Does anyone like being called “atypical”? That adjective often conveys a foreign-ness or other-ness, and not in a good way. If you agree, you will be glad to know that a colleague, Dr. Junaid Siddiqui of the Cleveland Clinic, and I are about to publish an opinion piece entitled, “Time to Retire the Term “Atypical Parkinsonism.”
Over my career as a movement disorders subspecialist, I’ve heard both from professional colleagues and my patients that the term “atypical Parkinsonism” for PSP, CBD, MSA and a few other conditions is unwelcome. First, it implies that those conditions are simply unusual variants of Parkinson’s disease. However, they are actually independent diseases at the microscopical, molecular, and clinical levels with some features in common with PD. A similar problem applies to the term “Parkinson-plus.” PSP, CBD, and MSA aren’t simply PD with some additional features.
Yes, those three disease do include some degree of “Parkinsonism,” but that only means that they share a collection of outward slowness, muscle rigidity, impaired balance, and in some cases, tremor. Of course, the Parkinsonism of PSP, CBD, and MSA differ from that of PD. But that’s not because the first three are atypical versions of the fourth – it’s because they’re fundamentally different diseases.
That’s the scientific argument, but there’s also an emotional one. As I mentioned at the outset, no one wants their uncommon disorder to be considered an appendage of some other, more frequent one with superficial similarities. That would suggest that the uncommon condition is unworthy of its own approaches to support, treatment, and scientific study.
So, Dr. Siddiqi and I propose replacing the terms “atypical Parkinsonism,” “atypical Parkinsonian disorder,” and “Parkinson-plus disorder” with “Parkinson-like disorder.” This avoids the implication of inferiority and other-ness without losing the “Parkinson” term familiar to every physician.
The “-like” term has precedent in “Huntington-like disorder,” “polio-like syndrome,” and “stroke-like syndrome,” and that’s only in neurology. Yes, changing medical language can be a heavy lift, but it’s been done before. Examples just in movement disorders are Steele-Richardson-Olszewski syndrome to PSP, paralysis agitans to Parkinson’s disease, striatonigral degeneration to MSA-Parkinson, sporadic olivopontocerebellar ataxia to MSA-cerebellar, and corticodentatonigral degeneration to corticobasal degeneration.
Glossary of proposed terminology:
| Existing | Proposed | Definition/comments |
| Parkinson’s disease | Parkinson’s disease | No change proposed |
| parkinsonism | Parkinsonism | A group of phenotypic features, not specific disease(s). The first letter should be upper-case. |
| Parkinsonisms | Parkinsonian disorder | Multiple members of a group of specific disorders featuring Parkinsonism |
| Primary parkinsonism | Primary Parkinsonian disorder | Any neurodegenerative disorder featuring Parkinsonism as a major component, at least in a majority of cases |
| Secondary parkinsonism | Secondary Parkinsonian disorder | Any non-degenerative disorder featuring Parkinsonism in at least some cases or at some point in the illness |
| Atypical Parkinsonism or typical Parkinsonian disorder | Parkinson-like disorder | Reserve “Parkinsonism” for a group of phenotypic features. Reserve “Parkinson-like” for specific diseases. Replace “Parkinson-plus” with “Parkinson-like disorder” as well. |
Our paper will appear in the journal Parkinsonism and Related Disorders in a few days or weeks, at which time I’ll post you a link. Of course, if the journal itself follows our recommendation to confine the term “Parkinsonism” to a collection of signs and symptoms rather than allowing it to refer to specific diseases, then it will have to change its own name! But — one step at a time, I always tell my students and patients.
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