Is ‘Atypical Parkinsonism’ a Useful Term?

Parkinson’s disease (PD) was named in 1872 for British surgeon James Parkinson, who first described “the shaking palsy” more than a half-century earlier. Ever since then, a murky and imprecise lexicon has developed around a wide variety of conditions with characteristics that overlap with, are related to, or are differentiated from PD.

This language, particularly the term “atypical Parkinsonism,” can cause confusion for patients, families and medical teams and create stigma for individuals receiving a diagnosis. That’s why Cleveland Clinic movement disorders specialist Junaid H. Siddiqui, MD, and Lawrence I. Golbe, MD, Emeritus Professor of Neurology at Rutgers Robert Wood Johnson Medical School, are suggesting updates to terms pertaining to these conditions.

Their proposal, Time to retire the term “atypical Parkinsonism,” was published in Parkinsonism and Related Disorders.

In their, article the authors make the case for:

1. Retaining the term Parkinson’s disease (PD)
2. Retiring “typical” and “atypical” to classify primary Parkinsonian disorders
3. Replacing “atypical” with “Parkinson-like disorder”
4. Using “Parkinsonism” only to describe a phenotypic syndrome
5. Avoiding “Parkinsonisms” to describe disease entities

"The inconsistent and imprecise use of the term 'Parkinsonism' has created unnecessary confusion for patients, clinicians and researchers,” Dr. Siddiqui explains. “In addition, we have seen that the designation 'atypical Parkinsonism' can often feel discouraging to patients and create a sense of 'otherness.’ Refinements to the terminology can eliminate these issues and resolve problems of logic that beset the existing language.”

Background

Currently, three major entities are characterized by Parkinsonism, a syndrome of bradykinesia with rigidity, tremor or both:

• Parkinson’s disease is a degenerative disorder characterized by Lewy bodies and emphasizing the brainstem.
• Atypical Parkinsonian disorders — which the authors propose be renamed Parkinson-like disorders — are degenerative disorders that resemble PD and are faster to progress, causing earlier falls or memory changes. They include dementia with Lewy bodies (DLB), multiple system atrophy (MSA), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). These diseases have also been referred to as “Parkinson-plus syndromes.”
• Secondary Parkinsonian disorders typically arise from non-degenerative causes and include Parkinsonism phenotype but are caused by identifiable conditions other than the primary Parkinsonian disorders. These include normal pressure hydrocephalus (NPH), vascular Parkinsonism, drug-induced Parkinsonism (DIP) and more.

The case for change

Under their proposed nomenclature, “secondary Parkinsonian disorders” would continue to be used for mostly non-degenerative Parkinsonian disorders.

“Parkinsonism,” however, calls for well-considered usage, the authors write. The term is often employed to describe both a clinical phenotype and specific diseases, which is confusing.

They suggest Parkinsonisms (plural) should be retired and that Parkinsonism be used only as the name for the phenotype.

“Parkinsonism was designed to be just a phenotype description,” says Dr. Siddiqui. “Unfortunately, even movement disorder neurologists tend to use it loosely to refer to the Parkinson-like disorders or even PD, thus adding to confusion when patients ask if they have parkinsonism or Parkinson's disease. Also, just like water or furniture, parkinsonism is a mass noun. There is no need to use the plural. Just as we say 'bodies of water' but we do not say 'waters' or we 'pieces of furniture' but we not 'furnitures,’ we should not be saying ‘parkinsonisms.’”

They also propose replacing “atypical Parkinsonism” and “Parkinson-plus syndrome” with “Parkinson-like disorders” to underscore and clarify that these conditions are not forms of PD. Parkinson-like disorders would include MSA, DLB, PSP and CBD.

“Atypical Parkinsonism” may connote, for some, lack of treatability or poor prognosis, the authors note, which can cause distress for patients. And “Parkinson-plus syndrome” erroneously implies these diseases are forms of PD.

The name “Parkinson-like disorders” carries no such connotations.

The road to change

While changing medical nomenclature is never an easy task, progress begins with conversations, says Dr. Siddiqui.

“We can begin to build momentum by consistently using and promoting updated terminology in clinical practice and teaching, and by including the topic in professional discussions,” he says. “Social platforms such as LinkedIn provide a space to raise awareness. Eventually, we may be able to approach organizations such as the Movement Disorder Society to provide an avenue for broader adoption. Change may be slow, but it starts with each of us taking the initiative to lead by example."