Education about Lewy Body Dementia, Progressive Supranuclear Palsy, Multiple System Atrophy, and Corticobasal Degeneration—the four atypical parkinsonism disorders—is one of the three missions of Brain Support Network (BSN). Our educational efforts focus on those with a diagnosis, caregivers, families, and friends. Healthcare professionals are welcome here as well.
This section offers the briefest possible summary of neurological disorders and atypical parkinsonian disorders.
Taxonomy of Neurological Disorders
Depending on who is doing the counting, the number of neurological disorders varies widely. The National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institute of Health (NIH), lists 447 different neurological disorders. The University of California at San Francisco (UCSF) reports that there are “more than 600 diseases of the nervous system, such as brain tumors, epilepsy, Parkinson’s disease and stroke.”
Within neurological disorders, there are two key categories: memory disorders and movement disorders. A memory disorder specialist focuses on treating cognitive and memory conditions. The most common memory disorder is Alzheimer’s Disease. The term memory disorder is an imprecise term because someone can have dementia or cognitive issues without having memory problems. Memory disorders might also be thought of as a euphemism; it sounds nicer to be taking a family member to a “memory disorder clinic” than a “dementia clinic.”
A movement disorder specialist focuses on treating conditions related to the body’s movement or limb movement. The most common movement disorder is essential tremor. Second most common is Parkinson’s Disease.
Such specialization within neurology is both good and bad. It’s good because, if you have a dementia disorder, you want to see a specialist who sees people with such disorders every day. But it’s a negative when it comes to many disorders that have both cognitive/memory and movement components. If you have a movement disorder and see a movement disorder specialist, that physician may overlook the cognitive aspects of the disorder. And your family may not be aware of the full picture.
Categorization of Atypical Parkinsonism Disorders
The four atypical Parkinsonism Disorders (LBD, PSP, MSA, and CBD) each manifest different degrees of memory disorder symptoms.
Lewy Body Dementia can be viewed as a cognitive/memory disorder (though many with LBD have no memory problems) and a movement disorder; it depends entirely on the symptoms. A further wrinkle is that, if psychiatric symptoms are predominant, someone may see a psychiatrist.
Similarly, Progressive Supranuclear Palsy and Corticobasal Degeneration can be viewed as a cognitive/memory disorder (though most with PSP or CBD have no memory problems) and a movement disorder; it depends entirely on the symptoms.
By definition, dementia is an exclusionary criteria for Multiple System Atrophy such that it is always classified as a movement disorder. While there can be cognitive symptoms with MSA, dementia symptoms rule out an MSA diagnosis.
Throughout the medical research community and literature, there is a tension between memory/cognitive disorder specialists and movement disorder specialists. In developing diagnostic criteria for certain disorders, such as for CBD, specialists in the two disorder types have such different outlooks on symptoms and testing, that the resulting criteria are often a hodge-podge, pleasing no one.
We investigate this tension in our section on Atypical Parkinsonisms.