therapies for Parkinson’s disease, there also are none for Parkinsonisms.
“New drugs are now being developed, which are currently in clinical trials, and may have an effect on the prevention of tau protein aggregation,” added Dr. Zyne. “If these drugs prove to be successful, they may have a significant impact on the lives of people with Parkinsonisms.”
What causes Parkinsonisms, and what research is being done?
Like Parkinson’s disease, it is believed that there are both genetic and environmental risk factors for Parkinsonisms, but no one is certain. While government funding for research for Parkinsonisms has been very modest over the years, CurePSP has been the leader in raising new funds for innovative research projects – including a genetics whole genome study which has implicated several new gene loci. Since 1997, when CurePSP began its research program, more than $10 million has been raised for various basic research and clinical projects.
What is PAN doing to help?
The Parkinson’s Action Network strives to maintain a balance between advocating in support of policies and funding to support people who already have Parkinson’s disease, as well as funding and policies to shape a brighter future. There certainly are research overlaps between Parkinson’s disease and Parkinsonisms, as well as overlap in policies, such as Social Security Disability Insurance and Medicare, which impact both populations.
It is important to educate and raise awareness in order to secure federal funding for research. Studies around Parkinson’s disease and Parkinsonisms can inform each other and get us closer to better treatments and, hopefully, cures. Learn more about our work to increase federal research funding.
Many PAN advocates coordinate or attend support group meetings attended by people who have Parkinsonisms, and because diseases like PSP, CBD, and MSA are not as well-known and have fewer people with the disease, there aren’t specific, dedicated support networks available. PAN looks forward to reaching out to this community through CurePSP to be even more inclusive in our advocacy efforts.