August 1, 2026

@michaelokun

One of the best discussions at the Aspen course was the use of the term parkinsonism. Parkinsonism is a broad clinical syndrome characterized by bradykinesia possibly accompanied by rest tremor, rigidity, and/or postural instability, regardless of the underlying cause. Levodopa-responsive parkinsonism refers to patients whose symptoms improve substantially with levodopa therapy, most commonly those with Parkinson's disease, though some other conditions may also show partial responsiveness. Most experts don't use the word parkinsonism to describe the common levodopa responsive condition. Atypical parkinsonism describes a group of neurodegenerative disorders, such as multiple system atrophy (MSA), progressive supranuclear palsy (PSP), corticobasal syndrome (CBS), and dementia with Lewy bodies (DLB), which often have additional neurological features, progress more rapidly, and typically exhibit a limited or short-lived response to levodopa. In contrast, secondary parkinsonism results from an identifiable external or acquired cause, including dopamine-blocking medications, vascular disease, toxins, normal pressure hydrocephalus, brain injury, infections, or metabolic disorders, and treatment focuses on addressing the underlying cause rather than the neurodegenerative process itself. While these categories may overlap clinically, distinguishing among them is essential because prognosis, treatment, and expected response to dopaminergic therapy differ substantially.